Managed File

Extend default managed_file widget, which is a part of Form API, by a set of useful features. See examples below to be involved.

Usage

These additional options for element with '#type' => 'managed_file' is come with this module:

Add the Browse files link before the file input to use one of available file managers:

// Also could be "ckfinder".
'#widget' => 'imce',

Tired to add an image styles for every managed file field?

// Add an additional "select" element with image styles.
'#styles' => TRUE,

Want a preview of the uploaded file?

// Append a preview of the uploaded file.
'#preview' => TRUE,

Also this module implements an API of the File MD5 module.

Complete example

$form['image'] = [
  '#type' => 'managed_file',
  '#title' => t('Image'),
  // Also could be "ckfinder".
  '#widget' => 'imce',
  // Add an additional "select" element with image styles. When this is TRUE,
  // then return value will be an array with two properties: "fid" and "style"
  // instead of usual file ID as a string.
  '#styles' => TRUE,
  // Append a preview of the uploaded file.
  '#preview' => TRUE,
];

Tracking the usage of file

Remember, that to successfully track the file in your Drupal system you have to invoke the managed_file_element_submit() in a submit callback of the form.

Take a look at the module for testing as an example of complete implementation.