The WGBH.org Development Blog

One of the great things about open source software is, obviously, that there are all of these great people out there writing code and making it available to everyone. In the world of Drupal this means that there are tons of great contributed modules that are pretty much invaluable to a site like WGBH.org, like Views and CCK.

It also means that those of us who have to maintain a Drupal site need to keep up with the improvements and changes to all of this code by periodically upgrading the code bade. Often times this usually just means grabbing the updated code and running the upgrade script. Things usually go pretty smoothly.

Except when they don’t.

Take, for example, the other day when I saw (thanks to the CVS Deploy module) that there was a new release candidate version of CCK (from 6.x-2.0-rc6 to 6.x-2.0-rc7). I went ahead and grabbed the new code and ran the upgrade script against my development installation (don’t want to do this on the live system!). Then I checked out our TV schedules grid and it looked like so:

Using my years of web development experience and my highly developed technical acumen I quickly deduced that something was wrong! The quesiton was, what?

So I went to the issue queue for CCK and found that, indeed, the latest RC version of CCK required the latest development version of Views.

OK, since I’m reluctant to use development snapshots of modules, I figured that there would probably be a new RC version of Views coming out soon with the required fixes to allow CCK and Views to once again play nice together. Sure enough, in another day or two there was a new version of Views (6.x-2.0-rc1 to 6.x-2.0-rc2). I then upgraded Views (again, on the development suite) and got this:

Hmmm. Better, but still not quite right. Basically, there seemed to be a problem with passing in date arguments to the view used to generate the schedule grid; there was a similar problem with the full day schedules.

Soooo, I then went to the Views issue queue and, sure enough, found out there was a problem with the new RC release of Views and it’s interaction with the Date module. Namely, that the date filters normally available to Views were now missing, which is what I saw.

Once again I figured that, rather than go to the development version of Date, I’d just hang tight and see if a new RC of Date was released soon. Bing, bang, boom - the next day it was! After then upgrading Date from 6.x-2.0-rc2 to 6.x-2.0-rc3 (and also upgrading Views again, as a new RC was released in the meantime, to 6.x-2.0-rc3) and checking the site I saw…. this!

Whew! Everything was back to normal.

The lesson here? Some might look at this and say, boy, what a pain in the rear this open source stuff is! But not me. On the contrary, I think it demonstrates the greatness of open source and the community of people out there responding to problems, fixing bugs and generally making my life much easier. Sure, patience is sometimes required, but that’s a very small price to pay, in my opinion.

So, a big thanks to all the folks who build Drupal and Views and CCK and Date and all of those other modules! Well done, folks.

Like Big Brown coming down the stretch at the Belmont Stakes last week, us coders here at WGBH Online are bearing down on the finish line that is the rebuild of the TV Programs and Schedules module, well ahead of the pack… er, on second thought, maybe Big Brown at Belmont isn’t the best analogy.

In any case, deadlines are looming! We’re scheduled for a database freeze at the end of the month, by which time we need to have principal development completed and the code ready for some serious testing and tuning. At this point Pete is busy working on the search functionality and I’m tying up as many loose ends as possible.

I’d like to use today’s post to discuss one particularly funky and challenging bit of functionality that is finally working - the episode page sidebar!

Now tell me the name alone - episode page sidebar - doesn’t send a chill down your spine! It does mine, at least.

Let’s take a look-see at this little puppy to see what we’re talking about:

As you can see episode page sidebars will display information related to the series or episode (e.g. related programs or events) , as well as a search box, and some promotional content (e.g. shop, support). Nothing out of the ordinary here. We do the same thing on our current episode pages.

So how would this be implemented in Drupal? Easy, you say! Each item could be managed as a block. Voila! Hardly any technical expertise at all required here.

Not so fast, partner. There are a few additional requirements.

(1) There needs to be a default set of these items, that would display on all episode pages, unless…

(2) An editor chooses to create a series-specific version of a particular sidebar item, in which case s/he needs to be able to create it, relate it the series and have that override the default item on all episode pages for that series, unless…

(3) An editor chooses to create an episode-specific sidebar item, in which case s/he needs to be able to create it, relate it to the episode and have it override any default or series-specific version of that item.

OK, maybe it’s not so simple.

Here’s what we’ve noodled up to make this all happen.

(1) Since the search box is the one sidebar item which will always be there at the top and cannot be overridden, that is indeed managed as a stand alone Drupal block and positioned at the top of the heap.

(2) All other items in the sidebar are managed using a custom (CCK) content type called a content box. Content boxes are pretty simple and have the following attributes: title (for internal use only), a body (which contains all of the content to display, including any optional title or header), and an optional parent content item (like a TV program or episode), managed as a node reference. Also, using the Scheduler module, each content box can have specific publish and expiration dates. Content boxes will be able to have images, which will be added to the body using the Image Assist module.

(3) In order to determine where a content box displays in the sidebar we defined a fixed taxonomy vocabulary (Content Box Location), which is a hierarchical set of terms (e.g. TV -> Programs -> Sidebar -> Events). The display order of the sidebar items is determined by the order of the terms within the vocabulary. The idea here is that content boxes will eventually be used on other parts of the site once it’s all on Drupal. At that point we’ll be able to define additional terms in the vocabulary for other locations on the site (e.g. Radio Home Page -> Coming Up).

(4) Default sidebar content boxes are then defined as content boxes that are assigned a TV -> Program -> Sidebar tag, are not explicitly related to a series or episode node and which have the word default in their (internal) title.

(5) Series sidebar content boxes are defined as content boxes that are assigned a TV -> Program -> Sidebar tag and are explicitly related to a series node.

(6) Episode sidebar content boxes are defined as content boxes that are assigned a TV -> Program -> Sidebar tag and are explicitly related to an episode node.

Got all that? Good, because this will be on the final.

Given that set up, here’s how we actually construct the sidebar for a given episode.

We have a block view that selects all of the default episode sidebar content boxes. In the theme file for that view display, we then call a second block display for the sidebar view that takes a parent node id as an argument. We call this first to get any sidebar views related to the parent series and then again to get any sidebar views related to the episode. All of these content boxes that we’ve gotten back are then merged according to the rules above and the final list is displayed.

Almost forgot, the Related Programs sidebar content box adds one additional layer of complexity. The contents of that box are generated using a related programs view, which finds up to three related series using another taxonomy vocubulary (TV Program Genres). It’s pretty straightforward, unless…

See, easy peasy lemon squeezy, as my kids say!

I don’t know about where you live, but this week coming up is school vacation week around here. As the father of two of bundles of joy, I’ll be taking next week off have some Q.T. with the family as we parade around northern New England, doing what families do (e.g. goofing off, yelling, getting chocolate out of the kids’ hair, etc.).

That means, sadly, that I’ll have to tear myself away from Drupal 6 for a week (really, not a problem, believe me). In preparation for the week off I’ve been busy as all get out trying to reach the milestone that we’ve dubbed the first code merge. By that I mean it’s the first chance for Pete and I to merge the work we’ve been doing on the first phase of our rebuild, the new TV Programs and Schedule module.

Up until now, we’ve working separately (a separate peace, if you will), developing on our own Drupal installs on our development server. Pete has been creating a theme to match the current WGBH.org template (look and feel changes to the site will come in phase 2). I’ve been busy getting the PBS/TV Guide XML data import running, as well as working up the basic functionality of our Programs A-Z page and the Full Day Schedules by Channel pages.

Anyway, it’s high time that we finally incorporated each other’s changes into our own working install. So, this week was devoted to working out a process, not just for a one time code merge, but for rolling out our development work to each other, as well as to a staging area and to live installs going forward.

Currently, we’ve basically got a theme and a custom module for TV schedules. Managing the code is easy; everything is managed in a local SVN repository. Core Drupal and contributed modules and themes are pulled down via CVS and checked into SVN. So the entire code tree can be easily managed across multiple developers and pushed up to staging and live environments via SVN commands.

The tricky part - scratch that - the headache inducing part - no, sorry, scratch that too - the bang-your-head-against-the-wall-in-frustration part - is managing all of the information that’s stored in MySQL. How do we track changes to database structures (DDL) and the actual content that needs to be shared across installs (DML)?

Good question. The answer? Well, there is no easy answer that I’m aware of. The first guess is do a database dump (that’s what it’s called, I swear) of all of the structures and content. In theory that file can be managed via SVN or CVS. Problem there is you usually have lots of junk in your development database that you don’t want to replicate to staging or live environments, or even other development installs. So then you have to start weeding stuff out of the dump, which gets messy fast.

What to do, then? Here’s the strategy we’re going to use, and which i spent most of the week working on:

(1) Create a custom Drupal installation profile. This is used when first setting up a Drupal site. The WGBH profile installs a bunch of modules, sets the default theme (our WGBH.org theme) as well the administration theme (currently Zen Classic, a sub-theme of Zen - nice and clean and simple).

(2) TV Schedules module installation file. This is where most of the action is. Here we do a whole of bunch things like:

• Create CCK content types (e.g. TV Channel, TV Program, etc.)
• Create nodes for certain content types (e.g. channels)
• Create Views (e.g. Programs A-Z)
• Create a number of blocks and position them on our themes
• Add menu links
• Tweak a number of variable settings

I’d like to use the module install and upgrade files to manage changes to database objects and content. The install and upgrade files can be managed in SVN and used to roll out changes to development/staging/live environments. The tricky part is extracting the relevant changes from the database. That’s where it gets messy.

For this initial code merge, I relied mainly on the CCK export/import functionality to get the content type definitions. In theory, this is pretty straightforward. I used the export function on my development install to generate the code to recreate the content types. I added the code to module install file. That should have been it for the content types.

Except that it wasn’t.

CCK (like Views) on Drupal 6 is still in an alpha state, meaning there are unfinished bits, bugs, and general unforeseen shenanigans involved in using it. I found that the export/import process was a bit lacking. It copied the basic content type and field definitions just fine. However, field groupings were lost, and certain field attributes didn’t survive the transfer.

In the end what I did was perform the export/import in the module install file to create the basic types and fields (and related database objects) and then overwrite the data in the CCK definition tables using a database dump of that content from my development database. That part was put into a SQL file which, for now, has to be manually run in MySQL after the module is loaded.

It’s a bit clunky and not ideal, but I figure that part can go away once CCK for D6 is finished.

The good news is the Views export/import process worked much more smoothly. I was able to take the export code and run it from the module install file and the views were created as expected. No (or minimal) data tweaking was necessary. Yay!

Aside from that, creating actual nodes, blocks and menu links in the install file was all pretty straightforward. All in all, though, it took the better of the week to work it all out and get the process in good enough shape to hand off the Pete for testing.

Going forward, it will continue to be a bit of work to continue this process of tracking database changes. But, for now, it’s the best way I know of to proceed. If anybody has a better suggestion, I’m all ears! Please share.

Oh yeah, one annoying issue I’ve had with Views 2 is the lack of support for argument handling. Where the heck did that go? Am I missing something obvious? I found that the views object has a view_php attribute/method which seems to function the same way (I put my D5 view handling code in there), but there is no place in Views UI that I could find to add that code to a view. I had to do it manually.

Again, if you know more about this, let me know! That little problem alone gave 5 or 6 new gray hairs.

There you have it! For now, I need a break from the code and all that cursing.

Forgive me, Father, for it’s been 12 days since my last post, mainly because we’ve been very busy here at WGBH Online. The good news is all of that busy-ness has paid off because…

(drum roll please)

the WGBH.org rebuild has been completed! That’s right! Check her out.

Ok, I’m lying. It’s a lame attempt at an April Fools joke.

But I wasn’t lying about the being busy part. Busy we sure have been.

Since our last chat we now have our new development server up and running. With the help of IT I have configured a new development environment, where by core and contributed Drupal code is being downloaded from the Drupal CVS repository and managed locally in our new SVN repository.

Wheeeee!

Pete and I are now working away in this new environment. Pete is working at replicating the current look and feel and styles of WGBH.org in a WGBH theme. I’ve been porting the TV Programs and Schedules code that I had already written in Drupal 5 to Drupal 6.

Building on Drupal 6 has already proved to be an adventure (think Survivorman - but more dangerous), as we’re currently working with the HEAD versions of CCK and Views (and a few other modules). Needless to say, I’ve already had a few bang-my-head-against-the-wall moments with buggy code. But we will persevere!

Oh yeah and we’ve also decided (for now) to go with Zen Classic as our administration theme. I like the clean, plain simpleness of it. It’s also close to the look our of current CMS, so should be less of a shock to the systems of our content producers when they’re introduced to it. This choice, of course, is subject to change…

Meanwhile, IT continues to build out the new hardware and reconfigure the old hardware that will all be used for the new version of WGBH.org. Specification meetings continue apace and, oh yeah, we’re still looking for a project manager for the whole rebuild.

All that and Spring has sprung!

That’s about where we’re at.