In this chapter we learn other ways to interact with our database beyond the simple db_select() query from the earlier video. This example walks through writing a module that that saves and displays data about how many times a user has visited a specific page. We learn about db_select(), db_insert(), db_update(), db_merge(), db_delete() and introduce the concept of "get and set" helper functions.
In this chapter we learn how to create a new database table. This example walks through creating a module that defines the the properties of our new table and also programatically creating that table. We learn about hook_schema() and hook_update_N() in our module's install file.
Trainers note: This video starts out with a module that implements hook_node_view() and stores data about views in the $_SESSION variable. It also states that we built this earlier in the series. However, that's not true. We did talk about hook_node_view() in https://drupalize.me/videos/event-driven-hook-system, but we never actually wrote the $_SESSION handling part. So, if you're following along and want the same sample code we start with make sure you download the code attached to this node.
In this excerpt from the Overview of Drupal 7, Angie Byron, talks about the Database API in Drupal 7. This was a round table discussion with other Lullabots on the line who ask and answer questions, in addition to Angie's presentation. This lays a good foundation for how the database system works in Drupal and sets you up for the hands-on tutorials that follow.
Additional resources
This video goes through the process of changing some of the properties of a form with the hook_form_alter() function. This hook is a very powerful tool to be able to modify existing Drupal forms, created by core or contributed modules, and tailor them to your needs.
This video shows how a module can integrate with Drupal's theme system by exposing a new themeable item to the theme registry with hook_theme(), and then creates a function in order the customize the output of that themeable item. The then video demonstrates how the theme layer can override the markup defined with theme functions at the module layer.
This presentation provides an overview of the different phases of the form submission and validation process that Drupal uses with the Forms API. This will give you a good foundation for implementing forms yourself in the following videos.
This video shows how to target a specific form with the hook_form_FORM_ID_alter and creating a customized validation function for a form.
Note: There is a typo in this video. (The code is correct in the downloadable example file attached to the previous video.)
In the demo_validate_password() function, the following line shown in the video if (in_array($form['values']['pass'], $badpasswords)) { should be if (in_array($form_state['values']['pass'], $badpasswords)) {.
In this lesson, we pull our work together by creating a new view on the site that uses the work we've done so far with exposing our data, and creating our handlers. Once we create the view, we'll export it and add it to our module as a default view.
In this lesson Joe demonstrates how to extend the default views sort handler and create a new one for use on our table that will allow us to sort the data returned from a query with the rows that belong to the currently logged in user at the top of the list. This lesson builds on information from the previous couple of lessons regarding implementing views handlers and general coding for views best practices.
In this lesson Joe takes a look at writing a custom filter handler by building on the knowledge gained about writing handlers from the previous lessons. Filter handlers control how data in a table is treated when being used in the context of a views filter including things like how the data is represented, what the form for filtering looks like and more.
In our original Databasics module, we had some access control around who could see the tab we are providing on the user page. Now that we have switched that tab to being a view, we need to still add that access control back. In this lesson, we will work with a new feature of Views: plugins. We will create an access plugin that gives us the freedom to add our own custom access control, along with settings to give our users a choice about what access they'd like to use.
Domain Access can do its magic because of the Drupal node access system. In this tutorial we'll walk through the basics of how this system works, highlighting the two main methods, and then explain why this may be important information for you. We won't be diving into the code side of things, but instead outline the basic concepts for anyone who needs to interact with this system. When using a module like Domain Access, you should be aware of the Drupal context in which you are working, even if you hopefully never have to dive into the details.
Additional resources
Controlling Access to Content Overview (drupal.org handbook)
Node access developer documentation (api.drupal.org)
Before we set up a multisite we need to understand how Apache and Drupal work together to deliver the site we intend. In this lesson we'll look at the documentation for Drupal multisites, and then discuss the way you need to set up your Drupal directories. We'll also review the workflow that Apache and Drupal go through to get the correct site displaying in the browser.
Additional resources
Multi-site - Sharing the same code base (drupal.org)
In this lesson we'll be building a simple university site, udrupal.com, with different areas, each with their own website: the main site, a news site, and an alumni site. The news site is simply a subdomain of the main domain name, news.udrupal.com, and the alumni site actually has its own separate domain name, udrupalalumni.com. To get this done, you're going to learn how to confirm the DNS is working for the domain names. That is, that they are currently pointing to the right server. Then we're going to configure an Apache vhost on our server so that Apache knows where to find our Drupal code base. We'll finish things up by installing our main Drupal site, udrupal.com.
Additional resources
With our domains and Apache configuration in place, we need to make sure all three sites can be installed at the different domains by creating our multisite directories in the sites folder. In this tutorial, we'll create the necessary Drupal site directories and settings files for the three sites so they are all running smoothly, check the domains and install the other two sites, and wrap up by changing the theme on the alumni site.
Before we get started, you should make sure you have two empty databases created for the two new sites we'll be installing.
In this tutorial we're going to be working directly on a server using the command line. You can feel free to use a GUI interface for your site, like an SFTP app or just your local machine file browser and editor apps. If you want to brush up on using the command line, you can check out our free Command Line Basics series.
If we want to do development work on the university multisite, we need to do a few things to have this run smoothly in a local development environment with all of those URLs. The sites.php file is going to let us define aliases for the site configuration folders in /sites. In this tutorial we'll explain why local development with multisite is tricky, and how to get it set up properly.
Additional resources
example.sites.php (api.drupal.org)
Drush is a really great tool for managing your Drupal site quickly and easily. If you don't already know about Drush, you should definitely check it out. When working with a multisite installation though, Drush can get confused if you don't give it all the information it needs. In this lesson we'll walk through how to use Drush properly with a multisite installation, covering both how to manage just an individual site and how to work with all of your sites at the same time.
One of the best ways to improve both the speed, and relevancy, of search results for a Drupal site is to stop using the Drupal core search module and start using Apache Solr. Solr is a Java-based application that provides an API for interacting with Apache Lucene via HTTP to facilitate the creation of excellent applications for performing full-text content searches, with a special focus on internet-based search applications. The quick pitch for why you should use Solr is it's insanely fast, especially when compared with Drupal's default Search module, and it can be scaled to handle millions of search queries per second and huge piles of data.
Since Solr is a third party application we need a way to bridge the gap between Solr and Drupal. Really, there are two parts to this puzzle: getting the data out of Drupal and into Solr so it can be processed and indexed, and passing a search query from Drupal to Solr in order to retrieve, and display, search results. For that, we'll use the Search API module, and the Search API Solr module.
In order to demonstrate a real-world use case we'll pretend that we're the owner of a website that contains a database of fish species. As the database has grown over time we've begun to feel the limits of Drupal's MySQL full-text search and want to improve our search tools. Using Solr will allow for better matches in full-text search, faster searches, and a lot of additional functionality like partial word matches, spell checking, facets, and more.
In this series we'll cover:
- What Apache Solr is and why you should consider using it
- Installing Solr and configuring it to work well with Drupal content
- The contributed Search API module
- The contributed Search API Solr module
- Configuring Drupal to send content to Solr for indexing
- Retrieving search results from Solr and displaying them in Drupal on both a stand-alone page and with the Views module
- Using Solr field boosting to influence result relevancy
- Using the contributed Facet API module with Solr to allow for faceted search results
- Configuring stop words, synonyms, and promoted search results in Solr
This series is for anyone that wants to improve the quality of the search functionality of their Drupal-powered site. There is some system administration required to install Solr, but it's pretty straightforward. Almost everything else is done via configuration in Drupal's, or Solr's, user interface and by editing simple XML configuration files. So, no PHP, or module development experience required. We do however assume that you're already familiar with basic Drupal administration.
Additional resources
Apache Solr is a world class search application built on top of the Lucene indexer. Before we start trying to integrate Solr with Drupal lets talk about what Solr is, and what makes it so good, as well as how Solr differs from the Drupal core database-backed Search module. This tutorial is a short presentation explaining Solr, Lucene, and things to consider when choosing Solr as a search technology.
Lucene is an open-source search indexer written in Java and governed by the Apache foundation. It is the underlying library that handles storing indexed content, and does so in a way that makes it extremely flexible. By treating each record as a document made up of any number of different fields Lucene is capable of storing just about anything you throw at it, as long as the resource can be broken up into fields and the textual data can be extracted from those fields. This makes it a good choice for indexing web based content where you might be dealing with HTML, PDF, XML, Microsoft Word, and all kinds of other document formats.
Solr, is an HTTP API for interacting with the Lucene application that makes it easier to create custom search applications. Like Lucene it is also open source, written in Java, and governed by the Apache foundation. Solr's extensive use of XML configuration files allows you to modify almost everything about how Solr works without having to write any Java. This makes it a great choice for anyone that's familiar with PHP but doesn't have Java experience.
When compared with Drupal core's Search module, or any MySQL full-text search tool, Solr has some distinct advantages. Including:
- Best-in-class stemming and tokenization
- Scalability; it's designed to scale both vertically and horizontally as needed
- Built-in support for facets, geospatial searches, and other advanced query options
In addition to these advantages, using Solr for your search can dramatically improve your Drupal site's performance by eliminating costly full-text queries, which can quickly turn MySQL into a bottleneck for sites with even a modest amount of content.
By the end of this tutorial you should be able to explain the advantages that Solr provides over Drupal core's search module and why it's a good choice for building ultra-fast, and accurate, search applications.
Additional resources
When it comes to integrating Apache Solr with Drupal there are currently two different modules that can be used, Search API, and the Apache Solr module. While both are valid options, for this series we've chosen to focus on the Search API module because amongst other things it's generally more flexible, and based on conversations with people in the community who are working on Solr integration it is currently seeing more focused development efforts and will likely superseded the Apache Solr module sometime in the future.
This tutorial provides some background information on the Search API module and why we've chosen to use it. We'll look at how the Search API module bridges the gap between Solr and Drupal, and explain some of the commonly used terms we'll encounter in the module's UI and codebase.
By the end of this lesson you should be able to explain the Search API module's terminology, requirements, and position in the Drupal ecosphere, as well as be able to make a good case for why someone should choose the Search API module as a starting point for creating better search tools in Drupal.