View source for PLG migrate

= Introduction =

As of Geeklog 1.6.0, the install script has a new option (in addition to "New Install" and "Upgrade"), called '''Migrate'''. You will use the migrate option when moving your Geeklog site from one webserver to another (e.g. when changing hosting services). Naturally, this will require changes in the configuration, e.g. paths and URLs. The install script handles all that for the Geeklog core functionality, but plugins will need to perform these changes too. That's what the <code>PLG_migrate</code> function is for.


= The API =

<pre>function PLG_migrate($type, $old_conf)</pre>

As usual, <code>$type</code> is the plugin type ('calendar', 'forum', ...). <code>$old_conf</code> contains a copy of the <code>$_CONF</code> with the values before the migration, i.e. paths and URLs of the old site.

The plugin will then have to implement a function

<pre>function plugin_migrate_foo($old_conf)</pre>

In that function, the plugin can update its configuration, as needed. It has access to the current <code>$_CONF</code> array (if declared <code>global</code>, as usual), so it can easily check the options that need to be updated.

There is also a convenience function that the plugin has access to which will update the site's URL in the database. That function takes a list of tables and field names which list text fields to be searched for the old URL. For example, for the Links plugin:

<pre>$tables = array(
    'linkcategories'    => 'cid, description',
    'links'             => 'lid, description, url',
    'linksubmission'    => 'lid, description, url'
);</pre>

This array lists the 3 tables to be updated (linkcategories, links, linksubmission). On the right side, you'll see the fields to be updated. Please note that the first field listes ''has'' to be the table's index (in the above example: cid = category ID, lid = link ID). The other fields are supposed to be text fields, i.e. of one of the various text types (VARCHAR, TEXT, MEDIUMTEXT, ...).

With this, you can then easily update your plugin's tables to point to the new URL:

<pre>if ($old_conf['site_url'] != $_CONF['site_url']) {
    INST_updateSiteUrl($old_conf['site_url'], $_CONF['site_url'], $tables);
}</pre>

Please note that the <code>INST_updateSiteUrl</code> function is only available inside the plugin's migrate function.


= Migration + Upgrade =

Since Geeklog's install script can also handle plugin upgrades, there may be cases where plugins will need to be ''both'' migrated ''and'' upgraded. In that case, <code>PLG_migrate</code> will be ''called first'', i.e. migrate first, then upgrade.


[[Category:Plugin Development]]