Provides Drupal stream wrapper registry.

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.

Provide a facility for managing and querying user-defined stream wrappers in PHP. PHP's internal stream_get_wrappers() doesn't return the class registered to handle a stream, which we need to be able to find the handler for class instantiation.

If a module registers a scheme that is already registered with PHP, the existing scheme will be unregistered and replaced with the specified class.

A stream is referenced as "scheme://target".

The optional $filter parameter can be used to retrieve only the stream wrappers that are appropriate for particular usage. For example, this returns only stream wrappers that use local file storage:

$local_stream_wrappers = file_get_stream_wrappers(STREAM_WRAPPERS_LOCAL);

The $filter parameter can only filter to types containing a particular flag. In some cases, you may want to filter to types that do not contain a particular flag. For example, you may want to retrieve all stream wrappers that are not writable, or all stream wrappers that are not local. PHP's array_diff_key() function can be used to help with this. For example, this returns only stream wrappers that do not use local file storage:

$remote_stream_wrappers = array_diff_key(file_get_stream_wrappers(STREAM_WRAPPERS_ALL), file_get_stream_wrappers(STREAM_WRAPPERS_LOCAL));

Parameters

$filter: (Optional) Filters out all types except those with an on bit for each on bit in $filter. For example, if $filter is STREAM_WRAPPERS_WRITE_VISIBLE, which is equal to (STREAM_WRAPPERS_READ | STREAM_WRAPPERS_WRITE | STREAM_WRAPPERS_VISIBLE), then only stream wrappers with all three of these bits set are returned. Defaults to STREAM_WRAPPERS_ALL, which returns all registered stream wrappers.

Return value

An array keyed by scheme, with values containing an array of information about the stream wrapper, as returned by hook_stream_wrappers(). If $filter is omitted or set to STREAM_WRAPPERS_ALL, the entire Drupal stream wrapper registry is returned. Otherwise only the stream wrappers whose 'type' bitmask has an on bit for each bit specified in $filter are returned.

See also

hook_stream_wrappers()

hook_stream_wrappers_alter()

Related topics

8 calls to file_get_stream_wrappers()

file_field_settings_form in modules/file/file.field.inc

Implements hook_field_settings_form().

file_stream_wrapper_get_class in includes/file.inc

Returns the stream wrapper class name for a given scheme.

image_field_settings_form in modules/image/image.field.inc

Implements hook_field_settings_form().

image_gd_save in modules/system/image.gd.inc

GD helper to write an image resource to a destination file.

image_style_flush in modules/image/image.module

Flushes cached media for a style.

... See full list

2 string references to 'file_get_stream_wrappers'

StreamWrapperTest::setUp in modules/simpletest/tests/file.test

Sets up a Drupal site for running functional and integration tests.

StreamWrapperTest::testPharStreamWrapperRegistration in modules/simpletest/tests/file.test

Tests that phar stream wrapper is registered as expected.

File

includes/file.inc, line 130

Code

function file_get_stream_wrappers($filter = STREAM_WRAPPERS_ALL) {
    $wrappers_storage =& drupal_static(__FUNCTION__);
    if (!isset($wrappers_storage)) {
        $wrappers = module_invoke_all('stream_wrappers');
        foreach ($wrappers as $scheme => $info) {
            // Add defaults.
            $wrappers[$scheme] += array(
                'type' => STREAM_WRAPPERS_NORMAL,
            );
        }
        drupal_alter('stream_wrappers', $wrappers);
        $existing = stream_get_wrappers();
        foreach ($wrappers as $scheme => $info) {
            // We only register classes that implement our interface.
            if (in_array('DrupalStreamWrapperInterface', class_implements($info['class']), TRUE)) {
                // Record whether we are overriding an existing scheme.
                if (in_array($scheme, $existing, TRUE)) {
                    $wrappers[$scheme]['override'] = TRUE;
                    stream_wrapper_unregister($scheme);
                }
                else {
                    $wrappers[$scheme]['override'] = FALSE;
                }
                if (($info['type'] & STREAM_WRAPPERS_LOCAL) == STREAM_WRAPPERS_LOCAL) {
                    stream_wrapper_register($scheme, $info['class']);
                }
                else {
                    stream_wrapper_register($scheme, $info['class'], STREAM_IS_URL);
                }
            }
            // Pre-populate the static cache with the filters most typically used.
            $wrappers_storage[STREAM_WRAPPERS_ALL][$scheme] = $wrappers[$scheme];
            if (($info['type'] & STREAM_WRAPPERS_WRITE_VISIBLE) == STREAM_WRAPPERS_WRITE_VISIBLE) {
                $wrappers_storage[STREAM_WRAPPERS_WRITE_VISIBLE][$scheme] = $wrappers[$scheme];
            }
        }
    }
    if (!isset($wrappers_storage[$filter])) {
        $wrappers_storage[$filter] = array();
        foreach ($wrappers_storage[STREAM_WRAPPERS_ALL] as $scheme => $info) {
            // Bit-wise filter.
            if (($info['type'] & $filter) == $filter) {
                $wrappers_storage[$filter][$scheme] = $info;
            }
        }
    }
    return $wrappers_storage[$filter];
}

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