Get the form fields as defined in the form xml file

Question

I have a set of fields that have been defined in an xml file and then I load the fields with $form->loadFile('myFormName'). Before displaying the fields I would like to manipulate the fields based on a series of parameters defined in the config. I was looking at the joomla profile plugin and the onContentPrepareForm function is doing something very similar to what I want to do. However I see that list fields that are to be manipulated are manually defined in an array.

I have looked through the joomla API but I have not found a function that will return a list of fields. Is there a way to generate dynamically the list of fields from the information that has been loaded with $form->loadFile('myForm')?

Answer 1

There is Joomla\CMS\Form\Form::getFieldset() method for returning an array of fields belonging to a fieldset as Joomla\CMS\Form\FormField objects.

$fieldNames = [];

foreach ($form->getFieldset('myFormName') as $field)
{
    $fieldNames[] = $field->fieldname;
}

Answer 2

After further reading of the joomla documentation, unless I've missed something, there isn't a ready made function to get the field names as defined in a xml form field file. There is a [getXml][1] method (function) which returns the XML form object. From there using [SimpleXMLElement::xpath][2] I was able to iterate through the simple xml elements and create dynamically an array of the form field names.

    $fieldNames = array();
    foreach ($form->getXml()->xpath('//fields//fieldset') as $key => $fieldset) {
        if (((string)$fieldset->attributes()->{'name'} == 'myFormName')) {
            foreach ($fieldset->xpath('field') as $field) {
                $fieldNames[] = (string)$field->attributes()->{'name'};
            }
        }
    }

In the first xpath I find all the fieldset objects currently loaded into the form. I then select the fieldset I want by the name. Using xpath again I select the field object and put the names into my $fieldNames array. This way I avoid having to hard-code the fields I want to manipulate. If I update the xml file then the list of fields is automatically updated in the php code. Perhaps something similar could be done in the joomla profile plugin. [1]: https://api.joomla.org/cms-4/#method_getXml [2]: https://www.php.net/manual/en/simplexmlelement.xpath.php