StreamWrapperInterface.php

<?php

namespace Drupal\Core\StreamWrapper;


/**
 * Defines a Drupal stream wrapper extension.
 *
 * Provides a Drupal interface and classes to implement PHP stream wrappers for
 * public, private, and temporary files. Extends the PhpStreamWrapperInterface
 * with methods expected by Drupal stream wrapper classes.
 *
 * A stream wrapper is an abstraction of a file system that allows Drupal to
 * use the same set of methods to access both local files and remote resources.
 *
 * Note that PHP 5.2 fopen() only supports URIs of the form "scheme://target"
 * despite the fact that according to RFC 3986 a URI's scheme component
 * delimiter is in general just ":", not "://".  Because of this PHP limitation
 * and for consistency Drupal will only accept URIs of form "scheme://target".
 *
 * @see http://www.faqs.org/rfcs/rfc3986.html
 * @see http://bugs.php.net/bug.php?id=47070
 */
interface StreamWrapperInterface extends PhpStreamWrapperInterface {
    
    /**
     * Stream wrapper bit flags that are the basis for composite types.
     *
     * Note that 0x0002 is skipped, because it was the value of a constant that
     * has since been removed.
     */
    
    /**
     * A filter that matches all wrappers.
     */
    const ALL = 0x0;
    
    /**
     * Refers to a local file system location.
     */
    const LOCAL = 0x1;
    
    /**
     * Wrapper is readable (almost always true).
     */
    const READ = 0x4;
    
    /**
     * Wrapper is writable.
     */
    const WRITE = 0x8;
    
    /**
     * Exposed in the UI and potentially web accessible.
     */
    const VISIBLE = 0x10;
    
    /**
     * Composite stream wrapper bit flags that are usually used as the types.
     */
    
    /**
     * Defines the stream wrapper bit flag for a hidden file.
     *
     * This is not visible in the UI or accessible via web, but readable and
     * writable; for instance, the temporary directory for file uploads.
     */
    const HIDDEN = 0xc;
    
    /**
     * Hidden, readable and writable using local files.
     */
    const LOCAL_HIDDEN = 0xd;
    
    /**
     * Visible, readable and writable.
     */
    const WRITE_VISIBLE = 0x1c;
    
    /**
     * Visible and read-only.
     */
    const READ_VISIBLE = 0x14;
    
    /**
     * The default 'type' flag.
     *
     * This does not include StreamWrapperInterface::LOCAL, because PHP grants a
     * greater trust level to local files (for example, they can be used in an
     * "include" statement, regardless of the "allow_url_include" setting), so
     * stream wrappers need to explicitly opt-in to this.
     */
    const NORMAL = 0x1c;
    
    /**
     * Visible, readable and writable using local files.
     */
    const LOCAL_NORMAL = 0x1d;
    
    /**
     * Returns the type of stream wrapper.
     *
     * @return int
     */
    public static function getType();
    
    /**
     * Returns the name of the stream wrapper for use in the UI.
     *
     * @return string|\Drupal\Core\StringTranslation\TranslatableMarkup
     *   The stream wrapper name.
     */
    public function getName();
    
    /**
     * Returns the description of the stream wrapper for use in the UI.
     *
     * @return string|\Drupal\Core\StringTranslation\TranslatableMarkup
     *   The stream wrapper description.
     */
    public function getDescription();
    
    /**
     * Sets the absolute stream resource URI.
     *
     * This allows you to set the URI. Generally is only called by the factory
     * method.
     *
     * @param string $uri
     *   A string containing the URI that should be used for this instance.
     */
    public function setUri($uri);
    
    /**
     * Returns the stream resource URI.
     *
     * @return string
     *   Returns the current URI of the instance.
     */
    public function getUri();
    
    /**
     * Returns a web accessible URL for the resource.
     *
     * This function should return a URL that can be embedded in a web page
     * and accessed from a browser. For example, the external URL of
     * "youtube://random_string" might be
     * "http://www.youtube.com/watch?v=random_string".
     *
     * @return string
     *   Returns a string containing a web accessible URL for the resource.
     */
    public function getExternalUrl();
    
    /**
     * Returns canonical, absolute path of the resource.
     *
     * Implementation placeholder. PHP's realpath() does not support stream
     * wrappers. We provide this as a default so that individual wrappers may
     * implement their own solutions.
     *
     * @return string
     *   Returns a string with absolute pathname on success (implemented
     *   by core wrappers), or FALSE on failure or if the registered
     *   wrapper does not provide an implementation.
     */
    public function realpath();
    
    /**
     * Gets the name of the directory from a given path.
     *
     * This method is usually accessed through
     * \Drupal\Core\File\FileSystemInterface::dirname(), which wraps around the
     * normal PHP dirname() function, which does not support stream wrappers.
     *
     * @param string $uri
     *   An optional URI.
     *
     * @return string
     *   A string containing the directory name, or FALSE if not applicable.
     *
     * @see \Drupal\Core\File\FileSystemInterface::dirname()
     */
    public function dirname($uri = NULL);

}