#codeigniter ajax

So I ran into some stupid bugs and not-so-stupid bugs so I quickly wanted to share this with anyone who might see this, and to review what I learned today also.

Let me describe the page I'm building right now -

I'm building a website for an artist and that website has a backend where you can edit/upload pictures and their titles. For the edit section I have a grid of pictures that you can select in order to load their information into form elements. I want to do this with AJAX (using jQuery) so I make it send an AJAX request (probably not the right terminology but hopefully you know what I mean) to a CodeIgniter controller.

Now the first problem was my lack of understanding/realizing that there is going to be a problem sending data to/from CodeIgniter and jQuery. So basically there are helper functions for PHP and Javascript that facilitate with translating string<->JSON object. This is due to the fact that PHP can only pass a string as data to Javascript. We then convert that string-form JSON into a JSON object in Javascript by using jQuery's jQuery.parseJSON(). http://api.jquery.com/jQuery.parseJSON/

The code is pretty simple so I think I'll just post the code and it should be pretty clear how to do this. If not - definitely leave a comment and I'll reply ASAP if anyone actually needs help with this :)

http://snipt.net/ehdeelee/ajax-call-from-javascript

http://snipt.net/ehdeelee/ajax-receiver-from-codeigniter

We all need web 2.0 applications and that too google crawlable.

So in case you are using Codeigniter and looking for ajax requests with features like History(back and forth) , SEO based URL. This post might save some time.

For URL change and History features, I am using jquery address plugin here you might use some other alternative.

We will have to modify codeigniter Router class little bit.  The class is at system/core/Router.php

Search for 

// Fetch the complete URI string $this->uri->_fetch_uri_string();

Add few lines after that : 

/**-----------------CHeck Ajax Request ---------------- **/

if(!empty($_SERVER['HTTP_X_REQUESTED_WITH']) && 

strtolower($_SERVER['HTTP_X_REQUESTED_WITH']) == 'xmlhttprequest') 

define('IS_AJAX',true); else define('IS_AJAX',false);

/**----------------- Assign a variable ----------------**/

Now in your controller, check if IS_AJAX is true, if yes then output a json

Javascript to be used.

jQuery.address.crawlable.(1).init(function(){

jQuery("a").address(); //initialising address plugin for all the links.

}).change(function(e){

var url = $(this).attr("href");

var content = $("content");

jQuery.post(url,'',function(response){

content.html(response.content);

},'json');

});