silverstripe-framework/Assets/Storage/AssetStore.php

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<?php
namespace SilverStripe\Assets\Storage;
/**
* Represents an abstract asset persistence layer. Acts as a backend to files.
*
* Asset storage is identified by the following values arranged into a tuple:
*
* - "Filename" - Descriptive path for a file, although not necessarily a physical location. This could include
* custom directory names as a parent, as well as an extension.
* - "Hash" - The SHA1 of the file. This means that multiple files with the same Filename could be
* stored independently (depending on implementation) as long as they have different hashes.
* When a variant is identified, this value will refer to the hash of the file it was generated
* from, not the hash of the actual generated file.
* - "Variant" - An arbitrary string (which should not contain filesystem invalid characters) used
* to identify an asset which is a variant of an original. The asset storage backend has no knowledge
* of the mechanism used to generate this file, and is up to user code to perform the actual
* generation. An empty variant identifies this file as the original file.
*
* Write options have an additional $config parameter to provide additional options to the backend.
* This is an associative array. Standard array options include 'visibility' and 'conflict'.
*
* 'conflict' config option determines the conflict resolution mechanism.
* When assets are stored in the backend, user code may request one of the following conflict resolution
* mechanisms:
*
* - CONFLICT_OVERWRITE - If there is an existing file with this tuple, overwrite it.
* - CONFLICT_RENAME - If there is an existing file with this tuple, pick a new Filename for it and return it.
* This option is not allowed for use when storing variants, which should not modify the underlying
* Filename tuple value.
* - CONFLICT_USE_EXISTING - If there is an existing file with this tuple, return the tuple for the
* existing file instead.
* - CONFLICT_EXCEPTION - If there is an existing file with this tuple, throw an exception.
*
* 'visibility' config option determines whether the file should be marked as publicly visible.
* This may be assigned to one of the below values:
*
* - VISIBILITY_PUBLIC: This file may be accessed by any public user.
* - VISIBILITY_PROTECTED: This file must be whitelisted for individual users before being made available to that user.
*/
interface AssetStore {
/**
* Exception on file conflict
*/
const CONFLICT_EXCEPTION = 'exception';
/**
* Overwrite on file conflict
*/
const CONFLICT_OVERWRITE = 'overwrite';
/**
* Rename on file conflict. Rename rules will be determined by the backend.
*
* This option is not allowed for use when storing variants, which should not modify the underlying
* Filename tuple value.
*/
const CONFLICT_RENAME = 'rename';
/**
* On conflict, use existing file
*/
const CONFLICT_USE_EXISTING = 'existing';
/**
* Protect this file
*/
const VISIBILITY_PROTECTED = 'protected';
/**
* Make this file public
*/
const VISIBILITY_PUBLIC = 'public';
/**
* Return list of feature capabilities of this backend as an array.
* Array keys will be the options supported by $config, and the
* values will be the list of accepted values for each option (or
* true if any value is allowed).
*
* @return array
*/
public function getCapabilities();
/**
* Assign a set of data to the backend
*
* @param string $data Raw binary/text content
* @param string $filename Name for the resulting file
* @param string $hash Hash of original file, if storing a variant.
* @param string $variant Name of variant, if storing a variant.
* @param array $config Write options. {@see AssetStore}
* @return array Tuple associative array (Filename, Hash, Variant) Unless storing a variant, the hash
* will be calculated from the given data.
*/
public function setFromString($data, $filename, $hash = null, $variant = null, $config = array());
/**
* Assign a local file to the backend.
*
* @param string $path Absolute filesystem path to file
* @param string $filename Optional path to ask the backend to name as.
* Will default to the filename of the $path, excluding directories.
* @param string $hash Hash of original file, if storing a variant.
* @param string $variant Name of variant, if storing a variant.
* @param array $config Write options. {@see AssetStore}
* @return array Tuple associative array (Filename, Hash, Variant) Unless storing a variant, the hash
* will be calculated from the local file content.
*/
public function setFromLocalFile($path, $filename = null, $hash = null, $variant = null, $config = array());
/**
* Assign a stream to the backend
*
* @param resource $stream Streamable resource
* @param string $filename Name for the resulting file
* @param string $hash Hash of original file, if storing a variant.
* @param string $variant Name of variant, if storing a variant.
* @param array $config Write options. {@see AssetStore}
* @return array Tuple associative array (Filename, Hash, Variant) Unless storing a variant, the hash
* will be calculated from the raw stream.
*/
public function setFromStream($stream, $filename, $hash = null, $variant = null, $config = array());
/**
* Get contents of a given file
*
* @param string $filename Filename (not including assets)
* @param string $hash sha1 hash of the file content.
* If a variant is requested, this is the hash of the file before it was modified.
* @param string|null $variant Optional variant string for this file
* @return string Data from the file.
*/
public function getAsString($filename, $hash, $variant = null);
/**
* Get a stream for this file
*
* @param string $filename Filename (not including assets)
* @param string $hash sha1 hash of the file content.
* If a variant is requested, this is the hash of the file before it was modified.
* @param string|null $variant Optional variant string for this file
* @return resource Data stream
*/
public function getAsStream($filename, $hash, $variant = null);
/**
* Get the url for the file
*
* @param string $filename Filename (not including assets)
* @param string $hash sha1 hash of the file content.
* If a variant is requested, this is the hash of the file before it was modified.
* @param string|null $variant Optional variant string for this file
* @param bool $grant Ensures that the url for any protected assets is granted for the current user.
* If set to true, and the file is currently in protected mode, the asset store will ensure the
* returned URL is accessible for the duration of the current session / user.
* This will have no effect if the file is in published mode.
* This will not grant access to users other than the owner of the current session.
* @return string public url to this resource
*/
public function getAsURL($filename, $hash, $variant = null, $grant = true);
/**
* Get metadata for this file, if available
*
* @param string $filename Filename (not including assets)
* @param string $hash sha1 hash of the file content.
* If a variant is requested, this is the hash of the file before it was modified.
* @param string|null $variant Optional variant string for this file
* @return array|null File information, or null if no metadata available
*/
public function getMetadata($filename, $hash, $variant = null);
/**
* Get mime type of this file
*
* @param string $filename Filename (not including assets)
* @param string $hash sha1 hash of the file content.
* If a variant is requested, this is the hash of the file before it was modified.
* @param string|null $variant Optional variant string for this file
* @return string Mime type for this file
*/
public function getMimeType($filename, $hash, $variant = null);
/**
* Determine visibility of the given file
*
* @param string $filename
* @param string $hash
* @return string one of values defined by the constants VISIBILITY_PROTECTED or VISIBILITY_PUBLIC, or
* null if the file does not exist
*/
public function getVisibility($filename, $hash);
/**
* Determine if a file exists with the given tuple
*
* @param string $filename Filename (not including assets)
* @param string $hash sha1 hash of the file content.
* If a variant is requested, this is the hash of the file before it was modified.
* @param string|null $variant Optional variant string for this file
* @return bool Flag as to whether the file exists
*/
public function exists($filename, $hash, $variant = null);
/**
* Delete a file (and all variants) identified by the given filename and hash
*
* @param string $filename
* @param string $hash
* @return bool Flag if a file was deleted
*/
public function delete($filename, $hash);
/**
* Publicly expose the file (and all variants) identified by the given filename and hash
*
* @param string $filename Filename (not including assets)
* @param string $hash sha1 hash of the file content.
*/
public function publish($filename, $hash);
/**
* Protect a file (and all variants) from public access, identified by the given filename and hash.
*
* A protected file can be granted access to users on a per-session or per-user basis as response
* to any future invocations of {@see grant()} or {@see getAsURL()} with $grant = true
*
* @param string $filename Filename (not including assets)
* @param string $hash sha1 hash of the file content.
*/
public function protect($filename, $hash);
/**
* Ensures that access to the specified protected file is granted for the current user.
* If this file is currently in protected mode, the asset store will ensure the
* returned asset for the duration of the current session / user.
* This will have no effect if the file is in published mode.
* This will not grant access to users other than the owner of the current session.
* Does not require a member to be logged in.
*
* @param string $filename
* @param string $hash
*/
public function grant($filename, $hash);
/**
* Revoke access to the given file for the current user.
* Note: This will have no effect if the given file is public
*
* @param string $filename
* @param string $hash
*/
public function revoke($filename, $hash);
/**
* Check if the current user can view the given file.
*
* @param string $filename
* @param string $hash
* @return bool True if the file is verified and grants access to the current session / user.
*/
public function canView($filename, $hash);
}