init

at-server/vendor/github.com/gorilla/websocket/.travis.yml

@@ -0,0 +1,19 @@
+language: go
+sudo: false
+
+matrix:
+  include:
+    - go: 1.7.x
+    - go: 1.8.x
+    - go: 1.9.x
+    - go: 1.10.x
+    - go: 1.11.x
+    - go: tip
+  allow_failures:
+    - go: tip
+
+script:
+  - go get -t -v ./...
+  - diff -u <(echo -n) <(gofmt -d .)
+  - go vet $(go list ./... | grep -v /vendor/)
+  - go test -v -race ./...

at-server/vendor/github.com/gorilla/websocket/AUTHORS

@@ -0,0 +1,9 @@
+# This is the official list of Gorilla WebSocket authors for copyright
+# purposes.
+#
+# Please keep the list sorted.
+
+Gary Burd <[email protected]>
+Google LLC (https://opensource.google.com/)
+Joachim Bauch <[email protected]>
+

at-server/vendor/github.com/gorilla/websocket/LICENSE

@@ -0,0 +1,22 @@
+Copyright (c) 2013 The Gorilla WebSocket Authors. All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+  Redistributions of source code must retain the above copyright notice, this
+  list of conditions and the following disclaimer.
+
+  Redistributions in binary form must reproduce the above copyright notice,
+  this list of conditions and the following disclaimer in the documentation
+  and/or other materials provided with the distribution.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

at-server/vendor/github.com/gorilla/websocket/README.md

@@ -0,0 +1,64 @@
+# Gorilla WebSocket
+
+Gorilla WebSocket is a [Go](http://golang.org/) implementation of the
+[WebSocket](http://www.rfc-editor.org/rfc/rfc6455.txt) protocol.
+
+[![Build Status](https://travis-ci.org/gorilla/websocket.svg?branch=master)](https://travis-ci.org/gorilla/websocket)
+[![GoDoc](https://godoc.org/github.com/gorilla/websocket?status.svg)](https://godoc.org/github.com/gorilla/websocket)
+
+### Documentation
+
+* [API Reference](http://godoc.org/github.com/gorilla/websocket)
+* [Chat example](https://github.com/gorilla/websocket/tree/master/examples/chat)
+* [Command example](https://github.com/gorilla/websocket/tree/master/examples/command)
+* [Client and server example](https://github.com/gorilla/websocket/tree/master/examples/echo)
+* [File watch example](https://github.com/gorilla/websocket/tree/master/examples/filewatch)
+
+### Status
+
+The Gorilla WebSocket package provides a complete and tested implementation of
+the [WebSocket](http://www.rfc-editor.org/rfc/rfc6455.txt) protocol. The
+package API is stable.
+
+### Installation
+
+    go get github.com/gorilla/websocket
+
+### Protocol Compliance
+
+The Gorilla WebSocket package passes the server tests in the [Autobahn Test
+Suite](http://autobahn.ws/testsuite) using the application in the [examples/autobahn
+subdirectory](https://github.com/gorilla/websocket/tree/master/examples/autobahn).
+
+### Gorilla WebSocket compared with other packages
+
+<table>
+<tr>
+<th></th>
+<th><a href="http://godoc.org/github.com/gorilla/websocket">github.com/gorilla</a></th>
+<th><a href="http://godoc.org/golang.org/x/net/websocket">golang.org/x/net</a></th>
+</tr>
+<tr>
+<tr><td colspan="3"><a href="http://tools.ietf.org/html/rfc6455">RFC 6455</a> Features</td></tr>
+<tr><td>Passes <a href="http://autobahn.ws/testsuite/">Autobahn Test Suite</a></td><td><a href="https://github.com/gorilla/websocket/tree/master/examples/autobahn">Yes</a></td><td>No</td></tr>
+<tr><td>Receive <a href="https://tools.ietf.org/html/rfc6455#section-5.4">fragmented</a> message<td>Yes</td><td><a href="https://code.google.com/p/go/issues/detail?id=7632">No</a>, see note 1</td></tr>
+<tr><td>Send <a href="https://tools.ietf.org/html/rfc6455#section-5.5.1">close</a> message</td><td><a href="http://godoc.org/github.com/gorilla/websocket#hdr-Control_Messages">Yes</a></td><td><a href="https://code.google.com/p/go/issues/detail?id=4588">No</a></td></tr>
+<tr><td>Send <a href="https://tools.ietf.org/html/rfc6455#section-5.5.2">pings</a> and receive <a href="https://tools.ietf.org/html/rfc6455#section-5.5.3">pongs</a></td><td><a href="http://godoc.org/github.com/gorilla/websocket#hdr-Control_Messages">Yes</a></td><td>No</td></tr>
+<tr><td>Get the <a href="https://tools.ietf.org/html/rfc6455#section-5.6">type</a> of a received data message</td><td>Yes</td><td>Yes, see note 2</td></tr>
+<tr><td colspan="3">Other Features</tr></td>
+<tr><td><a href="https://tools.ietf.org/html/rfc7692">Compression Extensions</a></td><td>Experimental</td><td>No</td></tr>
+<tr><td>Read message using io.Reader</td><td><a href="http://godoc.org/github.com/gorilla/websocket#Conn.NextReader">Yes</a></td><td>No, see note 3</td></tr>
+<tr><td>Write message using io.WriteCloser</td><td><a href="http://godoc.org/github.com/gorilla/websocket#Conn.NextWriter">Yes</a></td><td>No, see note 3</td></tr>
+</table>
+
+Notes:
+
+1. Large messages are fragmented in [Chrome's new WebSocket implementation](http://www.ietf.org/mail-archive/web/hybi/current/msg10503.html).
+2. The application can get the type of a received data message by implementing
+   a [Codec marshal](http://godoc.org/golang.org/x/net/websocket#Codec.Marshal)
+   function.
+3. The go.net io.Reader and io.Writer operate across WebSocket frame boundaries.
+  Read returns when the input buffer is full or a frame boundary is
+  encountered. Each call to Write sends a single frame message. The Gorilla
+  io.Reader and io.WriteCloser operate on a single WebSocket message.
+

at-server/vendor/github.com/gorilla/websocket/client.go

@@ -0,0 +1,395 @@
+// Copyright 2013 The Gorilla WebSocket Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package websocket
+
+import (
+	"bytes"
+	"context"
+	"crypto/tls"
+	"errors"
+	"io"
+	"io/ioutil"
+	"net"
+	"net/http"
+	"net/http/httptrace"
+	"net/url"
+	"strings"
+	"time"
+)
+
+// ErrBadHandshake is returned when the server response to opening handshake is
+// invalid.
+var ErrBadHandshake = errors.New("websocket: bad handshake")
+
+var errInvalidCompression = errors.New("websocket: invalid compression negotiation")
+
+// NewClient creates a new client connection using the given net connection.
+// The URL u specifies the host and request URI. Use requestHeader to specify
+// the origin (Origin), subprotocols (Sec-WebSocket-Protocol) and cookies
+// (Cookie). Use the response.Header to get the selected subprotocol
+// (Sec-WebSocket-Protocol) and cookies (Set-Cookie).
+//
+// If the WebSocket handshake fails, ErrBadHandshake is returned along with a
+// non-nil *http.Response so that callers can handle redirects, authentication,
+// etc.
+//
+// Deprecated: Use Dialer instead.
+func NewClient(netConn net.Conn, u *url.URL, requestHeader http.Header, readBufSize, writeBufSize int) (c *Conn, response *http.Response, err error) {
+	d := Dialer{
+		ReadBufferSize:  readBufSize,
+		WriteBufferSize: writeBufSize,
+		NetDial: func(net, addr string) (net.Conn, error) {
+			return netConn, nil
+		},
+	}
+	return d.Dial(u.String(), requestHeader)
+}
+
+// A Dialer contains options for connecting to WebSocket server.
+type Dialer struct {
+	// NetDial specifies the dial function for creating TCP connections. If
+	// NetDial is nil, net.Dial is used.
+	NetDial func(network, addr string) (net.Conn, error)
+
+	// NetDialContext specifies the dial function for creating TCP connections. If
+	// NetDialContext is nil, net.DialContext is used.
+	NetDialContext func(ctx context.Context, network, addr string) (net.Conn, error)
+
+	// Proxy specifies a function to return a proxy for a given
+	// Request. If the function returns a non-nil error, the
+	// request is aborted with the provided error.
+	// If Proxy is nil or returns a nil *URL, no proxy is used.
+	Proxy func(*http.Request) (*url.URL, error)
+
+	// TLSClientConfig specifies the TLS configuration to use with tls.Client.
+	// If nil, the default configuration is used.
+	TLSClientConfig *tls.Config
+
+	// HandshakeTimeout specifies the duration for the handshake to complete.
+	HandshakeTimeout time.Duration
+
+	// ReadBufferSize and WriteBufferSize specify I/O buffer sizes. If a buffer
+	// size is zero, then a useful default size is used. The I/O buffer sizes
+	// do not limit the size of the messages that can be sent or received.
+	ReadBufferSize, WriteBufferSize int
+
+	// WriteBufferPool is a pool of buffers for write operations. If the value
+	// is not set, then write buffers are allocated to the connection for the
+	// lifetime of the connection.
+	//
+	// A pool is most useful when the application has a modest volume of writes
+	// across a large number of connections.
+	//
+	// Applications should use a single pool for each unique value of
+	// WriteBufferSize.
+	WriteBufferPool BufferPool
+
+	// Subprotocols specifies the client's requested subprotocols.
+	Subprotocols []string
+
+	// EnableCompression specifies if the client should attempt to negotiate
+	// per message compression (RFC 7692). Setting this value to true does not
+	// guarantee that compression will be supported. Currently only "no context
+	// takeover" modes are supported.
+	EnableCompression bool
+
+	// Jar specifies the cookie jar.
+	// If Jar is nil, cookies are not sent in requests and ignored
+	// in responses.
+	Jar http.CookieJar
+}
+
+// Dial creates a new client connection by calling DialContext with a background context.
+func (d *Dialer) Dial(urlStr string, requestHeader http.Header) (*Conn, *http.Response, error) {
+	return d.DialContext(context.Background(), urlStr, requestHeader)
+}
+
+var errMalformedURL = errors.New("malformed ws or wss URL")
+
+func hostPortNoPort(u *url.URL) (hostPort, hostNoPort string) {
+	hostPort = u.Host
+	hostNoPort = u.Host
+	if i := strings.LastIndex(u.Host, ":"); i > strings.LastIndex(u.Host, "]") {
+		hostNoPort = hostNoPort[:i]
+	} else {
+		switch u.Scheme {
+		case "wss":
+			hostPort += ":443"
+		case "https":
+			hostPort += ":443"
+		default:
+			hostPort += ":80"
+		}
+	}
+	return hostPort, hostNoPort
+}
+
+// DefaultDialer is a dialer with all fields set to the default values.
+var DefaultDialer = &Dialer{
+	Proxy:            http.ProxyFromEnvironment,
+	HandshakeTimeout: 45 * time.Second,
+}
+
+// nilDialer is dialer to use when receiver is nil.
+var nilDialer = *DefaultDialer
+
+// DialContext creates a new client connection. Use requestHeader to specify the
+// origin (Origin), subprotocols (Sec-WebSocket-Protocol) and cookies (Cookie).
+// Use the response.Header to get the selected subprotocol
+// (Sec-WebSocket-Protocol) and cookies (Set-Cookie).
+//
+// The context will be used in the request and in the Dialer
+//
+// If the WebSocket handshake fails, ErrBadHandshake is returned along with a
+// non-nil *http.Response so that callers can handle redirects, authentication,
+// etcetera. The response body may not contain the entire response and does not
+// need to be closed by the application.
+func (d *Dialer) DialContext(ctx context.Context, urlStr string, requestHeader http.Header) (*Conn, *http.Response, error) {
+	if d == nil {
+		d = &nilDialer
+	}
+
+	challengeKey, err := generateChallengeKey()
+	if err != nil {
+		return nil, nil, err
+	}
+
+	u, err := url.Parse(urlStr)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	switch u.Scheme {
+	case "ws":
+		u.Scheme = "http"
+	case "wss":
+		u.Scheme = "https"
+	default:
+		return nil, nil, errMalformedURL
+	}
+
+	if u.User != nil {
+		// User name and password are not allowed in websocket URIs.
+		return nil, nil, errMalformedURL
+	}
+
+	req := &http.Request{
+		Method:     "GET",
+		URL:        u,
+		Proto:      "HTTP/1.1",
+		ProtoMajor: 1,
+		ProtoMinor: 1,
+		Header:     make(http.Header),
+		Host:       u.Host,
+	}
+	req = req.WithContext(ctx)
+
+	// Set the cookies present in the cookie jar of the dialer
+	if d.Jar != nil {
+		for _, cookie := range d.Jar.Cookies(u) {
+			req.AddCookie(cookie)
+		}
+	}
+
+	// Set the request headers using the capitalization for names and values in
+	// RFC examples. Although the capitalization shouldn't matter, there are
+	// servers that depend on it. The Header.Set method is not used because the
+	// method canonicalizes the header names.
+	req.Header["Upgrade"] = []string{"websocket"}
+	req.Header["Connection"] = []string{"Upgrade"}
+	req.Header["Sec-WebSocket-Key"] = []string{challengeKey}
+	req.Header["Sec-WebSocket-Version"] = []string{"13"}
+	if len(d.Subprotocols) > 0 {
+		req.Header["Sec-WebSocket-Protocol"] = []string{strings.Join(d.Subprotocols, ", ")}
+	}
+	for k, vs := range requestHeader {
+		switch {
+		case k == "Host":
+			if len(vs) > 0 {
+				req.Host = vs[0]
+			}
+		case k == "Upgrade" ||
+			k == "Connection" ||
+			k == "Sec-Websocket-Key" ||
+			k == "Sec-Websocket-Version" ||
+			k == "Sec-Websocket-Extensions" ||
+			(k == "Sec-Websocket-Protocol" && len(d.Subprotocols) > 0):
+			return nil, nil, errors.New("websocket: duplicate header not allowed: " + k)
+		case k == "Sec-Websocket-Protocol":
+			req.Header["Sec-WebSocket-Protocol"] = vs
+		default:
+			req.Header[k] = vs
+		}
+	}
+
+	if d.EnableCompression {
+		req.Header["Sec-WebSocket-Extensions"] = []string{"permessage-deflate; server_no_context_takeover; client_no_context_takeover"}
+	}
+
+	if d.HandshakeTimeout != 0 {
+		var cancel func()
+		ctx, cancel = context.WithTimeout(ctx, d.HandshakeTimeout)
+		defer cancel()
+	}
+
+	// Get network dial function.
+	var netDial func(network, add string) (net.Conn, error)
+
+	if d.NetDialContext != nil {
+		netDial = func(network, addr string) (net.Conn, error) {
+			return d.NetDialContext(ctx, network, addr)
+		}
+	} else if d.NetDial != nil {
+		netDial = d.NetDial
+	} else {
+		netDialer := &net.Dialer{}
+		netDial = func(network, addr string) (net.Conn, error) {
+			return netDialer.DialContext(ctx, network, addr)
+		}
+	}
+
+	// If needed, wrap the dial function to set the connection deadline.
+	if deadline, ok := ctx.Deadline(); ok {
+		forwardDial := netDial
+		netDial = func(network, addr string) (net.Conn, error) {
+			c, err := forwardDial(network, addr)
+			if err != nil {
+				return nil, err
+			}
+			err = c.SetDeadline(deadline)
+			if err != nil {
+				c.Close()
+				return nil, err
+			}
+			return c, nil
+		}
+	}
+
+	// If needed, wrap the dial function to connect through a proxy.
+	if d.Proxy != nil {
+		proxyURL, err := d.Proxy(req)
+		if err != nil {
+			return nil, nil, err
+		}
+		if proxyURL != nil {
+			dialer, err := proxy_FromURL(proxyURL, netDialerFunc(netDial))
+			if err != nil {
+				return nil, nil, err
+			}
+			netDial = dialer.Dial
+		}
+	}
+
+	hostPort, hostNoPort := hostPortNoPort(u)
+	trace := httptrace.ContextClientTrace(ctx)
+	if trace != nil && trace.GetConn != nil {
+		trace.GetConn(hostPort)
+	}
+
+	netConn, err := netDial("tcp", hostPort)
+	if trace != nil && trace.GotConn != nil {
+		trace.GotConn(httptrace.GotConnInfo{
+			Conn: netConn,
+		})
+	}
+	if err != nil {
+		return nil, nil, err
+	}
+
+	defer func() {
+		if netConn != nil {
+			netConn.Close()
+		}
+	}()
+
+	if u.Scheme == "https" {
+		cfg := cloneTLSConfig(d.TLSClientConfig)
+		if cfg.ServerName == "" {
+			cfg.ServerName = hostNoPort
+		}
+		tlsConn := tls.Client(netConn, cfg)
+		netConn = tlsConn
+
+		var err error
+		if trace != nil {
+			err = doHandshakeWithTrace(trace, tlsConn, cfg)
+		} else {
+			err = doHandshake(tlsConn, cfg)
+		}
+
+		if err != nil {
+			return nil, nil, err
+		}
+	}
+
+	conn := newConn(netConn, false, d.ReadBufferSize, d.WriteBufferSize, d.WriteBufferPool, nil, nil)
+
+	if err := req.Write(netConn); err != nil {
+		return nil, nil, err
+	}
+
+	if trace != nil && trace.GotFirstResponseByte != nil {
+		if peek, err := conn.br.Peek(1); err == nil && len(peek) == 1 {
+			trace.GotFirstResponseByte()
+		}
+	}
+
+	resp, err := http.ReadResponse(conn.br, req)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	if d.Jar != nil {
+		if rc := resp.Cookies(); len(rc) > 0 {
+			d.Jar.SetCookies(u, rc)
+		}
+	}
+
+	if resp.StatusCode != 101 ||
+		!strings.EqualFold(resp.Header.Get("Upgrade"), "websocket") ||
+		!strings.EqualFold(resp.Header.Get("Connection"), "upgrade") ||
+		resp.Header.Get("Sec-Websocket-Accept") != computeAcceptKey(challengeKey) {
+		// Before closing the network connection on return from this
+		// function, slurp up some of the response to aid application
+		// debugging.
+		buf := make([]byte, 1024)
+		n, _ := io.ReadFull(resp.Body, buf)
+		resp.Body = ioutil.NopCloser(bytes.NewReader(buf[:n]))
+		return nil, resp, ErrBadHandshake
+	}
+
+	for _, ext := range parseExtensions(resp.Header) {
+		if ext[""] != "permessage-deflate" {
+			continue
+		}
+		_, snct := ext["server_no_context_takeover"]
+		_, cnct := ext["client_no_context_takeover"]
+		if !snct || !cnct {
+			return nil, resp, errInvalidCompression
+		}
+		conn.newCompressionWriter = compressNoContextTakeover
+		conn.newDecompressionReader = decompressNoContextTakeover
+		break
+	}
+
+	resp.Body = ioutil.NopCloser(bytes.NewReader([]byte{}))
+	conn.subprotocol = resp.Header.Get("Sec-Websocket-Protocol")
+
+	netConn.SetDeadline(time.Time{})
+	netConn = nil // to avoid close in defer.
+	return conn, resp, nil
+}
+
+func doHandshake(tlsConn *tls.Conn, cfg *tls.Config) error {
+	if err := tlsConn.Handshake(); err != nil {
+		return err
+	}
+	if !cfg.InsecureSkipVerify {
+		if err := tlsConn.VerifyHostname(cfg.ServerName); err != nil {
+			return err
+		}
+	}
+	return nil
+}

at-server/vendor/github.com/gorilla/websocket/client_clone.go

@@ -0,0 +1,16 @@
+// Copyright 2013 The Gorilla WebSocket Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build go1.8
+
+package websocket
+
+import "crypto/tls"
+
+func cloneTLSConfig(cfg *tls.Config) *tls.Config {
+	if cfg == nil {
+		return &tls.Config{}
+	}
+	return cfg.Clone()
+}

at-server/vendor/github.com/gorilla/websocket/client_clone_legacy.go

@@ -0,0 +1,38 @@
+// Copyright 2013 The Gorilla WebSocket Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build !go1.8
+
+package websocket
+
+import "crypto/tls"
+
+// cloneTLSConfig clones all public fields except the fields
+// SessionTicketsDisabled and SessionTicketKey. This avoids copying the
+// sync.Mutex in the sync.Once and makes it safe to call cloneTLSConfig on a
+// config in active use.
+func cloneTLSConfig(cfg *tls.Config) *tls.Config {
+	if cfg == nil {
+		return &tls.Config{}
+	}
+	return &tls.Config{
+		Rand:                     cfg.Rand,
+		Time:                     cfg.Time,
+		Certificates:             cfg.Certificates,
+		NameToCertificate:        cfg.NameToCertificate,
+		GetCertificate:           cfg.GetCertificate,
+		RootCAs:                  cfg.RootCAs,
+		NextProtos:               cfg.NextProtos,
+		ServerName:               cfg.ServerName,
+		ClientAuth:               cfg.ClientAuth,
+		ClientCAs:                cfg.ClientCAs,
+		InsecureSkipVerify:       cfg.InsecureSkipVerify,
+		CipherSuites:             cfg.CipherSuites,
+		PreferServerCipherSuites: cfg.PreferServerCipherSuites,
+		ClientSessionCache:       cfg.ClientSessionCache,
+		MinVersion:               cfg.MinVersion,
+		MaxVersion:               cfg.MaxVersion,
+		CurvePreferences:         cfg.CurvePreferences,
+	}
+}

at-server/vendor/github.com/gorilla/websocket/compression.go

@@ -0,0 +1,148 @@
+// Copyright 2017 The Gorilla WebSocket Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package websocket
+
+import (
+	"compress/flate"
+	"errors"
+	"io"
+	"strings"
+	"sync"
+)
+
+const (
+	minCompressionLevel     = -2 // flate.HuffmanOnly not defined in Go < 1.6
+	maxCompressionLevel     = flate.BestCompression
+	defaultCompressionLevel = 1
+)
+
+var (
+	flateWriterPools [maxCompressionLevel - minCompressionLevel + 1]sync.Pool
+	flateReaderPool  = sync.Pool{New: func() interface{} {
+		return flate.NewReader(nil)
+	}}
+)
+
+func decompressNoContextTakeover(r io.Reader) io.ReadCloser {
+	const tail =
+	// Add four bytes as specified in RFC
+	"\x00\x00\xff\xff" +
+		// Add final block to squelch unexpected EOF error from flate reader.
+		"\x01\x00\x00\xff\xff"
+
+	fr, _ := flateReaderPool.Get().(io.ReadCloser)
+	fr.(flate.Resetter).Reset(io.MultiReader(r, strings.NewReader(tail)), nil)
+	return &flateReadWrapper{fr}
+}
+
+func isValidCompressionLevel(level int) bool {
+	return minCompressionLevel <= level && level <= maxCompressionLevel
+}
+
+func compressNoContextTakeover(w io.WriteCloser, level int) io.WriteCloser {
+	p := &flateWriterPools[level-minCompressionLevel]
+	tw := &truncWriter{w: w}
+	fw, _ := p.Get().(*flate.Writer)
+	if fw == nil {
+		fw, _ = flate.NewWriter(tw, level)
+	} else {
+		fw.Reset(tw)
+	}
+	return &flateWriteWrapper{fw: fw, tw: tw, p: p}
+}
+
+// truncWriter is an io.Writer that writes all but the last four bytes of the
+// stream to another io.Writer.
+type truncWriter struct {
+	w io.WriteCloser
+	n int
+	p [4]byte
+}
+
+func (w *truncWriter) Write(p []byte) (int, error) {
+	n := 0
+
+	// fill buffer first for simplicity.
+	if w.n < len(w.p) {
+		n = copy(w.p[w.n:], p)
+		p = p[n:]
+		w.n += n
+		if len(p) == 0 {
+			return n, nil
+		}
+	}
+
+	m := len(p)
+	if m > len(w.p) {
+		m = len(w.p)
+	}
+
+	if nn, err := w.w.Write(w.p[:m]); err != nil {
+		return n + nn, err
+	}
+
+	copy(w.p[:], w.p[m:])
+	copy(w.p[len(w.p)-m:], p[len(p)-m:])
+	nn, err := w.w.Write(p[:len(p)-m])
+	return n + nn, err
+}
+
+type flateWriteWrapper struct {
+	fw *flate.Writer
+	tw *truncWriter
+	p  *sync.Pool
+}
+
+func (w *flateWriteWrapper) Write(p []byte) (int, error) {
+	if w.fw == nil {
+		return 0, errWriteClosed
+	}
+	return w.fw.Write(p)
+}
+
+func (w *flateWriteWrapper) Close() error {
+	if w.fw == nil {
+		return errWriteClosed
+	}
+	err1 := w.fw.Flush()
+	w.p.Put(w.fw)
+	w.fw = nil
+	if w.tw.p != [4]byte{0, 0, 0xff, 0xff} {
+		return errors.New("websocket: internal error, unexpected bytes at end of flate stream")
+	}
+	err2 := w.tw.w.Close()
+	if err1 != nil {
+		return err1
+	}
+	return err2
+}
+
+type flateReadWrapper struct {
+	fr io.ReadCloser
+}
+
+func (r *flateReadWrapper) Read(p []byte) (int, error) {
+	if r.fr == nil {
+		return 0, io.ErrClosedPipe
+	}
+	n, err := r.fr.Read(p)
+	if err == io.EOF {
+		// Preemptively place the reader back in the pool. This helps with
+		// scenarios where the application does not call NextReader() soon after
+		// this final read.
+		r.Close()
+	}
+	return n, err
+}
+
+func (r *flateReadWrapper) Close() error {
+	if r.fr == nil {
+		return io.ErrClosedPipe
+	}
+	err := r.fr.Close()
+	flateReaderPool.Put(r.fr)
+	r.fr = nil
+	return err
+}

at-server/vendor/github.com/gorilla/websocket/conn.go

@@ -0,0 +1,1165 @@
+// Copyright 2013 The Gorilla WebSocket Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package websocket
+
+import (
+	"bufio"
+	"encoding/binary"
+	"errors"
+	"io"
+	"io/ioutil"
+	"math/rand"
+	"net"
+	"strconv"
+	"sync"
+	"time"
+	"unicode/utf8"
+)
+
+const (
+	// Frame header byte 0 bits from Section 5.2 of RFC 6455
+	finalBit = 1 << 7
+	rsv1Bit  = 1 << 6
+	rsv2Bit  = 1 << 5
+	rsv3Bit  = 1 << 4
+
+	// Frame header byte 1 bits from Section 5.2 of RFC 6455
+	maskBit = 1 << 7
+
+	maxFrameHeaderSize         = 2 + 8 + 4 // Fixed header + length + mask
+	maxControlFramePayloadSize = 125
+
+	writeWait = time.Second
+
+	defaultReadBufferSize  = 4096
+	defaultWriteBufferSize = 4096
+
+	continuationFrame = 0
+	noFrame           = -1
+)
+
+// Close codes defined in RFC 6455, section 11.7.
+const (
+	CloseNormalClosure           = 1000
+	CloseGoingAway               = 1001
+	CloseProtocolError           = 1002
+	CloseUnsupportedData         = 1003
+	CloseNoStatusReceived        = 1005
+	CloseAbnormalClosure         = 1006
+	CloseInvalidFramePayloadData = 1007
+	ClosePolicyViolation         = 1008
+	CloseMessageTooBig           = 1009
+	CloseMandatoryExtension      = 1010
+	CloseInternalServerErr       = 1011
+	CloseServiceRestart          = 1012
+	CloseTryAgainLater           = 1013
+	CloseTLSHandshake            = 1015
+)
+
+// The message types are defined in RFC 6455, section 11.8.
+const (
+	// TextMessage denotes a text data message. The text message payload is
+	// interpreted as UTF-8 encoded text data.
+	TextMessage = 1
+
+	// BinaryMessage denotes a binary data message.
+	BinaryMessage = 2
+
+	// CloseMessage denotes a close control message. The optional message
+	// payload contains a numeric code and text. Use the FormatCloseMessage
+	// function to format a close message payload.
+	CloseMessage = 8
+
+	// PingMessage denotes a ping control message. The optional message payload
+	// is UTF-8 encoded text.
+	PingMessage = 9
+
+	// PongMessage denotes a pong control message. The optional message payload
+	// is UTF-8 encoded text.
+	PongMessage = 10
+)
+
+// ErrCloseSent is returned when the application writes a message to the
+// connection after sending a close message.
+var ErrCloseSent = errors.New("websocket: close sent")
+
+// ErrReadLimit is returned when reading a message that is larger than the
+// read limit set for the connection.
+var ErrReadLimit = errors.New("websocket: read limit exceeded")
+
+// netError satisfies the net Error interface.
+type netError struct {
+	msg       string
+	temporary bool
+	timeout   bool
+}
+
+func (e *netError) Error() string   { return e.msg }
+func (e *netError) Temporary() bool { return e.temporary }
+func (e *netError) Timeout() bool   { return e.timeout }
+
+// CloseError represents a close message.
+type CloseError struct {
+	// Code is defined in RFC 6455, section 11.7.
+	Code int
+
+	// Text is the optional text payload.
+	Text string
+}
+
+func (e *CloseError) Error() string {
+	s := []byte("websocket: close ")
+	s = strconv.AppendInt(s, int64(e.Code), 10)
+	switch e.Code {
+	case CloseNormalClosure:
+		s = append(s, " (normal)"...)
+	case CloseGoingAway:
+		s = append(s, " (going away)"...)
+	case CloseProtocolError:
+		s = append(s, " (protocol error)"...)
+	case CloseUnsupportedData:
+		s = append(s, " (unsupported data)"...)
+	case CloseNoStatusReceived:
+		s = append(s, " (no status)"...)
+	case CloseAbnormalClosure:
+		s = append(s, " (abnormal closure)"...)
+	case CloseInvalidFramePayloadData:
+		s = append(s, " (invalid payload data)"...)
+	case ClosePolicyViolation:
+		s = append(s, " (policy violation)"...)
+	case CloseMessageTooBig:
+		s = append(s, " (message too big)"...)
+	case CloseMandatoryExtension:
+		s = append(s, " (mandatory extension missing)"...)
+	case CloseInternalServerErr:
+		s = append(s, " (internal server error)"...)
+	case CloseTLSHandshake:
+		s = append(s, " (TLS handshake error)"...)
+	}
+	if e.Text != "" {
+		s = append(s, ": "...)
+		s = append(s, e.Text...)
+	}
+	return string(s)
+}
+
+// IsCloseError returns boolean indicating whether the error is a *CloseError
+// with one of the specified codes.
+func IsCloseError(err error, codes ...int) bool {
+	if e, ok := err.(*CloseError); ok {
+		for _, code := range codes {
+			if e.Code == code {
+				return true
+			}
+		}
+	}
+	return false
+}
+
+// IsUnexpectedCloseError returns boolean indicating whether the error is a
+// *CloseError with a code not in the list of expected codes.
+func IsUnexpectedCloseError(err error, expectedCodes ...int) bool {
+	if e, ok := err.(*CloseError); ok {
+		for _, code := range expectedCodes {
+			if e.Code == code {
+				return false
+			}
+		}
+		return true
+	}
+	return false
+}
+
+var (
+	errWriteTimeout        = &netError{msg: "websocket: write timeout", timeout: true, temporary: true}
+	errUnexpectedEOF       = &CloseError{Code: CloseAbnormalClosure, Text: io.ErrUnexpectedEOF.Error()}
+	errBadWriteOpCode      = errors.New("websocket: bad write message type")
+	errWriteClosed         = errors.New("websocket: write closed")
+	errInvalidControlFrame = errors.New("websocket: invalid control frame")
+)
+
+func newMaskKey() [4]byte {
+	n := rand.Uint32()
+	return [4]byte{byte(n), byte(n >> 8), byte(n >> 16), byte(n >> 24)}
+}
+
+func hideTempErr(err error) error {
+	if e, ok := err.(net.Error); ok && e.Temporary() {
+		err = &netError{msg: e.Error(), timeout: e.Timeout()}
+	}
+	return err
+}
+
+func isControl(frameType int) bool {
+	return frameType == CloseMessage || frameType == PingMessage || frameType == PongMessage
+}
+
+func isData(frameType int) bool {
+	return frameType == TextMessage || frameType == BinaryMessage
+}
+
+var validReceivedCloseCodes = map[int]bool{
+	// see http://www.iana.org/assignments/websocket/websocket.xhtml#close-code-number
+
+	CloseNormalClosure:           true,
+	CloseGoingAway:               true,
+	CloseProtocolError:           true,
+	CloseUnsupportedData:         true,
+	CloseNoStatusReceived:        false,
+	CloseAbnormalClosure:         false,
+	CloseInvalidFramePayloadData: true,
+	ClosePolicyViolation:         true,
+	CloseMessageTooBig:           true,
+	CloseMandatoryExtension:      true,
+	CloseInternalServerErr:       true,
+	CloseServiceRestart:          true,
+	CloseTryAgainLater:           true,
+	CloseTLSHandshake:            false,
+}
+
+func isValidReceivedCloseCode(code int) bool {
+	return validReceivedCloseCodes[code] || (code >= 3000 && code <= 4999)
+}
+
+// BufferPool represents a pool of buffers. The *sync.Pool type satisfies this
+// interface.  The type of the value stored in a pool is not specified.
+type BufferPool interface {
+	// Get gets a value from the pool or returns nil if the pool is empty.
+	Get() interface{}
+	// Put adds a value to the pool.
+	Put(interface{})
+}
+
+// writePoolData is the type added to the write buffer pool. This wrapper is
+// used to prevent applications from peeking at and depending on the values
+// added to the pool.
+type writePoolData struct{ buf []byte }
+
+// The Conn type represents a WebSocket connection.
+type Conn struct {
+	conn        net.Conn
+	isServer    bool
+	subprotocol string
+
+	// Write fields
+	mu            chan bool // used as mutex to protect write to conn
+	writeBuf      []byte    // frame is constructed in this buffer.
+	writePool     BufferPool
+	writeBufSize  int
+	writeDeadline time.Time
+	writer        io.WriteCloser // the current writer returned to the application
+	isWriting     bool           // for best-effort concurrent write detection
+
+	writeErrMu sync.Mutex
+	writeErr   error
+
+	enableWriteCompression bool
+	compressionLevel       int
+	newCompressionWriter   func(io.WriteCloser, int) io.WriteCloser
+
+	// Read fields
+	reader        io.ReadCloser // the current reader returned to the application
+	readErr       error
+	br            *bufio.Reader
+	readRemaining int64 // bytes remaining in current frame.
+	readFinal     bool  // true the current message has more frames.
+	readLength    int64 // Message size.
+	readLimit     int64 // Maximum message size.
+	readMaskPos   int
+	readMaskKey   [4]byte
+	handlePong    func(string) error
+	handlePing    func(string) error
+	handleClose   func(int, string) error
+	readErrCount  int
+	messageReader *messageReader // the current low-level reader
+
+	readDecompress         bool // whether last read frame had RSV1 set
+	newDecompressionReader func(io.Reader) io.ReadCloser
+}
+
+func newConn(conn net.Conn, isServer bool, readBufferSize, writeBufferSize int, writeBufferPool BufferPool, br *bufio.Reader, writeBuf []byte) *Conn {
+
+	if br == nil {
+		if readBufferSize == 0 {
+			readBufferSize = defaultReadBufferSize
+		} else if readBufferSize < maxControlFramePayloadSize {
+			// must be large enough for control frame
+			readBufferSize = maxControlFramePayloadSize
+		}
+		br = bufio.NewReaderSize(conn, readBufferSize)
+	}
+
+	if writeBufferSize <= 0 {
+		writeBufferSize = defaultWriteBufferSize
+	}
+	writeBufferSize += maxFrameHeaderSize
+
+	if writeBuf == nil && writeBufferPool == nil {
+		writeBuf = make([]byte, writeBufferSize)
+	}
+
+	mu := make(chan bool, 1)
+	mu <- true
+	c := &Conn{
+		isServer:               isServer,
+		br:                     br,
+		conn:                   conn,
+		mu:                     mu,
+		readFinal:              true,
+		writeBuf:               writeBuf,
+		writePool:              writeBufferPool,
+		writeBufSize:           writeBufferSize,
+		enableWriteCompression: true,
+		compressionLevel:       defaultCompressionLevel,
+	}
+	c.SetCloseHandler(nil)
+	c.SetPingHandler(nil)
+	c.SetPongHandler(nil)
+	return c
+}
+
+// Subprotocol returns the negotiated protocol for the connection.
+func (c *Conn) Subprotocol() string {
+	return c.subprotocol
+}
+
+// Close closes the underlying network connection without sending or waiting
+// for a close message.
+func (c *Conn) Close() error {
+	return c.conn.Close()
+}
+
+// LocalAddr returns the local network address.
+func (c *Conn) LocalAddr() net.Addr {
+	return c.conn.LocalAddr()
+}
+
+// RemoteAddr returns the remote network address.
+func (c *Conn) RemoteAddr() net.Addr {
+	return c.conn.RemoteAddr()
+}
+
+// Write methods
+
+func (c *Conn) writeFatal(err error) error {
+	err = hideTempErr(err)
+	c.writeErrMu.Lock()
+	if c.writeErr == nil {
+		c.writeErr = err
+	}
+	c.writeErrMu.Unlock()
+	return err
+}
+
+func (c *Conn) read(n int) ([]byte, error) {
+	p, err := c.br.Peek(n)
+	if err == io.EOF {
+		err = errUnexpectedEOF
+	}
+	c.br.Discard(len(p))
+	return p, err
+}
+
+func (c *Conn) write(frameType int, deadline time.Time, buf0, buf1 []byte) error {
+	<-c.mu
+	defer func() { c.mu <- true }()
+
+	c.writeErrMu.Lock()
+	err := c.writeErr
+	c.writeErrMu.Unlock()
+	if err != nil {
+		return err
+	}
+
+	c.conn.SetWriteDeadline(deadline)
+	if len(buf1) == 0 {
+		_, err = c.conn.Write(buf0)
+	} else {
+		err = c.writeBufs(buf0, buf1)
+	}
+	if err != nil {
+		return c.writeFatal(err)
+	}
+	if frameType == CloseMessage {
+		c.writeFatal(ErrCloseSent)
+	}
+	return nil
+}
+
+// WriteControl writes a control message with the given deadline. The allowed
+// message types are CloseMessage, PingMessage and PongMessage.
+func (c *Conn) WriteControl(messageType int, data []byte, deadline time.Time) error {
+	if !isControl(messageType) {
+		return errBadWriteOpCode
+	}
+	if len(data) > maxControlFramePayloadSize {
+		return errInvalidControlFrame
+	}
+
+	b0 := byte(messageType) | finalBit
+	b1 := byte(len(data))
+	if !c.isServer {
+		b1 |= maskBit
+	}
+
+	buf := make([]byte, 0, maxFrameHeaderSize+maxControlFramePayloadSize)
+	buf = append(buf, b0, b1)
+
+	if c.isServer {
+		buf = append(buf, data...)
+	} else {
+		key := newMaskKey()
+		buf = append(buf, key[:]...)
+		buf = append(buf, data...)
+		maskBytes(key, 0, buf[6:])
+	}
+
+	d := time.Hour * 1000
+	if !deadline.IsZero() {
+		d = deadline.Sub(time.Now())
+		if d < 0 {
+			return errWriteTimeout
+		}
+	}
+
+	timer := time.NewTimer(d)
+	select {
+	case <-c.mu:
+		timer.Stop()
+	case <-timer.C:
+		return errWriteTimeout
+	}
+	defer func() { c.mu <- true }()
+
+	c.writeErrMu.Lock()
+	err := c.writeErr
+	c.writeErrMu.Unlock()
+	if err != nil {
+		return err
+	}
+
+	c.conn.SetWriteDeadline(deadline)
+	_, err = c.conn.Write(buf)
+	if err != nil {
+		return c.writeFatal(err)
+	}
+	if messageType == CloseMessage {
+		c.writeFatal(ErrCloseSent)
+	}
+	return err
+}
+
+func (c *Conn) prepWrite(messageType int) error {
+	// Close previous writer if not already closed by the application. It's
+	// probably better to return an error in this situation, but we cannot
+	// change this without breaking existing applications.
+	if c.writer != nil {
+		c.writer.Close()
+		c.writer = nil
+	}
+
+	if !isControl(messageType) && !isData(messageType) {
+		return errBadWriteOpCode
+	}
+
+	c.writeErrMu.Lock()
+	err := c.writeErr
+	c.writeErrMu.Unlock()
+	if err != nil {
+		return err
+	}
+
+	if c.writeBuf == nil {
+		wpd, ok := c.writePool.Get().(writePoolData)
+		if ok {
+			c.writeBuf = wpd.buf
+		} else {
+			c.writeBuf = make([]byte, c.writeBufSize)
+		}
+	}
+	return nil
+}
+
+// NextWriter returns a writer for the next message to send. The writer's Close
+// method flushes the complete message to the network.
+//
+// There can be at most one open writer on a connection. NextWriter closes the
+// previous writer if the application has not already done so.
+//
+// All message types (TextMessage, BinaryMessage, CloseMessage, PingMessage and
+// PongMessage) are supported.
+func (c *Conn) NextWriter(messageType int) (io.WriteCloser, error) {
+	if err := c.prepWrite(messageType); err != nil {
+		return nil, err
+	}
+
+	mw := &messageWriter{
+		c:         c,
+		frameType: messageType,
+		pos:       maxFrameHeaderSize,
+	}
+	c.writer = mw
+	if c.newCompressionWriter != nil && c.enableWriteCompression && isData(messageType) {
+		w := c.newCompressionWriter(c.writer, c.compressionLevel)
+		mw.compress = true
+		c.writer = w
+	}
+	return c.writer, nil
+}
+
+type messageWriter struct {
+	c         *Conn
+	compress  bool // whether next call to flushFrame should set RSV1
+	pos       int  // end of data in writeBuf.
+	frameType int  // type of the current frame.
+	err       error
+}
+
+func (w *messageWriter) fatal(err error) error {
+	if w.err != nil {
+		w.err = err
+		w.c.writer = nil
+	}
+	return err
+}
+
+// flushFrame writes buffered data and extra as a frame to the network. The
+// final argument indicates that this is the last frame in the message.
+func (w *messageWriter) flushFrame(final bool, extra []byte) error {
+	c := w.c
+	length := w.pos - maxFrameHeaderSize + len(extra)
+
+	// Check for invalid control frames.
+	if isControl(w.frameType) &&
+		(!final || length > maxControlFramePayloadSize) {
+		return w.fatal(errInvalidControlFrame)
+	}
+
+	b0 := byte(w.frameType)
+	if final {
+		b0 |= finalBit
+	}
+	if w.compress {
+		b0 |= rsv1Bit
+	}
+	w.compress = false
+
+	b1 := byte(0)
+	if !c.isServer {
+		b1 |= maskBit
+	}
+
+	// Assume that the frame starts at beginning of c.writeBuf.
+	framePos := 0
+	if c.isServer {
+		// Adjust up if mask not included in the header.
+		framePos = 4
+	}
+
+	switch {
+	case length >= 65536:
+		c.writeBuf[framePos] = b0
+		c.writeBuf[framePos+1] = b1 | 127
+		binary.BigEndian.PutUint64(c.writeBuf[framePos+2:], uint64(length))
+	case length > 125:
+		framePos += 6
+		c.writeBuf[framePos] = b0
+		c.writeBuf[framePos+1] = b1 | 126
+		binary.BigEndian.PutUint16(c.writeBuf[framePos+2:], uint16(length))
+	default:
+		framePos += 8
+		c.writeBuf[framePos] = b0
+		c.writeBuf[framePos+1] = b1 | byte(length)
+	}
+
+	if !c.isServer {
+		key := newMaskKey()
+		copy(c.writeBuf[maxFrameHeaderSize-4:], key[:])
+		maskBytes(key, 0, c.writeBuf[maxFrameHeaderSize:w.pos])
+		if len(extra) > 0 {
+			return c.writeFatal(errors.New("websocket: internal error, extra used in client mode"))
+		}
+	}
+
+	// Write the buffers to the connection with best-effort detection of
+	// concurrent writes. See the concurrency section in the package
+	// documentation for more info.
+
+	if c.isWriting {
+		panic("concurrent write to websocket connection")
+	}
+	c.isWriting = true
+
+	err := c.write(w.frameType, c.writeDeadline, c.writeBuf[framePos:w.pos], extra)
+
+	if !c.isWriting {
+		panic("concurrent write to websocket connection")
+	}
+	c.isWriting = false
+
+	if err != nil {
+		return w.fatal(err)
+	}
+
+	if final {
+		c.writer = nil
+		if c.writePool != nil {
+			c.writePool.Put(writePoolData{buf: c.writeBuf})
+			c.writeBuf = nil
+		}
+		return nil
+	}
+
+	// Setup for next frame.
+	w.pos = maxFrameHeaderSize
+	w.frameType = continuationFrame
+	return nil
+}
+
+func (w *messageWriter) ncopy(max int) (int, error) {
+	n := len(w.c.writeBuf) - w.pos
+	if n <= 0 {
+		if err := w.flushFrame(false, nil); err != nil {
+			return 0, err
+		}
+		n = len(w.c.writeBuf) - w.pos
+	}
+	if n > max {
+		n = max
+	}
+	return n, nil
+}
+
+func (w *messageWriter) Write(p []byte) (int, error) {
+	if w.err != nil {
+		return 0, w.err
+	}
+
+	if len(p) > 2*len(w.c.writeBuf) && w.c.isServer {
+		// Don't buffer large messages.
+		err := w.flushFrame(false, p)
+		if err != nil {
+			return 0, err
+		}
+		return len(p), nil
+	}
+
+	nn := len(p)
+	for len(p) > 0 {
+		n, err := w.ncopy(len(p))
+		if err != nil {
+			return 0, err
+		}
+		copy(w.c.writeBuf[w.pos:], p[:n])
+		w.pos += n
+		p = p[n:]
+	}
+	return nn, nil
+}
+
+func (w *messageWriter) WriteString(p string) (int, error) {
+	if w.err != nil {
+		return 0, w.err
+	}
+
+	nn := len(p)
+	for len(p) > 0 {
+		n, err := w.ncopy(len(p))
+		if err != nil {
+			return 0, err
+		}
+		copy(w.c.writeBuf[w.pos:], p[:n])
+		w.pos += n
+		p = p[n:]
+	}
+	return nn, nil
+}
+
+func (w *messageWriter) ReadFrom(r io.Reader) (nn int64, err error) {
+	if w.err != nil {
+		return 0, w.err
+	}
+	for {
+		if w.pos == len(w.c.writeBuf) {
+			err = w.flushFrame(false, nil)
+			if err != nil {
+				break
+			}
+		}
+		var n int
+		n, err = r.Read(w.c.writeBuf[w.pos:])
+		w.pos += n
+		nn += int64(n)
+		if err != nil {
+			if err == io.EOF {
+				err = nil
+			}
+			break
+		}
+	}
+	return nn, err
+}
+
+func (w *messageWriter) Close() error {
+	if w.err != nil {
+		return w.err
+	}
+	if err := w.flushFrame(true, nil); err != nil {
+		return err
+	}
+	w.err = errWriteClosed
+	return nil
+}
+
+// WritePreparedMessage writes prepared message into connection.
+func (c *Conn) WritePreparedMessage(pm *PreparedMessage) error {
+	frameType, frameData, err := pm.frame(prepareKey{
+		isServer:         c.isServer,
+		compress:         c.newCompressionWriter != nil && c.enableWriteCompression && isData(pm.messageType),
+		compressionLevel: c.compressionLevel,
+	})
+	if err != nil {
+		return err
+	}
+	if c.isWriting {
+		panic("concurrent write to websocket connection")
+	}
+	c.isWriting = true
+	err = c.write(frameType, c.writeDeadline, frameData, nil)
+	if !c.isWriting {
+		panic("concurrent write to websocket connection")
+	}
+	c.isWriting = false
+	return err
+}
+
+// WriteMessage is a helper method for getting a writer using NextWriter,
+// writing the message and closing the writer.
+func (c *Conn) WriteMessage(messageType int, data []byte) error {
+
+	if c.isServer && (c.newCompressionWriter == nil || !c.enableWriteCompression) {
+		// Fast path with no allocations and single frame.
+
+		if err := c.prepWrite(messageType); err != nil {
+			return err
+		}
+		mw := messageWriter{c: c, frameType: messageType, pos: maxFrameHeaderSize}
+		n := copy(c.writeBuf[mw.pos:], data)
+		mw.pos += n
+		data = data[n:]
+		return mw.flushFrame(true, data)
+	}
+
+	w, err := c.NextWriter(messageType)
+	if err != nil {
+		return err
+	}
+	if _, err = w.Write(data); err != nil {
+		return err
+	}
+	return w.Close()
+}
+
+// SetWriteDeadline sets the write deadline on the underlying network
+// connection. After a write has timed out, the websocket state is corrupt and
+// all future writes will return an error. A zero value for t means writes will
+// not time out.
+func (c *Conn) SetWriteDeadline(t time.Time) error {
+	c.writeDeadline = t
+	return nil
+}
+
+// Read methods
+
+func (c *Conn) advanceFrame() (int, error) {
+	// 1. Skip remainder of previous frame.
+
+	if c.readRemaining > 0 {
+		if _, err := io.CopyN(ioutil.Discard, c.br, c.readRemaining); err != nil {
+			return noFrame, err
+		}
+	}
+
+	// 2. Read and parse first two bytes of frame header.
+
+	p, err := c.read(2)
+	if err != nil {
+		return noFrame, err
+	}
+
+	final := p[0]&finalBit != 0
+	frameType := int(p[0] & 0xf)
+	mask := p[1]&maskBit != 0
+	c.readRemaining = int64(p[1] & 0x7f)
+
+	c.readDecompress = false
+	if c.newDecompressionReader != nil && (p[0]&rsv1Bit) != 0 {
+		c.readDecompress = true
+		p[0] &^= rsv1Bit
+	}
+
+	if rsv := p[0] & (rsv1Bit | rsv2Bit | rsv3Bit); rsv != 0 {
+		return noFrame, c.handleProtocolError("unexpected reserved bits 0x" + strconv.FormatInt(int64(rsv), 16))
+	}
+
+	switch frameType {
+	case CloseMessage, PingMessage, PongMessage:
+		if c.readRemaining > maxControlFramePayloadSize {
+			return noFrame, c.handleProtocolError("control frame length > 125")
+		}
+		if !final {
+			return noFrame, c.handleProtocolError("control frame not final")
+		}
+	case TextMessage, BinaryMessage:
+		if !c.readFinal {
+			return noFrame, c.handleProtocolError("message start before final message frame")
+		}
+		c.readFinal = final
+	case continuationFrame:
+		if c.readFinal {
+			return noFrame, c.handleProtocolError("continuation after final message frame")
+		}
+		c.readFinal = final
+	default:
+		return noFrame, c.handleProtocolError("unknown opcode " + strconv.Itoa(frameType))
+	}
+
+	// 3. Read and parse frame length.
+
+	switch c.readRemaining {
+	case 126:
+		p, err := c.read(2)
+		if err != nil {
+			return noFrame, err
+		}
+		c.readRemaining = int64(binary.BigEndian.Uint16(p))
+	case 127:
+		p, err := c.read(8)
+		if err != nil {
+			return noFrame, err
+		}
+		c.readRemaining = int64(binary.BigEndian.Uint64(p))
+	}
+
+	// 4. Handle frame masking.
+
+	if mask != c.isServer {
+		return noFrame, c.handleProtocolError("incorrect mask flag")
+	}
+
+	if mask {
+		c.readMaskPos = 0
+		p, err := c.read(len(c.readMaskKey))
+		if err != nil {
+			return noFrame, err
+		}
+		copy(c.readMaskKey[:], p)
+	}
+
+	// 5. For text and binary messages, enforce read limit and return.
+
+	if frameType == continuationFrame || frameType == TextMessage || frameType == BinaryMessage {
+
+		c.readLength += c.readRemaining
+		if c.readLimit > 0 && c.readLength > c.readLimit {
+			c.WriteControl(CloseMessage, FormatCloseMessage(CloseMessageTooBig, ""), time.Now().Add(writeWait))
+			return noFrame, ErrReadLimit
+		}
+
+		return frameType, nil
+	}
+
+	// 6. Read control frame payload.
+
+	var payload []byte
+	if c.readRemaining > 0 {
+		payload, err = c.read(int(c.readRemaining))
+		c.readRemaining = 0
+		if err != nil {
+			return noFrame, err
+		}
+		if c.isServer {
+			maskBytes(c.readMaskKey, 0, payload)
+		}
+	}
+
+	// 7. Process control frame payload.
+
+	switch frameType {
+	case PongMessage:
+		if err := c.handlePong(string(payload)); err != nil {
+			return noFrame, err
+		}
+	case PingMessage:
+		if err := c.handlePing(string(payload)); err != nil {
+			return noFrame, err
+		}
+	case CloseMessage:
+		closeCode := CloseNoStatusReceived
+		closeText := ""
+		if len(payload) >= 2 {
+			closeCode = int(binary.BigEndian.Uint16(payload))
+			if !isValidReceivedCloseCode(closeCode) {
+				return noFrame, c.handleProtocolError("invalid close code")
+			}
+			closeText = string(payload[2:])
+			if !utf8.ValidString(closeText) {
+				return noFrame, c.handleProtocolError("invalid utf8 payload in close frame")
+			}
+		}
+		if err := c.handleClose(closeCode, closeText); err != nil {
+			return noFrame, err
+		}
+		return noFrame, &CloseError{Code: closeCode, Text: closeText}
+	}
+
+	return frameType, nil
+}
+
+func (c *Conn) handleProtocolError(message string) error {
+	c.WriteControl(CloseMessage, FormatCloseMessage(CloseProtocolError, message), time.Now().Add(writeWait))
+	return errors.New("websocket: " + message)
+}
+
+// NextReader returns the next data message received from the peer. The
+// returned messageType is either TextMessage or BinaryMessage.
+//
+// There can be at most one open reader on a connection. NextReader discards
+// the previous message if the application has not already consumed it.
+//
+// Applications must break out of the application's read loop when this method
+// returns a non-nil error value. Errors returned from this method are
+// permanent. Once this method returns a non-nil error, all subsequent calls to
+// this method return the same error.
+func (c *Conn) NextReader() (messageType int, r io.Reader, err error) {
+	// Close previous reader, only relevant for decompression.
+	if c.reader != nil {
+		c.reader.Close()
+		c.reader = nil
+	}
+
+	c.messageReader = nil
+	c.readLength = 0
+
+	for c.readErr == nil {
+		frameType, err := c.advanceFrame()
+		if err != nil {
+			c.readErr = hideTempErr(err)
+			break
+		}
+		if frameType == TextMessage || frameType == BinaryMessage {
+			c.messageReader = &messageReader{c}
+			c.reader = c.messageReader
+			if c.readDecompress {
+				c.reader = c.newDecompressionReader(c.reader)
+			}
+			return frameType, c.reader, nil
+		}
+	}
+
+	// Applications that do handle the error returned from this method spin in
+	// tight loop on connection failure. To help application developers detect
+	// this error, panic on repeated reads to the failed connection.
+	c.readErrCount++
+	if c.readErrCount >= 1000 {
+		panic("repeated read on failed websocket connection")
+	}
+
+	return noFrame, nil, c.readErr
+}
+
+type messageReader struct{ c *Conn }
+
+func (r *messageReader) Read(b []byte) (int, error) {
+	c := r.c
+	if c.messageReader != r {
+		return 0, io.EOF
+	}
+
+	for c.readErr == nil {
+
+		if c.readRemaining > 0 {
+			if int64(len(b)) > c.readRemaining {
+				b = b[:c.readRemaining]
+			}
+			n, err := c.br.Read(b)
+			c.readErr = hideTempErr(err)
+			if c.isServer {
+				c.readMaskPos = maskBytes(c.readMaskKey, c.readMaskPos, b[:n])
+			}
+			c.readRemaining -= int64(n)
+			if c.readRemaining > 0 && c.readErr == io.EOF {
+				c.readErr = errUnexpectedEOF
+			}
+			return n, c.readErr
+		}
+
+		if c.readFinal {
+			c.messageReader = nil
+			return 0, io.EOF
+		}
+
+		frameType, err := c.advanceFrame()
+		switch {
+		case err != nil:
+			c.readErr = hideTempErr(err)
+		case frameType == TextMessage || frameType == BinaryMessage:
+			c.readErr = errors.New("websocket: internal error, unexpected text or binary in Reader")
+		}
+	}
+
+	err := c.readErr
+	if err == io.EOF && c.messageReader == r {
+		err = errUnexpectedEOF
+	}
+	return 0, err
+}
+
+func (r *messageReader) Close() error {
+	return nil
+}
+
+// ReadMessage is a helper method for getting a reader using NextReader and
+// reading from that reader to a buffer.
+func (c *Conn) ReadMessage() (messageType int, p []byte, err error) {
+	var r io.Reader
+	messageType, r, err = c.NextReader()
+	if err != nil {
+		return messageType, nil, err
+	}
+	p, err = ioutil.ReadAll(r)
+	return messageType, p, err
+}
+
+// SetReadDeadline sets the read deadline on the underlying network connection.
+// After a read has timed out, the websocket connection state is corrupt and
+// all future reads will return an error. A zero value for t means reads will
+// not time out.
+func (c *Conn) SetReadDeadline(t time.Time) error {
+	return c.conn.SetReadDeadline(t)
+}
+
+// SetReadLimit sets the maximum size for a message read from the peer. If a
+// message exceeds the limit, the connection sends a close message to the peer
+// and returns ErrReadLimit to the application.
+func (c *Conn) SetReadLimit(limit int64) {
+	c.readLimit = limit
+}
+
+// CloseHandler returns the current close handler
+func (c *Conn) CloseHandler() func(code int, text string) error {
+	return c.handleClose
+}
+
+// SetCloseHandler sets the handler for close messages received from the peer.
+// The code argument to h is the received close code or CloseNoStatusReceived
+// if the close message is empty. The default close handler sends a close
+// message back to the peer.
+//
+// The handler function is called from the NextReader, ReadMessage and message
+// reader Read methods. The application must read the connection to process
+// close messages as described in the section on Control Messages above.
+//
+// The connection read methods return a CloseError when a close message is
+// received. Most applications should handle close messages as part of their
+// normal error handling. Applications should only set a close handler when the
+// application must perform some action before sending a close message back to
+// the peer.
+func (c *Conn) SetCloseHandler(h func(code int, text string) error) {
+	if h == nil {
+		h = func(code int, text string) error {
+			message := FormatCloseMessage(code, "")
+			c.WriteControl(CloseMessage, message, time.Now().Add(writeWait))
+			return nil
+		}
+	}
+	c.handleClose = h
+}
+
+// PingHandler returns the current ping handler
+func (c *Conn) PingHandler() func(appData string) error {
+	return c.handlePing
+}
+
+// SetPingHandler sets the handler for ping messages received from the peer.
+// The appData argument to h is the PING message application data. The default
+// ping handler sends a pong to the peer.
+//
+// The handler function is called from the NextReader, ReadMessage and message
+// reader Read methods. The application must read the connection to process
+// ping messages as described in the section on Control Messages above.
+func (c *Conn) SetPingHandler(h func(appData string) error) {
+	if h == nil {
+		h = func(message string) error {
+			err := c.WriteControl(PongMessage, []byte(message), time.Now().Add(writeWait))
+			if err == ErrCloseSent {
+				return nil
+			} else if e, ok := err.(net.Error); ok && e.Temporary() {
+				return nil
+			}
+			return err
+		}
+	}
+	c.handlePing = h
+}
+
+// PongHandler returns the current pong handler
+func (c *Conn) PongHandler() func(appData string) error {
+	return c.handlePong
+}
+
+// SetPongHandler sets the handler for pong messages received from the peer.
+// The appData argument to h is the PONG message application data. The default
+// pong handler does nothing.
+//
+// The handler function is called from the NextReader, ReadMessage and message
+// reader Read methods. The application must read the connection to process
+// pong messages as described in the section on Control Messages above.
+func (c *Conn) SetPongHandler(h func(appData string) error) {
+	if h == nil {
+		h = func(string) error { return nil }
+	}
+	c.handlePong = h
+}
+
+// UnderlyingConn returns the internal net.Conn. This can be used to further
+// modifications to connection specific flags.
+func (c *Conn) UnderlyingConn() net.Conn {
+	return c.conn
+}
+
+// EnableWriteCompression enables and disables write compression of
+// subsequent text and binary messages. This function is a noop if
+// compression was not negotiated with the peer.
+func (c *Conn) EnableWriteCompression(enable bool) {
+	c.enableWriteCompression = enable
+}
+
+// SetCompressionLevel sets the flate compression level for subsequent text and
+// binary messages. This function is a noop if compression was not negotiated
+// with the peer. See the compress/flate package for a description of
+// compression levels.
+func (c *Conn) SetCompressionLevel(level int) error {
+	if !isValidCompressionLevel(level) {
+		return errors.New("websocket: invalid compression level")
+	}
+	c.compressionLevel = level
+	return nil
+}
+
+// FormatCloseMessage formats closeCode and text as a WebSocket close message.
+// An empty message is returned for code CloseNoStatusReceived.
+func FormatCloseMessage(closeCode int, text string) []byte {
+	if closeCode == CloseNoStatusReceived {
+		// Return empty message because it's illegal to send
+		// CloseNoStatusReceived. Return non-nil value in case application
+		// checks for nil.
+		return []byte{}
+	}
+	buf := make([]byte, 2+len(text))
+	binary.BigEndian.PutUint16(buf, uint16(closeCode))
+	copy(buf[2:], text)
+	return buf
+}

at-server/vendor/github.com/gorilla/websocket/conn_write.go

@@ -0,0 +1,15 @@
+// Copyright 2016 The Gorilla WebSocket Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build go1.8
+
+package websocket
+
+import "net"
+
+func (c *Conn) writeBufs(bufs ...[]byte) error {
+	b := net.Buffers(bufs)
+	_, err := b.WriteTo(c.conn)
+	return err
+}

at-server/vendor/github.com/gorilla/websocket/conn_write_legacy.go

@@ -0,0 +1,18 @@
+// Copyright 2016 The Gorilla WebSocket Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build !go1.8
+
+package websocket
+
+func (c *Conn) writeBufs(bufs ...[]byte) error {
+	for _, buf := range bufs {
+		if len(buf) > 0 {
+			if _, err := c.conn.Write(buf); err != nil {
+				return err
+			}
+		}
+	}
+	return nil
+}

at-server/vendor/github.com/gorilla/websocket/doc.go

@@ -0,0 +1,180 @@
+// Copyright 2013 The Gorilla WebSocket Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package websocket implements the WebSocket protocol defined in RFC 6455.
+//
+// Overview
+//
+// The Conn type represents a WebSocket connection. A server application calls
+// the Upgrader.Upgrade method from an HTTP request handler to get a *Conn:
+//
+//  var upgrader = websocket.Upgrader{
+//      ReadBufferSize:  1024,
+//      WriteBufferSize: 1024,
+//  }
+//
+//  func handler(w http.ResponseWriter, r *http.Request) {
+//      conn, err := upgrader.Upgrade(w, r, nil)
+//      if err != nil {
+//          log.Println(err)
+//          return
+//      }
+//      ... Use conn to send and receive messages.
+//  }
+//
+// Call the connection's WriteMessage and ReadMessage methods to send and
+// receive messages as a slice of bytes. This snippet of code shows how to echo
+// messages using these methods:
+//
+//  for {
+//      messageType, p, err := conn.ReadMessage()
+//      if err != nil {
+//          log.Println(err)
+//          return
+//      }
+//      if err := conn.WriteMessage(messageType, p); err != nil {
+//          log.Println(err)
+//          return
+//      }
+//  }
+//
+// In above snippet of code, p is a []byte and messageType is an int with value
+// websocket.BinaryMessage or websocket.TextMessage.
+//
+// An application can also send and receive messages using the io.WriteCloser
+// and io.Reader interfaces. To send a message, call the connection NextWriter
+// method to get an io.WriteCloser, write the message to the writer and close
+// the writer when done. To receive a message, call the connection NextReader
+// method to get an io.Reader and read until io.EOF is returned. This snippet
+// shows how to echo messages using the NextWriter and NextReader methods:
+//
+//  for {
+//      messageType, r, err := conn.NextReader()
+//      if err != nil {
+//          return
+//      }
+//      w, err := conn.NextWriter(messageType)
+//      if err != nil {
+//          return err
+//      }
+//      if _, err := io.Copy(w, r); err != nil {
+//          return err
+//      }
+//      if err := w.Close(); err != nil {
+//          return err
+//      }
+//  }
+//
+// Data Messages
+//
+// The WebSocket protocol distinguishes between text and binary data messages.
+// Text messages are interpreted as UTF-8 encoded text. The interpretation of
+// binary messages is left to the application.
+//
+// This package uses the TextMessage and BinaryMessage integer constants to
+// identify the two data message types. The ReadMessage and NextReader methods
+// return the type of the received message. The messageType argument to the
+// WriteMessage and NextWriter methods specifies the type of a sent message.
+//
+// It is the application's responsibility to ensure that text messages are
+// valid UTF-8 encoded text.
+//
+// Control Messages
+//
+// The WebSocket protocol defines three types of control messages: close, ping
+// and pong. Call the connection WriteControl, WriteMessage or NextWriter
+// methods to send a control message to the peer.
+//
+// Connections handle received close messages by calling the handler function
+// set with the SetCloseHandler method and by returning a *CloseError from the
+// NextReader, ReadMessage or the message Read method. The default close
+// handler sends a close message to the peer.
+//
+// Connections handle received ping messages by calling the handler function
+// set with the SetPingHandler method. The default ping handler sends a pong
+// message to the peer.
+//
+// Connections handle received pong messages by calling the handler function
+// set with the SetPongHandler method. The default pong handler does nothing.
+// If an application sends ping messages, then the application should set a
+// pong handler to receive the corresponding pong.
+//
+// The control message handler functions are called from the NextReader,
+// ReadMessage and message reader Read methods. The default close and ping
+// handlers can block these methods for a short time when the handler writes to
+// the connection.
+//
+// The application must read the connection to process close, ping and pong
+// messages sent from the peer. If the application is not otherwise interested
+// in messages from the peer, then the application should start a goroutine to
+// read and discard messages from the peer. A simple example is:
+//
+//  func readLoop(c *websocket.Conn) {
+//      for {
+//          if _, _, err := c.NextReader(); err != nil {
+//              c.Close()
+//              break
+//          }
+//      }
+//  }
+//
+// Concurrency
+//
+// Connections support one concurrent reader and one concurrent writer.
+//
+// Applications are responsible for ensuring that no more than one goroutine
+// calls the write methods (NextWriter, SetWriteDeadline, WriteMessage,
+// WriteJSON, EnableWriteCompression, SetCompressionLevel) concurrently and
+// that no more than one goroutine calls the read methods (NextReader,
+// SetReadDeadline, ReadMessage, ReadJSON, SetPongHandler, SetPingHandler)
+// concurrently.
+//
+// The Close and WriteControl methods can be called concurrently with all other
+// methods.
+//
+// Origin Considerations
+//
+// Web browsers allow Javascript applications to open a WebSocket connection to
+// any host. It's up to the server to enforce an origin policy using the Origin
+// request header sent by the browser.
+//
+// The Upgrader calls the function specified in the CheckOrigin field to check
+// the origin. If the CheckOrigin function returns false, then the Upgrade
+// method fails the WebSocket handshake with HTTP status 403.
+//
+// If the CheckOrigin field is nil, then the Upgrader uses a safe default: fail
+// the handshake if the Origin request header is present and the Origin host is
+// not equal to the Host request header.
+//
+// The deprecated package-level Upgrade function does not perform origin
+// checking. The application is responsible for checking the Origin header
+// before calling the Upgrade function.
+//
+// Compression EXPERIMENTAL
+//
+// Per message compression extensions (RFC 7692) are experimentally supported
+// by this package in a limited capacity. Setting the EnableCompression option
+// to true in Dialer or Upgrader will attempt to negotiate per message deflate
+// support.
+//
+//  var upgrader = websocket.Upgrader{
+//      EnableCompression: true,
+//  }
+//
+// If compression was successfully negotiated with the connection's peer, any
+// message received in compressed form will be automatically decompressed.
+// All Read methods will return uncompressed bytes.
+//
+// Per message compression of messages written to a connection can be enabled
+// or disabled by calling the corresponding Conn method:
+//
+//  conn.EnableWriteCompression(false)
+//
+// Currently this package does not support compression with "context takeover".
+// This means that messages must be compressed and decompressed in isolation,
+// without retaining sliding window or dictionary state across messages. For
+// more details refer to RFC 7692.
+//
+// Use of compression is experimental and may result in decreased performance.
+package websocket

at-server/vendor/github.com/gorilla/websocket/json.go

@@ -0,0 +1,60 @@
+// Copyright 2013 The Gorilla WebSocket Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package websocket
+
+import (
+	"encoding/json"
+	"io"
+)
+
+// WriteJSON writes the JSON encoding of v as a message.
+//
+// Deprecated: Use c.WriteJSON instead.
+func WriteJSON(c *Conn, v interface{}) error {
+	return c.WriteJSON(v)
+}
+
+// WriteJSON writes the JSON encoding of v as a message.
+//
+// See the documentation for encoding/json Marshal for details about the
+// conversion of Go values to JSON.
+func (c *Conn) WriteJSON(v interface{}) error {
+	w, err := c.NextWriter(TextMessage)
+	if err != nil {
+		return err
+	}
+	err1 := json.NewEncoder(w).Encode(v)
+	err2 := w.Close()
+	if err1 != nil {
+		return err1
+	}
+	return err2
+}
+
+// ReadJSON reads the next JSON-encoded message from the connection and stores
+// it in the value pointed to by v.
+//
+// Deprecated: Use c.ReadJSON instead.
+func ReadJSON(c *Conn, v interface{}) error {
+	return c.ReadJSON(v)
+}
+
+// ReadJSON reads the next JSON-encoded message from the connection and stores
+// it in the value pointed to by v.
+//
+// See the documentation for the encoding/json Unmarshal function for details
+// about the conversion of JSON to a Go value.
+func (c *Conn) ReadJSON(v interface{}) error {
+	_, r, err := c.NextReader()
+	if err != nil {
+		return err
+	}
+	err = json.NewDecoder(r).Decode(v)
+	if err == io.EOF {
+		// One value is expected in the message.
+		err = io.ErrUnexpectedEOF
+	}
+	return err
+}

at-server/vendor/github.com/gorilla/websocket/mask.go

@@ -0,0 +1,54 @@
+// Copyright 2016 The Gorilla WebSocket Authors. All rights reserved.  Use of
+// this source code is governed by a BSD-style license that can be found in the
+// LICENSE file.
+
+// +build !appengine
+
+package websocket
+
+import "unsafe"
+
+const wordSize = int(unsafe.Sizeof(uintptr(0)))
+
+func maskBytes(key [4]byte, pos int, b []byte) int {
+	// Mask one byte at a time for small buffers.
+	if len(b) < 2*wordSize {
+		for i := range b {
+			b[i] ^= key[pos&3]
+			pos++
+		}
+		return pos & 3
+	}
+
+	// Mask one byte at a time to word boundary.
+	if n := int(uintptr(unsafe.Pointer(&b[0]))) % wordSize; n != 0 {
+		n = wordSize - n
+		for i := range b[:n] {
+			b[i] ^= key[pos&3]
+			pos++
+		}
+		b = b[n:]
+	}
+
+	// Create aligned word size key.
+	var k [wordSize]byte
+	for i := range k {
+		k[i] = key[(pos+i)&3]
+	}
+	kw := *(*uintptr)(unsafe.Pointer(&k))
+
+	// Mask one word at a time.
+	n := (len(b) / wordSize) * wordSize
+	for i := 0; i < n; i += wordSize {
+		*(*uintptr)(unsafe.Pointer(uintptr(unsafe.Pointer(&b[0])) + uintptr(i))) ^= kw
+	}
+
+	// Mask one byte at a time for remaining bytes.
+	b = b[n:]
+	for i := range b {
+		b[i] ^= key[pos&3]
+		pos++
+	}
+
+	return pos & 3
+}

at-server/vendor/github.com/gorilla/websocket/mask_safe.go

@@ -0,0 +1,15 @@
+// Copyright 2016 The Gorilla WebSocket Authors. All rights reserved.  Use of
+// this source code is governed by a BSD-style license that can be found in the
+// LICENSE file.
+
+// +build appengine
+
+package websocket
+
+func maskBytes(key [4]byte, pos int, b []byte) int {
+	for i := range b {
+		b[i] ^= key[pos&3]
+		pos++
+	}
+	return pos & 3
+}

at-server/vendor/github.com/gorilla/websocket/prepared.go

@@ -0,0 +1,102 @@
+// Copyright 2017 The Gorilla WebSocket Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package websocket
+
+import (
+	"bytes"
+	"net"
+	"sync"
+	"time"
+)
+
+// PreparedMessage caches on the wire representations of a message payload.
+// Use PreparedMessage to efficiently send a message payload to multiple
+// connections. PreparedMessage is especially useful when compression is used
+// because the CPU and memory expensive compression operation can be executed
+// once for a given set of compression options.
+type PreparedMessage struct {
+	messageType int
+	data        []byte
+	mu          sync.Mutex
+	frames      map[prepareKey]*preparedFrame
+}
+
+// prepareKey defines a unique set of options to cache prepared frames in PreparedMessage.
+type prepareKey struct {
+	isServer         bool
+	compress         bool
+	compressionLevel int
+}
+
+// preparedFrame contains data in wire representation.
+type preparedFrame struct {
+	once sync.Once
+	data []byte
+}
+
+// NewPreparedMessage returns an initialized PreparedMessage. You can then send
+// it to connection using WritePreparedMessage method. Valid wire
+// representation will be calculated lazily only once for a set of current
+// connection options.
+func NewPreparedMessage(messageType int, data []byte) (*PreparedMessage, error) {
+	pm := &PreparedMessage{
+		messageType: messageType,
+		frames:      make(map[prepareKey]*preparedFrame),
+		data:        data,
+	}
+
+	// Prepare a plain server frame.
+	_, frameData, err := pm.frame(prepareKey{isServer: true, compress: false})
+	if err != nil {
+		return nil, err
+	}
+
+	// To protect against caller modifying the data argument, remember the data
+	// copied to the plain server frame.
+	pm.data = frameData[len(frameData)-len(data):]
+	return pm, nil
+}
+
+func (pm *PreparedMessage) frame(key prepareKey) (int, []byte, error) {
+	pm.mu.Lock()
+	frame, ok := pm.frames[key]
+	if !ok {
+		frame = &preparedFrame{}
+		pm.frames[key] = frame
+	}
+	pm.mu.Unlock()
+
+	var err error
+	frame.once.Do(func() {
+		// Prepare a frame using a 'fake' connection.
+		// TODO: Refactor code in conn.go to allow more direct construction of
+		// the frame.
+		mu := make(chan bool, 1)
+		mu <- true
+		var nc prepareConn
+		c := &Conn{
+			conn:                   &nc,
+			mu:                     mu,
+			isServer:               key.isServer,
+			compressionLevel:       key.compressionLevel,
+			enableWriteCompression: true,
+			writeBuf:               make([]byte, defaultWriteBufferSize+maxFrameHeaderSize),
+		}
+		if key.compress {
+			c.newCompressionWriter = compressNoContextTakeover
+		}
+		err = c.WriteMessage(pm.messageType, pm.data)
+		frame.data = nc.buf.Bytes()
+	})
+	return pm.messageType, frame.data, err
+}
+
+type prepareConn struct {
+	buf bytes.Buffer
+	net.Conn
+}
+
+func (pc *prepareConn) Write(p []byte) (int, error)        { return pc.buf.Write(p) }
+func (pc *prepareConn) SetWriteDeadline(t time.Time) error { return nil }

at-server/vendor/github.com/gorilla/websocket/proxy.go

@@ -0,0 +1,77 @@
+// Copyright 2017 The Gorilla WebSocket Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package websocket
+
+import (
+	"bufio"
+	"encoding/base64"
+	"errors"
+	"net"
+	"net/http"
+	"net/url"
+	"strings"
+)
+
+type netDialerFunc func(network, addr string) (net.Conn, error)
+
+func (fn netDialerFunc) Dial(network, addr string) (net.Conn, error) {
+	return fn(network, addr)
+}
+
+func init() {
+	proxy_RegisterDialerType("http", func(proxyURL *url.URL, forwardDialer proxy_Dialer) (proxy_Dialer, error) {
+		return &httpProxyDialer{proxyURL: proxyURL, fowardDial: forwardDialer.Dial}, nil
+	})
+}
+
+type httpProxyDialer struct {
+	proxyURL   *url.URL
+	fowardDial func(network, addr string) (net.Conn, error)
+}
+
+func (hpd *httpProxyDialer) Dial(network string, addr string) (net.Conn, error) {
+	hostPort, _ := hostPortNoPort(hpd.proxyURL)
+	conn, err := hpd.fowardDial(network, hostPort)
+	if err != nil {
+		return nil, err
+	}
+
+	connectHeader := make(http.Header)
+	if user := hpd.proxyURL.User; user != nil {
+		proxyUser := user.Username()
+		if proxyPassword, passwordSet := user.Password(); passwordSet {
+			credential := base64.StdEncoding.EncodeToString([]byte(proxyUser + ":" + proxyPassword))
+			connectHeader.Set("Proxy-Authorization", "Basic "+credential)
+		}
+	}
+
+	connectReq := &http.Request{
+		Method: "CONNECT",
+		URL:    &url.URL{Opaque: addr},
+		Host:   addr,
+		Header: connectHeader,
+	}
+
+	if err := connectReq.Write(conn); err != nil {
+		conn.Close()
+		return nil, err
+	}
+
+	// Read response. It's OK to use and discard buffered reader here becaue
+	// the remote server does not speak until spoken to.
+	br := bufio.NewReader(conn)
+	resp, err := http.ReadResponse(br, connectReq)
+	if err != nil {
+		conn.Close()
+		return nil, err
+	}
+
+	if resp.StatusCode != 200 {
+		conn.Close()
+		f := strings.SplitN(resp.Status, " ", 2)
+		return nil, errors.New(f[1])
+	}
+	return conn, nil
+}

at-server/vendor/github.com/gorilla/websocket/server.go

@@ -0,0 +1,363 @@
+// Copyright 2013 The Gorilla WebSocket Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package websocket
+
+import (
+	"bufio"
+	"errors"
+	"io"
+	"net/http"
+	"net/url"
+	"strings"
+	"time"
+)
+
+// HandshakeError describes an error with the handshake from the peer.
+type HandshakeError struct {
+	message string
+}
+
+func (e HandshakeError) Error() string { return e.message }
+
+// Upgrader specifies parameters for upgrading an HTTP connection to a
+// WebSocket connection.
+type Upgrader struct {
+	// HandshakeTimeout specifies the duration for the handshake to complete.
+	HandshakeTimeout time.Duration
+
+	// ReadBufferSize and WriteBufferSize specify I/O buffer sizes. If a buffer
+	// size is zero, then buffers allocated by the HTTP server are used. The
+	// I/O buffer sizes do not limit the size of the messages that can be sent
+	// or received.
+	ReadBufferSize, WriteBufferSize int
+
+	// WriteBufferPool is a pool of buffers for write operations. If the value
+	// is not set, then write buffers are allocated to the connection for the
+	// lifetime of the connection.
+	//
+	// A pool is most useful when the application has a modest volume of writes
+	// across a large number of connections.
+	//
+	// Applications should use a single pool for each unique value of
+	// WriteBufferSize.
+	WriteBufferPool BufferPool
+
+	// Subprotocols specifies the server's supported protocols in order of
+	// preference. If this field is not nil, then the Upgrade method negotiates a
+	// subprotocol by selecting the first match in this list with a protocol
+	// requested by the client. If there's no match, then no protocol is
+	// negotiated (the Sec-Websocket-Protocol header is not included in the
+	// handshake response).
+	Subprotocols []string
+
+	// Error specifies the function for generating HTTP error responses. If Error
+	// is nil, then http.Error is used to generate the HTTP response.
+	Error func(w http.ResponseWriter, r *http.Request, status int, reason error)
+
+	// CheckOrigin returns true if the request Origin header is acceptable. If
+	// CheckOrigin is nil, then a safe default is used: return false if the
+	// Origin request header is present and the origin host is not equal to
+	// request Host header.
+	//
+	// A CheckOrigin function should carefully validate the request origin to
+	// prevent cross-site request forgery.
+	CheckOrigin func(r *http.Request) bool
+
+	// EnableCompression specify if the server should attempt to negotiate per
+	// message compression (RFC 7692). Setting this value to true does not
+	// guarantee that compression will be supported. Currently only "no context
+	// takeover" modes are supported.
+	EnableCompression bool
+}
+
+func (u *Upgrader) returnError(w http.ResponseWriter, r *http.Request, status int, reason string) (*Conn, error) {
+	err := HandshakeError{reason}
+	if u.Error != nil {
+		u.Error(w, r, status, err)
+	} else {
+		w.Header().Set("Sec-Websocket-Version", "13")
+		http.Error(w, http.StatusText(status), status)
+	}
+	return nil, err
+}
+
+// checkSameOrigin returns true if the origin is not set or is equal to the request host.
+func checkSameOrigin(r *http.Request) bool {
+	origin := r.Header["Origin"]
+	if len(origin) == 0 {
+		return true
+	}
+	u, err := url.Parse(origin[0])
+	if err != nil {
+		return false
+	}
+	return equalASCIIFold(u.Host, r.Host)
+}
+
+func (u *Upgrader) selectSubprotocol(r *http.Request, responseHeader http.Header) string {
+	if u.Subprotocols != nil {
+		clientProtocols := Subprotocols(r)
+		for _, serverProtocol := range u.Subprotocols {
+			for _, clientProtocol := range clientProtocols {
+				if clientProtocol == serverProtocol {
+					return clientProtocol
+				}
+			}
+		}
+	} else if responseHeader != nil {
+		return responseHeader.Get("Sec-Websocket-Protocol")
+	}
+	return ""
+}
+
+// Upgrade upgrades the HTTP server connection to the WebSocket protocol.
+//
+// The responseHeader is included in the response to the client's upgrade
+// request. Use the responseHeader to specify cookies (Set-Cookie) and the
+// application negotiated subprotocol (Sec-WebSocket-Protocol).
+//
+// If the upgrade fails, then Upgrade replies to the client with an HTTP error
+// response.
+func (u *Upgrader) Upgrade(w http.ResponseWriter, r *http.Request, responseHeader http.Header) (*Conn, error) {
+	const badHandshake = "websocket: the client is not using the websocket protocol: "
+
+	if !tokenListContainsValue(r.Header, "Connection", "upgrade") {
+		return u.returnError(w, r, http.StatusBadRequest, badHandshake+"'upgrade' token not found in 'Connection' header")
+	}
+
+	if !tokenListContainsValue(r.Header, "Upgrade", "websocket") {
+		return u.returnError(w, r, http.StatusBadRequest, badHandshake+"'websocket' token not found in 'Upgrade' header")
+	}
+
+	if r.Method != "GET" {
+		return u.returnError(w, r, http.StatusMethodNotAllowed, badHandshake+"request method is not GET")
+	}
+
+	if !tokenListContainsValue(r.Header, "Sec-Websocket-Version", "13") {
+		return u.returnError(w, r, http.StatusBadRequest, "websocket: unsupported version: 13 not found in 'Sec-Websocket-Version' header")
+	}
+
+	if _, ok := responseHeader["Sec-Websocket-Extensions"]; ok {
+		return u.returnError(w, r, http.StatusInternalServerError, "websocket: application specific 'Sec-WebSocket-Extensions' headers are unsupported")
+	}
+
+	checkOrigin := u.CheckOrigin
+	if checkOrigin == nil {
+		checkOrigin = checkSameOrigin
+	}
+	if !checkOrigin(r) {
+		return u.returnError(w, r, http.StatusForbidden, "websocket: request origin not allowed by Upgrader.CheckOrigin")
+	}
+
+	challengeKey := r.Header.Get("Sec-Websocket-Key")
+	if challengeKey == "" {
+		return u.returnError(w, r, http.StatusBadRequest, "websocket: not a websocket handshake: `Sec-WebSocket-Key' header is missing or blank")
+	}
+
+	subprotocol := u.selectSubprotocol(r, responseHeader)
+
+	// Negotiate PMCE
+	var compress bool
+	if u.EnableCompression {
+		for _, ext := range parseExtensions(r.Header) {
+			if ext[""] != "permessage-deflate" {
+				continue
+			}
+			compress = true
+			break
+		}
+	}
+
+	h, ok := w.(http.Hijacker)
+	if !ok {
+		return u.returnError(w, r, http.StatusInternalServerError, "websocket: response does not implement http.Hijacker")
+	}
+	var brw *bufio.ReadWriter
+	netConn, brw, err := h.Hijack()
+	if err != nil {
+		return u.returnError(w, r, http.StatusInternalServerError, err.Error())
+	}
+
+	if brw.Reader.Buffered() > 0 {
+		netConn.Close()
+		return nil, errors.New("websocket: client sent data before handshake is complete")
+	}
+
+	var br *bufio.Reader
+	if u.ReadBufferSize == 0 && bufioReaderSize(netConn, brw.Reader) > 256 {
+		// Reuse hijacked buffered reader as connection reader.
+		br = brw.Reader
+	}
+
+	buf := bufioWriterBuffer(netConn, brw.Writer)
+
+	var writeBuf []byte
+	if u.WriteBufferPool == nil && u.WriteBufferSize == 0 && len(buf) >= maxFrameHeaderSize+256 {
+		// Reuse hijacked write buffer as connection buffer.
+		writeBuf = buf
+	}
+
+	c := newConn(netConn, true, u.ReadBufferSize, u.WriteBufferSize, u.WriteBufferPool, br, writeBuf)
+	c.subprotocol = subprotocol
+
+	if compress {
+		c.newCompressionWriter = compressNoContextTakeover
+		c.newDecompressionReader = decompressNoContextTakeover
+	}
+
+	// Use larger of hijacked buffer and connection write buffer for header.
+	p := buf
+	if len(c.writeBuf) > len(p) {
+		p = c.writeBuf
+	}
+	p = p[:0]
+
+	p = append(p, "HTTP/1.1 101 Switching Protocols\r\nUpgrade: websocket\r\nConnection: Upgrade\r\nSec-WebSocket-Accept: "...)
+	p = append(p, computeAcceptKey(challengeKey)...)
+	p = append(p, "\r\n"...)
+	if c.subprotocol != "" {
+		p = append(p, "Sec-WebSocket-Protocol: "...)
+		p = append(p, c.subprotocol...)
+		p = append(p, "\r\n"...)
+	}
+	if compress {
+		p = append(p, "Sec-WebSocket-Extensions: permessage-deflate; server_no_context_takeover; client_no_context_takeover\r\n"...)
+	}
+	for k, vs := range responseHeader {
+		if k == "Sec-Websocket-Protocol" {
+			continue
+		}
+		for _, v := range vs {
+			p = append(p, k...)
+			p = append(p, ": "...)
+			for i := 0; i < len(v); i++ {
+				b := v[i]
+				if b <= 31 {
+					// prevent response splitting.
+					b = ' '
+				}
+				p = append(p, b)
+			}
+			p = append(p, "\r\n"...)
+		}
+	}
+	p = append(p, "\r\n"...)
+
+	// Clear deadlines set by HTTP server.
+	netConn.SetDeadline(time.Time{})
+
+	if u.HandshakeTimeout > 0 {
+		netConn.SetWriteDeadline(time.Now().Add(u.HandshakeTimeout))
+	}
+	if _, err = netConn.Write(p); err != nil {
+		netConn.Close()
+		return nil, err
+	}
+	if u.HandshakeTimeout > 0 {
+		netConn.SetWriteDeadline(time.Time{})
+	}
+
+	return c, nil
+}
+
+// Upgrade upgrades the HTTP server connection to the WebSocket protocol.
+//
+// Deprecated: Use websocket.Upgrader instead.
+//
+// Upgrade does not perform origin checking. The application is responsible for
+// checking the Origin header before calling Upgrade. An example implementation
+// of the same origin policy check is:
+//
+//	if req.Header.Get("Origin") != "http://"+req.Host {
+//		http.Error(w, "Origin not allowed", http.StatusForbidden)
+//		return
+//	}
+//
+// If the endpoint supports subprotocols, then the application is responsible
+// for negotiating the protocol used on the connection. Use the Subprotocols()
+// function to get the subprotocols requested by the client. Use the
+// Sec-Websocket-Protocol response header to specify the subprotocol selected
+// by the application.
+//
+// The responseHeader is included in the response to the client's upgrade
+// request. Use the responseHeader to specify cookies (Set-Cookie) and the
+// negotiated subprotocol (Sec-Websocket-Protocol).
+//
+// The connection buffers IO to the underlying network connection. The
+// readBufSize and writeBufSize parameters specify the size of the buffers to
+// use. Messages can be larger than the buffers.
+//
+// If the request is not a valid WebSocket handshake, then Upgrade returns an
+// error of type HandshakeError. Applications should handle this error by
+// replying to the client with an HTTP error response.
+func Upgrade(w http.ResponseWriter, r *http.Request, responseHeader http.Header, readBufSize, writeBufSize int) (*Conn, error) {
+	u := Upgrader{ReadBufferSize: readBufSize, WriteBufferSize: writeBufSize}
+	u.Error = func(w http.ResponseWriter, r *http.Request, status int, reason error) {
+		// don't return errors to maintain backwards compatibility
+	}
+	u.CheckOrigin = func(r *http.Request) bool {
+		// allow all connections by default
+		return true
+	}
+	return u.Upgrade(w, r, responseHeader)
+}
+
+// Subprotocols returns the subprotocols requested by the client in the
+// Sec-Websocket-Protocol header.
+func Subprotocols(r *http.Request) []string {
+	h := strings.TrimSpace(r.Header.Get("Sec-Websocket-Protocol"))
+	if h == "" {
+		return nil
+	}
+	protocols := strings.Split(h, ",")
+	for i := range protocols {
+		protocols[i] = strings.TrimSpace(protocols[i])
+	}
+	return protocols
+}
+
+// IsWebSocketUpgrade returns true if the client requested upgrade to the
+// WebSocket protocol.
+func IsWebSocketUpgrade(r *http.Request) bool {
+	return tokenListContainsValue(r.Header, "Connection", "upgrade") &&
+		tokenListContainsValue(r.Header, "Upgrade", "websocket")
+}
+
+// bufioReaderSize size returns the size of a bufio.Reader.
+func bufioReaderSize(originalReader io.Reader, br *bufio.Reader) int {
+	// This code assumes that peek on a reset reader returns
+	// bufio.Reader.buf[:0].
+	// TODO: Use bufio.Reader.Size() after Go 1.10
+	br.Reset(originalReader)
+	if p, err := br.Peek(0); err == nil {
+		return cap(p)
+	}
+	return 0
+}
+
+// writeHook is an io.Writer that records the last slice passed to it vio
+// io.Writer.Write.
+type writeHook struct {
+	p []byte
+}
+
+func (wh *writeHook) Write(p []byte) (int, error) {
+	wh.p = p
+	return len(p), nil
+}
+
+// bufioWriterBuffer grabs the buffer from a bufio.Writer.
+func bufioWriterBuffer(originalWriter io.Writer, bw *bufio.Writer) []byte {
+	// This code assumes that bufio.Writer.buf[:1] is passed to the
+	// bufio.Writer's underlying writer.
+	var wh writeHook
+	bw.Reset(&wh)
+	bw.WriteByte(0)
+	bw.Flush()
+
+	bw.Reset(originalWriter)
+
+	return wh.p[:cap(wh.p)]
+}

at-server/vendor/github.com/gorilla/websocket/trace.go

@@ -0,0 +1,19 @@
+// +build go1.8
+
+package websocket
+
+import (
+	"crypto/tls"
+	"net/http/httptrace"
+)
+
+func doHandshakeWithTrace(trace *httptrace.ClientTrace, tlsConn *tls.Conn, cfg *tls.Config) error {
+	if trace.TLSHandshakeStart != nil {
+		trace.TLSHandshakeStart()
+	}
+	err := doHandshake(tlsConn, cfg)
+	if trace.TLSHandshakeDone != nil {
+		trace.TLSHandshakeDone(tlsConn.ConnectionState(), err)
+	}
+	return err
+}

at-server/vendor/github.com/gorilla/websocket/trace_17.go

@@ -0,0 +1,12 @@
+// +build !go1.8
+
+package websocket
+
+import (
+	"crypto/tls"
+	"net/http/httptrace"
+)
+
+func doHandshakeWithTrace(trace *httptrace.ClientTrace, tlsConn *tls.Conn, cfg *tls.Config) error {
+	return doHandshake(tlsConn, cfg)
+}

at-server/vendor/github.com/gorilla/websocket/util.go

@@ -0,0 +1,237 @@
+// Copyright 2013 The Gorilla WebSocket Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package websocket
+
+import (
+	"crypto/rand"
+	"crypto/sha1"
+	"encoding/base64"
+	"io"
+	"net/http"
+	"strings"
+	"unicode/utf8"
+)
+
+var keyGUID = []byte("258EAFA5-E914-47DA-95CA-C5AB0DC85B11")
+
+func computeAcceptKey(challengeKey string) string {
+	h := sha1.New()
+	h.Write([]byte(challengeKey))
+	h.Write(keyGUID)
+	return base64.StdEncoding.EncodeToString(h.Sum(nil))
+}
+
+func generateChallengeKey() (string, error) {
+	p := make([]byte, 16)
+	if _, err := io.ReadFull(rand.Reader, p); err != nil {
+		return "", err
+	}
+	return base64.StdEncoding.EncodeToString(p), nil
+}
+
+// Octet types from RFC 2616.
+var octetTypes [256]byte
+
+const (
+	isTokenOctet = 1 << iota
+	isSpaceOctet
+)
+
+func init() {
+	// From RFC 2616
+	//
+	// OCTET      = <any 8-bit sequence of data>
+	// CHAR       = <any US-ASCII character (octets 0 - 127)>
+	// CTL        = <any US-ASCII control character (octets 0 - 31) and DEL (127)>
+	// CR         = <US-ASCII CR, carriage return (13)>
+	// LF         = <US-ASCII LF, linefeed (10)>
+	// SP         = <US-ASCII SP, space (32)>
+	// HT         = <US-ASCII HT, horizontal-tab (9)>
+	// <">        = <US-ASCII double-quote mark (34)>
+	// CRLF       = CR LF
+	// LWS        = [CRLF] 1*( SP | HT )
+	// TEXT       = <any OCTET except CTLs, but including LWS>
+	// separators = "(" | ")" | "<" | ">" | "@" | "," | ";" | ":" | "\" | <">
+	//              | "/" | "[" | "]" | "?" | "=" | "{" | "}" | SP | HT
+	// token      = 1*<any CHAR except CTLs or separators>
+	// qdtext     = <any TEXT except <">>
+
+	for c := 0; c < 256; c++ {
+		var t byte
+		isCtl := c <= 31 || c == 127
+		isChar := 0 <= c && c <= 127
+		isSeparator := strings.IndexRune(" \t\"(),/:;<=>?@[]\\{}", rune(c)) >= 0
+		if strings.IndexRune(" \t\r\n", rune(c)) >= 0 {
+			t |= isSpaceOctet
+		}
+		if isChar && !isCtl && !isSeparator {
+			t |= isTokenOctet
+		}
+		octetTypes[c] = t
+	}
+}
+
+func skipSpace(s string) (rest string) {
+	i := 0
+	for ; i < len(s); i++ {
+		if octetTypes[s[i]]&isSpaceOctet == 0 {
+			break
+		}
+	}
+	return s[i:]
+}
+
+func nextToken(s string) (token, rest string) {
+	i := 0
+	for ; i < len(s); i++ {
+		if octetTypes[s[i]]&isTokenOctet == 0 {
+			break
+		}
+	}
+	return s[:i], s[i:]
+}
+
+func nextTokenOrQuoted(s string) (value string, rest string) {
+	if !strings.HasPrefix(s, "\"") {
+		return nextToken(s)
+	}
+	s = s[1:]
+	for i := 0; i < len(s); i++ {
+		switch s[i] {
+		case '"':
+			return s[:i], s[i+1:]
+		case '\\':
+			p := make([]byte, len(s)-1)
+			j := copy(p, s[:i])
+			escape := true
+			for i = i + 1; i < len(s); i++ {
+				b := s[i]
+				switch {
+				case escape:
+					escape = false
+					p[j] = b
+					j++
+				case b == '\\':
+					escape = true
+				case b == '"':
+					return string(p[:j]), s[i+1:]
+				default:
+					p[j] = b
+					j++
+				}
+			}
+			return "", ""
+		}
+	}
+	return "", ""
+}
+
+// equalASCIIFold returns true if s is equal to t with ASCII case folding.
+func equalASCIIFold(s, t string) bool {
+	for s != "" && t != "" {
+		sr, size := utf8.DecodeRuneInString(s)
+		s = s[size:]
+		tr, size := utf8.DecodeRuneInString(t)
+		t = t[size:]
+		if sr == tr {
+			continue
+		}
+		if 'A' <= sr && sr <= 'Z' {
+			sr = sr + 'a' - 'A'
+		}
+		if 'A' <= tr && tr <= 'Z' {
+			tr = tr + 'a' - 'A'
+		}
+		if sr != tr {
+			return false
+		}
+	}
+	return s == t
+}
+
+// tokenListContainsValue returns true if the 1#token header with the given
+// name contains a token equal to value with ASCII case folding.
+func tokenListContainsValue(header http.Header, name string, value string) bool {
+headers:
+	for _, s := range header[name] {
+		for {
+			var t string
+			t, s = nextToken(skipSpace(s))
+			if t == "" {
+				continue headers
+			}
+			s = skipSpace(s)
+			if s != "" && s[0] != ',' {
+				continue headers
+			}
+			if equalASCIIFold(t, value) {
+				return true
+			}
+			if s == "" {
+				continue headers
+			}
+			s = s[1:]
+		}
+	}
+	return false
+}
+
+// parseExtensions parses WebSocket extensions from a header.
+func parseExtensions(header http.Header) []map[string]string {
+	// From RFC 6455:
+	//
+	//  Sec-WebSocket-Extensions = extension-list
+	//  extension-list = 1#extension
+	//  extension = extension-token *( ";" extension-param )
+	//  extension-token = registered-token
+	//  registered-token = token
+	//  extension-param = token [ "=" (token | quoted-string) ]
+	//     ;When using the quoted-string syntax variant, the value
+	//     ;after quoted-string unescaping MUST conform to the
+	//     ;'token' ABNF.
+
+	var result []map[string]string
+headers:
+	for _, s := range header["Sec-Websocket-Extensions"] {
+		for {
+			var t string
+			t, s = nextToken(skipSpace(s))
+			if t == "" {
+				continue headers
+			}
+			ext := map[string]string{"": t}
+			for {
+				s = skipSpace(s)
+				if !strings.HasPrefix(s, ";") {
+					break
+				}
+				var k string
+				k, s = nextToken(skipSpace(s[1:]))
+				if k == "" {
+					continue headers
+				}
+				s = skipSpace(s)
+				var v string
+				if strings.HasPrefix(s, "=") {
+					v, s = nextTokenOrQuoted(skipSpace(s[1:]))
+					s = skipSpace(s)
+				}
+				if s != "" && s[0] != ',' && s[0] != ';' {
+					continue headers
+				}
+				ext[k] = v
+			}
+			if s != "" && s[0] != ',' {
+				continue headers
+			}
+			result = append(result, ext)
+			if s == "" {
+				continue headers
+			}
+			s = s[1:]
+		}
+	}
+	return result
+}

at-server/vendor/github.com/gorilla/websocket/x_net_proxy.go

@@ -0,0 +1,473 @@
+// Code generated by golang.org/x/tools/cmd/bundle. DO NOT EDIT.
+//go:generate bundle -o x_net_proxy.go golang.org/x/net/proxy
+
+// Package proxy provides support for a variety of protocols to proxy network
+// data.
+//
+
+package websocket
+
+import (
+	"errors"
+	"io"
+	"net"
+	"net/url"
+	"os"
+	"strconv"
+	"strings"
+	"sync"
+)
+
+type proxy_direct struct{}
+
+// Direct is a direct proxy: one that makes network connections directly.
+var proxy_Direct = proxy_direct{}
+
+func (proxy_direct) Dial(network, addr string) (net.Conn, error) {
+	return net.Dial(network, addr)
+}
+
+// A PerHost directs connections to a default Dialer unless the host name
+// requested matches one of a number of exceptions.
+type proxy_PerHost struct {
+	def, bypass proxy_Dialer
+
+	bypassNetworks []*net.IPNet
+	bypassIPs      []net.IP
+	bypassZones    []string
+	bypassHosts    []string
+}
+
+// NewPerHost returns a PerHost Dialer that directs connections to either
+// defaultDialer or bypass, depending on whether the connection matches one of
+// the configured rules.
+func proxy_NewPerHost(defaultDialer, bypass proxy_Dialer) *proxy_PerHost {
+	return &proxy_PerHost{
+		def:    defaultDialer,
+		bypass: bypass,
+	}
+}
+
+// Dial connects to the address addr on the given network through either
+// defaultDialer or bypass.
+func (p *proxy_PerHost) Dial(network, addr string) (c net.Conn, err error) {
+	host, _, err := net.SplitHostPort(addr)
+	if err != nil {
+		return nil, err
+	}
+
+	return p.dialerForRequest(host).Dial(network, addr)
+}
+
+func (p *proxy_PerHost) dialerForRequest(host string) proxy_Dialer {
+	if ip := net.ParseIP(host); ip != nil {
+		for _, net := range p.bypassNetworks {
+			if net.Contains(ip) {
+				return p.bypass
+			}
+		}
+		for _, bypassIP := range p.bypassIPs {
+			if bypassIP.Equal(ip) {
+				return p.bypass
+			}
+		}
+		return p.def
+	}
+
+	for _, zone := range p.bypassZones {
+		if strings.HasSuffix(host, zone) {
+			return p.bypass
+		}
+		if host == zone[1:] {
+			// For a zone ".example.com", we match "example.com"
+			// too.
+			return p.bypass
+		}
+	}
+	for _, bypassHost := range p.bypassHosts {
+		if bypassHost == host {
+			return p.bypass
+		}
+	}
+	return p.def
+}
+
+// AddFromString parses a string that contains comma-separated values
+// specifying hosts that should use the bypass proxy. Each value is either an
+// IP address, a CIDR range, a zone (*.example.com) or a host name
+// (localhost). A best effort is made to parse the string and errors are
+// ignored.
+func (p *proxy_PerHost) AddFromString(s string) {
+	hosts := strings.Split(s, ",")
+	for _, host := range hosts {
+		host = strings.TrimSpace(host)
+		if len(host) == 0 {
+			continue
+		}
+		if strings.Contains(host, "/") {
+			// We assume that it's a CIDR address like 127.0.0.0/8
+			if _, net, err := net.ParseCIDR(host); err == nil {
+				p.AddNetwork(net)
+			}
+			continue
+		}
+		if ip := net.ParseIP(host); ip != nil {
+			p.AddIP(ip)
+			continue
+		}
+		if strings.HasPrefix(host, "*.") {
+			p.AddZone(host[1:])
+			continue
+		}
+		p.AddHost(host)
+	}
+}
+
+// AddIP specifies an IP address that will use the bypass proxy. Note that
+// this will only take effect if a literal IP address is dialed. A connection
+// to a named host will never match an IP.
+func (p *proxy_PerHost) AddIP(ip net.IP) {
+	p.bypassIPs = append(p.bypassIPs, ip)
+}
+
+// AddNetwork specifies an IP range that will use the bypass proxy. Note that
+// this will only take effect if a literal IP address is dialed. A connection
+// to a named host will never match.
+func (p *proxy_PerHost) AddNetwork(net *net.IPNet) {
+	p.bypassNetworks = append(p.bypassNetworks, net)
+}
+
+// AddZone specifies a DNS suffix that will use the bypass proxy. A zone of
+// "example.com" matches "example.com" and all of its subdomains.
+func (p *proxy_PerHost) AddZone(zone string) {
+	if strings.HasSuffix(zone, ".") {
+		zone = zone[:len(zone)-1]
+	}
+	if !strings.HasPrefix(zone, ".") {
+		zone = "." + zone
+	}
+	p.bypassZones = append(p.bypassZones, zone)
+}
+
+// AddHost specifies a host name that will use the bypass proxy.
+func (p *proxy_PerHost) AddHost(host string) {
+	if strings.HasSuffix(host, ".") {
+		host = host[:len(host)-1]
+	}
+	p.bypassHosts = append(p.bypassHosts, host)
+}
+
+// A Dialer is a means to establish a connection.
+type proxy_Dialer interface {
+	// Dial connects to the given address via the proxy.
+	Dial(network, addr string) (c net.Conn, err error)
+}
+
+// Auth contains authentication parameters that specific Dialers may require.
+type proxy_Auth struct {
+	User, Password string
+}
+
+// FromEnvironment returns the dialer specified by the proxy related variables in
+// the environment.
+func proxy_FromEnvironment() proxy_Dialer {
+	allProxy := proxy_allProxyEnv.Get()
+	if len(allProxy) == 0 {
+		return proxy_Direct
+	}
+
+	proxyURL, err := url.Parse(allProxy)
+	if err != nil {
+		return proxy_Direct
+	}
+	proxy, err := proxy_FromURL(proxyURL, proxy_Direct)
+	if err != nil {
+		return proxy_Direct
+	}
+
+	noProxy := proxy_noProxyEnv.Get()
+	if len(noProxy) == 0 {
+		return proxy
+	}
+
+	perHost := proxy_NewPerHost(proxy, proxy_Direct)
+	perHost.AddFromString(noProxy)
+	return perHost
+}
+
+// proxySchemes is a map from URL schemes to a function that creates a Dialer
+// from a URL with such a scheme.
+var proxy_proxySchemes map[string]func(*url.URL, proxy_Dialer) (proxy_Dialer, error)
+
+// RegisterDialerType takes a URL scheme and a function to generate Dialers from
+// a URL with that scheme and a forwarding Dialer. Registered schemes are used
+// by FromURL.
+func proxy_RegisterDialerType(scheme string, f func(*url.URL, proxy_Dialer) (proxy_Dialer, error)) {
+	if proxy_proxySchemes == nil {
+		proxy_proxySchemes = make(map[string]func(*url.URL, proxy_Dialer) (proxy_Dialer, error))
+	}
+	proxy_proxySchemes[scheme] = f
+}
+
+// FromURL returns a Dialer given a URL specification and an underlying
+// Dialer for it to make network requests.
+func proxy_FromURL(u *url.URL, forward proxy_Dialer) (proxy_Dialer, error) {
+	var auth *proxy_Auth
+	if u.User != nil {
+		auth = new(proxy_Auth)
+		auth.User = u.User.Username()
+		if p, ok := u.User.Password(); ok {
+			auth.Password = p
+		}
+	}
+
+	switch u.Scheme {
+	case "socks5":
+		return proxy_SOCKS5("tcp", u.Host, auth, forward)
+	}
+
+	// If the scheme doesn't match any of the built-in schemes, see if it
+	// was registered by another package.
+	if proxy_proxySchemes != nil {
+		if f, ok := proxy_proxySchemes[u.Scheme]; ok {
+			return f(u, forward)
+		}
+	}
+
+	return nil, errors.New("proxy: unknown scheme: " + u.Scheme)
+}
+
+var (
+	proxy_allProxyEnv = &proxy_envOnce{
+		names: []string{"ALL_PROXY", "all_proxy"},
+	}
+	proxy_noProxyEnv = &proxy_envOnce{
+		names: []string{"NO_PROXY", "no_proxy"},
+	}
+)
+
+// envOnce looks up an environment variable (optionally by multiple
+// names) once. It mitigates expensive lookups on some platforms
+// (e.g. Windows).
+// (Borrowed from net/http/transport.go)
+type proxy_envOnce struct {
+	names []string
+	once  sync.Once
+	val   string
+}
+
+func (e *proxy_envOnce) Get() string {
+	e.once.Do(e.init)
+	return e.val
+}
+
+func (e *proxy_envOnce) init() {
+	for _, n := range e.names {
+		e.val = os.Getenv(n)
+		if e.val != "" {
+			return
+		}
+	}
+}
+
+// SOCKS5 returns a Dialer that makes SOCKSv5 connections to the given address
+// with an optional username and password. See RFC 1928 and RFC 1929.
+func proxy_SOCKS5(network, addr string, auth *proxy_Auth, forward proxy_Dialer) (proxy_Dialer, error) {
+	s := &proxy_socks5{
+		network: network,
+		addr:    addr,
+		forward: forward,
+	}
+	if auth != nil {
+		s.user = auth.User
+		s.password = auth.Password
+	}
+
+	return s, nil
+}
+
+type proxy_socks5 struct {
+	user, password string
+	network, addr  string
+	forward        proxy_Dialer
+}
+
+const proxy_socks5Version = 5
+
+const (
+	proxy_socks5AuthNone     = 0
+	proxy_socks5AuthPassword = 2
+)
+
+const proxy_socks5Connect = 1
+
+const (
+	proxy_socks5IP4    = 1
+	proxy_socks5Domain = 3
+	proxy_socks5IP6    = 4
+)
+
+var proxy_socks5Errors = []string{
+	"",
+	"general failure",
+	"connection forbidden",
+	"network unreachable",
+	"host unreachable",
+	"connection refused",
+	"TTL expired",
+	"command not supported",
+	"address type not supported",
+}
+
+// Dial connects to the address addr on the given network via the SOCKS5 proxy.
+func (s *proxy_socks5) Dial(network, addr string) (net.Conn, error) {
+	switch network {
+	case "tcp", "tcp6", "tcp4":
+	default:
+		return nil, errors.New("proxy: no support for SOCKS5 proxy connections of type " + network)
+	}
+
+	conn, err := s.forward.Dial(s.network, s.addr)
+	if err != nil {
+		return nil, err
+	}
+	if err := s.connect(conn, addr); err != nil {
+		conn.Close()
+		return nil, err
+	}
+	return conn, nil
+}
+
+// connect takes an existing connection to a socks5 proxy server,
+// and commands the server to extend that connection to target,
+// which must be a canonical address with a host and port.
+func (s *proxy_socks5) connect(conn net.Conn, target string) error {
+	host, portStr, err := net.SplitHostPort(target)
+	if err != nil {
+		return err
+	}
+
+	port, err := strconv.Atoi(portStr)
+	if err != nil {
+		return errors.New("proxy: failed to parse port number: " + portStr)
+	}
+	if port < 1 || port > 0xffff {
+		return errors.New("proxy: port number out of range: " + portStr)
+	}
+
+	// the size here is just an estimate
+	buf := make([]byte, 0, 6+len(host))
+
+	buf = append(buf, proxy_socks5Version)
+	if len(s.user) > 0 && len(s.user) < 256 && len(s.password) < 256 {
+		buf = append(buf, 2 /* num auth methods */, proxy_socks5AuthNone, proxy_socks5AuthPassword)
+	} else {
+		buf = append(buf, 1 /* num auth methods */, proxy_socks5AuthNone)
+	}
+
+	if _, err := conn.Write(buf); err != nil {
+		return errors.New("proxy: failed to write greeting to SOCKS5 proxy at " + s.addr + ": " + err.Error())
+	}
+
+	if _, err := io.ReadFull(conn, buf[:2]); err != nil {
+		return errors.New("proxy: failed to read greeting from SOCKS5 proxy at " + s.addr + ": " + err.Error())
+	}
+	if buf[0] != 5 {
+		return errors.New("proxy: SOCKS5 proxy at " + s.addr + " has unexpected version " + strconv.Itoa(int(buf[0])))
+	}
+	if buf[1] == 0xff {
+		return errors.New("proxy: SOCKS5 proxy at " + s.addr + " requires authentication")
+	}
+
+	// See RFC 1929
+	if buf[1] == proxy_socks5AuthPassword {
+		buf = buf[:0]
+		buf = append(buf, 1 /* password protocol version */)
+		buf = append(buf, uint8(len(s.user)))
+		buf = append(buf, s.user...)
+		buf = append(buf, uint8(len(s.password)))
+		buf = append(buf, s.password...)
+
+		if _, err := conn.Write(buf); err != nil {
+			return errors.New("proxy: failed to write authentication request to SOCKS5 proxy at " + s.addr + ": " + err.Error())
+		}
+
+		if _, err := io.ReadFull(conn, buf[:2]); err != nil {
+			return errors.New("proxy: failed to read authentication reply from SOCKS5 proxy at " + s.addr + ": " + err.Error())
+		}
+
+		if buf[1] != 0 {
+			return errors.New("proxy: SOCKS5 proxy at " + s.addr + " rejected username/password")
+		}
+	}
+
+	buf = buf[:0]
+	buf = append(buf, proxy_socks5Version, proxy_socks5Connect, 0 /* reserved */)
+
+	if ip := net.ParseIP(host); ip != nil {
+		if ip4 := ip.To4(); ip4 != nil {
+			buf = append(buf, proxy_socks5IP4)
+			ip = ip4
+		} else {
+			buf = append(buf, proxy_socks5IP6)
+		}
+		buf = append(buf, ip...)
+	} else {
+		if len(host) > 255 {
+			return errors.New("proxy: destination host name too long: " + host)
+		}
+		buf = append(buf, proxy_socks5Domain)
+		buf = append(buf, byte(len(host)))
+		buf = append(buf, host...)
+	}
+	buf = append(buf, byte(port>>8), byte(port))
+
+	if _, err := conn.Write(buf); err != nil {
+		return errors.New("proxy: failed to write connect request to SOCKS5 proxy at " + s.addr + ": " + err.Error())
+	}
+
+	if _, err := io.ReadFull(conn, buf[:4]); err != nil {
+		return errors.New("proxy: failed to read connect reply from SOCKS5 proxy at " + s.addr + ": " + err.Error())
+	}
+
+	failure := "unknown error"
+	if int(buf[1]) < len(proxy_socks5Errors) {
+		failure = proxy_socks5Errors[buf[1]]
+	}
+
+	if len(failure) > 0 {
+		return errors.New("proxy: SOCKS5 proxy at " + s.addr + " failed to connect: " + failure)
+	}
+
+	bytesToDiscard := 0
+	switch buf[3] {
+	case proxy_socks5IP4:
+		bytesToDiscard = net.IPv4len
+	case proxy_socks5IP6:
+		bytesToDiscard = net.IPv6len
+	case proxy_socks5Domain:
+		_, err := io.ReadFull(conn, buf[:1])
+		if err != nil {
+			return errors.New("proxy: failed to read domain length from SOCKS5 proxy at " + s.addr + ": " + err.Error())
+		}
+		bytesToDiscard = int(buf[0])
+	default:
+		return errors.New("proxy: got unknown address type " + strconv.Itoa(int(buf[3])) + " from SOCKS5 proxy at " + s.addr)
+	}
+
+	if cap(buf) < bytesToDiscard {
+		buf = make([]byte, bytesToDiscard)
+	} else {
+		buf = buf[:bytesToDiscard]
+	}
+	if _, err := io.ReadFull(conn, buf); err != nil {
+		return errors.New("proxy: failed to read address from SOCKS5 proxy at " + s.addr + ": " + err.Error())
+	}
+
+	// Also need to discard the port number
+	if _, err := io.ReadFull(conn, buf[:2]); err != nil {
+		return errors.New("proxy: failed to read port from SOCKS5 proxy at " + s.addr + ": " + err.Error())
+	}
+
+	return nil
+}