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- View Offline
- Creating your first module
- Interacting with hooks
- Working with permissions and roles
- Controlling access
- Adding a menu item to an admin interface
- Using the Form API (FAPI) to quickly create a form
- Creating custom form validation
- Manually creating a custom content type
- Validating user input
- Importing content using feeds
- Creating a block
- Understanding best practices and coding standards
Skill Level Advanced
Similar to help, permissions can be created with a hook. In particular, Drupal 7 uses hook_permission which applies permissions defined in a module so they can be used from the user permissions page along with granting or restricting who can execute actions. Hook permission returns an array in a standardized format. Looking at the API documentation I can see that hook permissions takes no parameters. So the only thing I need to do is generate the array structure. Though hook_permissions array consists of a key that contains the name of the permission followed by a nested array definition that contains at the minimum two key value pairs.
A title and description each passed through the t function. There are additional options, but they are used internally and rarely. Open the IDE and navigate to the windfarms.module, start with an appropriate doc block for the new hook which implements hook permission. Create a new function named windfarms permission. Hook permission takes no parameters. Next, add a return statement followed by an array definition.
The key is the name of the permission. This is commonly all lowercase with words separated by spaces. I will use administer windfarms as the key followed by a second array definition. In the sub-array I will define the title which will be properly capitalized in human readable. This is displayed in the administrative interfaces. Since this is user-facing, I will wrap the title value in the t function to facilitate translation. Finally, I will add the description.
This is usually a sentence long also wrapped in the t function, and shown in the same administrative interfaces. Perform administrative tasks on Wind Farms functionality. Save the module, return to the browser, and refresh the Permissions page. As you can see, the page does not list the new permission. The reason for this is because the permissions are cached. This is a normal issue encountered when developing in certain areas within Drupal.
A change is made but does not show up immediately. To rectify this, clear the Drupal caches, go to Configuration, and then under Development click Performance, click the button Clear All Caches. Now return to the People page. Then the Permissions tab. The Wind Farms permission will now be shown.
If you're logged in as UID 1, the root user and the first user that was created on the system, then you'll always have this permission. When a module is installed, administrators will be automatically granted the module permissions as well. Since the permission was added after the module was installed, the permission is not granted at this time. To allow other administrators to manage Wind Farms check the box under administrators for the Administer Wind Farms permission, then click Save permissions. Now that roles and permissions have been described and a new permission Administer Wind Farms has been implemented using hook permission, a protected administrative interface can be created for managing custom settings associated with custom functionality in addition to the content itself.