Web Development

Drupal modules: release early, release often (please)

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Something I see quite a good amount of with Drupal modules is a tendency to hold onto fixes committed to CVS for some time. I believe this is counter productive. While yes, it is good to hold onto new, big features until they have simmered for a while and proven to be stable, smaller updates and especially bug fixes, should be rolled out regularly.

A case in point is my recent discovery that certain letters can break customized Views if you use the APIs to change the query from an equality statement to an approximation / SQL "LIKE" statement. The wizard that he is, Earl Miles, who is the lead developer on some of Drupal's most powerful modules including Views itself, took time out of his busy day and replied to my post with a link to a discussion on drupal.org which even included a patch to fix the issue. This was totally wonderful, expected, and I truly appreciate Earl's efforts for doing this.

The frustrating part for me, though, is that Earl himself provided the first patch for this issue back on September 5th, 2007. A whole fourteen months ago! And it still hasn't been rolled into an official release. A known bug, with a patch available from the main author itself, sits unreleased for a year? That's just a little bit crazy.

I believe that the Drupal development community needs to get real and become more agile with their code releases. An active project should not sit for over a year with no releases, there should have been several releases, if only bug fix point releases (Views 5.x-1.6.1 anyone?). And if the project teams can't handle the added workload, perhaps they could ask for some help? I honestly believe this would greatly help the community.

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Drupal views queries don't like "silly" arguments

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I had a weird problem with Drupal the other day.

I'm using a module I wrote which uses the views_query_alter() hook to change a views' query from doing "node.title = blah" to "node.title like blah" for a super-simple search engine. Should be simple enough. Well, it turned out that people testing it were having erratic results depending on what they tried to search. At first it was thought that the search was not being case insensitive because searching for "silly" returned no results while searching for "Silly" worked fine, but the database tables were configured correctly (MySQL, table collation set to "utf8_general_ci"), so it had to be something else.

The original query WHERE statement was "node.title = '%s'", so I wrote a function that looked something like this:

function mymodule_views_query_alter(&$query, $view, $summary, $level) {
if ($view->name == 'mycustomsearch') {
$query->where[2] = "node.title like '%%%s%%'";
}
}

Normally this would be processed by the Views module and would turn the query WHERE statement into "node.title like '%silly%'", which is what we wanted. Except that in certain circumstances it wasn't happening like that.

After some digging, thanks to the Devel module, I discovered that the query was actually ending up as "node.title like 'nodeilly%'" if the word entered was "silly". You'll note, first off, that instead of the first percentage sign it says "node". You'll also note that the first "s" is missing. As soon as I saw this I realized what was going on - somewhere the Views module was ending up with the string "node.title like '%silly%'" and for some reason the "%s" part was getting replaced with the table name, i.e. "node". Go figure.

So then came the fix.

As I was in a slight time crunch I didn't feel I had the time to dig further unto the Views code to work out a fix, so for now I just searched for alternative SQL syntax. This seemed odd to me, though, as I was basically looking for another way in MySQL for doing an SQL "LIKE" statement. As it turns out, there is another way - regular expressions.

MySQL supports a set of commands for doing regular-expression-based comparisons using the command REGEXP or RLIKE (one is an alias for the other). The syntax ended up like the following:

$query->where[1] = "node.title rlike '.*%s.*'";

Before I could unleash that upon the world I wanted to filter the input a bit more to avoid potential for security problems. In a rather heavy-handed fashion I set the input string to be filtered as follows, which only allows numbers, letters and spaces through:

$query->where_args[4] = ereg_replace("[^A-Za-z0-9 ]", "", trim($query->where_args[$]));

Putting it all together I finally had a search engine that finally let people search for the word "silly". Go figure.

Note: I do intend delving into the code to work out a hopeful fix for the root problem rather than a workaround in my module, but I felt completing the project sooner was more important than having a 100% correct fix, which will come later.

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Overriding CSS can be a pain

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One of the difficulties with Drupal is that with so many modules needed to make a good site you can end up with a dozen or more different CSS files. On occasions when you need to tweak the CSS to match a specific design, or fix something for IE6, it can take quite a while to dig down to the exact definition you need. You might try throwing random snippets of CSS at the problem to try to make it go away, but they usually won't work.

What I've found is that to successfully override CSS you have to repeat the exact same definition as the original, no matter how obtuse it my seem. So if you want to override one simple paragraph you may have to assign some pretty strange CSS, eg.:

* html .span-6 {margin-right: 5px;}

If that's what is already being used, then that's what you have to do to override it.

It may be a bit frustrating, but following that simple guideline has saved my bacon several times.

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"Build Your Own Ruby On Rails Web Applications" review

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This was 90% written in January 2007 but the draft was misplaced. Apologies to ORUG who organized obtained a copy for me in exchange for this review.


Ruby on Rails is a simply wonderful technology to develop web applications in. Like all technologies, especially ones with such depth and, at times, unique ways of working, it can take some time to get started using it to develop your own sites. Patrick Lenz comes to the rescue with his Build Your Own Ruby On Rails Web Applications book that I recommend for beginners.

"What's it all abou'?"

Over the course of the book's 400+ pages Mr Lenz gives a good foundation to build from, from installing all of the requisite tools, to basics of how to use the Ruby language that forms the basis of this system, to lots of good advice on testing your applications. The book builds up layer upon layer as it steps you through building a site similar to the community-driven link rating system Digg, all of which follow commonly used "best practices" (the techniques that help your sites be more stable, more flexible, etc).

Likes

The book reads very easily and does a good job of explaining the sample code provided as part of the Digg application.

Dislikes

An unfortunately common trait with many introductory books on technical topics is to hint at subjects related to the technology at hand, but then disregard it with a wave of the editor's delete key. This book was missing three key concepts that would have greatly rounded it off for beginners:

  • Sending email. This topic was waved away but would have been very valuable. When you think about it, the majority of web applications send email - either notifications, for verifying new accounts, or for custom newsletters, it is an extremely relevant topic and shouldn't have been skipped.
  • Interaction with 3rd party APIs. Lots of web applications use 3rd party APIs, whether it's verifying credit cards, submitting orders, obtaining mapping data, or getting the weather, there are a many, many good uses they can be put to (check if it's raining in your area, if so find stores that stock umbrellas and give you a map to them..). Interestingly this topic wasn't even mentioned, which was disappointing. Hopefully the next edition will have some good coverage.
  • REST. Everyone knows developers need more REST. Puns aside, Representational State Transfer is a new, and most would say improved, technique to pass data to and from web pages, APIs and services. Based off a more logical use of the HTTP system that binds the web together, REST defines that if you submit an ID in the URL you are reading a record, if you are submitting a form then you're either updating or creating a new record, etc, and so applications are structured to behave more cleanly in this regard. REST support was added to Rails v1.2, which this book is focused on, but it was a major oversight to not cover it. Again, a second edition should set the record straight.

Eth Ned

While not a perfect book, it does succeed with its intended goal, of easing you into writing your own Ruby on Rails applications. Some of the missing topics would have made the book more useful to intermediary users, but they shouldn't detract too much for beginners.

Recommended for beginners

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Rails tip: restful_authentication without a username

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I've personal never understood the point of having a username for web sites when 99% of them also require an email address that is unique to you - just use the email address! In the world of Rails development many developers use the excellent restful_authentication to provide the user login structure, but again out of the box it uses a username. Silly thing. So instead, here's how to make restful_authentication sit rather happy with just an email address.

The first issue is the create_users migration. By default a :login attribute is added which can be simply removed - yes, that's it. Next off is the User model. The first part of this is to remove all references to "login" from the validation statements, so e.g. instead of validates_presence_of :login, :email you have validates_presence_of :email

The second part is a little tricker: all methods that use :login have to be changed to use :email, e.g. the encrypt_password() method uses the login to make the security a little stronger, and, more importantly, the self.authentication() method is based off :login.

Once those changes have been done you can proceed to the next step. The next step is to update the views, both the users/new.rhtml and sessions/new.rhtml files need to tweaked. For users/new.rhtml just remove the paragraph that has the login field and you're done. For the sessions/new.rhtml file you need to replace all references of "login" to "email". The final part is to update the sessions controller, and once again just replace "login" with "email". That should do it. Now load up your app and enjoy simpler authentication!

Bonus Tip:

Now, make your user model even more useful and add first_name and last_name fields to the migration and app/views/user/new.rhtml file. One little thing to watch for - due to how restful_authentication works you'll want to also add those two fields to the attr_accessible line in your User.rb model file. Other than that, you'll make life much easier for both you and your users.

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