Previous Up Next - Pun

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A link between pages plugin

I found my previous solution to be slow and inflexible. What I instead did was to write my own little plugin. In the version 0.2 I succeeded with doing an fens post error, and miss the link in the next to last page. Sigh.

<?php
/*
*Plugin Name: Previous Up Next - pun
*Plugin URI: https://properhoc.com/programming/previous-up-next-pun/
*Description: Creates links between the current page, its parents and its nearest siblings. Add a [pun] shortcode (intended). It also add a [punno] shortcode. 
*Version: 0.3
*Author: Mauriz Blomqvist - properHoc
*Author URI: https://properhoc.com
*/


//Adds the [pun] shortcode where the default texts before the links
//are 'Up a level : ', 'Previous post : ','Next post : ' respectively.
// The [punno] shortcode has no text as default. 
include('shortcodes.php');

function previous_up_next($previous_text=' ', $up_text=' ', $next_text=' '){
	global $post;
	$previous_post='';
	$parent_post='';
	$next_post='';
	$page_ID=get_the_ID();
	// Get parent ID and post information - if any.
	if ($page_ID) {
		$parent_ID = wp_get_post_parent_id($page_ID);
		if ($parent_ID){
			$parent_post=get_post($parent_ID);
			// Get list of siblings, i.e. a list of all pages with the same parent as the current page.  
			$siblings=get_pages('child_of='. $parent_ID . '&parent='. $parent_ID. '&' . 'sort_column=menu_order&sort_order=asc');	
			$number_of_siblings=count($siblings);
			// Find the current page in the list of siblings if we have more than one child. 
			if (1<$number_of_siblings){
					for ($p=0; $p<$number_of_siblings; $p++) {
						if ($page_ID==$siblings[$p]->ID) break;
					}
				// If it is not the fist page, then retrieve the previous page. 	
				if (0<$p){
					$previous_post=$siblings[$p-1];
				}
				// If it is not the last page, then retrieve the next page. 
				if ($p<$number_of_siblings-1){
					$next_post=$siblings[$p+1];
				} 
				
			} 
			
		}
		
		// Collect the output. 
		// This will most likely be done in a somewhat more flexible way in the future. 
		$output='';
		if ($parent_post!=''){
			$output.=$up_text.'<a href="'.get_permalink($parent_post->ID).'">'.$parent_post->post_title.'</a>';
		}
		if ($previous_post!=''){
			$output.='<br /> '.$previous_text.'<a href="'.get_permalink($previous_post->ID).'">'.$previous_post->post_title.'</a>';
		}
		if ($next_post!=''){
			$output.='<br /> '.$next_text.'<a href="'.get_permalink($next_post->ID).'">'.$next_post->post_title.'</a>';
		}
		return $output; 
		
	}
	
	
}

<?php

*Plugin Name: Previous Up Next - pun

*Plugin URI: https://properhoc.com/programming/previous-up-next-pun/

*Description: Creates links between the current page, its parents and its nearest siblings. Add a [pun] shortcode (intended). It also add a [punno] shortcode.

*Version: 0.3

*Author: Mauriz Blomqvist - properHoc

*Author URI: https://properhoc.com

//Adds the [pun] shortcode where the default texts before the links

//are 'Up a level : ', 'Previous post : ','Next post : ' respectively.

// The [punno] shortcode has no text as default.

include('shortcodes.php');

function previous_up_next($previous_text=' ', $up_text=' ', $next_text=' '){

global $post;

$previous_post='';

$parent_post='';

$next_post='';

$page_ID=get_the_ID();

// Get parent ID and post information - if any.

if ($page_ID) {

$parent_ID = wp_get_post_parent_id($page_ID);

if ($parent_ID){

$parent_post=get_post($parent_ID);

// Get list of siblings, i.e. a list of all pages with the same parent as the current page.

$siblings=get_pages('child_of='. $parent_ID . '&parent='. $parent_ID. '&' . 'sort_column=menu_order&sort_order=asc');

$number_of_siblings=count($siblings);

// Find the current page in the list of siblings if we have more than one child.

if (1<$number_of_siblings){

for ($p=0; $p<$number_of_siblings; $p++) {

if ($page_ID==$siblings[$p]->ID) break;

}

// If it is not the fist page, then retrieve the previous page.

if (0<$p){

$previous_post=$siblings[$p-1];

}

// If it is not the last page, then retrieve the next page.

if ($p<$number_of_siblings-1){

$next_post=$siblings[$p+1];

}

// Collect the output.

// This will most likely be done in a somewhat more flexible way in the future.

$output='';

if ($parent_post!=''){

$output.=$up_text.'<a href="'.get_permalink($parent_post->ID).'">'.$parent_post->post_title.'</a>';

}

if ($previous_post!=''){

$output.='<br /> '.$previous_text.'<a href="'.get_permalink($previous_post->ID).'">'.$previous_post->post_title.'</a>';

}

if ($next_post!=''){

$output.='<br /> '.$next_text.'<a href="'.get_permalink($next_post->ID).'">'.$next_post->post_title.'</a>';

}

return $output;

}

The shortcode part is as follows:

<?php

    // Default is no text before link:
    add_shortcode('punno', 'next_up_previous_shortcode_no');
    //Default is 'Up a level : ', 'Previous page : ','Next page : '   
    add_shortcode('pun', 'next_up_previous_shortcode');
    
    function next_up_previous_shortcode($attributes) {
        extract(shortcode_atts(array(
            'previous_text'=>'Previous post : ',
            'up_text'=>'Up a level : ',
            'next_text' => 'Next post : '
        ), $attributes));
        return previous_up_next($previous_text,$up_text,$next_text);        
    }
    
    function next_up_previous_shortcode_no($attributes) {
        extract(shortcode_atts(array(
            'previous_text'=>'',
            'up_text'=>'',
            'next_text' => ''
        ), $attributes));
        return previous_up_next($previous_text,$up_text,$next_text);        
    }

<?php

// Default is no text before link:

add_shortcode('punno', 'next_up_previous_shortcode_no');

//Default is 'Up a level : ', 'Previous page : ','Next page : '

add_shortcode('pun', 'next_up_previous_shortcode');

function next_up_previous_shortcode($attributes) {

extract(shortcode_atts(array(

'previous_text'=>'Previous post : ',

'up_text'=>'Up a level : ',

'next_text' => 'Next post : '

), $attributes));

return previous_up_next($previous_text,$up_text,$next_text);

}

function next_up_previous_shortcode_no($attributes) {

extract(shortcode_atts(array(

'previous_text'=>'',

'up_text'=>'',

'next_text' => ''

), $attributes));

return previous_up_next($previous_text,$up_text,$next_text);

}

I have also changed the functions.php file in a child of the Theme I am using. This adds shortcode to the the beginning and the end of each page. Those shortcodes will then be turned to calls of the previous_up_next function.

<?php

add_action( 'wp_enqueue_scripts', 'theme_enqueue_styles' );
function theme_enqueue_styles() {
    wp_enqueue_style( 'parent-style', get_template_directory_uri() . '/style.css' );

}

add_filter('the_content','add_my_c1');

function add_my_c1($content) {
    $lineup='<a href="http://media.properhoc.com/2017/01/lineup.png"><img class="aligncenter size-full wp-image-391" src="https://media.properhoc.com/2017/01/lineup.png" alt="" width="654" height="3" /></a>';
    $linedown='<a href="http://media.properhoc.com/2015/10/linelow.png"><img class="aligncenter size-full wp-image-409" src="https://media.properhoc.com/2015/10/linelow.png" alt="" width="654" height="3" /></a>';
    $up_text = '[pun]'.$lineup;
    $low_text = $lineup.chr(0x0D).'[pun]'.$lineup.'Last modified: [last-modified]';

    $content = $up_text.$content.$low_text;    
    return $content;
}

?>

<?php

add_action( 'wp_enqueue_scripts', 'theme_enqueue_styles' );

function theme_enqueue_styles() {

wp_enqueue_style( 'parent-style', get_template_directory_uri() . '/style.css' );

}

add_filter('the_content','add_my_c1');

function add_my_c1($content) {

$lineup='<a href="http://media.properhoc.com/2017/01/lineup.png"><img class="aligncenter size-full wp-image-391" src="https://media.properhoc.com/2017/01/lineup.png" alt="" width="654" height="3" /></a>';

$linedown='<a href="http://media.properhoc.com/2015/10/linelow.png"><img class="aligncenter size-full wp-image-409" src="https://media.properhoc.com/2015/10/linelow.png" alt="" width="654" height="3" /></a>';

$up_text = '[pun]'.$lineup;

$low_text = $lineup.chr(0x0D).'[pun]'.$lineup.'Last modified: [last-modified]';

$content = $up_text.$content.$low_text;

return $content;

}

Up a level : Programming
Previous page : A bit of PHP
Next page : The first (a tad larger) bit of JavaScript on this site

Last modified: Nov 11, 2017 @ 20:25