POST JSON data via CURL and grabbing it

Question

I am trying to pass a json data as param for cURL POST. However, I am stuck at grabbing it and saving it on db.

cURL file:

$data = array("name" => "Hagrid", "age" => "36");                                                                    
$data_string = json_encode($data);                                                                                   

$url = 'http://localhost/project/test_curl';

$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, $url);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($ch, CURLOPT_HTTPHEADER, array(                                                                          
                                    'Content-Type: application/json')                                                                                           
                                    );                       
curl_setopt($ch, CURLOPT_POST, 1);
curl_setopt($ch, CURLOPT_POSTFIELDS, $data_string);                                                                                                     

$result = curl_exec($ch);  

//based on http://www.lornajane.net/posts/2011/posting-json-data-with-php-curl

test_curl file:

    $order_info = $_POST; // this seems to not returning anything

    //SAVE TO DB... saving empty...

What did I miss? Weew....

Answer 1

You are sending the data as raw JSON in the body, it will not populate the $_POST variable.

You need to do one of two things:

1. You can change the content type to one that will populate the $_POST array
2. You can read the raw body data.

I would recommend option two if you have control over both ends of the communication, as it will keep the request body size to a minimum and save bandwidth over time. (Edit: I didn't really emphasize here that the amount of bandwidth it will save is negligible, only a few bytes per request, this would only be a valid concern is very high traffic environments. However I still recommend option two because it is the cleanest way)

In your test_curl file, do this:

$fp = fopen('php://input', 'r');
$rawData = stream_get_contents($fp);

$postedJson = json_decode($rawData);

var_dump($postedJson);

If you want to populate the $_POST variable, you will need to change the way you send the data to the server:

$data = array (
  'name' => 'Hagrid',
  'age' => '36'
);

$bodyData = array (
  'json' => json_encode($data)
);
$bodyStr = http_build_query($bodyData);

$url = 'http://localhost/project/test_curl';

$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, $url);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($ch, CURLOPT_HTTPHEADER, array(
  'Content-Type: application/x-www-form-urlencoded',
  'Content-Length: '.strlen($bodyStr)
));
curl_setopt($ch, CURLOPT_POST, 1);
curl_setopt($ch, CURLOPT_POSTFIELDS, $bodyStr);

$result = curl_exec($ch);

The raw, undecoded JSON will now be available in $_POST['json'].