File System
Contents
Filestore
Location
Elgg’s filestore is located in the site’s dataroot
that is configured during
installation, and can be modified via site settings in Admin interface.
Directory Structure
The structure of the filestore is tied to file ownership by Elgg entities. Whenever
the first file owned by an entity is written to the filestore, a directory corresponding
to the entity GUID will be created within a parent bucket directory (buckets are bound to 5000 guids).
E.g. files owned by user with guid 7777 will be located in 5000/7777/
.
When files are created, filenames can contain subdirectory names (often referred to as
$prefix throughout the code). For instance, avatars of the above user, can be found
under 5000/7777/profile/
.
File Objects
Writing Files
To write a file to the filestore, you would use an instance of ElggFile
. Even though
ElggFile
extends ElggObject and can be stored as an actual Elgg entity, that is not
always necessary (e.g. when writing thumbs of an image).
$file = new ElggFile();
$file->owner_guid = 7777;
$file->setFilename('portfolio/files/sample.txt');
$file->open('write');
$file->write('Contents of the file');
$file->close();
// to uprade this file to an entity
$file->save();
Reading Files
You can read file contents using instanceof of ElggFile
.
// from an Elgg entity
$file = get_entity($file_guid);
readfile($file->getFilenameOnFilestore());
// arbitrary file on the filestore
$file = new ElggFile();
$file->owner_guid = 7777;
$file->setFilename('portfolio/files/sample.txt');
// option 1
$file->open('read');
$contents = $file->grabFile();
$file->close();
// option 2
$contents = file_get_contents($file->getFilenameOnFilestore());
Serving Files
You can serve files from filestore using elgg_get_inline_url()
and elgg_get_download_url()
.
Both functions accept 3 arguments:
``file`` An instance of
ElggFile
to be served``use_cookie`` If set to true, validity of the URL will be limited to current session
``expires`` Expiration time of the URL
You can use use_cookie
and expires
arguments as means of access control. For example,
users avatars in most cases have a long expiration time and do not need to be restricted by
current session - this will allows browsers to cache the images and file service will
send appropriate Not Modified
headers on consecutive requests.
The default behaviour of use_cookie
can be controlled on the admin security settings page.
For entities that are under Elgg’s access control, you may want to use cookies to ensure that access settings are respected and users do not share download URLs with somebody else.
You can also invalidated all previously generated URLs by updating file’s modified time, e.g.
by using touch()
.
Embedding Files
Please note that due to their nature inline and download URLs are not suitable for embedding. Embed URLs must be permanent, whereas inline and download URLs are volatile (bound to user session and file modification time).
To embed an entity icon, use elgg_get_embed_url()
.
Handling File Uploads
In order to implement an action that saves a single file uploaded by a user, you can use the following approach:
// in your form
echo elgg_view('input/file', [
'name' => 'upload',
'label' => 'Select an image to upload',
'help' => 'Only jpeg, gif and png images are supported',
]);
// in your action
$uploaded_file = elgg_get_uploaded_file('upload');
if (!$uploaded_file) {
return elgg_error_response("No file was uploaded");
}
$supported_mimes = [
'image/jpeg',
'image/png',
'image/gif',
];
$mime_type = elgg()->mimetype->getMimeType($uploaded_file->getPathname());
if (!in_array($mime_type, $supported_mimes)) {
return elgg_error_response("{$mime_type} is not supported");
}
$file = new ElggFile();
$file->owner_guid = elgg_get_logged_in_user_guid();
if ($file->acceptUploadedFile($uploaded_file)) {
$file->save();
}
If your file input supports multiple files, you can iterate through them in your action:
// in your form
echo elgg_view('input/file', [
'name' => 'upload[]',
'multiple' => true,
'label' => 'Select images to upload',
]);
// in your action
foreach (elgg_get_uploaded_files('upload') as $upload) {
$file = new ElggFile();
$file->owner_guid = elgg_get_logged_in_user_guid();
if ($file->acceptUploadedFile($upload)) {
$file->save();
}
}
Note
If images are uploaded their is an automatic attempt to fix the orientation of the image.
Temporary files
If you ever need a temporary file you can use elgg_get_temp_file()
. You’ll get an instance of an ElggTempFile
which has all the
file functions of an ElggFile
, but writes it’s data to the systems temp folder.
Warning
It’s not possible to save the ElggTempFile
to the database. You’ll get an Elgg\Exceptions\Filesystem\IOException
if you try.