Writing Wordpress Modules

Ziycon wrote: »

I'm looking for a good tutorial/examples on writing wordpress modules with custom functionality, can anyone recommend any?

Also if you want to add custom fields to all/specific site pages, the Advanced Custom Fields plugin will do almost everything you could want.

Ziycon wrote: »

It's to have a custom feature that will exist on one page that has some complex logic in it but only ever exists on the one page.

Is it going to have an admistrative screen in the Wordpress CMS, ie. Is it something that will be updated by logged-in users?

Probably don't need that plugin tutorial I posted earlier so.

It might be just a case of a building something into your WordPress theme. Find the .php file you need to update (depends on the theme, could be header.php, content.php, content-page.php, etc.), locate where you want the functionality to appear and paste in the code inside conditional statement like if page(page id here){do stuff}

For stuff like this I use shortcodes that I put where I want.

You write a plugin and your shortcode function does what it needs to and returns a string of html that will appear in the page.
The plugin is independent of the theme and is uploaded to the wp-content/plugins directory and activated in the Dashboard.

As an example, here is a tiny plugin that I wrote for generating anchor and target links:
[PHP]<?php
/*
Plugin Name: Anchor/Target shortcodes
Plugin URI: http://www.damiencarbery.com
Description: Shortcodes for generating anchor and target links.
Author: Damien Carbery
Version: 0.1

$Id: anchor-target-shortcodes.php 2297 2014-01-01 21:53:29Z damien $
*/


function ats_helper_shortcode($atts, $content, $code) {
switch ($code) {
// [anchor_link text='More Info' name='target']
case 'anchor_link':
extract(shortcode_atts(array(
'name' => '',
'text' => '',
), $atts));
return '<a href="#'.$name.'">'.$text.'</a>';
break;
// [target_link name='target']
case 'target_link':
extract(shortcode_atts(array(
'name' => '',
), $atts));
return '<a id="'.$name.'"></a>';
break;

default:
return '';
}
}

add_shortcode('anchor_link', 'ats_helper_shortcode');
add_shortcode('target_link', 'ats_helper_shortcode');
?>[/PHP]