How to get rid of unused tags? And how to merge tags?

Omeka Classic Development
3

Hi.
I’ve been working on the “merge” part, and manage to have it working by changing the code (if anybody wants to try to turn the changes into a plugin, is more than welcome, although maybe the changes could be implemented in the core of a future release). Here’s what I’ve done:

file application/controllers/TagsController.php (modified the last 5 lines)

public function renameAjaxAction() {
        $csrf = new Omeka_Form_SessionCsrf;
        $oldTagId = $_POST['pk'];
        $oldTag = $this->_helper->db->findById($oldTagId);
        $oldName = $oldTag->name;
        $newName = trim($_POST['value']);
        $error = __('Error occurred.');

        $oldTag->name = $newName;
        $this->_helper->viewRenderer->setNoRender();
        if ($csrf->isValid($_POST)) {
			if ($oldTag->save(false)) {
				$this->getResponse()->setBody($newName);
			} else {
				$newTag = $this->_helper->db->findOrNew($newName);
				$newTagId = $newTag->id;
				$this->_helper->db->mergeTags($oldTagId, $newTagID);
			}
		} else {
	        $this->getResponse()->setHttpResponseCode(500);
			$this->getResponse()->setBody($error);
        }
    }
}

and file application/models/Table/Tag.php (new function added)

public function mergeTags($oldTagId, $newTagId) {
        $db = $this->getDb();
        $sql = "UPDATE $db->RecordsTag SET tag_id = $newTagId, time = CURRENT_TIMESTAMP WHERE tag_id = $oldTagId AND record_id NOT IN (SELECT record_id FROM (SELECT DISTINCT record_id FROM $db->RecordsTag WHERE tag_id = $newTagId) AS tmptable)";
		$db->query($sql);
		$sql = "DELETE FROM $db->RecordsTag WHERE tag_id = $oldTagId";
		$db->query($sql);
		$sql = "DELETE FROM $db->Tag WHERE id = $oldTagId";
		$db->query($sql);
}

Now, here’re some possible improvements, in case anybody wanted to contribute:

  1. before the merging takes place, a message box asking for confirmation;
  2. after the merging has taken place, update the count of the tag, at the same time hiding the emptied one;
  3. error message in case of mishap during the merging.

Hope this helps.