Adds "http://schema.org/Recipe" microdata with aggregateRating. Replaces the default "http://schema.org/Article"

mrp_rating_result_recipe_microdata.php

<?php
/**
 * Adds "http://schema.org/Recipe" microdata with aggregateRating. Replaces the default 
 * "http://schema.org/Article"
 * 
 * @param unknown $microdata
 * @param unknown $rating_form_id
 * @param unknown $post_id
 * @param unknown $rating_result
 * @return string
 */
function mrp_rating_result_recipe_microdata( $microdata, $rating_form_id, $post_id, $rating_result) {
	
	$microdata = '<div itemscope itemtype="' . "http://schema.org/Recipe" . '" style="display: none;">';
	
	$post_obj = get_post( $post_id );
		
	$image = wp_get_attachment_image_src( get_post_thumbnail_id( $post_id ) );
	$image_content = '';
	if ( isset( $image[0] ) ) {
		$image_content = $image[0];
	}
	
	$user_info = get_userdata( $post_obj->post_author );
	$author = $user_info->display_name;
	
	// typically you would store this kind of data in the post meta table
	/* 
	$prep_time = get_post_meta( $post_id, 'prep_time' ); // e.g. PT15M
	$cook_time = get_post_meta( $post_id, 'cook_time' ); // e.g. PT1H
	$ingredients = get_post_meta( $post_id, 'ingredients' ); // e.g. array( '3 or 4 ripe bananas, smashed', '1 egg', '3/4 cup of sugar' );
	$instructions = get_post_meta( $post_id, 'instructions' ); // e.g. Preheat the oven to 350 degrees. Mix in the ingredients in a bowl. Add the flour last. Pour the mixture into a loaf pan and bake for one hour.
	$nutrition_info = get_post_meta( $post_id, 'nutrition_info' ); // e.g. array( 'calories' => '240 calories', 'fatContent' => '9 grams fat' );
	*/
	
	$prep_time = 'PT15M';
	$cook_time = 'PT1H';
	$ingredients = array( '3 or 4 ripe bananas, smashed', '1 egg', '3/4 cup of sugar' );
	$instructions = 'Preheat the oven to 350 degrees. Mix in the ingredients in a bowl. Add the flour last. Pour the mixture into a loaf pan and bake for one hour.';
	$nutrition_info = array( 'calories' => '240 calories', 'fatContent' => '9 grams fat' );
	
	// lets construct the microdata
	$microdata .= '<meta itemprop="name" content="' . $post_obj->post_title . '" />';
	$microdata .= '<meta itemprop="description" content="' . $post_obj->post_excerpt . '">';
	$microdata .= '<meta itemprop="author" content="' . $author . '" />';
	$microdata .= '<meta itemprop="prepTime" content="' . $prep_time . '">';
	$microdata .= '<meta itemprop="cookTime" content="' . $cook_time . '">';
	$microdata .= '<meta itemprop="datePublished" content="' . date( 'Y-m-d', strtotime( $post_obj->post_date ) ) . '" />';
	$microdata .= '<meta itemprop="image" content="' . $image_content . '" />';
	
	$microdata .= '<div itemprop="nutrition" itemscope itemtype="http://schema.org/NutritionInformation">';
	foreach ( $nutrition_info as $name => $content ) {
		$microdata .= '<meta itemprop="' . $name . '" content="' . $content . '" />';
	}
	$microdata .= '</div>';
	
	foreach ( $ingredients as $ingredient ) {
		$microdata .= '<meta itemprop="recipeIngredient" content="' . $ingredient . '" />';
	}

	$microdata .= '<meta itemprop="recipeInstructions" content="' . $instructions . '" />';
	
	// add aggregate rating
	$microdata .= '<span itemprop="aggregateRating" itemscope itemtype="http://schema.org/AggregateRating">'
			. '<span itemprop="ratingValue">' . $rating_result['adjusted_star_result'] . '</span>/<span itemprop="bestRating">5</span>'
			. '<span itemprop="ratingCount">' . $rating_result['count_entries'] . '</span>'
			. '</span>';
	
	$microdata .= '</div>';
	
	return $microdata;
}
add_filter( 'mrp_rating_result_microdata', 'mrp_rating_result_recipe_microdata', 10, 4 );