WordPress Tip: bloginfo as a shortcode

I often need to help move a client’s redesigned website into WordPress at a new webhost. During this process, the client’s domain must remain pointing to the old website so there is no interruption in traffic. Repointing the domain becomes one of the last steps of the process.

WordPress addresses a potential problem here with a Template tag called bloginfo. Inside my theme’s templates, I use bloginfo(‘url’) rather than hardcoding my site’s URL. The actual URL is maintained in the Dashboard under Settings > General > WordPress address (URL). bloginfo(‘template_url’) adds the current theme path to the URL. Often when programming, computing a value gives you more flexibility than hardcoding a value.

Another area where I would like to have this flexibility is inside the actual content of the post. If I upload an image using the Media Uploader, it immediately computes the URL for the image. But I don’t want to have to come back later after the domain has been repointed to edit the URLs in the post. Can’t I have the same delayed computation that bloginfo(‘url’) provides, but inside the content?

Solution 1: Shortcodes for your URLs

Edit your theme’s functions.php

function my_url($atts, $content = null) {
  return get_bloginfo('url'); 
}
add_shortcode("url", "my_url");  
 
function my_template_url($atts, $content = null) {
  return get_bloginfo('template_url'); 
}
add_shortcode("template_url", "my_template_url");  
 
function my_images_url($atts, $content = null) {
  return get_bloginfo('template_url') . '/images'; 
}
add_shortcode("images_url", "my_images_url");

Using this shortcode, I can upload the image, insert the image into the post, and then modify the URL to use the shortcode. I don’t have to return to edit the URL later.

  <img src="[images_url]/chunky.jpg" />

Solution 2: Shortcode for bloginfo itself

I found this solution at Blue Anvil

function bloginfo_shortcode( $atts ) {
    extract(shortcode_atts(array(
        'key' => '',
    ), $atts));
    return get_bloginfo($key);
}
add_shortcode('bloginfo', 'bloginfo_shortcode');

Demo

That was uploaded with the Media Uploader, and here’s the final markup

<a href="[bloginfo key='url']/wp-content/uploads/2010/02/chunky-e1266723693872.jpg">
<img src="[bloginfo key='url']/wp-content/uploads/2010/02/chunky-e1266723693872-225x300.jpg" 
alt="" title="chunky" width="225" height="300" class="alignnone size-medium wp-image-462" /></a>

CodeIgniter Tip: Body class tags

WordPress 2.8 came out with the body_class() function which allows you to hang your per-page (or per-whatever) CSS off of dynamically generated class attributes on the body HTML tag. I’m going to show you how to have some of that flexibility when using the CodeIgniter PHP framework.

CodeIgniter URLs often take the form of http://my-cool-website.com/account/change-password, where account is the controller and change-password is the function. I want CodeIgniter to automatically put a CSS class “account-change-password” on the body tag whenver a user visits that page.

Step 1. Edit controllers/application.php

Application is the superclass of all of my other controllers, including the Account controller. Here we add 2 variables and populate them in the Application() constructor.

class Application extends Controller {
 
  var $controller;
  var $function;
 
	function Application() {
	  parent::Controller();
	  $this->controller = $this->uri->rsegment(1); // The Controller
          $this->function = $this->uri->rsegment(2); // The Function
	}

Step 2. Edit the body tag in your layout template

<body class="<?php echo $this->controller; ?>-<?php echo $this->function; ?>">

now you’re ready to make up some CSS such as

body.account-change-password  #main-content ul {
  list-style-type: none;
}

So now your page elements can have alternate CSS targeted to which controller-function page is currently displaying.