Getting JSON in PHP from jQuery .ajax() - php

Question

I'm having trouble getting JSON data sent from JavaScript to PHP. Here is my Javascript:
var noteData = {
nData: {
"postID": $postID,
"commentPar": $commentPar,
"commentValue": $commentValue
}
}
var sendData = JSON.stringify(noteData);
$.ajax({
type: "POST",
url: templateUrl+"/addnote.php",
data: sendData,
dataType : 'json',
success: function(data) {
alert(data);
console.log(sendData);
},
error: function(e) {
console.log(e.message);
console.log(noteData);
console.log(sendData);
alert("error");
}
});
Here is how I just test if the data is even being passed to PHP, it always returns back null.
<?php
$nData = json_decode($_POST['nData']);
echo json_encode($nData);
?>
What am I doing wrong?

Answer 1

You are sending the data as raw JSON to PHP, not as POST parameter.
There are two alternatives. The first one leaves your PHP intact:
var noteData = {
nData: {
"postID": $postID,
"commentPar": $commentPar,
"commentValue": $commentValue
}
}
var sendData = JSON.stringify(noteData);
$.ajax({
type: "POST",
url: templateUrl+"/addnote.php",
data: {
nData: sendData
},
dataType : 'json',
success: function(data) {
alert(data);
console.log(sendData);
},
error: function(e) {
console.log(e.message);
console.log(noteData);
console.log(sendData);
alert("error");
}
});
The second one modifies the PHP side alone. You need to read the input stream directly to obtain the raw data.
<?php
$nData = json_decode(file_get_contents('php://input'));
echo json_encode($nData);
This one might be slightly different depending on the server configuration. See the documentation on the input stream wrappers.

Answer 2

Tell your post request that you are sending json object
contentType: "application/json"