simple_embed.php

<?php  #if (!defined('DB_NAME')) die('No direct script access allowed');
/*
Plugin Name: Simple Embed
Plugin URI:  https://github.com/IET-OU/oer-evidence-hub-org/#Juxtalearn
Description: Remove the "chrome" from any Wordpress page, making it embeddable '/page?embed=1&comments=0&target=_blank' [JuxtaLearn].
Author:  Nick Freear
Author URI:  https://github.com/nfreear
Version:  1.3
*/
define('SIMPLE_EMBED_REGISTER_FILE',
	preg_replace('@/Users/[^\/]+/[^\/]+/[^\/]+@', '',    # Mac OS X
		preg_replace( '@\/var\/www\/[^\/]+@', '', __FILE__ ) # Linux
));


class Simple_Embed {

	// http://w3.org/TR/html-markup/a.html#a.attrs.target
	const TARGET_REGEX = '/^(_blank|_self|_parent|_top)$/';

	protected $is_embed = false;
	protected $has_comments = true;
	protected $target = '_top';


	public function __construct() {

		$this->is_embed = $this->_get( 'embed' );
		if ( 0 === $this->_get( 'comments' ) ) {  //< 1
			$this->has_comments = false;
		}
		$try_target = $this->_get( 'target' );
		if ( $try_target && preg_match( self::TARGET_REGEX, $try_target ) ) {
			$this->target = $try_target;
		}

		if ( $this->is_embed || ! $this->has_comments ) {
			add_filter( 'body_class', array( &$this, 'body_class' ) );
			add_action( 'wp_enqueue_scripts', array( &$this, 'enqueue_scripts' ) );
		}
		if ( $this->is_embed ) {
			define( 'SIMPLE_EMBED_IS_EMBED', true );

			add_action( 'wp_head', array( &$this, 'head_target' ), 1 );
			add_action( 'wp_footer', array( &$this, 'footer_script' ) ); //, 500);

			# http://www.youtube.com/embed/vvEmahPNEcI
			header( 'X-Frame-Options: ALLOWALL' );
			header( 'X-Content-Type-Options: nosniff' );
		}
	}

	/** WP action: body_class.
  */
	public function body_class( $classes ) {
		if ( ! $this->has_comments ) {
			if ( is_array( $classes ) ) {
				// 'body_class' action.
				$classes[] = 'se-no-comments';
			} else {
				// 'admin_body_class' action.
				$classes .= ' se-no-comments';
			}
		}

		if ( ! $this->is_embed ) { return $classes;
		}

		if ( is_array( $classes ) ) {
			$classes[] = 'simple-embed';
			$classes[] = is_user_logged_in() ? 'se-login-yes' : 'se-login-no';
		} else {
			$classes .= ' simple-embed ';
			$classes .= is_user_logged_in() ? 'se-login-yes' : 'se-login-no';
		}
		return $classes;
	}

	/** WP action. */
	public function enqueue_scripts() {
		wp_enqueue_style('simple-embed', plugins_url(
			'css/simple-embed.css', SIMPLE_EMBED_REGISTER_FILE
		));
	}

	/** WP action. */
	public function head_target() {
		$title = ('_blank' == $this->target) ? __( 'Opens in new window' ) : '';
		?>
		<base id="se-bt" target="<?php echo $this->target ?>" title="<?php echo $title ?>" />
		<?php
	}

	/** WP action. */
	public function footer_script() {

		// Display basic user info on button click.
		$user = wp_get_current_user();
		$info = 'Logged in as: [unknown]';
		if ( $user instanceof WP_User ) {
			$info = sprintf('Logged in as: %s (role: %s, via: %s)',
			$user->user_login, $this->get_current_user_role(), $this->get_user_auth_method());

			if ( 0 == $user->ID ) {
				  $info = __( 'Not logged in.' );
			}
		}

		$parent_url = isset( $_SERVER['HTTP_REFERER'] ) ? $_SERVER['HTTP_REFERER'] : null;

		?>
		<script>
		  document.documentElement.className += " simple-embed";
		  simple_embed = { parent_url: <?php echo json_encode( $parent_url )?> }
	  </script>
	  <script id="simple-embed-js-1">
	  jQuery(function ($) {
		  // Set link titles when target='_blank'
		  $("a:not( [title] )").attr("title", $("base").attr("title"));

		  // User info widget.
		  // $(".entry-content:first").append(
		  $("body").prepend(
		    "<button id='se-info-btn' title='User information'><i>i</i></button>"
		  );
		  $("#se-info-btn").on("click", function () {
				alert("User Information:\n\n" + <?php echo json_encode( $info ) ?>);
		  });
	  });
	  </script>
		<?php
	}


	/** Utilities.
  */
	protected function _get( $key, $default = null ) {
		return isset( $_GET[ $key ] ) ? $_GET[ $key ] : $default;
	}

	# http://wordpress.org/support/topic/how-to-get-the-current-logged-in-users-role#post-1691825
	/**
   * Returns the translated role of the current user. If that user has
   * no role for the current blog, it returns false.
   *
   * @return string The name of the current role
   */
	function get_current_user_role() {
		global $wp_roles;
		$current_user = wp_get_current_user();
		$roles = $current_user->roles;
		$role = array_shift( $roles );
		$t_role = isset( $wp_roles->role_names[ $role ] ) ? $wp_roles->role_names[ $role ] : null;
		return translate_user_role( $t_role );
	}

	protected function get_user_auth_method() {
		global $current_user;
		$via = get_user_meta( $current_user->ID, '_jxl_clipit_auth_method', $single = true );
		return $via ? $via : '- ';
	}

}
$simple_embed = new Simple_Embed();