Extract Shortcode Attributes for a given shortcode on save_post.

parse_shortcode_atts.php

<?php 
/**
 * Extracts Shortcode Attributes from the post content
 * @param $content
 *
 * @uses get_shortcode_regex
 * @uses shortcode_parse_atts
 *
 * @return array
 */
function parse_shortcode_atts( $content, $shortcode ) {

	//Returns a sting consisting of all registered shortcodes.
	$pattern = get_shortcode_regex();

	//Checks the post content to see if any shortcodes are present.
	$shortcodes = preg_match_all( '/'. $pattern .'/s', $content, $matches );

	//Check to see which key our Attributes are sotred in.
	$shortcode_key = array_search( $shortcode, $matches[2] );

	//Create an new array of atts for our shortcode only.
	$shortcode_atts[] = $matches[3][$shortcode_key];

	//Ensure we don't have an empty strings
	$shortcode_atts= array_filter( $shortcode_atts );

	if ( ! empty( $shortcode_atts ) ) {

		//Pull out shortcode attributes based on the above key.
		$shortcode_atts = shortcode_parse_atts( implode( ',', $shortcode_atts ) );

		//Remove random commas from last value
		$shortcode_atts = array_map( function ( $att ) {
			return $att = str_replace( ',', '', $att );
		}, $shortcode_atts );

		$tags = array();

		foreach ( $shortcode_atts as $atts ) {
			$temp             = explode( '=', $atts );
			$tags[ $temp[0] ] = str_replace( '"', '', $temp[1] );
		}
		return $tags;
	}

	//If no attributes are returned, then an ID Att isn't present.
	return false;
}