Basic autopaging functionality. Splits over two pages, includes an option to...

Basic autopaging functionality. Splits over two pages, includes an option to disable. Filter exists to modify supported post types.

automatically-paginate-posts.php

+<?php
+/*
+Plugin Name: Automatically Paginate Posts
+Plugin URI:
+Description: Automatically inserts the &lt;!--nextpage--&gt; Quicktag into WordPress posts, pages, or custom post type content.
+Version: 0.1
+Author: Erick Hitter (Oomph, Inc.)
+Author URI: http://www.thinkoomph.com/
+
+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.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program; if not, write to the Free Software
+Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+*/
+
+class Automatically_Paginate_Posts {
+	/**
+	 * Class variables
+	 */
+	private $post_types;
+
+	private $meta_key_disable_autopaging = '_disable_autopaging';
+
+	/**
+	 * Register actions and filters
+	 *
+	 * @uses add_action, add_filter
+	 * @return null
+	 */
+	public function __construct() {
+		add_action( 'init', array( $this, 'action_init' ) );
+		add_action( 'add_meta_boxes', array( $this, 'action_add_meta_boxes' ) );
+		add_action( 'save_post', array( $this, 'action_save_post' ) );
+		add_filter( 'the_posts', array( $this, 'filter_the_posts' ) );
+	}
+
+	/**
+	 *
+	 */
+	public function action_init() {
+		//Post types
+		$this->post_types = apply_filters( 'autopaging_post_types', array( 'post', 'page' ) );
+	}
+
+	/**
+	 * Add autopaging metabox
+	 *
+	 * @uses this::get_option, add_metabox
+	 * @action add_meta_box
+	 * @return null
+	 */
+	function action_add_meta_boxes() {
+		add_meta_box( 'autopaging', 'Post Autopaging', array( $this, 'meta_box_autopaging' ), 'post', 'side' );
+	}
+
+	/**
+	 * Render autopaging metabox
+	 *
+	 * @param object $post
+	 * @uses esc_attr, checked, wp_nonce_field
+	 * @return string
+	 */
+	function meta_box_autopaging( $post ) {
+	?>
+		<p>
+			<input type="checkbox" name="<?php echo esc_attr( $this->meta_key_disable_autopaging ); ?>" id="<?php echo esc_attr( $this->meta_key_disable_autopaging ); ?>_checkbox" value="1"<?php checked( (bool) get_post_meta( $post->ID, $this->meta_key_disable_autopaging, true ) ); ?> /> <label for="<?php echo esc_attr( $this->meta_key_disable_autopaging ); ?>_checkbox">Disable autopaging for this post?</label>
+		</p>
+		<p class="description">Check the box above to prevent this post from automatically being split over two pages.</p>
+		<p class="description">Note that if the <code>&lt;!--nextpage--&gt;</code> Quicktag is used to manually page this post, automatic paging won't be applied, regardless of the setting above.</p>
+	<?php
+		wp_nonce_field( $this->meta_key_disable_autopaging, $this->meta_key_disable_autopaging . '_wpnonce' );
+	}
+
+	/**
+	 * Save autopaging metabox
+	 *
+	 * @param int $post_id
+	 * @uses DOING_AUTOSAVE, wp_verify_nonce, update_post_meta, delete_post_meta
+	 * @action save_post
+	 * @return null
+	 */
+	function action_save_post( $post_id ) {
+		if ( defined( 'DOING_AUTOSAVE' ) && DOING_AUTOSAVE )
+			return;
+
+		if ( isset( $_POST[ $this->meta_key_disable_autopaging . '_wpnonce' ] ) && wp_verify_nonce( $_POST[ $this->meta_key_disable_autopaging . '_wpnonce' ], $this->meta_key_disable_autopaging ) ) {
+			$disable = isset( $_POST[ $this->meta_key_disable_autopaging ] ) ? true : false;
+
+			if ( $disable )
+				update_post_meta( $post_id, $this->meta_key_disable_autopaging, true );
+			else
+				delete_post_meta( $post_id, $this->meta_key_disable_autopaging );
+		}
+	}
+
+	/**
+	 * Automatically page posts by injecting <!--nextpage--> Quicktag.
+	 * Only applied if the post type matches specified options and post doesn't already contain the Quicktag.
+	 *
+	 * @param array $posts
+	 * @uses is_admin, get_post_meta
+	 * @filter the_posts
+	 * @return array
+	 */
+	function filter_the_posts( $posts ) {
+		if ( ! is_admin() ) {
+			foreach( $posts as $the_post ) {
+				if ( in_array( $the_post->post_type, $this->post_types ) && ! preg_match( '#<!--nextpage-->#i', $the_post->post_content ) && ! (bool) get_post_meta( $the_post->ID, $this->meta_key_disable_autopaging, true ) ) {
+					//Start with post content, but alias to protect the raw content.
+					$content = $the_post->post_content;
+
+					//Normalize post content to simplify paragraph counting and automatic paging. Accounts for content that hasn't been cleaned up by TinyMCE.
+					$content = preg_replace( '#<p>(.+?)</p>#i', "$1\r\n\r\n", $content );
+					$content = preg_replace( '#<br(\s*/)?>#i', "\r\n", $content );
+
+					//Count paragraphs
+					$count = preg_match_all( '#\r\n\r\n#', $content, $matches );
+
+					//Keep going, if we have something to count.
+					if ( is_int( $count ) && 0 < $count ) {
+						//Explode content at double line breaks
+						$content = explode( "\r\n\r\n", $content );
+
+						//Determine where to insert Quicktag and insert
+						$insert_before = ceil( count( $content ) / 2 );
+
+						$content[ $insert_before ] = '<!--nextpage-->' . $content[ $insert_before ];
+
+						//Reunite content
+						$content = implode( "\r\n\r\n", $content );
+
+						//And, overwrite the original content
+						$the_post->post_content = $content;
+					}
+
+					//Lastly, clean up.
+					unset( $content );
+				}
+			}
+		}
+
+		return $posts;
+	}
+}
+new Automatically_Paginate_Posts;
+?>
\ No newline at end of file

readme.txt

 === Automatically Paginate Posts ===
-Contributors: ethitter
+Contributors: ethitter, thinkoomph
 Donate link:
 Tags: paginate, nextpage, Quicktag
 Requires at least: 3.4