July Meeting - TC Posse Takes Over

Summertime flies when you're having fun! This meeting is scheduled for tomorrow night!

We're doing lightning talks, which means that each of us is spending 5 minutes going over a tool, module, hack, or programming tip. If you're not up to giving a presentation, we're looking for scribes: each talk needs a volunteer to write it up as it happens!

For those of you not actively following the wiki updates, the currently suggested presentations are here:

• Turning designs into Zen sub-themes - Samir M. Nassar (SteamedPenguin)
• Beginning Drupal Hacking with Bazaar - Kyle Cunningham (CitizenKane)
• Using patch and diff: Becoming a patch tester for modules and core - Samir M. Nassar (SteamedPenguin)
• Using patch and diff: You found a bug! Now fix it. -Samir M. Nassar (SteamedPenguin)
• Using the coder module - Samir M. Nassar (SteamedPenguin)
• Custom cosmetic tweaks you can do with APIs when theming doesn't cut it, starring hook_form_alter(). - Gabe Ormsby (gormsby)

There's room for a few more presentations, and plenty of room for people willing to act as a scribe ( writing up a presentation as it happens ) If nobody objects, perhaps we can use the comments here to volunteer for presentations so that they go out to the email subscribers.

Sorry guys i wont be able to make it. I will be leaving over seas in a couple of days for about 3 weeks and just busy getting things together.

Sorry again.

Situation - You need to override a core (or contrib) module's behavior. More specifically, we want to adjust a form in some way. It would be possible to edit the files you want, but that's BAD Drupal development. We want to do make changes without killing our chance to benefit from future versions of those modules.

Tool: hook_form_alter()

"Before building [a] form, the form_alter() hook is called. Any module that implements the form_alter() hook can modify anything in the form. This is the primary way to change, override, and munge forms that are created by modules other than your own."
- Pro Drupal Development, John VanDyk and Matt Westgate

So, we're going to write a very simple example module to do just this. Some good resources for creating modules:
Drupal 5.x - http://drupal.org/node/82920
Drupal 6.x - http://drupal.org/node/206753
NOTE: This is a Drupal 5 example.

In this example, "nsa" is indicative of the "Narrow Sidebar Alliance" module - our theoretical client whose site we're customizing. Our module contains one function:

By enabling this module, Drupal will ask it for feedback any time a any form is presented to the screen. This is the magic of hook_form_alter in general and illustrative of Drupal's overall coolness in general.

The function nsa_hook_form_alter looks at the name of the form ($form_id) being presented to see if it is one of the forms we want to change.

A quick review of the user.module and search.module tells us the names of the forms we want to affect: the search block form ("search_block_form") or user login form ("user_login_block"). Per Gabe's notes:

Identifying your form id and its form elements

Lucky case: Take "id" of HTML form element as the form id, try the form field names as sub-arrays, and try the field attributes as keys for the sub-arrays, change "-" to "_", and see if you win:

In our module, is successfully targeted using "search_block_form" as the Drupal id, "name" and "pass" as array keys for the elements, and "#size" for the size attribute.

Unlucky case: You may have to dig through the module code:
In our module, the actually has "user_login_block" as the Drupal id.

If the $form_id is either of those two:

... then we want to make some changes, specifically changing the width of the text boxes people type in:

... at the end of it all, our new version of the form is handed back to Drupal for more magic, until eventually it shows to the user.

Thanks Gabe!

Drew Gorton
_{Gorton Studios}