If you've read the first couple of installments of this series, you should have a pretty good idea of what the "semantic web" is by now. By providing precise meaning to a site's content, applications can take advantage of these machine-readable hints to link data together across sites in a myraid of ways. Before you jump in the deep end of the semantic web pool, there's a few more things you should have a clear understanding of.As I previously defined, RDF stands for Resource Description Framework. This is a family of standards for describing content on the web. The vast majority of current and future Drupal implementations of RDF are actually RDFa (Resource Description Framework in Attributes), a set of extensions to XHTML. RDF is normally implemented using XML; while this is possible with Drupal, RDFa allows Drupal to implement RDF as part of the standard content displays.
Even if you're not ready to implement RDF into your Drupal site, there's still a number of reasons why you should be excited about the Semantic Web. The fact that data will be linked from web site to web site (regardless of the underlying technology running the site) will lead to powerful Semantic Web applications - most of which haven't even been imagined yet. First and foremost, search will be revolutionized. Imagine being able to search for a specific person - not just the person's name. This is a subtle but important distinction. Currently, when you type "Dave Matthews" into your favorite search engine, the results you see are based on the words "Dave" and "Matthews". You'll see results about Dave Matthews, about people with the name "Dave" and/or "Matthews", about the orgin of the words "Dave" and "Matthews", etc... The search engine doesn't know that you're looking for a specific person with the name "Dave Matthews". With the Semantic Web, you'll be able to specify, "find me the person with the name 'Dave Matthews'". You'll even be able to perform "deeper" searches by specifying things like "find me all events having to do with Drupal taking place between now and July". Other than search, the Semantic Web will also provide you with the ability to do stuff with this data. For example, let's say you perform the Drupal events search from the previous paragraph and you're looking at the results. Because the data returned will have meta-data attached to it, future software tools will allow you to click on a returned event, and see if you're available on that date and time. If so, another click will seamlessly add it to your calendar. If you're familiar with Mac OS X, it's like data detectors on steriods. Really good steriods.
RDF. Semantic Web. Giant Global Graph. Food for Robots. By now you've probably heard all of these phrases, but relatively few of us have actually done anything with them. For example, I try to follow all the RDF modules on Drupal.org, read all the blog posts regarding Drupal and RDF but I've yet to implement anything having to do with RDF on any of the sites I develop or maintain. Why is this? Am I behind the curve?The answer is two-fold. First, I have yet to have any clients specifically ask for RDF functionality in their web sites. Secondly, I hadn't been convinced that recommending that my clients spend the time and money to implement an RDF solution is a sensible move for them. The reason I decided to research and write this series of articles is to figure out if and why I should recommend implementing RDF functionality to my clients.Prior to performing the research for this series, my knowledge of RDF was limited to water-cooler-conversation type knowledge. Big on bulletpoints, small on details. I was aware that RDF will, in the future, be used by search engines to provide better search results. I was also aware that by "tagging" web site content with RDF would enable a "richer" experience. The one example I would relay to people was a vCard-powered business card embedded on a web page using microformats that allowed the user's computer to do something with the contact information. Amusingly, it turned out that my one RDF example didn't even involve RDF, and that the vCard format was actually called hCard when used as a microformat. I had a lot to learn.
At the most recent Florida Drupal User's Group meetup, I gave a quick rundown of some of the new stuff that has made it into Drupal 7 core. It was by no means an in-depth look, it was mainly designed to give people a quick update on what they have to look forward to in the next version of Drupal.
It could have been an April Fools joke. On April 1st we got the call. "We have mockups for the design of the site, and we need the theme done in 2 weeks. After that we can discuss the XML import part of the project. We need to go live at the beginning of May." We knew it would be a challenge, but we made it happen - on May 7th the site went live.
This article is also available in French from KolossalDrupal.com. The extremely useful Node Import module has been around for over 4 years now - which is an eternity in Drupal-land - but in recent days other newer, shinier import modules have hit the scene. While these modules certainly are useful for many applications, sometimes the tried-and-true works just fine. In this article, I'm going to show you how to use the Node Import module to import data in CSV format (comma separated values) and map that content to existing content types that include node reference, text, and integer fields - including multi-select checkboxes.
Sometimes in our lives, we all have pain, we all have sorrow. And sometimes we also have to launch Drupal sites into the wild blue yonder. It's during these times that we separate the grown-ups from the n00bs, and we see how well our site performs under heavy load. Many of us didn't need to worry about speed, page size, and server load in our younger years when we were building sites for Uncle Don and Aunt Sue, but eventually you get that big client, and you need some help. Testing your site's performance There are several ways to test, and a few metrics to acquaint yourself with. Not all metrics are created equal, but all of them are important at one time or other. In Part I of this post, you will be reading about testing with the Apache Benchmark tool on the command line.
This article is also available in French, courtesy of KolossalDrupal.org. When it comes to starter themes in Drupal, there are two names that seem to always rise to the top: Zen and Blueprint. This article is about the latter, and how to get started with it. So, why is Blueprint a good starter theme? First and foremost, it's incorporates the Blueprint CSS Framework, an open-source project all on its own. The framework was designed to speed up CSS development time - specifically "layout" CSS where various HTML elements are positioned on the page. It also provides "sensible typography", a stylesheet for printed pages, and other features. The "layout" aspect of Blueprint is based on a grid-based system that breaks up the page into any number of columns that are very accessible from CSS. This is where the true power of Blueprint appears. What advantage does this give you as a Drupal theme developer? First and foremost, it cuts down on your development time by virtually guaranteeing that (providing you use the Blueprint CSS as designed) cross-browser CSS "float" issues are a thing of the past. Need a page layout that breaks up an entire page into any number of blocks? No need to get the Panels module involved, it's easy to do with Blueprint. You can Panel-fy pages without all the overhead (or learning curve).
Rounded corners are all the rage - and they have been for quite some time in web design. The way they "soften" up a design make them quite attractive to designers and decision-makers. Unfortunately, implementing rounded corners in a web page is not nearly as easy as it is to implement in a mockup using an image application. When talking about rounded corners, there are 2 distinct user cases to be considered - the first is when creating rounded corners only on the top corners of an area - this is commonly seen on tabs and block headers. The alternative use case is when all four corners of an area are rounded - this is usually seen in blocks and around content areas. This article will focus on the the case where all four corners need to be rounded. The result will be a method of adding the ability to optionally apply a rounded border to any block on your site in a way that doesn't break when the block is resized. By the end of the article, you should be able to add this option to just about any Drupal theme - the relevant files you'll need are available for download at the end of this article.
Keeping a site's design as clean as possible is something all (well, okay, maybe not "all") designers and developers strive for. One relatively easy thing that you can do towards this goal is removing the supporting (and often unnecessary) text around your site's search field. I'm talking about the "Enter search terms" or "Search this site" text that floats innocently above or next to the text input box. Is this really necessary? I don't think so. A much cleaner way of presenting a search box is with some default text inside the input field that automatically disappears when the user moves the cursor into the field.
Ubercart is arguably the leading ecommerce module suite for Drupal. It allows site admins to sell virtually just about anything online, including physical products, downloadable products, and event admissions. Often, when selling event admissions, it is desirable for the registrant to be able to fill out a profile during the checkout process that can be posted on the site once the transaction is complete. The UC Node Checkout module was built for this purpose. This is the way last year's Do It With Drupal conference handled registrations - with these exact modules. Setting it up can be a little tricky, as it is not entirely a straight-forward process. Ryan Szrama, the de-facto leader of the Ubercart project, demoed this module during the recent DrupalCon DC. I thought I'd take the time to reproduce what Ryan did, as it is a great introduction to this module. Keep in mind it won't be an exact reproduction, but it should be pretty close. This article will assume you're familiar with some very basic Ubercart concepts, if you're not, don't worry, this isn't rocket science. One thing you'll need to do if you're playing along at home is to create the "keys" directory for test credit card payments - full info on this is located at admin/store/settings/payment/edit/methods in your Drupal install (assuming you already have Ubercart enabled).
The Flag module is one of those modules that in its previous incarnation (as the Views Bookmarks module) was a bit inflexible and often (at least in my cases) required some manual tweaking of the code to get it to do exactly what I wanted (no offense to the original authors, I actually used it a surprising number of times). The updated and renamed module is a breath of fresh air - it is an ease to install and configure for any number of use cases - in this article, I'll demonstrate how you can set up a list of the best comments on your site. The Flag module is extremely useful mainly due to its excellent integration with other Drupal modules - specifically Views and Actions (part of Drupal 6 core). It's also chock-full of AJAX-y goodness (flagging items doesn't require a full page refresh) and a plethora of configuration options.
This article is also available in French. Displaying hierarchical content is a common request of database-driven web sites. Drupal gives you great flexibility in doing this without writing a single line of code, using a couple of battle-tested modules. As an example, let's say you're building an automotive web site. Your site is going to have a list of automotive brands and the vehicles they build. You'd like to only have to enter each brand's information into the database once, then simply refer to that brand whenever you add one of their vehicles to the site. In this example, I have 2 brands, Chevy and Jeep, and each brand has 3 vehicles. Drupal's powerful CCK module allows you to define different content types for your web site. The Node Reference module, included with the rest of CCK, allows you to set up hierarchical relationships between content types.
The "summary" list is Views is a really handy feature, but unless it is properly configured, it can lead to an inconsistent experience for end-users. The goal of this post is to demonstrate how a little bit of configuration can provide a very consistent user experience. Here's a quick example of what I'm trying to avoid: consider the following content type called, "Food": As you can see, it is a very simple content type, with only a single added field, "field_food_type". This text field is set up to require the user to select one of its options. When creating a view to show all "Food" nodes, there might be too many to display all at once - you'd like to break up the view by food type in order to allow the user to drill down to the food they're looking for. Using a single Views 2 "Page" display, this is easy to do - just add an argument for the food type and have it display a summary when no argument is present: This will result in the showing only the food types when the page is displayed with no arguments: When one of the food types is clicked on, you'll see a list of matching foods: This works great and is easy to set up if this is what you're looking for. However, I find that often I'd like the summary and a listing of matching content to be displayed at all times. When there is no argument present, then I want a paged list of all the content as well as the summary. When an argument is present, I want the filtered content but I still also want the summary. This can be quite easily done using a display attachment.
I recently had a site that I do volunteer work for ask me if I could create an image slideshow for them on the home page of their Drupal 5.x-powered site. They wanted to showcase various large images on their homepage fading from one to another, as well as be able to control what images were contained in the slideshow. The solution had to be easy to use and maintain as they don't have a dedicated IT person on staff.