Using AJAX returned JSON encoded data in Codeigniter - json

Question

I am relatively new to codeigniter. While I was trying to perform a searching operation on my data base using AJAX, The code is returned as successful and the data is retrieved but, This data is JSON encoded and is in the javascript portion of my view so I am unable to use the json_decode function of codeigniter
public function lookup(){
$keyword = $this->input->post('term');
$data['response'] = 'false'; //Set default response
$query = $this->MAutocomplete->lookup($keyword); //Search DB
if( ! empty($query) )
{
$data['response'] = 'true'; //Set response
$data['message'] = array(); //Create array
foreach( $query as $row )
{
$data['message'][] = array(
'id'=>$row->id,
'value' => $row->firstname,
); //Add a row to array
}
}
echo json_encode($data); //echo json string
}
the data is accessed in the javascript as data.message.
Please tell me is there anyway i can use this data in the php part of my program
<?php
class MAutocomplete extends CI_Model{
function lookup($keyword){
$this->load->database();
$this->db->select('*');
$this->db->from('Students');
$this->db->like('firstName',$keyword,'after');
$query = $this->db->get();
// echo '<pre>'; print_r($query->result()); exit;
return $query->result();
}
}

Answer 1

I think you need to parse json response in Ajax's success function using JSON.parse().Like this..
$.ajax({
url:'',//your url
dataType:'JSON',
data:'',//your data
success:function(response){
data = JSON.parse(response);
alert(data.message.value);//alerts value
}
});
In controller use count rather than empty.To check the array
if( count($query) >0 )
{
$data['response'] = 'true'; //Set response
$data['message'] = array(); //Create array
foreach( $query as $row )
{
$data['message'][] = array(
'id'=>$row->id,
'value' => $row->firstname,
); //Add a row to array
}
}

Answer 2

You should use to response:
return $this->output
->set_content_type('application/json')
->set_output(json_encode($data));