How to check if library is present in vendor folder?

Question

I have a form in which I am providing some options to users. But I want the options to appear in the form on the basis of presence of 3rd party libraries in vendor directory. I want something like this:

public function buildForm(array $form, FormStateInterface $form_state) { $form['settings']['tools'] = array( '#type' => 'radios', '#title' => $this->t('tools'), '#options' => array(), '#default_value' => $this->config('module.settings')->get('tools'), ); if(check_whether_xyz_library_is present_in_vendor_folder) { $form['settings']['tools']['#options'] = array('xyz' => 'xyz'); }

The vendor folder is present in the module directory itself and I am using composer to download third party dependencies. Since I do not want to check this during installation of module but during form rendering then I suppose hook_requirements is not option. Any ideas on how to do so?

Answer 1

If you are talking about libraries, which are defined in files like *.libraries.yml, then you can use this:

\Drupal::service('library.discovery')->getLibraryByName('MODULE_NAME', 'LIBRARY_NAME')

You'll receive an array with all data including paths to check that files are exist.

Answer 2

Since you mention that "the vendor folder is present in the module directory itself", you could check that a vendor file exists within your module:

$module_path = drupal_get_path('module', 'MY_MODULE');    
if (file_exists($module_path . '/js/MY_FILE.js')) {
  // ...
}

Another option would be to store the vendor library in the libraries folder, and check if the library exists with libraries_get_path():

$name = 'foo';    // your library name here.
if (function_exists('libraries_get_path') && file_exists(libraries_get_path($name))) {
  // ...
} 

Answer 3

The way external libraries are loaded and stored may change before (and even after) Drupal 8 release. Further sites build using composer may have the libraries installed in a different place than sites build with "manually" placed modules. Therefore I advise not to check the content of a vendor directory, but directly check for the presence of the library or one of its classes by using class_exists(). This way your code is independent of the library location.