Submitting JSON data via JQuery ajax.post to PHP - php

Question

Im submitting Data to a php file via AJAX using POST.
It worked fine with just submitting strings, but now I wanted to submit my JS Object with JSON and decode it on PHP side.
In the console I can see, that my data is submitted correctly but on PHP side json_decode returns NULL.
I've tried the following:
this.getAbsence = function()
{
alert(JSON.stringify(this));
jQuery.ajax({
type: "POST",
contentType: "application/json; charset=utf-8",
url: "ajax/selectSingle.php?m=getAbsence",
data: JSON.stringify(this),
success : function(data){
alert(data);
}
});
}
PHP:
echo $_POST['data'];
echo json_decode($_POST['data']);
echo var_dump(json_decode($_POST['data']));
And:
this.getAbsence = function()
{
alert(JSON.stringify(this));
jQuery.ajax({
type: "POST",
contentType: "application/json; charset=utf-8",
url: "ajax/selectSingle.php?m=getAbsence",
data: {'Absence' : JSON.stringify(this)},
success : function(data){
alert(data);
}
});
}
PHP:
echo $_POST['Absence'];
echo json_decode($_POST['Absence']);
echo var_dump(json_decode($_POST['Absence']));
The alert was just to check everything is alright...
And yea usual string were echoed correctly :-)

Answer 1

Where you went wrong in your code in the first code is that you must have used this:
var_dump(json_decode(file_get_contents("php://input"))); //and not $_POST['data']
Quoting from PHP Manual
php://input is a read-only stream that allows you to read raw data from the request body.
Since in your case, you are submitting a JSON in the body, you have to read it from this stream. Usual method of $_POST['field_name'] wont work, because the post body is not in an URLencoded format.
In the second part, you must have used this:
contentType: "application/json; charset=utf-8",
url: "ajax/selectSingle.php?m=getAbsence",
data: JSON.stringify({'Absence' : JSON.stringify(this)}),
UPDATE:
When request has a content type application/json, PHP wont parse the request and give you the JSON object in $_POST, you must parse it yourself from the raw HTTP body. The JSON string is retrieved using file_get_contents("php://input");.
If you must get that using $_POSTyou would make it:
data: {"data":JSON.stringify({'Absence' : JSON.stringify(this)})},
And then in PHP do:
$json = json_decode($_POST['data']);

Answer 2

Single quotes are not valid for php's json_encode, use the double quotes for both field names and values.

Answer 3

To me, it looks like you should reformat your AJAX object. The url-property should only be the URL for the target php-file and any data that needs to be posted should be in the form of a query-string in the data-property.
The following should work as you expected:
this.getAbsence = function() {
var strJSONData = JSON.stringify(this);
alert(strJSONData);
jQuery.ajax({
type: 'POST',
contentType: 'application/json; charset=utf-8',
url: 'ajax/selectSingle.php',
data: 'm=getAbsence&Absence=' + strJSONData,
success: function(data) {
alert(data);
}
});
}

Answer 4

try this
var vThis = this;
this.getAbsence = function()
{
alert(JSON.stringify(vThis));
jQuery.ajax({
type: "POST",
contentType: "application/json; charset=utf-8",
url: "ajax/selectSingle.php?m=getAbsence",
data: JSON.stringify(vThis),
success : function(data){
alert(data);
}
});
}
EDIT
I think we can also do this!
var vThis = this;
this.getAbsence = function()
{
alert(JSON.stringify(vThis));
jQuery.ajax({
type: "POST",
dataType: "json",
url: "ajax/selectSingle.php?m=getAbsence",
data: vThis,
success : function(data){
alert(data);
}
});
}
and in PHP
print_r($_POST);

Answer 5

On PHP side try this:
$sectionValue = htmlspecialchars($_POST['sectionValue'], ENT_QUOTES);
$dataToWrite = json_decode(html_entity_decode($sectionValue, ENT_QUOTES, "utf-8" ), true);