What way should I use to load a file from a module?

Question

What way should I use to load a file from a module?

I am writing a module which is divided into 3 parts

• Custom core will be in the module which contains basic functions required for project

• Custom notification section will handle the notifications to show on site (It has a section on site where user can see all notifications.)

• Custom mail will handle mail (Users will get email on each activity.)

So I have now a module file and 2 include files, but I am confused on how to include them in .module file.

There are 3 different methods available, but I am not sure which one is best and what the major differences between them are.

1. require_once drupal_get_path('module', 'custom_module')
2. files[] = mail.inc
3. module_load_include('inc', 'custom_module', 'mail.inc')

I tried them, and they all are working fine for now; I don't have much experience to guess future issues.

Answer 1

module_load_include() is a wrapper around require_once, with some sugar, so those are essentially equivalent. In the Drupal world, it would make sense to use the Drupal-specific function.

The files[] directive is for class autoloading - you don't use it to include files as such, just to make classes in those files available automatically when you need them.

You shouldn't use module_load_include() at the top of a module (or any other) file, it should be used only after Drupal has been bootstrapped. From the docs:

Do not use this function in a global context since it requires Drupal to be fully bootstrapped, use require_once DRUPAL_ROOT . '/path/file' instead.

Answer 2

The best way for drupal to know you have included files is having it in the files[] directive, as Clive says this is perfect for classes, but you can also use it for any files.

Using module_load_include() you can add some loading logic, you can load also files from another module, and for best performance you can load them from within a function or a conditional structure. That way is only loaded when you are using it.