silverstripe-framework/src/Control/ContentNegotiator.php
Damian Mooyman d20ab50f9d API Stronger Injector service unregistration
BUG Fix up test regressions
FIX director references to request object
API Move all middlewares to common namespace
API Implement RequestHandlerMiddlewareAdapter
ENHANCEMENT Improve IP address parsing
Fix up PHPDoc / psr2 linting
BUG Fix property parsing in TrustedProxyMiddleware
BUG Fix Director::is_https()
2017-06-27 13:32:39 +12:00

230 lines
8.4 KiB
PHP

<?php
namespace SilverStripe\Control;
use SilverStripe\Core\Config\Config;
use SilverStripe\Core\Config\Configurable;
use SilverStripe\Core\Injector\Injectable;
/**
* The content negotiator performs "text/html" or "application/xhtml+xml" switching. It does this through
* the public static function ContentNegotiator::process(). By default, ContentNegotiator will comply to
* the Accept headers the clients sends along with the HTTP request, which is most likely
* "application/xhtml+xml" (see "Order of selection" below).
*
* Order of selection between html or xhtml is as follows:
* - if PHP has already sent the HTTP headers, default to "html" (we can't send HTTP Content-Type headers
* any longer)
* - if a GET variable ?forceFormat is set, it takes precedence (for testing purposes)
* - if the user agent is detected as W3C Validator we always deliver "xhtml"
* - if an HTTP Accept header is sent from the client, we respect its order (this is the most common case)
* - if none of the above matches, fallback is "html"
*
* ContentNegotiator doesn't enable you to send content as a true XML document through the "text/xml"
* or "application/xhtml+xml" Content-Type.
*
* Please see http://webkit.org/blog/68/understanding-html-xml-and-xhtml/ for further information.
*
* @todo Check for correct XHTML doctype in xhtml()
* @todo Allow for other HTML4 doctypes (e.g. Transitional) in html()
* @todo Make content replacement and doctype setting two separately configurable behaviours
*
* Some developers might know what they're doing and don't want ContentNegotiator messing with their
* HTML4 doctypes, but still find it useful to have self-closing tags removed.
*/
class ContentNegotiator
{
use Injectable;
use Configurable;
/**
* @config
*
* @var string
*/
private static $content_type = '';
/**
* @config
*
* @var string
*/
private static $encoding = 'utf-8';
/**
* @config
*
* @var bool
*/
private static $enabled = false;
/**
* @config
*
* @var string
*/
private static $default_format = 'html';
/**
* Returns true if negotiation is enabled for the given response. By default, negotiation is only
* enabled for pages that have the xml header.
*
* @param HTTPResponse $response
* @return bool
*/
public static function enabled_for($response)
{
$contentType = $response->getHeader("Content-Type");
// Disable content negotiation for other content types
if ($contentType
&& substr($contentType, 0, 9) != 'text/html'
&& substr($contentType, 0, 21) != 'application/xhtml+xml'
) {
return false;
}
if (static::config()->get('enabled')) {
return true;
} else {
return (substr($response->getBody(), 0, 5) == '<' . '?xml');
}
}
/**
* @param HTTPResponse $response
*/
public static function process(HTTPResponse $response)
{
if (!self::enabled_for($response)) {
return;
}
$mimes = array(
"xhtml" => "application/xhtml+xml",
"html" => "text/html",
);
$q = array();
if (headers_sent()) {
$chosenFormat = static::config()->get('default_format');
} elseif (isset($_GET['forceFormat'])) {
$chosenFormat = $_GET['forceFormat'];
} else {
// The W3C validator doesn't send an HTTP_ACCEPT header, but it can support xhtml. We put this
// special case in here so that designers don't get worried that their templates are HTML4.
if (isset($_SERVER['HTTP_USER_AGENT']) && substr($_SERVER['HTTP_USER_AGENT'], 0, 14) == 'W3C_Validator/') {
$chosenFormat = "xhtml";
} else {
foreach ($mimes as $format => $mime) {
$regExp = '/' . str_replace(array('+','/'), array('\+','\/'), $mime) . '(;q=(\d+\.\d+))?/i';
if (isset($_SERVER['HTTP_ACCEPT']) && preg_match($regExp, $_SERVER['HTTP_ACCEPT'], $matches)) {
$preference = isset($matches[2]) ? $matches[2] : 1;
if (!isset($q[$preference])) {
$q[$preference] = $format;
}
}
}
if ($q) {
// Get the preferred format
krsort($q);
$chosenFormat = reset($q);
} else {
$chosenFormat = Config::inst()->get('SilverStripe\\Control\\ContentNegotiator', 'default_format');
}
}
}
$negotiator = new ContentNegotiator();
$negotiator->$chosenFormat( $response );
}
/**
* Check user defined content type and use it, if it's empty use the strict application/xhtml+xml.
* Replaces a few common tags and entities with their XHTML representations (<br>, <img>, &nbsp;
* <input>, checked, selected).
*
* @param HTTPResponse $response
*
* @todo Search for more xhtml replacement
*/
public function xhtml(HTTPResponse $response)
{
$content = $response->getBody();
$encoding = Config::inst()->get('SilverStripe\\Control\\ContentNegotiator', 'encoding');
$contentType = Config::inst()->get('SilverStripe\\Control\\ContentNegotiator', 'content_type');
if (empty($contentType)) {
$response->addHeader("Content-Type", "application/xhtml+xml; charset=" . $encoding);
} else {
$response->addHeader("Content-Type", $contentType . "; charset=" . $encoding);
}
$response->addHeader("Vary", "Accept");
// Fix base tag
$content = preg_replace(
'/<base href="([^"]*)"><!--\[if[[^\]*]\] \/><!\[endif\]-->/',
'<base href="$1" />',
$content
);
$content = str_replace('&nbsp;', '&#160;', $content);
$content = str_replace('<br>', '<br />', $content);
$content = str_replace('<hr>', '<hr />', $content);
$content = preg_replace('#(<img[^>]*[^/>])>#i', '\\1/>', $content);
$content = preg_replace('#(<input[^>]*[^/>])>#i', '\\1/>', $content);
$content = preg_replace('#(<param[^>]*[^/>])>#i', '\\1/>', $content);
$content = preg_replace("#(\<option[^>]*[\s]+selected)(?!\s*\=)#si", "$1=\"selected\"$2", $content);
$content = preg_replace("#(\<input[^>]*[\s]+checked)(?!\s*\=)#si", "$1=\"checked\"$2", $content);
$response->setBody($content);
}
/**
* Performs the following replacements:
* - Check user defined content type and use it, if it's empty use the text/html.
* - If find a XML header replaces it and existing doctypes with HTML4.01 Strict.
* - Replaces self-closing tags like <img /> with unclosed solitary tags like <img>.
* - Replaces all occurrences of "application/xhtml+xml" with "text/html" in the template.
* - Removes "xmlns" attributes and any <?xml> Pragmas.
*
* @param HTTPResponse $response
*/
public function html(HTTPResponse $response)
{
$encoding = $this->config()->get('encoding');
$contentType = $this->config()->get('content_type');
if (empty($contentType)) {
$response->addHeader("Content-Type", "text/html; charset=" . $encoding);
} else {
$response->addHeader("Content-Type", $contentType . "; charset=" . $encoding);
}
$response->addHeader("Vary", "Accept");
$content = $response->getBody();
$hasXMLHeader = (substr($content, 0, 5) == '<' . '?xml' );
// Fix base tag
$content = preg_replace(
'/<base href="([^"]*)" \/>/',
'<base href="$1"><!--[if lte IE 6]></base><![endif]-->',
$content
);
$content = preg_replace("#<\\?xml[^>]+\\?>\n?#", '', $content);
$content = str_replace(array('/>','xml:lang','application/xhtml+xml'), array('>','lang','text/html'), $content);
// Only replace the doctype in templates with the xml header
if ($hasXMLHeader) {
$content = preg_replace(
'/<!DOCTYPE[^>]+>/',
'<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">',
$content
);
}
$content = preg_replace('/<html xmlns="[^"]+"/', '<html ', $content);
$response->setBody($content);
}
}