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<?php
/**
* Entry Views - A WordPress script for counting post views.
*
* Entry views is a script for calculating the number of views a post gets. It is meant to be basic and
* not a full-featured solution. The idea is to allow theme/plugin authors to quickly load this file and
* build functions on top of it to suit their project needs. This is an AJAX-based solution, so only visitors
* to your site with JavaScript enabled in their browser will update the view count. It is possible to do this
* without AJAX but not recommend (see notes below).
*
* By default, no post types are supported. You have to register support for 'entry-views' for the post types
* you wish to use this extension with.
*
* Not using AJAX: You can call up entry_views_update() at any time and pass it a post ID to update the
* count, but this has problems. Any links with rel="next" or rel="prefetch" will cause some browsers to prefetch
* the data for that particular page. This can cause the view count to be skewed. To try and avoid this
* issue, you need to disable/remove adjacent_posts_rel_link_wp_head(). However, this is not bullet-proof
* as it cannot control links it doesn't know about.
* @link http://core.trac.wordpress.org/ticket/14568
*
* This program is free software; you can redistribute it and/or modify it under the terms of the GNU
* General Public License as published by the Free Software Foundation; either version 2 of the License,
* or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without
* even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
*
* @package EntryViews
* @version 0.2.1
* @author Justin Tadlock <justin@justintadlock.com>
* @copyright Copyright (c) 2010 - 2012, Justin Tadlock
* @link http://justintadlock.com
* @license http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
*/
/* Add post type support for 'entry-views'. */
add_action( 'init', 'entry_views_post_type_support' );
/* Add the [entry-views] shortcode. */
add_shortcode( 'entry-views', 'entry_views_get' );
/* Registers the entry views extension scripts if we're on the correct page. */
add_action( 'template_redirect', 'entry_views_load' );
/* Add the entry views AJAX actions to the appropriate hooks. */
add_action( 'wp_ajax_entry_views', 'entry_views_update_ajax' );
add_action( 'wp_ajax_nopriv_entry_views', 'entry_views_update_ajax' );
/**
* Adds support for 'entry-views' to the 'post', 'page', and 'attachment' post types (default WordPress
* post types). For all other post types, the theme should explicitly register support for this feature.
*
* @since 0.2.0
* @access private
* @return void
*/
function entry_views_post_type_support() {
/* Add support for entry-views to the 'post' post type. */
add_post_type_support( 'post', array( 'entry-views' ) );
/* Add support for entry-views to the 'page' post type. */
add_post_type_support( 'page', array( 'entry-views' ) );
/* Add support for entry-views to the 'attachment' post type. */
add_post_type_support( 'attachment', array( 'entry-views' ) );
}
/**
* Checks if we're on a singular post view and if the current post type supports the 'entry-views'
* extension. If so, set the $post_id variable and load the needed JavaScript.
*
* @since 0.1.0
* @access private
* @return void
*/
function entry_views_load() {
global $entry_views;
/* Check if we're on a singular post view. */
if ( is_singular() ) {
/* Get the post object. */
$post = get_queried_object();
/* Check if the post type supports the 'entry-views' feature. */
if ( post_type_supports( $post->post_type, 'entry-views' ) ) {
/* Set the post ID for later use because we wouldn't want a custom query to change this. */
$entry_views->post_id = get_queried_object_id();
/* Enqueue the jQuery library. */
wp_enqueue_script( 'jquery' );
/* Load the entry views JavaScript in the footer. */
add_action( 'wp_footer', 'entry_views_load_scripts' );
}
}
}
/**
* Updates the number of views when on a singular view of a post. This function uses post meta to store
* the number of views per post. By default, the meta key is 'Views', but you can filter this with the
* 'entry_views_meta_key' hook.
*
* @since 0.1.0
* @access public
* @param int $post_id The ID of the post to update the meta for.
* @return void
*/
function entry_views_update( $post_id = '' ) {
/* If we're on a singular view of a post, calculate the number of views. */
if ( !empty( $post_id ) ) {
/* Allow devs to override the meta key used. By default, this is 'Views'. */
$meta_key = apply_filters( 'entry_views_meta_key', 'Views' );
/* Get the number of views the post currently has. */
$old_views = get_post_meta( $post_id, $meta_key, true );
/* Add +1 to the number of current views. */
$new_views = absint( $old_views ) + 1;
/* Update the view count with the new view count. */
update_post_meta( $post_id, $meta_key, $new_views, $old_views );
}
}
/**
* Gets the number of views a specific post has. It also doubles as a shortcode, which is called with the
* [entry-views] format.
*
* @since 0.1.0
* @access public
* @param array $attr Attributes for use in the shortcode.
* @return string
*/
function entry_views_get( $attr = '' ) {
/* Merge the defaults and the given attributes. */
$attr = shortcode_atts( array( 'before' => '', 'after' => '', 'post_id' => get_the_ID() ), $attr );
/* Allow devs to override the meta key used. */
$meta_key = apply_filters( 'entry_views_meta_key', 'Views' );
/* Get the number of views the post has. */
$views = intval( get_post_meta( $attr['post_id'], $meta_key, true ) );
/* Returns the formatted number of views. */
return $attr['before'] . number_format_i18n( $views ) . $attr['after'];
}
/**
* Callback function hooked to 'wp_ajax_entry_views' and 'wp_ajax_nopriv_entry_views'. It checks the
* AJAX nonce and passes the given $post_id to the entry views update function.
*
* @since 0.1.0
* @access private
* @return void
*/
function entry_views_update_ajax() {
/* Check the AJAX nonce to make sure this is a valid request. */
check_ajax_referer( 'entry_views_ajax' );
/* If the post ID is set, set it to the $post_id variable and make sure it's an integer. */
if ( isset( $_POST['post_id'] ) )
$post_id = absint( $_POST['post_id'] );
/* If $post_id isn't empty, pass it to the entry_views_update() function to update the view count. */
if ( !empty( $post_id ) )
entry_views_update( $post_id );
}
/**
* Displays a small script that sends an AJAX request for the page. It passes the $post_id to the AJAX
* callback function for updating the meta.
*
* @since 0.1.0
* @access private
* @return void
*/
function entry_views_load_scripts() {
global $entry_views;
/* Create a nonce for the AJAX request. */
$nonce = wp_create_nonce( 'entry_views_ajax' );
/* Display the JavaScript needed. */
echo '<script type="text/javascript">/* <![CDATA[ */ jQuery(document).ready( function() { jQuery.post( "' . admin_url( 'admin-ajax.php' ) . '", { action : "entry_views", _ajax_nonce : "' . $nonce . '", post_id : ' . $entry_views->post_id . ' } ); } ); /* ]]> */</script>' . "\n";
}
?>
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