Drupal 7 Module Development

Creating Your First Module
The help hook
Drupal defines a hook called hook_help(). The help hook is invoked (called) when
a user browses the help system. Each module can have one implementation of
hook_help(). Our module provides brief help text by implementing the help hook.
function first_help($path, $arg) {
if ($path == 'admin/help#first') {
return t('A demonstration module.');
}
}
How does this function become a hook implementation? Strictly by virtue of its
name: first_help(). The name follows the hook pattern. If the hook is named
hook_help(), then to implement it, we replace the word hook with the name of
the module. Thus, to implement hook_help(), we simply declare a function in
our first module named first_help().
Each hook has its own parameters, and all core Drupal hooks are documented at
http://api.drupal.org.
A hook_help() implementation takes two arguments:
• $path: The help system URI path
• $arg: The arguments used when accessing this URL
In our case, we are only concerned with the first of these two. Basically, the help
system works by matching URI paths to help text. Our module needs to declare
what help text should be returned for specific URIs.
Specifically, the module-wide help text should be made available at the URI admin/
help#MODULE_NAME, where MODULE_NAME is the machine-readable name of the module.
Our function works by checking the $path. If the $path is set to admin/help#first,
the default help screen for a module, then it will return some simple help text.
If we were to enable our new module and then look at Drupal's help text page with
our new module enabled, we would see this:
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