Php ajax call for same php script response null - php

Question

I am developing a single page script i.e. category.php for category management.
This script have an input button to invoke AJAX call.
<input type="button" id="btn" />
Jquery code to bind click event and call ajax. I want json response.
$(document).ready(function(e) {
$('#btn').click(function(e) {
id=1;
jQuery.ajax({
type: 'post',
url: 'category.php',
success: function(data) {
if(data.rstatus==1){
alert(data.text);
}else
alert(data);
},
data:{'id':id}
});
});
});
A php code to entertain AJAX call.
if(!empty($_SERVER['HTTP_X_REQUESTED_WITH']) &&
strtolower($_SERVER['HTTP_X_REQUESTED_WITH']) == 'xmlhttprequest') {
$jsonResponse=array('rstatus'=>1,'id'=>$_POST['id']);
header("Content-type: application/json");
json_encode($jsonResponse);
die();
}
Problem:
This ajax call is unable to produce correct response in call back function, and cause error in firebug console.
TypeError: data is null
In FIREBUG Headers are as follow:
Response Headers
> Cache-Control no-cache, must-revalidate Connection Keep-Alive
> Content-Length 0 Content-Type application/json Date Tue, 26 Mar 2013
> 12:45:52 GMT Expires Mon, 26 Jul 1997 05:00:00 GMT
> Keep-Alive timeout=5, max=98 Last-Modified Tue, 26 Mar 2013
> 12:45:52GMT Pragma no-cache Server Apache/2.4.3 (Win32) OpenSSL/1.0.1c
> PHP/5.4.7 X-Powered-By PHP/5.4.7
Request Headers
> > Accept */* Accept-Encoding gzip, deflate
> > Accept-Language en-US,en;q=0.5 Content-Length 4
> > Content-Type application/x-www-form-urlencoded; charset=UTF-8
> > Cookie __gads=ID=39701a3d85dce702:T=1350383638:S=ALNI_MY_rHGVQ-qNxH4UGmbY_G-IuVcDkA;
> > __utma=141011373.593047819.1350426838.1364292528.1364295112.314;PHPSESSID=1s73cho6ildjt80jtudt8nq0f5 Host abc.com Referer http://www.abc.com/category.php
> > User-Agent Mozilla/5.0 (Windows NT 5.1; rv:19.0) Gecko/20100101
> > Firefox/19.0 X-Requested-With XMLHttpRequest

Answer 1

It's look like your response content is empty. You forgot an echo.
if(!empty($_SERVER['HTTP_X_REQUESTED_WITH']) && strtolower($_SERVER['HTTP_X_REQUESTED_WITH']) == 'xmlhttprequest') {
$jsonResponse=array('rstatus'=>1,'id'=>$_POST['id']);
header("Content-type: application/json");
echo json_encode($jsonResponse);
die();
}
If you want to response a json, you must put it in the response content. In Php, you just have to use echo to put something in the response content.

Answer 2

This doesn't work simply because $_SERVER doesn't contain that information. All request headers aren't really stored there. Have a look at getallheaders (http://php.net/manual/en/function.getallheaders.php)
Edit: Oh, also you need to echo the response. $_SERVER may contain the information you need in this case, but it is not reliable and portable. I'd still advise you to use getallheaders

Answer 3

don't use HTTP_X_REQUESTED_WITH - barely works in jQuery
try to send additional var, like
data:{'id':id, 'request':'xmlhttprequest'}