Posting JSON to PHP script

Question

I am stuck a long time with trying to send a JSON from javascript to a PHP script : the sending is fine (I can see the JSON in fiddler) yet I receive nothing in the PHP script :

javascript:

var person = {
 name: 'yoel',
 age: 28
};
xmlhttp.open("POST","http://localhost:8888/statisticsdb.php",true);
xmlhttp.setRequestHeader("Content-Type", "application/json");
xmlhttp.send(JSON.stringify(person)); 

php :

echo 'trying to print ' . var_dump($_POST["name"]);

I would expect obviously to see SOMETHING but var_dump returns nothing. Help would be much appreciated!

• Carlo Moretti: you could use jQuery, it has a very simple $.post() method where you can simply pass the JSON Object as parameter: $.post('URL',person,success:function())

Answer 1

try:

$data = json_decode(file_get_contents('php://input'));
var_dump($data->name);

the reason for this is, that the body of your POST-request is:

{"name":"yoel","age":28}

though, php expects something like (ref):

name=yoel&age=28

The json string can not be parsed properly, and thus $_POST will be empty.

• user1551120: Thanks for the quick and helpful reply , much appreciated!

Answer 2

$_POST holds value decoded from request having Content-Type application/x-www-form-urlencoded, i.e. it parses:

param1=value1&param2=value2

into:

array( 'param1' => 'value1', 'param2' => 'value2')

If you send data in json format, you have to json_decode it from the raw php input:

$input = file_get_contents('php://input');
$jsonData = json_decode($input);

And you'll have a PHP object filled with your json stuff.

Answer 3

Add this:

xmlhttp.setRequestHeader("Content-length", JSON.stringify(person).length);

• random_user_name: I don't think this solves the problem - there is already an accepted solution, also.