How to retrieve values from a JSON Object in PHP - php

Question

I've tried this many times now, using difference methods and none of them have worked for me, so I'm asking this question.
I have a small form that takes in 4 pieces of information, a persons title, first name, middle name and last name. When I hit a button, a JSON Object is formed, and sent as post data through a jQuery.ajax method.
JSON Sent to PHP file:
{
"title": "Mr",
"firstName":"Banana",
"middleName":"Slippy",
"lastName":"McDougle"
}
Ajax call on button press:
function insertPerson(obj, callback){
$.ajax({
type: "POST",
data: "json=" + JSON.stringify(obj),
url: "insertData.php",
success: function(obj){
if (callback){ callback(obj) };
},
error: function(error){
console.log("Error:");
console.log(error);
}
});
}
I pass in a Javascript Object that is then stringyfied and posted as a parameter name 'json'.
In my php file I assign the posted string to a variable, name $json, I then decode using json_decode(), do some funky business, and send a response back to the browser.
insertData.php:
require ('connect.php');
header('Content-type: application/json');
$json_string = $_POST['json'];
$json = json_decode($json_string);
...do server related inserts/selects etc...
echo json_encode($json->title);
At the moment I just want to return the title property of the json object that was sent in the post request, but anything I return comes back as null. If I echo back the string, without decoding it, then I get the following:
{\"title\":\"Mr\",\"firstName\":\"Banana\",\"middleName\":\"Slippy\",\"lastName\":\"McDougle\"}
If I try to extract values using:
$title = $json->title;
and put that into a MYSQL statement, it's inserted as null or blank, nothing gets input.
Am I doing something wrong? Or have I somehow got an outdated version of PHP to handle JSON? And help is greatly appreciated.

Answer 1

Why do you want to send JSON to the PHP script? What's wrong with using a query string?
$.ajax({
type: "POST",
data: obj,
url: "insertData.php",
success: function(obj){
if (callback){ callback(obj) };
},
error: function(error){
console.log("Error:");
console.log(error);
}
});
This will convert obj to a query string, and then you can just do $_POST['firstName'] and $_POST['lastName'].

Answer 2

I think this is the best shot for you.
jQuery Ajax POST example with PHP