Add Cacheable Gists to Your WordPress Site

gist.css

.gist {
  color: #e4322e;
}

.gistdiv {
	padding: 0;
	margin: 0;
}

.gist .gist-file {
	border: none;
	font-family: 'Inconsolata', "Bitstream Vera Sans Mono", monospace;
	margin-bottom: 1em;
}

.gist .gist-file .gist-meta {
	overflow: hidden;
	font-size: 14px;
	font-weight: 300;
	padding: .5em;
	color: #666;
	font-family: 'Open Sans', sans-serif;
	background-color: transparent;
}

.gist .gist-file .gist-meta a {
	color: #2FC2EF;
}

.gist .gist-file .gist-meta a:visited {
	color: #2FC2EF;
}

.gist .gist-file .gist-data {
	overflow: auto;
	word-wrap: normal;
	background-color: #F8F8F8;
	border-top: 1px solid #DDD;
	border-bottom: 1px solid #DDD;
	font-size: 100%;
}

.gist .gist-file .gist-data pre {
	font-family: 'Inconsolata', 'Bitstream Vera Sans Mono', 'Courier', monospace;
	background: transparent !important;
	margin: 0 !important;
	border: none !important;
	padding: .25em .5em .5em .5em !important;
}

.gist .gist-file .gist-data .gist-highlight {
	background: transparent !important;
}

.gist .gist-file .gist-data .gist-line-numbers {
	background-color: #ececec;
	color: #aaa;
	border-right: 1px solid #ddd;
	text-align: right;
}

.gist .gist-file .gist-data .gist-line-numbers span {
	clear: right;
	display: block;
}

.gist-syntax {
	background: #ffffff;
}

.gist-syntax .c {
	color: #999988;
	font-style: italic
}

/* Comment */
.gist-syntax .err {
	color: #a61717;
	background-color: #e3d2d2
}

/* Error */
.gist-syntax .k {
	color: #a79d00;
	font-weight: normal
}

/* Keyword */
.gist-syntax .o {
	color: #849a22;
	font-weight: bold
}

/* Operator */
.gist-syntax .cm {
	color: #999988;
	font-style: italic
}

/* Comment.Multiline */
.gist-syntax .cp {
	color: #dc322f;
	font-weight: normal
}

/* Comment.Preproc */
.gist-syntax .c1 {
	color: #999988;
	font-style: italic
}

/* Comment.Single */
.gist-syntax .cs {
	color: #999999;
	font-weight: bold;
	font-style: italic
}

/* Comment.Special */
.gist-syntax .gd {
	color: #000000;
	background-color: #ffdddd
}

/* Generic.Deleted */
.gist-syntax .gd .x {
	color: #000000;
	background-color: #ffaaaa
}

/* Generic.Deleted.Specific */
.gist-syntax .ge {
	color: #000000;
	font-style: italic
}

/* Generic.Emph */
.gist-syntax .gr {
	color: #aa0000
}

/* Generic.Error */
.gist-syntax .gh {
	color: #999999;
}

/* Generic.Heading */
.gist-syntax .gi {
	color: #000000;
	background-color: #ddffdd
}

/* Generic.Inserted */
.gist-syntax .gi .x {
	color: #000000;
	background-color: #aaffaa;
}

/* Generic.Inserted.Specific */
.gist-syntax .go {
	color: #888888;
}

/* Generic.Output */
.gist-syntax .gp {
	color: #555555;
}

/* Generic.Prompt */
.gist-syntax .gs {
	font-weight: bold
}

/* Generic.Strong */
.gist-syntax .gu {
	color: #aaaaaa;
}

/* Generic.Subheading */
.gist-syntax .gt {
	color: #aa0000;
}

/* Generic.Traceback */
.gist-syntax .kc {
	color: #000000;
	font-weight: bold
}

/* Keyword.Constant */
.gist-syntax .kd {
	color: #000000;
	font-weight: bold
}

/* Keyword.Declaration */
.gist-syntax .kp {
	color: #000000;
	font-weight: bold
}

/* Keyword.Pseudo */
.gist-syntax .kr {
	color: #000000;
	font-weight: bold
}

/* Keyword.Reserved */
.gist-syntax .kt {
	color: #445588;
	font-weight: bold
}

/* Keyword.Type */
.gist-syntax .m {
	color: #009999
}

/* Literal.Number */
.gist-syntax .s {
	color: #d14
}

/* Literal.String */
.gist-syntax .na {
	color: #657b83
}

/* Name.Attribute */
.gist-syntax .nb {
	color: #0086B3
}

/* Name.Builtin */
.gist-syntax .nc {
	color: #445588;
	font-weight: bold
}

/* Name.Class */
.gist-syntax .no {
	color: #008080
}

/* Name.Constant */
.gist-syntax .ni {
	color: #800080
}

/* Name.Entity */
.gist-syntax .ne {
	color: #990000;
	font-weight: bold
}

/* Name.Exception */
.gist-syntax .nf {
	color: #657b83;
	font-weight: normal
}

/* Name.Function */
.gist-syntax .nn {
	color: #555555
}

/* Name.Namespace */
.gist-syntax .nt {
	color: #000080
}

/* Name.Tag */
.gist-syntax .nv {
	color: #258ad1
}

/* Name.Variable */
.gist-syntax .ow {
	color: #000000;
	font-weight: bold
}

/* Operator.Word */
.gist-syntax .w {
	color: #bbbbbb
}

/* Text.Whitespace */
.gist-syntax .mf {
	color: #009999
}

/* Literal.Number.Float */
.gist-syntax .mh {
	color: #009999
}

/* Literal.Number.Hex */
.gist-syntax .mi {
	color: #4cc0cb
}

/* Literal.Number.Integer */
.gist-syntax .mo {
	color: #009999
}

/* Literal.Number.Oct */
.gist-syntax .sb {
	color: #d14
}

/* Literal.String.Backtick */
.gist-syntax .sc {
	color: #d14
}

/* Literal.String.Char */
.gist-syntax .sd {
	color: #d14
}

/* Literal.String.Doc */
.gist-syntax .s2 {
	color: #d14
}

/* Literal.String.Double */
.gist-syntax .se {
	color: #d14
}

/* Literal.String.Escape */
.gist-syntax .sh {
	color: #d14
}

/* Literal.String.Heredoc */
.gist-syntax .si {
	color: #d14
}

/* Literal.String.Interpol */
.gist-syntax .sx {
	color: #d14
}

/* Literal.String.Other */
.gist-syntax .sr {
	color: #009926
}

/* Literal.String.Regex */
.gist-syntax .s1 {
	color: #4cc0cb
}

/* Literal.String.Single */
.gist-syntax .ss {
	color: #990073
}

/* Literal.String.Symbol */
.gist-syntax .bp {
	color: #999999
}

/* Name.Builtin.Pseudo */
.gist-syntax .vc {
	color: #008080
}

/* Name.Variable.Class */
.gist-syntax .vg {
	color: #008080
}

/* Name.Variable.Global */
.gist-syntax .vi {
	color: #008080
}

/* Name.Variable.Instance */
.gist-syntax .il {
	color: #009999
}

/* Function call */
.gist-syntax .nx {
	color: #687b89;
}

/* HTML */
.gist-syntax .x {
	color: #258bd2;
}

pretty-cacheable-gists.php

<?php

/**
 * Namespacing for Pretty Cacheable Gists.
 *
 * Pretty Cacheable Gists caches gists locally and adds a nice stylesheet to make them prettier.
 * The Gist embed is detected on save and added as a post of type "cgist". When the post is rendered,
 * rather than show embed the Gist via Javascript, it is loaded from the cgist post's meta data. This
 * allows for quicker rendering and easy caching.
 */
class cgistPrettyCacheableGists {

	/**
	 * Key for the cache incrementor.
	 *
	 * @var string
	 */
	private $_incrementor_key = 'ztol-gist-incrementor';

	/**
	 * Key for the transient that holds the queued Gist IDs.
	 *
	 * @var string
	 */
	private $_queued_gist_ids_key = 'ztol-queued-gists';

	/**
	 * Queue the events.
	 */
	public function __construct() {
		add_action( 'init', array( $this, 'init_actions' ) );
		add_action( 'save_post', array( $this, 'queue_gists' ), 99, 2 );

		add_filter( 'the_content', array( $this, 'render_gist' ), 100 );

		add_action( 'wp_print_styles', array( $this, 'wp_print_styles' ) );
	}

	/**
	 * Run functions on init.
	 *
	 * @return void
	 */
	public function init_actions() {
		$this->_register_post_type();
		$this->_register_taxonomy();

		add_action( 'ztol_create_gists', array( $this, 'create_gists' ) );
	}

	/**
	 * Register the CPT.
	 *
	 * @return void
	 */
	private function _register_post_type() {
		$args = array(
			'labels' => array(
				'name' => 'Gists',
				'singular_name' => 'Gist',
				'add_new' => 'Add New Gist',
				'add_new_item' => 'Add New Gist',
				'edit_item' => 'Edit Gist',
				'new_item' => 'New Gist',
				'all_items' => 'All Gists',
				'view_item' => 'View Gist',
				'search_items' => 'Search Gists',
				'not_found' =>  'No gists found',
				'not_found_in_trash' => 'No gists found in Trash',
				'parent_item_colon' => '',
				'menu_name' => 'Gists'
			),
			'description' => 'Gists used in content throughout the site.',
			'public' => true,
			'publicly_queryable' => false,
			'exclude_from_search' => true,
			'rewrite' => false,
			'query_var' => false,
			'menu_position' => 5,
			'can_export' => true,
			'supports' => array( 'title' ),
			'taxonomies' => array( 'cgist-language' )
		);

		register_post_type( 'cgist', $args );
	}

	/**
	 * Register the taxonomy.
	 *
	 * @return void
	 */
	private function _register_taxonomy() {
		register_taxonomy(
			'cgist-language',
			array(
				'cgist'
			),
			array(
				'hierarchical' => true,
				'labels' => array(
					'name' => 'Languages',
					'singular_name' => 'Language',
					'search_items' =>  'Languages',
					'all_items' => 'All Languages',
					'parent_item' => 'Parent Language',
					'parent_item_colon' => 'Parent Language:',
					'edit_item' => 'Edit Language',
					'update_item' => 'Update Language',
					'add_new_item' => 'Add New Language',
					'new_item_name' => 'New Language Name',
					'menu_name' => 'Language',
				),
				'show_ui' => true,
				'query_var' => true,
				'rewrite' => array(
					'slug' => 'genre'
				),
			)
		);
	}

	/**
	 * Get linked Gists and queue for gist creation.
	 *
	 * Examines post content for Gist link. If it is found, the ID is extracted and added
	 * to a queue. An event is scheduled that will loop through the queue and process the
	 * each ID into a post of cgist type.
	 *
	 * @param $post_id
	 * @return void
	 */
	public function queue_gists( $post_id ) {
		if ( ! $post = get_post( $post_id ) )
			return;

		if ( ! $gist_ids = $this->_extract_gist_id( $post->post_content ) )
			return;

		$clean_gist_ids = array();

		foreach ( $gist_ids as $id )
			$clean_gist_ids[] = absint( $id );

		$this->_add_gists_to_queue( $clean_gist_ids );
	}

	/**
	 * Add id(s) to the Gist queue and schedules even to process Gist IDs.
	 *
	 * @param $ids array|int
	 */
	private function _add_gists_to_queue( $ids ) {
		if ( ! is_array( $ids ) && ! absint( $ids ) )
			return;

		if ( ! is_array( $ids ) )
			$ids = (array) $ids;

		if ( empty( $ids ) )
			return;

		$currently_queued_ids = get_transient( $this->_queued_gist_ids_key );

		// Merge with previous values if present. Remove duplicates if they exist
		$ids_to_queue = false !== $currently_queued_ids ? array_unique( array_merge( $currently_queued_ids, $ids ) ) : $ids;

		if ( ! empty( $ids_to_queue ) )
			set_transient( $this->_queued_gist_ids_key, $ids_to_queue );

		if ( get_transient( $this->_queued_gist_ids_key ) && ! wp_next_scheduled( 'ztol_create_gists' ) )
			wp_schedule_single_event( time(), 'ztol_create_gists' );
	}

	/**
	 * Extract the Gist URL and create a new post of cgist type.
	 *
	 * This function extracts a Gist URL from the post content, extracts the ID from that
	 * URL, makes a request for that Gist, and finally adds the Gist as a new post.
	 *
	 * @return void
	 */
	public function create_gists() {
		$gist_ids = get_transient( $this->_queued_gist_ids_key );

		if ( false == $gist_ids )
			return;

		$posts = array();

		// Foreach Gist ID, get the Gist information
		foreach ( $gist_ids as $id ) {

			// Verify that it doesn't already exist
			if ( ! $this->_get_gist( $id ) ) {

				// Get the Gist information
				if ( $post_data = $this->_retrieve_gist_information( $id ) ) {

					// Get the nice embeddable format
					if ( $embed_html = $this->_retrieve_embed_content( $id ) ) {
						$post_data['post_meta']['embed_content'] = $embed_html;
						$posts[] = $post_data;
					}
				}
			}
		}

		// Foreach Gist, add a new post
		foreach ( $posts as $post_data )
			$this->_insert_gist( $post_data );

		// Since posts are added, remove the queued IDs
		delete_transient( $this->_queued_gist_ids_key );
	}

	/**
	 * Get Gist ID from a Gist URL in a post's content.
	 *
	 * @param $content
	 * @return array|bool
	 */
	private function _extract_gist_id( $content ) {
		if ( empty( $content ) )
			return false;

		// Match a regular gist URL (e.g., https://gist.github.com/1149945)
		$pattern = '#[^"]https:\/\/gist\.github\.com\/([0-9]+)[^"]#';
		preg_match_all( $pattern, $content, $matches );

		if ( empty( $matches ) )
			return false;

		$clean_matches = array();
		foreach ( $matches[1] as $value ) {
			if ( $clean_val = absint( $value ) )
				$clean_matches[] = $clean_val;
		}

		if ( ! empty( $clean_matches ) )
			return $clean_matches;
		else
			return false;
	}

	/**
	 * Gets the code from the Gist.
	 *
	 * @param $gist_body
	 * @return bool|string
	 */
	private function _clean_gist_embed_content( $gist_body ) {
		$decoded = json_decode( $gist_body );

		if ( isset( $decoded->div ) )
			return $decoded->div;
		else
			return false;
	}

	/**
	 * Get Gist code from Gist JSON endpoint.
	 *
	 * I use this to get the actual code because it returns the code in the syntax highlighted
	 * version of the code. The code returned in the other API call returns the raw code.
	 *
	 * @param $gist_id
	 * @return bool|string
	 */
	private function _retrieve_embed_content( $gist_id ) {
		if ( ! $gist_id = absint( $gist_id ) )
			return false;

		$url = 'https://gist.github.com/' . absint( $gist_id ) . '.json';
		$response = wp_remote_get( $url );
		$response_code = wp_remote_retrieve_response_code( $response );

		if ( 200 != $response_code )
			return false;

		$body = wp_remote_retrieve_body( $response );
		$html = $this->_clean_gist_embed_content( $body );

		if ( ! empty( $html ) )
			return $html;
		else
			return false;
	}

	/**
	 * Get ALL of the Gist details from the GitHub API.
	 *
	 * Note that this API call is different than the previous method. This returns
	 * all of the information available for the Gist. Not all of the information is used.
	 *
	 * @param $gist_id
	 * @return array|bool
	 */
	private function _retrieve_gist_information( $gist_id ) {
		if ( ! $gist_id = absint( $gist_id ) )
			return false;

		$url = 'https://api.github.com/gists/' . $gist_id;
		$response = wp_remote_get( $url );
		$response_code = wp_remote_retrieve_response_code( $response );

		if ( 200 != $response_code )
			return false;

		$body = wp_remote_retrieve_body( $response );
		$decoded = json_decode( $body );

		// Currently only supports single file gists
		foreach ( $decoded->files as $filename => $information ) {
			$file = $filename;
			break;
		}

		if ( ! isset( $file ) )
			return false;

		// Get file type for later use
		$file_types = $this->_get_file_types();
		$file_type = isset( $file_types[ wp_strip_all_tags( $decoded->files->$file->type ) ] ) ? $file_types[ wp_strip_all_tags( $decoded->files->$file->type ) ] : 'PHP';

		$data = array(
			'post' => array(
				'post_title' => wp_strip_all_tags( $decoded->description )
			),
			'post_meta' => array(
				'gist_id' => absint( $decoded->id ),
				'url' => esc_url_raw( $decoded->html_url ),
				'raw_file_url' => esc_url_raw( $decoded->files->$file->raw_url ),
				'raw_content' => $decoded->files->$file->content
			),
			'taxonomies' => array(
				'cgist-language' => array(
					$file_type
				)
			)
		);

		return $data;
	}

	/**
	 * Saves the Gist as a post of cgist type.
	 *
	 * Creates a new post for the Gist and saves the necessary metadata for later use.
	 * This function also adds the taxonomy terms for the Gist.
	 *
	 * @param $data
	 * @return bool|int|WP_Error
	 */
	private function _insert_gist( $data ) {
		if ( ! isset( $data['post_meta']['gist_id'] ) || ! absint( $data['post_meta']['gist_id'] ) )
			return false;

		// Verify that gist doesn't already exist
		if ( $this->_get_gist( $data['post_meta']['gist_id'] ) )
			return false;

		$defaults = array( 'post_status' => 'publish', 'post_type' => 'cgist' );
		$post_data = wp_parse_args( $data['post'], $defaults );

		// Insert the post
		if ( ! $id = wp_insert_post( $post_data ) )
			return false;

		// Add the taxonomies
		foreach ( $data['taxonomies'] as $taxonomy => $term ) {
			$concatenated_terms = implode( ',', $term );
			wp_set_object_terms( $id, $concatenated_terms, $taxonomy );
		}

		// Add the postmeta
		foreach ( $data['post_meta'] as $key => $value )
			update_post_meta( $id, '_cgist_' . $key, $value );

		return $id;
	}

	/**
	 * Mime-type to human readable relationships.
	 *
	 * @return array|void
	 */
	private function _get_file_types() {
		return apply_filters( 'cgist_file_types', array(
			'application/httpd-php' => 'PHP',
			'text/plain' => 'Text',
			'application/ruby' => 'Ruby'
		) );
	}

	/**
	 * Render the Gist content on page view.
	 *
	 * If a Gist URL is detected, it is displayed from the saved cgist content. If the
	 * cgist cannot be found, it is displayed as an embedded Gist.
	 *
	 * @param $content
	 * @return bool|mixed
	 */
	public function render_gist( $content ) {
		global $wp_query;

		$pattern = '#[^"]https:\/\/gist\.github\.com\/([0-9]+)[^"]#';
		preg_match_all( $pattern, $content, $matches );

		if ( empty( $matches ) )
			return false;

		foreach ( $matches[1] as $id ) {
			$id = absint( $id );
			if ( ! $id )
				continue;

			$embed = $this->_get_gist_content( $id );

			if ( is_single() || ( is_home() && 0 == $wp_query->current_post ) )
				$content = str_replace( 'https://gist.github.com/' . $id, $embed, $content );
			else
				$content = str_replace( 'https://gist.github.com/' . $id, '', $content );
		}

		return $content;
	}

	/**
	 * Gets a cgist.
	 *
	 * @param $id
	 * @return bool|WP_Query
	 */
	private function _get_gist( $id ) {
		if ( ! absint( $id ) )
			return false;

		$existing_gists = new WP_Query( array(
			'post_type' => 'cgist',
			'posts_per_page' => 1,
			'meta_query' => array(
				array(
					'key' => '_cgist_gist_id',
					'value' => $id,
					'type' => 'NUMERIC'
				)
			)
		) );

		if ( $existing_gists->post_count > 0)
			return $existing_gists;

		return false;
	}

	/**                    
	 * Get the Gist embed content from cache or generate it.
	 * 
	 * @param $id
	 * @return string
	 */
	private function _get_gist_content( $id ) {
		// Generate key
		$key = 'ztol-gist-' . md5( absint( $id ) . $this->_get_incrementor_value() );

		// Get content
		$gist_content = get_transient( $key );

		// If not there, generate it
		if ( false === $gist_content ) {
			$gist = $this->_get_gist( $id );

			/**
			 * If the Gist is not found in the local database, queue the Gist to be added from GitHub. Cache that value for
			 * only 5 minutes. Queue the Gist to be created in the system. If the Gist is found, load from local database and
			 * cache for 1 week.
			 */
			if ( ! $gist ) {
				$gist_content = '<script src="https://gist.github.com/' . $id . '.js"> </script>';
				$this->_add_gists_to_queue( $id );
				set_transient( $key, $gist_content, 300 );
			} else {
				$gist_content = get_post_meta( $gist->posts[0]->ID, '_cgist_embed_content', true );
				set_transient( $key, $gist_content, 86400 );
			}
		}
		return $gist_content;
	}

	/**
	 * Update the incrementor.
	 *
	 * Used to invalidate the breadcrumb cache whenever and event occurs that should
	 * signal the update of the cache.
	 *
	 * @return int
	 */
	public function update_incrementor() {
		$time = time();
		set_transient( $this->_incrementor_key, $time );
		return $time;
	}

	/**
	 * Get current incrementor value.
	 *
	 * Returns the value of the incrementor if it exists. If the incrementor does not exist,
	 * it will update the incrementor and effectively invalidate the cache.
	 *
	 * @return int
	 */
	private function _get_incrementor_value() {
		if ( $incrementor = get_transient( $this->_incrementor_key ) )
			return $incrementor;
		else
			return $this->update_incrementor();
	}

	/**
	 * Add the "pretty" stylesheet.
	 */
	public function wp_print_styles() {
		wp_enqueue_style( 'tollmanz_gist_kinda_solarized', get_stylesheet_directory_uri() . '/css/gist.css', array(), '1.0', 'all' );
	}
}

global $cgistPrettyCacheableGists;
$cgistPrettyCacheableGists = new cgistPrettyCacheableGists();

/**
 * Publicly callable version of cgistCacheableGists::update_incrementor.
 */
function tollmanz_invalidate_gists() {
	global $cgistPrettyCacheableGists;
	$cgistPrettyCacheableGists->update_incrementor();
}

Joey,

Thanks for the feedback as always! My thoughts:

• i18n was intentionally not added as its intent was for me and me only (but I think you understand that ;) )
• Thank you!
• These are actually different than you are thinking, but the point remains that you could not read it and that is a problem. The easiest way to follow would be:
  $post = get_post( $post_id ); if ( false === $post ) return;
• Nice catch
• Another good call! Always get messed up due to no wp_enqueue_styles.

i18n was intentionally not added as its intent was for me and me only (but I think you understand that ;) )

Yeah I figured as much, but easy enough to add :)

These are actually different than you are thinking, but the point remains that you could not read it and that is a problem. The easiest way to follow would be: $post = get_post( $post_id ); if ( false === $post ) return;

Right... I've always hated assigning variables inside if statements because of the lack of readability it creates, and that just confirms my hate for them :)

awesome job on this class! works awesome. only thing i had to change was this:

• for wp_remote_get(), i had to add an argument for 'sslverify' => false so that my server would actually retrieve the gist contents. otherwise, it failed and wouldn't ever cache it.

I will def. be thinking of more features as I keep using this. great job, it's exactly what I needed!