File Filters

zend-filter also comes with a set of classes for filtering file contents, and performing file operations such as renaming.

$_FILES

All file filter filter() implementations support either a file path string or a $_FILES array as the supplied argument. When a $_FILES array is passed in, the tmp_name is used for the file path.

Encrypt and Decrypt

These filters allow encrypting and decrypting file contents, and are derived from the Zend\Filter\Encrypt and Zend\Filter\Decrypt filters. Only file reading and writing operations are performed by the filer; encryption and decryption operations are performed by the parent classes.

Usage:

use Zend\Filter\File\Encrypt as EncryptFileFilter;
use Zend\Http\PhpEnvironment\Request;

$request = new Request();
$files   = $request->getFiles();
// i.e. $files['my-upload']['tmp_name'] === '/tmp/php5Wx0aJ'

$filter = new EncryptFileFilter([
    'adapter' => 'BlockCipher',
    'key' => '--our-super-secret-key--',
]);
$filter->filter($files['my-upload']);

In the above example, we pass options to our constructor in order to configure the filter. We could instead use use setter methods to inject these options:

use Zend\Filter\File\Encrypt as EncryptFileFilter;
use Zend\Http\PhpEnvironment\Request;

$request = new Request();
$files   = $request->getFiles();
// i.e. $files['my-upload']['tmp_name'] === '/tmp/php5Wx0aJ'

$filter = new EncryptFileFilter();
$filter->setAdapter('BlockCipher');
$filter->setKey('--our-super-secret-key--');
$filter->filter($files['my-upload']);

Check the Encrypt and Decrypt filter documentation for more information about options and adapters.

Lowercase

Zend\Filter\File\Lowercase can be used to convert all file contents to lowercase.

Supported Options

The following set of options are supported:

  • encoding: Set the encoding to use during conversion.

Basic Usage

use Zend\Filter\File\LowerCase;
use Zend\Http\PhpEnvironment\Request;

$request = new Request();
$files   = $request->getFiles();
// i.e. $files['my-upload']['tmp_name'] === '/tmp/php5Wx0aJ'

$filter = new LowerCase();
$filter->filter($files['my-upload']);

This example converts the contents of an uploaded file to lowercase. After this process, you can use the Rename or RenameUpload filter to replace this file with your original file, or read directly from file. But, don't forget, if you upload a file and send your $_FILES array to a filter method, the LowerCase filter will only change the temporary file (tmp_name index of array), not the original file. Let's check following example:

use Zend\Filter\File\LowerCase;
use Zend\Filter\File\Rename;
use Zend\Http\PhpEnvironment\Request;

$request = new Request();
$files   = $request->getFiles();
// i.e. $files['my-upload']['tmp_name'] === '/tmp/php5Wx0aJ'

$lowercaseFilter = new LowerCase();
$file = $lowercaseFilter->filter($files['userfile']);
$renameFilter = new Rename([
    'target'    => '/tmp/newfile.txt',
    'randomize' => true,
]);
$filename = $renameFilter->filter($file['tmp_name']);

With this example, the final, stored file on the server will have the lowercased content.

If you want to use a specific encoding when converting file content, you should specify the encoding when instantiating the LowerCase filter, or use the setEncoding method to change it.

use Zend\Filter\File\LowerCase;
use Zend\Http\PhpEnvironment\Request;

$request = new Request();
$files   = $request->getFiles();
// i.e. $files['my-upload']['tmp_name'] === '/tmp/php5Wx0aJ'

$filter = new LowerCase();
$filter->setEncoding('ISO-8859-1');
$filter->filter($files['my-upload']);

The LowerCase filter extends from the StringToLower filter; read the StringToLower documentation for more information about encoding and its exceptions.

Rename

Zend\Filter\File\Rename can be used to rename a file and/or move a file to a new path.

Supported Options

The following set of options are supported:

  • target (string; default: *): Target filename or directory; the new name of the source file.
  • source (string; default: *): Source filename or directory which will be renamed. Used to match the filtered file with an options set.
  • overwrite (boolean; default: false): Shall existing files be overwritten? If the file is unable to be moved into the target path, a Zend\Filter\Exception\RuntimeException will be thrown.
  • randomize (boolean; default: false): Shall target files have a random postfix attached? The random postfix will generated with uniqid('_') after the file name and before the extension. For example, file.txt might be randomized to file_4b3403665fea6.txt.

An array of option sets is also supported, where a single Rename filter instance can filter several files using different options. The options used for the filtered file will be matched from the source option in the options set.

Usage Examples

Move all filtered files to a different directory:

// 'target' option is assumed if param is a string
$filter = new \Zend\Filter\File\Rename('/tmp/');
echo $filter->filter('./myfile.txt');
// File has been moved to '/tmp/myfile.txt'

Rename all filtered files to a new name:

$filter = new \Zend\Filter\File\Rename('/tmp/newfile.txt');
echo $filter->filter('./myfile.txt');
// File has been renamed to '/tmp/newfile.txt'

Move to a new path, and randomize file names:

$filter = new \Zend\Filter\File\Rename([
    'target'    => '/tmp/newfile.txt',
    'randomize' => true,
]);
echo $filter->filter('./myfile.txt');
// File has been renamed to '/tmp/newfile_4b3403665fea6.txt'

Configure different options for several possible source files:

$filter = new \Zend\Filter\File\Rename([
    [
        'source'    => 'fileA.txt'
        'target'    => '/dest1/newfileA.txt',
        'overwrite' => true,
    ],
    [
        'source'    => 'fileB.txt'
        'target'    => '/dest2/newfileB.txt',
        'randomize' => true,
    ],
]);
echo $filter->filter('fileA.txt');
// File has been renamed to '/dest1/newfileA.txt'
echo $filter->filter('fileB.txt');
// File has been renamed to '/dest2/newfileB_4b3403665fea6.txt'

Public Methods

The Rename filter defines the following public methods in addition to filter(): follows:

  • getFile() : array: Returns the files to rename along with their new name and location.
  • setFile(string|array $options) : void: Sets the file options for renaming. Removes any previously set file options.
  • addFile(string|array $options) : void: Adds file options for renaming to the current list of file options.

RenameUpload

Zend\Filter\File\RenameUpload can be used to rename or move an uploaded file to a new path.

Supported Options

The following set of options are supported:

  • target (string; default: *): Target directory or full filename path.
  • overwrite (boolean; default: false): Shall existing files be overwritten? If the file is unable to be moved into the target path, a Zend\Filter\Exception\RuntimeException will be thrown.
  • randomize (boolean; default: false): Shall target files have a random postfix attached? The random postfix will generated with uniqid('_') after the file name and before the extension. For example, file.txt might be randomized to file_4b3403665fea6.txt.
  • use_upload_name (boolean; default: false): When true, this filter will use $_FILES['name'] as the target filename. Otherwise, the default target rules and the $_FILES['tmp_name'] will be used.
  • use_upload_extension (boolean; default: false): When true, the uploaded file will maintains its original extension if not specified. For example, if the uploaded file is file.txt and the target is mynewfile, the upload will be renamed to mynewfile.txt.

Using the upload name is unsafe

Be very careful when using the use_upload_name option. For instance, extremely bad things could happen if you were to allow uploaded .php files (or other CGI files) to be moved into the DocumentRoot.

It is generally a better idea to supply an internal filename to avoid security risks.

RenameUpload does not support an array of options like theRename filter. When filtering HTML5 file uploads with the multiple attribute set, all files will be filtered with the same option settings.

Usage Examples

Move all filtered files to a different directory:

use Zend\Http\PhpEnvironment\Request;

$request = new Request();
$files   = $request->getFiles();
// i.e. $files['my-upload']['tmp_name'] === '/tmp/php5Wx0aJ'
// i.e. $files['my-upload']['name'] === 'myfile.txt'

// 'target' option is assumed if param is a string
$filter = new \Zend\Filter\File\RenameUpload('./data/uploads/');
echo $filter->filter($files['my-upload']);
// File has been moved to './data/uploads/php5Wx0aJ'

// ... or retain the uploaded file name
$filter->setUseUploadName(true);
echo $filter->filter($files['my-upload']);
// File has been moved to './data/uploads/myfile.txt'

Rename all filtered files to a new name:

use Zend\Http\PhpEnvironment\Request;

$request = new Request();
$files   = $request->getFiles();
// i.e. $files['my-upload']['tmp_name'] === '/tmp/php5Wx0aJ'

$filter = new \Zend\Filter\File\Rename('./data/uploads/newfile.txt');
echo $filter->filter($files['my-upload']);
// File has been renamed to './data/uploads/newfile.txt'

Move to a new path and randomize file names:

use Zend\Http\PhpEnvironment\Request;

$request = new Request();
$files   = $request->getFiles();
// i.e. $files['my-upload']['tmp_name'] === '/tmp/php5Wx0aJ'

$filter = new \Zend\Filter\File\Rename(array(
    'target'    => './data/uploads/newfile.txt',
    'randomize' => true,
));
echo $filter->filter($files['my-upload']);
// File has been renamed to './data/uploads/newfile_4b3403665fea6.txt'

Uppercase

Zend\Filter\File\Uppercase can be used to convert all file contents to uppercase.

Supported Options

The following set of options are supported:

  • encoding: Set the encoding to use during conversion.

Basic Usage

use Zend\Filter\File\UpperCase;
use Zend\Http\PhpEnvironment\Request;

$request = new Request();
$files   = $request->getFiles();
// i.e. $files['my-upload']['tmp_name'] === '/tmp/php5Wx0aJ'

$filter = new UpperCase();
$filter->filter($files['my-upload']);

See the documentation on the LowerCase filter, above, for more information.

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