How to Use Filters and Actions of WordPress File Upload Plugin

WordPress File Upload plugin for WordPress makes use of filters and actions for allowing the administrator to perform some advanced pre and post processing of the uploaded files.

There are currently two filters and one action:

• Filter wfu_before_file_check: It is executed before file is uploaded and before any internal file checks, in order to allow the filter to perform its own checks or change some basic upload parameters, such as filename or userdata.
• Filter wfu_before_file_upload: It is executed right before file is uploaded, in order to allow the filter to change the file name.
• Action wfu_after_file_upload: It is executed after the upload process for each individual file has finished, in order to allow additional actions to be executed.

Suppose that we want to modify the filename of the uploaded file and add a timestamp at the end of it for every uploaded file. To do this, we will need to implement wfu_before_file_upload filter and write some php code.

For the moment the plugin does not provide a tool to write php code. We need to add a 3rd party plugin to allows us to do so. I personally like Custom css-js-php by Flippercode because it allows to easily write code for filters and actions. So, the instructions to implement the filter are the following:

1. Install Custom css-js-php plugin by Flippercode and activate it.
2. Go to CSS-JS-PHP section of your Dashboard and press “Add New PHP”.
3. Give any title, like “Uploaded Filename Timestamping”
4. Select Apply Using WP Filter.
5. In the Filter Name write wfu_before_file_upload.
6. Write the following code in the textbox below “Write your code here” and press Save.

function wfu_before_file_upload_handler($file_path, $file_unique_id) {
    // separate file name from file path
    $only_filename = basename($file_path);
    $only_filepath = substr($file_path, 0, - strlen($only_filename));
    // separate file extension from file name
    $dot_pos = strrpos($only_filename, ".");
    if ( $dot_pos ) {
        $ext_part = substr($only_filename, $dot_pos);
        $name_part = substr($only_filename, 0, $dot_pos);
    }
    // add timestamp to the end of name_part
    $current_datetime = gmdate("U");
    $only_filename = $name_part . "-" . gmdate("YmdHis", $current_datetime) . $ext_part;
    // return the full file path
    $file_path = $only_filepath . $only_filename;
    return $file_path;
}

Here is a screenshot:

After you do all the above and upload a file, the filename will get a timestamp. Within the above function you can do any other modification to the filename, however please note that the plugin will not check if the filename is valid (it has done so before the filter), so take care to modify the filename correctly.

Future versions of WordPress File Upload plugin will allow the administrator to add php code easily without the need of a 3rd party plugin.

Happy coding…

The Iptanus Team