$_POST variable is empty

Question

I created a ajax request in Javascript using json, but the $_POST variable is empty.

var userid = "james";
var score = 200; 
var jsondata = {
userid: userid,
score: score
};
data = JSON.stringify(jsondata);
req = new XMLHttpRequest();   
req.setRequestHeader("Content-Type", "application/json");
req.open("POST", 'functions.php', true);
req.send(data);

My functions.php file looks like this:

print "CONTENT_TYPE: " . $_SERVER['CONTENT_TYPE'] . "<BR />";
$data = file_get_contents('php://input');
print "DATA: <pre>";
var_dump($data);
var_dump($_POST);
var_dump($_GET);

However all of this gives me an empty array. Any help, please?

Try providing a key name with the data -- `var data = "name=james";` — Jonathan Lonowski, Apr 04 '15 at 05:45

score 0 · Answer 1 · answered Apr 04 '15 at 05:45

0

I think you are sending data incorrectly,

Use,

req.send("name=James");

answered Apr 04 '15 at 05:45

vaibhavmande

1,115
9
17

What about with JSON. My data is really JSON. var jsondata = { "userid": userid, "score": score }; data = JSON.stringify(jsondata); req.send(data); Is this correct, please? – Android Ninja Apr 04 '15 at 13:57
Thanks for your help. But It's still not working. Any other suggestions? – Android Ninja Apr 04 '15 at 14:32
@user99615 Please update your question to reflect what exactly you are doing. This will help you get an accurate answer. – vaibhavmande Apr 06 '15 at 05:53
updated. Please do you have a clue why _POST variable is empty. – Android Ninja Apr 06 '15 at 22:37

score 0 · Answer 2 · edited May 23 '17 at 10:24

0

$_POST only gets populated for form encoded and multipart encoded data. Your data is encoded as JSON and should be accessed through php://input (as per this question).

$data should contain the JSON. If it doesn't, then it is probably due to you failing to set the Content-Type header of the request.

req.setRequestHeader("Content-Type", "application/json");

edited May 23 '17 at 10:24

Community

1
1

answered Apr 06 '15 at 22:41

Quentin

914,110
126
1,211
1,335

Thank you for your help. I added req.setRequestHeader("Content-Type", "application/json"). I also tried req.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded'); but php://input still shows an empty array. – Android Ninja Apr 06 '15 at 23:51

mathieu · Answer 3 · 2015-04-07T00:33:19.123

Except that the line req.setRequestHeader("Content-Type", "application/json"); should be under req.open("POST", 'functions.php', true);because the state of the XHR object must be open to set a header, your code is perfectly operational.

Your problem is somewhere else.

How do you check what is your php displaying ?
Is your ini conf. appropriate ? Try to do ini_set("allow_url_fopen", true); before file_get_contents('php://input');
Check the paramter post_max_size in your php.ini. it should be 8M or 10M (no MB but M and only M, or php will interpete it as 0)

The best way to check the interpreted parameters of php.ini is to do an empty .php file with <?php phpinfo(); ?> and launch it; Then check the section "Core".

Thanks! This solved my problem. I used file_get_contents('php://input') and I finally got my json results. Thanks! — Android Ninja, Apr 07 '15 at 03:59

$_POST variable is empty

3 Answers3