How to store received EXIF ​​image metadata in WPdb?

Question

WordPress

Based on the built-in WP function , wp_read_image_metadataI created a custom wp_read_image_metadata_exifone that gets the EXIF ​​image fields I need. Next, I concocted a function that displays the values ​​of these fields in the media editor:

Code:

function wp_read_image_metadata_exif( $file ) {
  if ( ! file_exists( $file ) ) {
    return false;
  }

  list( , , $image_type ) = wp_getimagesize( $file );

  if ( is_callable( 'iptcparse' ) ) {
    wp_getimagesize( $file, $info );

    if ( ! empty( $info['APP13'] ) ) {

      if ( defined( 'WP_DEBUG' ) && WP_DEBUG
        && ! defined( 'WP_RUN_CORE_TESTS' )
      ) {
        $iptc = iptcparse( $info['APP13'] );
      } else {
        $iptc = @iptcparse( $info['APP13'] );
      }
      
      if ( ! empty( $iptc['2#090'][0] ) ) { // City.
        $meta['city'] = trim( $iptc['2#090'][0] );
      }
      if ( ! empty( $iptc['2#027'][0] ) ) { // Location Name.
        $meta['locationname'] = trim( $iptc['2#027'][0] );
      }
    }
  }

  return apply_filters( 'wp_read_image_metadata_exif', $meta, $file, $iptc );

}

function display_exif_fields ( $form_fields, $post ){

$type = get_post_mime_type( $post->ID );

$attachment_path = get_attached_file( $post->ID );

$metadata = wp_read_image_metadata_exif( $attachment_path );

  $form_fields['city'] = array(
    'label' => 'City',
    'input' => 'text',
    'value' => $metadata['city'],
    'helps' => '',
  );
  
  $form_fields['locationname'] = array(
    'label' => 'Location name',
    'input' => 'text',
    'value' => $metadata['locationname'],
    'helps' => '',
  );

    return $form_fields;
}

add_filter( 'attachment_fields_to_edit', 'display_exif_fields', 10, 2 );

Can you tell me how to store these values ​​in the WP database, in wp_postmeta?

Tried the following, doesn't work:

function save_exif_fields( $post, $attachment ) {
  if( isset( $attachment['city'] ) )
    update_post_meta( $post['ID'], 'city', $attachment['city'] );

  if( isset( $attachment['locationname'] ) )
update_post_meta( $post['ID'], 'locationname', esc_url( $attachment['locationname'] ) );

  return $post;
}

add_filter( 'attachment_fields_to_save', 'save_exif_fields', 10, 2 );

Answer 1

function display_exif_fields ( $form_fields, $post ){

$type = get_post_mime_type( $post->ID );

$attachment_path = get_attached_file( $post->ID );

$metadata = wp_read_image_metadata_exif( $attachment_path );

$city = get_post_meta( $post->ID, 'city', true );
$locationname = get_post_meta( $post->ID, 'locationname', true );

  $form_fields['city'] = array(
    'label' => 'City',
    'input' => 'text',
    'value' => !empty($city) ? $city : $metadata['city'],
    'helps' => '',
  );
  
  $form_fields['locationname'] = array(
    'label' => 'Location name',
    'input' => 'text',
    'value' => !empty($locationname) ? $locationname : $metadata['locationname'],
    'helps' => '',
  );

    return $form_fields;
}

add_filter( 'attachment_fields_to_edit', 'display_exif_fields', 10, 2 );


function save_exif_fields( $post, $attachment ) {

    $array = [ 'city', 'locationname' ];
    foreach ( $array as $one ) {
      if ( ! empty( $attachment[ $one ] ) ) {
        update_post_meta( $post[ 'ID' ], $one, $attachment[ $one ] );
      } else {
        delete_post_meta( $post[ 'ID' ], $one );
      }
    }

    return $post;
  }

  add_filter( 'attachment_fields_to_save', 'save_exif_fields', 10, 2 );

Answer 2

Everything seems to be correct, and update_post_meta( $post['ID'], 'locationname', esc_url( $attachment['locationname'] ) ); should work.
Check if all the parameters of the function are ok, perhaps something is missing somewhere, or instead of a string an array comes or it is empty there at all, etc.
If you need to save the array, then you need to serialize