hook_init() is not working in my custom module

Question

In my custom Drupal 7 module I am using CUSTOM_MODULE_NAME_init() function. But it is not triggered while page execution. Any suggestions?

Answer 1

1. Make sure that the module is enabled (don't laugh, I forget that sometimes).
2. Make sure that the page is not served from cache. Use hook_boot if you need to perform setup tasks for cached pages.
3. Use a debugger to step through the execution. hook_init is invoked at the end of _drupal_bootstrap_full.

Answer 2

Hook implementations are cached in Drupal 7. After implementing a new hook, you need to clear the cache. See What method is used to clear caches in the Drupal? for ways to do that.

Answer 3

As reported in the documentation for hook_init(), the hook is not invoked on cached pages. This means that, if the content of a page is found in cache, the hook implemented by your module is not invoked.

This hook is run at the beginning of the page request. It is typically used to set up global parameters which are needed later in the request. when this hook is called, all modules are already loaded in memory.

This hook is not run on cached pages.

To add CSS or JS that should be present on all pages, modules should not implement this hook, but declare these files in their .info file.