Does module_invoke() work for non core modules?

Question

I tried using module_invoke('casrel','nodeapi', $node, 'view'), but what I get for casrel_nodeapi() is a truncated $node and "load" instead of "view".

Does anybody have an idea on what is happening?

Answer 1

You are probably looking for module_invoke_all. The module_invoke function only invokes a module in a specific module (casrel.module in your example).

By the way, you usually do not need to invoke hook_nodeapi yourself. The node module invokes hook_nodeapi when necessary, if you just use the api functions (like node_view) correctly. If you need to alter a node before it's viewed, you need to implement hook_nodeapi instead of invoking it.

Answer 2

Does module_invoke() work for non core modules?

Yes, it does. For module_invoke() there isn't a difference between core modules, and third-party modules as the function doesn't verify the module being called is contained in a particular list, and Drupal doesn't have a way to know if a module is a Drupal core one, or not. There are many third-party modules that use module_invoke(), and none of them has issues with the function (if it is called with the right parameters).

I agree with marcvangend that you are invoking hook_nodeapi() directly when you should be using a function that Drupal make available. Still, if you are having issues with module_invoke(), then there is something wrong with your code, or you are not tracing correctly all the calls to the implementation of hook_nodeapi() for that module.
For example, when a module implements hook_nodeapi(), that hook is called from Drupal code. Are you sure that casrel_nodeapi('load') is being called from Drupal core, and it is not what module_invoke('casrel','nodeapi', $node, 'view') is causing? Consider that Drupal always invoke hook_nodeapi('load') before hook_nodeapi('view') because a node is first loaded, and then shown.