WordPress: Download and set featured image for a post from a URL

gga-set-featured-image-from-url.php

function gga_set_featured_image_from_url($post_id, $url) {

	$temp_file = download_url( $url );
	if (is_wp_error( $temp_file ))
		return $temp_file;

	$file_array['name'] = basename( $url );
	$file_array['tmp_name'] = $temp_file;

	$sideloaded_id =  media_handle_sideload( $file_array, $post_id );
	if (is_wp_error( $sideloaded_id )) {
		unlink($temp_file);
		return $sideloaded_id;
	}

	set_post_thumbnail( $post_id, $sideloaded_id );
	return $sideloaded_id;

}