Code-Snippets-Functions/Execute a function on a child site/AMP/amp-gravity-forms-submission-shim.txt

// Shim support for Gravity Form submissions on AMP pages.
add_action( 'gform_post_submission', function() {
	$location = null;
	foreach ( headers_list() as $header ) {
		if ( preg_match( '/^Location:\s*(.+)/i', $header, $matches ) ) {
			$location = $matches[1];
			break;
		}
	}

	if ( $location ) {
		header_remove( 'Location' );
		header( "AMP-Redirect-To: $location" );
		header( 'AMP-Access-Control-Allow-Source-Origin: ' . home_url() );
		header( 'Access-Control-Expose-Headers: AMP-Redirect-To, AMP-Access-Control-Allow-Source-Origin' );
		wp_send_json(
			[
				'message'     => __( 'Redirecting…', 'amp' ),
				'redirecting' => true, // Make sure that the submit-success doesn't get styled as success since redirection _could_ be to error page.
			],
			200
		);
	}
} );

// Use client-side validation UI instead of showing validation errors after page reload. Props Rahul Bansal at rtCamp.
add_filter( 'gform_field_content', function( $content, $field ) {
	if ( $field->isRequired ) {
		return str_replace( 'aria-required=', 'required=', $content );
	}
	return $content;
}, 10, 2 );