CiviCRM Community Forums (archive)

Hi there,

The best "forum" for this is now Stack Exchange:  http://civicrm.stackexchange.com.

First, I wanted to make sure you were aware of the "region lookup" extension, which does more or less what you want.  Even if it doesn't meet your needs, as a code example it's valuable: https://civicrm.org/extensions/civicrm-region-lookup

Second - you're right that it's possible to use a hook to add a trigger - but this is less common than handling the change in PHP.  PHP is simpler, though if you have high volume, the trigger will give better performance.

Either way - the first thing you'll want to do is get civix (https://github.com/totten/civix) up and running.  The easiest way to do that is via civicrm-buildkit (https://buildkit.civicrm.org/).  There's a presentation today at the NYC CiviCRM Meetup on buildkit using Vagrant, so if you like Vagrant, my guess is that the civicrm-buildkit Vagrantfile is mature now.

Once you have civix up, run "civix generate:module org.mydomain.mymodulename", and it auto-generates an extension for you.  Almost there!  Make sure that extension is enabled in your CiviCRM installation.

Now, you have a choice: use triggers or PHP.

If you use triggers, you need to define mymodulename_civicrm_trigger_info.  There's an example that sounds exactly like what you're trying to do here: https://wiki.civicrm.org/confluence/display/CRMDOC/hook_civicrm_trigger_info

If you use PHP, you can use either hook_civicrm_pre or hook_civicrm_post.  hook_civicrm_post is a little easier to use - but I can't recall if editing a custom field on an address triggers hook_civicrm_post for an address, leaving you in a potential endless loop situation.  I think you're fine.

I don't have a good example of hook_civicrm_post on addresses on my Github, but this is a really good example of hook_civicrm_post: https://github.com/PalanteJon/coop.palantetech.module.automaticsoftcredit/blob/master/automaticsoftcredit.php#L184

Hook references are documented here: https://wiki.civicrm.org/confluence/display/CRMDOC/Hook+Reference

John,

Thanks for the information. I've had a quick look. There is a lot of technology here that I am unfamiliar with.

Just to be clear, I don't need a PRE hook just a POST hook. If I was doing it in a trigger I would use an AFTER INSERT/UPDATE FOR EACH ROW trigger.

I need to grab the final geo_code_1/geo_code_2 from civicrm_addresses insert/update and query a table I have loaded. On getting a resulting value, I then write it to a custom field civicrm_value_* table setting the appropriate field value. Deletes are easier as the table is handled by civi as it is a civicrm_value_* object implementing a custom field.

So there is no chance of getting an insert/update look on civicrm_addresses.

My inclination is to modify the existing CiviCRM trigger (as I am a database guru of many years standing) but all the work can be lost if a trigger hook is deployed or an upgrade to the system occurs.

Simple is better!

Simon