This lesson will explore the use of EntityFieldQuery to retrieve lists of entities from Drupal without directly querying the database which can be problematic in a system where the underlying schema can change depending on configuration settings in the user interface. Again focusing on writing code that will work with any entity in Drupal and isn't hard coded to your particular setup.
Additional resources
In the next set of lessons we're going to be writing to the code to create our own custom entity type. The goal is to create a video entity that stores embed codes for YouTube videos and allows us to display the videos on our site. In this scenario we don't want all the overhead that comes with using the node system, like comments for example, so instead we're going to write our own custom entity for storing the data. We're going to take a look at the completed entity type that we're attempting to build and just walk through all the various components. We'll take a look at creating/updating, and deleting a video via the UI, and also the views integration and fieldability of our custom video entities.
This lesson introduces students to Entity classes and illustrates what each of the main Entity classes does, followed by a more in depth look at the CRUD operations provided by the base entity class, and finally demonstrates overriding the default Entity class with our own custom Entity object to define a defaultUrl() for our entities and a new implementation of hook_menu where we can view an entity.
Note: At the end of the this video code is added to hook_entity_info() that references a VideoEntityUIController class, however, the definition of that class is in our sample code, but was not shown being added here. And it is necessary to follow along with the videos. If you're following along you'll want to add the following code to the bottom of your videoasset.module file. If you're curious about what it does it's explained in the last part of this video.
/**
* Our custom controller for the admin ui.
*/
class VideoEntityUIController extends EntityDefaultUIController {}
Additional resources
Update your hook_entity_info implementation to take advantage of the Admin UI provided by the Entity API and quickly provide users of your site access to all the Entity CRUD operations via the UI. The API gives us a really good head start but we still need to write some code in order to provide a useable form for administrators. The API doesn’t make any assumptions about things like validating input so we also need to take care of that ourselves.
This video adds a new permission that allows privileged users administer our new videoasset entities. If you're following along as a user other than user 1 you'll need to make sure you give yourself the proper permissions. In the video, I'm logged in as the user with the ID of 1 so I'm just granted the permissions automatically.
Note: If you're following along with the videos in sequence there's an error that needs correcting. At the end of the previous video code was added to videoentity_entity_info() that references a VideoEntityUIController class, however, the definition of that class was not added. Which, will cause a PHP error because the class is missing.
In order to correct this error, you'll want to add the following code to the bottom of your videoentity.module file. This just ensures that the class is defined so that there are no errors. If you're curious about what it does it's explained in the last part of the previous video.
/**
* Our custom controller for the admin ui.
*/
class VideoEntityUIController extends EntityDefaultUIController {}
In a later tutorial in this series, we'll customize the form for our video entity by adding more code to this class.
Note: At 14:10 on line 36 this line is added:
'#value' => isset($VideoAsset->id) ? t('Update video asset') : t('Save video
asset'),It should be:
'#value' => isset($video->id) ? t('Update video asset') : t('Save video
asset'),
So far we’ve seen that you can use entity_load and entity_view to display your entity. But what if you want more control over how your content gets rendered? In this lesson we’ll take a look at overriding the buildContent() method of our entity controller to spruce up the output a bit. We'll also overrid the save() method of the controller in order to populate the created_at and updated_at fields automatically when saving a video entity.
Note: In order to improve upon the security of the code in this lesson you'll want to make sure you're escaping all user input properly. The following code:
$build['embedcode'] = array(
'#type' => 'markup',
'#markup' => '<iframe width="560" height="315" src="http://www.youtube.com/embed/'. $entity->embedcode . '" frameborder="0" allowfullscreen></iframe>',
);
Should be updated to use the check_url() function when outputting $entity->embedcode to ensure that user entered content is safe for use in the context of a URL.
$build['embedcode'] = array(
'#type' => 'markup',
'#markup' => '<iframe width="560" height="315" src="http://www.youtube.com/embed/'. check_url($entity->embedcode) . '" frameborder="0" allowfullscreen></iframe>',
);
Bundles are an implementation of an entity type to which fields can be attached. In this lesson we’ll take a look at configuring a single bundle type for our entities in order to allow us to make them fieldable by hardcoding the bundle information into hook_entity_info(). This is the most basic implementation of bundles. Then we’ll look at adding the ability to attach fields to our newly created bundle.
Because Omega doesn't make assumptions about your layout, it comes with lots of options and plenty of regions to work with. This is great but also has some down falls espcially if you are converting an exisiting theme that just doesn't need as many regions and zones. Along with removing regions you may need to add some as well. In this lesson we will demonstrate:
- Adding a region
- Removing regions
- Placing content into these regions
- Cleaning up the .info file
Once this is complete, we now have our converted theme setup just as it was before when it comes to the grid system and some blocks in place to make sure the layout is looking good.
NOTE: Kyle initially sets a position, but not the weight, of the footer_bottom region in this video, and then you'll see that he catches the mistake, and fixes it to have a weight of 3.
This chapter walks through the process of adding links to the contextual drop-down widgets new in Drupal 7. It also shows how using menu autoloaders can help simplify the code that you write in your page callback function since you won't have to do extra checking on the data.
As a note, if you are wondering why we started our function with an underscore (_), naming functions with an underscore in front of the name is a common convention in Drupal that sort of implies that "this function is for internal use by this module only" and shouldn't be called by itself. It's also a nice way to ensure that your internal functions are not colliding with the namespace of a hook or another module. Here's a good blog post about naming things.
Let’s talk about taking your image uploads and turning them into unique shapes with fabulous effects using the ImageCache Actions module.
We already know that being able to set a standard for image display creates consistency and a better user experience. Drupal comes with the ability to do basic image manipulation like resizing them. By downloading and enabling another module, ImageCache Actions, we can do fancy things to those images, making your display truly customized.
I am assuming that you already know how to create Image Style presets.
For this tutorial, you need to make sure the Image module that comes with Drupal Core and you also need to download and enable the ImageCache Actions module. This can be found at drupal.org/project/imagecache_actions.
This video walks through how to use the new hook_page_alter() in Drupal 7 by transforming an unordered list into an ordered list. Because all of the content, region & blocks are stored within a renderable array before being output to the page, then this new hook allows modules and themes to make changes to page before it is fully rendered.
This video walks through the basic use of Drupal 7's Render API for outputting content, and gives some hands-on experience in navigating and working with renderable arrays. We expand the Menu Magic module by creating several different kinds of page elements to show how renderable arrays work.
This chapter goes through the process of passing a wildcard variable to a function via an argument from the URL. It creates a MENU_LOCAL_TASK tab on the node which inverts the text to display upside down. It uses a page callback function that is included within a separate file in order to save on how much memory is used.
In this video you'll learn how to use api.drupal.org the canonical source for information about Drupal's hooks, APIs, and code documentation in order to find out information about implementing a particular hook, making use of a particular function or library of functions, and even gaining a better understanding of some of the big picture concepts behind Drupal's code and APIs.
Walks through some of the basics elements that are required and common for all Drupal modules. Then we create a simple demo module to see how it works.
This chapter describes how Drupal modules are able respond to specific events through the hook system. A couple of example hooks are implemented in order to see how this process works. This video builds on the demo module we created in the previous chapter.
It is very time consuming and error prone to repeat "click steps" among multiple sandboxes, development and production in order to get your new image styles to appear. In this video, I will show you how to write code that turns your "custom" image style into a "default" image style so that you can use source control to update all of your site environments.
I am assuming you already know how to create image styles in the administrative interface. Familiarity with basic module development is helpful, but if you follow the techniques and patterns I demonstrate, you will successfully export your image styles into a new custom module.
This chapter explains hook_page_alter(), which is another alter hook new to Drupal 7 and to the theme layer. Each page rendered by Drupal is contained within an array where the theme is able to go in and rearrange, delete or duplicate specific page elements.
Additional resources
This chapter shows some general best practices for keeping your template.php file clean as well as making it easier for designers to work primarily with the template files when possible to avoid them having to make too many changes to template.php. Specifically, some HTML classes are removed from the ninesixtyrobots_comment_form() function in template.php and moved to the comment-form.tpl.php template file, which is specified as an option in the ninesixtyrobots_theme() function. The rendering logic is also removed from the theme function and into a preprocess function so that it can be passed in as a variable to the new template file.
Additional resources
The ability of having alter hooks within the theme layer starts to blur the line between the logic and presentation, and so there are a few things to be aware of when using hook_form_alter() from the theme layer. The biggest thing to know is that the form rendering process has already gone through the creation and validation preparation process at the module layer, and so you shouldn't be drastically changing the functionality of a form at the theme layer. This form alter hook at the theme layer is primarily for aesthetic clean-up, styling and additional design. This chapter gives some specific examples of things to watch out for.
Additional resources
There are four alter hooks that are now available to the theme layer in Drupal 7. This chapter walks through two of those hooks, hook_css_alter() and hook_js_alter(). These hooks allow the theme layer to reorder, delete or replace specific CSS or JavaScript files that are being loaded by Drupal core or other contributed modules.