How to send and receive data to/from an API using CURL?

Question

I have to make an API. For this, I will receive the data from the mobile devices as JSON using POST. I have to work with this data and send the response back to the devices also as JSON. But I don't know how to take the data that I will receive. I have tried to make some tests using CURL to see how can I take this data but the $_POST is always empty. Can you please tell me how to send the data as JSON format to the API using CURL and how can I receive this data so I can work with it and send it back as response?

These are my test files:

curl.php:

    //set POST variables
    $url = 'http://test.dev/test.php';
    $data = array(
        'fname' => 'Test',
        'lname' => 'TestL',
        'test' => array(
            'first' => 'TestFirst',
            'second' => 'TestSecond'
        )
    );

    //open connection
    $ch = curl_init($url);

    $json_data = json_encode($data);

    curl_setopt($ch, CURLOPT_CUSTOMREQUEST, "POST");
    curl_setopt($ch, CURLOPT_POSTFIELDS, $json_data);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
    curl_setopt($ch, CURLOPT_HTTPHEADER, array(
            'Content-Type: application/json',
            'Content-Length: ' . strlen($json_data))
    );

    // execute post
    $result = curl_exec($ch);

    echo $result;

    //close connection
    curl_close($ch);

test.php:

var_dump($_POST);

The response that I get is:

array(0) { }

file_get_contents('php://') to get json value from request body — undefined_variable
– undefined_variable, Commented Sep 9, 2014 at 6:26
I have tried to use file_get_contents but I got the following errors: file_get_contents(): Invalid php:// URL specified in... file_get_contents(php://): failed to open stream: operation failed in... — Alexandru Mic
– Alexandru Mic, Commented Sep 9, 2014 at 7:07
file_get_contents('php://') will fetch you the json data submitted to your page...I think you missed single quotes — undefined_variable
– undefined_variable, Commented Sep 9, 2014 at 7:48

Community · Accepted Answer · 2017-05-23 11:49:22Z

1

You need to pass the POST data as a URL query string or as an array, the problem is you post data in JSON format, but PHP does not parse JSON automatically, so the $_POST array is empty. If you want it, you need do the parsing yourself in the test.php:

$raw_post = file_get_contents("php://input");
$data = json_decode($raw_post, true);
print_r($data);

same questions: 1 2

edited May 23, 2017 at 11:49

CommunityBot

11 silver badge

answered Sep 9, 2014 at 7:46

jfly

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