Drupal 7 Module Development

Drupal Permissions and Security
When our module is enabled, the settings for these two permissions will be changed
for the anonymous user.
The user_role_change_permissions() function is actually used
by the form submit handler for the Permissions form. By abstracting
this logic to a function, Drupal provides an easy API call for other
modules. When building your modules, you should look for similar
opportunities so that other developers can build off your code instead of
re-implementing similar logic.
Defining roles programmatically
Just as with permissions, Drupal 7 allows roles to be set through a simple function
call. The new user_role_save() and user_role_delete() functions provide the
tools your module needs.
The user_role_save() function merely adds a new named role to the {roles} table
and assigns it a proper role id ($rid). The user_role_delete() function removes
that role from the {roles} table, and also cleans out any associated permissions
stored in the {role_permission} table and any user role assignments stored in
the {users_roles} table.
Let's say that your module allows users to moderate other user accounts. This is a
powerful capability on a site, so your module automatically creates a new role that
contains the proper permissions.
As in our preceding example, we will use hook_enable() to create the new role.
/**
* Create a role for managing user accounts.
*/
function account_moderator_enable() {
// Create the 'account moderator' role.
user_role_save('account moderator');
}
After creating the role, we can also auto-assign a series of permissions:
/**
* Create a role for managing user accounts.
*/
function account_moderator_enable() {
// Create the 'account moderator' role.
user_role_save('account moderator');
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