Nice question. First of all, note that I consider the advanced metadata service in ILIAS to be lacking a good readme making clear, which hooks the interface is offering for tasks such as yours. Some time ago, I had to deal with this service as well and run into similar issues. Hopefully, your question helps to document this a little better an I myself am looking forward to other suggestions, knowing that mine is not really good as well. If you have any resources, helping pushing the introduction of good readme for services and also pushing services towards using the repository pattern with a clear interface would be highly appreciated.
Concering your question of what can be improved: I see three main issues in the lines of code:
- Storing an ID in the config of your plugin. Your plugin will unconfigurable for non-technical people. However, also for you this will be error prone, think about exporting-importing stuff from a test-installation to production.
- Access the value by query instead of the service.
- Using new and static functions inside your code making it untestable.
Step 1
Lets start with the first one. Note, that I did not manage to solve this one without introducing a new one (a new query). Bad I know. I hope that there is a better solution, I did not find one after quick research. You store the id, since the field title is not securely unique, right? This is correct, however, you could think about storing the tripplet of field_title, record_title and (maybe) scope. Note that you maybe do not need the scope since you want to use this globally. A function return you and array containing field_id and record_id could look like so:
function getFieldAndRecordIdByFieldTitles($field_title, $record_title, $scope_title){
$query = "select field.field_id,field.record_id from adv_mdf_definition as field
INNER JOIN adv_md_record as record ON record.record_id = field.record_id
INNER JOIN adv_md_record_scope as scope ON scope.record_id = field.record_id
INNER JOIN object_reference as ref ON scope.ref_id = ref.ref_id
INNER JOIN object_data as scope_data ON ref.obj_id = scope_data.obj_id
WHERE field.title='$field_title' AND record.title='$record_title' AND scope_data.title = '$scope_title'";
$set = $this->dic()->database()->query($query);
if($row = $this->dic()->database()->fetchAssoc($set))
{
return array_values($row);
}
}
Then get your values like so:
list($field_id,$record_id) = getFieldAndRecordIdByFieldTitles("my_field", "my_record", "my_scope");
Note that I am aware that I am introducing a new query here. Sorry, was the best I could come up with. I am sure there you find a better solution, if your research a bit, let us know if successful. However, we will remove one in the next step.
Step 2
Use the undocumented service, the get your value out of the advance meta data. Since you now have the record id and the field id, you can to that like so:
$record_values = new ilAdvancedMDValues($record_id, $obj_id);
$record_values->read();
$ADTGroup = $ilAdvancedMDValues->getADTGroup();
$ADT = $ilADTGroup->getElement($field_id);
$value = $ADT->getText();
/**if you have text, others are possible, such as:
switch (true) {
case ($ADT instanceof ilADTText):
break;
case ($ADT instanceof ilADTDate):
$value = $ADT->getDate();
break;
case ($ADT instanceof ilADTExternalLink):
$... = $ADT->getUrl();
$... = $ADT->getTitle();
break;
case ($ADT instanceof ilADTInternalLink):
$... = $ADT->setTargetRefId($value);
}
**/
Note that ADT's are also undocumented. There might be a better way, to get a value out of this.
Step 3
Wrap your statics and new into some injectable dependency. I usually use the bloated constructor pattern to do this. Looks like so:
public function __construct(InjectedSettings $mySettings = null)
{
if (!$mySettings) //Case in the default scenario
{
$this->mySettings = new InjectedSettings();
} else //used e.g. for unit tests, where you can stuff the constructor with a mock
{
$this->mySettings = $mySettings;
}
$this->mySettings->doSometing();
}
Note that this is not real dep. injection, still you still use new, but I think a very workable fix to use dep. injection at least for the test context in ilias.
Does this help? I hope there will be other (better answers as well).
