Hardcode cache paths in civicrm.settings.php

Unfortunately, provision_civicrm_regenerate_settings_file() appears to be pulling the template from CiviCRM core, where the necessary variables can't be populated. Assuming that we want to keep doing that, we should submit a PR to allow that setting to be passed in as a variable. At least we can then apply said patch to platforms we build pending merging into CiviCRM core.

In addition, we could add a hook to allow altering the list of civicrm.settings.php template search paths, so that we'd have the flexibility of overriding it in Aegir.

Another thing... It looks like the relevant variables are mis-labeled in civicrm.settings.php:

 // Override the Temporary Files directory.
 // $civicrm_setting['Directory Preferences']['customFileUploadDir'] = '/path/to/upload';

 // Override the custom files upload directory.
 // $civicrm_setting['Directory Preferences']['uploadDir'] = '/path/to/upload-dir' ;

I submitted the following issues upstream in CiviCRM's Jira:

1. CRM-19306: Incorrect documentation for some settings in civicrm.settings.php
2. CRM-19307: Allow setting upload paths in civicrm.settings.php.template
3. CRM-19308: Disallow false-y values for uploadDir setting

I don't see any really clean way of adding the setting. The best I've come up with so far would be to do something like:

$new_setting_line = "\$civicrm_setting['Directory Preferences']['uploadDir'] = 'upload';";
$str = preg_replace('/^.*?civicrm_settings.*uploadDir.*\n?/m', $new_setting_line, $str);

This *should* replace the entire line that matches both "civicrm_settings" and "uploadDir", and replace it with the line, uncommented, and set to the value we want to hardcode. Of course, we'd have to do the same for the "global $civicrm_settings;" line as well.

An alternative would be to drop using the template from CiviCRM core, and generate our own, similarly to how we generate settings.php for Drupal sites. While this'd give us a whole lot more flexibility, including masking database credentials, it'd also mean more maintenance, as we adapt to changes between CiviCRM versions.

Based on my research so far, I don't think there'll be an easy way to resolve CRM-19307. If I've missed anything, please don't hesitate to point it out.

In the short-term, I think a preg_replace()-based solution, as described above, should be reasonably stable. We could guard against changes to civicrm.settings.php.template, by adding a preg_match() to search for the same pattern, and throw a warning if it isn't found.

I'll work on a patch along these lines.

Here is a patch that adds some hooks that allow altering civicrm.settings.php in various ways.

Here's a patch that implements a couple of the hooks added in the previous patch, to hardcode uploadsDir.

Replaced patch from #9. Now hard-codes the full path.