Sending encoding response in json - php

Question

I am using a lot of jQuery in a project am working on.
I have a javascript function that makes an ajax request to a controller which returns data in JSON.
I would like to display a user friendly message informing the user that he/she has no information stored yet. But I'm confused as to how to send a response in JSON so my javascript function can determine whether the user has information to be displayed.
Here is my javascript function:
function latest_pheeds() {
var action = url+"pheeds/latest_pheeds";
$('#pheed-stream').html('<div class="loading"></div>');
$('.loading').append('<img src="'+pheed_loader_src+'" />');
$.ajax({
url:action,
type:'GET',
dataType:'json',
error: function () {
},
success:function(data) {
$('.loading').fadeOut('slow');
$.each(data,function(index,item) {
$('#pheed-stream').append
(
'<div class="pheed" id="'+item.pheed_id+'">'+
'<p><a class="user_trigger" href="users/info/'+item.user_id+'">'
+item.user_id+'</a></p>'+
'<p>'+item.pheed+'</p>'+
'<div class="pheed_meta">'+
'<span>'+item.datetime+' Ago</span>'+
'<span class="cm">'+item.comments+
'<img class="comment_trigger" src="/pheedbak/assets/img/comment.png" title="Click to comment on pheed" onclick="retrieve_comments('+item.pheed_id+')">'+
'</span>'+
'<span>'+item.repheeds+
' Repheeds'+
'<img class="repheed_trigger" src="/pheedbak/assets/img/communication.png" title="Click to repheed" onclick="repheed('+item.pheed_id+')">'+
'</span>'+
'<span>'+
'Favourite'+
'<img class="favourite_trigger" src="/pheedbak/assets/img/star.png" title="Click to make this a favourite" onclick="favourite_pheed('+item.pheed_id+')" />'+
'</span>'+
'</div>'+
'</div>'
);
});
}
});
}
And heres the controller function the ajax request is made to
function latest_pheeds() {
//Confirm if a user is logged before allowing access
if($this->isLogged() == true) {
//load the pheed model for database interaction
$this->load->model('pheed_model');
//load user model
$this->load->model('user_model');
//load comment model
$this->load->model('comment_model');
//store the pheeds to a the $data variable
$data = $this->pheed_model->get_latest_pheeds();
//Load the date helper to calculate time difference between post time and current time
$this->load->helper('date');
//Current time(unix timetamp)
$time = time();
//pheeds
$pheeds = array();
if(count($data) > 0 ) {
foreach($data as $pheed) {
$row['pheed_id'] = $pheed->pheed_id;
$row['user_id'] = $this->user_model->return_username($pheed->user_id);
$row['pheed'] = $pheed->pheed;
$row['datetime'] = timespan($pheed->datetime,$time);
$row['comments'] = $this->comment_model->count_comments($pheed->pheed_id);
$row['repheeds'] = $pheed->repheeds;
$pheeds[] = $row;
}
echo json_encode($pheeds);
$response['response'] = "Ok";
$res[] = $response;
echo json_encode($res)."\n";
}
} else {
}
It generates the JSON output,but the syntax is broken so i cant read it with javascript,
but once i get rid of the following code from the above method it works normally
$response['response'] = "Ok";
$res[] = $response;
echo json_encode($res)."\n";

Answer 1

You MUST only use json_encode($data) once in a response, if you want to output more stuff, you need to merge your data into one array and send that.
EDIT: To be clear, one way you could do it is like this:
echo json_encode(array('pheeds' => $pheeds, 'res' => $res));
Then in JS you will get an array with the keys "pheeds" and "res".
Although it may be of little practical significance, I would also recommend doing this before you echo the json encoded string:
header('Content-Type: application/json');