Taxonomy term mapping only if term already exists

Thanks for the good words and for your question.

You can use the “MLA Custom Field and IPTC/EXIF Mapping Actions and Filters (Hooks)” (see the Settings/Media Library Assistant Documentation tab for more information) to give you a place to remove the unwanted terms from the IPTC field before assigning terms to your taxonomies.

In your case, adding some code to the “mla_mapping_iptc_value” filter should do what you want. You can add some code to validate the IPTC keywords by checking them against the taxonomy. Then, you can remove any keywords you don’t want before passing the list of keywords you do want back from the filter.

I can give you more details and some sample code if that would be helpful. Take a look at the Documentation and the mla-mapping-hooks-example.php plugin and let me know how I can be more helpful. I will leave this topic unresolved until I hear back from you.

Thank you very much for your answer.
I won’t have much time to investigate in the few coming days, but will look at your solution before the end of the week and let you know if I need some more advice.

I’m already amazed by the results I’ve been able to produce with only shortcode parameters and some content template modifications.
What a great and very well designed plugin!

Thanks for the update; I’m glad you’re finding the plugin useful.

I am working through another support topic along the same lines:

Transferring tagged images from another plugin?

Something similar will work for you. Let me know how I can be more helpful.

I’m back working on my IPTC mapping.

As per you suggestion, I intend to use the WP function term_exists() in order to check whether each term exists in a specific taxonomy.
However, I didn’t succeed in displaying data in your mla_mapping_iptc_value_filterfunction:
– I cannot find where the error_log function displays the information (I’m using a mutualized hosting service)
– and PHP var_dump, which I use quite often in frontend, doesn’t seem to work in backend.

Is there another way to get the data structure and content?
Thanks for any hint.

Thanks for this update and progress report.

Accessing the error log on a remote shared server can be a challenge. Often, there is “cPanel” access which includes a “File Manager” that can help, but it varies among hosting providers.

Here is a technique I use in MLA; the PHP trigger_error function will display messages on the screen. It’s ugly but useful for testing. Add something like this to your code:

/* translators: 1: query filter details */
trigger_error( sprintf( __( '_execute_list_table_query $wp_filter = "%1$s".', 'media-library-assistant' ), var_export( $debug_array, true ) ), E_USER_WARNING );

You probably don’t need the i18n support, so you might want the simple form:

trigger_error( 'mla_mapping_iptc_value_filter $iptc_value = ' . var_export( $iptc_value, true ) ), E_USER_WARNING );

You’re limited to 1024 characters in the message, so you may need multiple messages to get everything you need.

I hope that helps. Keep me posted on your progress – good luck!

Got it!

Here is my code, in case it could be of some interest for someone else:

public static function mla_mapping_iptc_value_filter( $iptc_value, $setting_value, $post_id, $category, $attachment_metadata ) {
		$new_iptc = array();

		if ( $iptc_value && taxonomy_exists( $setting_value ) ) { 

			foreach ( $iptc_value as $term) {
				if ( term_exists( $term, $setting_value ) ) {
					$new_iptc[] = $term;
				}
			}
		}
		return $new_iptc;

	} // mla_mapping_iptc_value_filter

Thank you very much for the great help.
I’ll go on with some other customization and will ‘ring’ again for help if I get stuck elsewhere.

Here is an improved version of the code we produced in the process of working on a related support topic:

public static function mla_mapping_iptc_value_filter( $iptc_value, $setting_value, $post_id, $category, $attachment_metadata ) {
	if ( $iptc_value && taxonomy_exists( $setting_value ) ) {
		$new_iptc = array();
		foreach ( $iptc_value as $term) {
			if ( term_exists( $term, $setting_value ) ) {
				$new_iptc[] = $term;
			}
		}
		return $new_iptc;
	}

	return $iptc_value;
} // mla_mapping_iptc_value_filter

In this new version, the $new_iptc logic has been moved so it only applies to taxonomy rules and the original $iptc_value is returned in all other cases.