You are POSTing the json incorrectly -- but even if it were correct, you would not be able to test using print_r($_POST) (read why here). Instead, on your second page, you can nab the incoming request using file_get_contents("php://input"), which will contain the POSTed json. To view the received data in a more readable format, try this:

echo '<pre>'.print_r(json_decode(file_get_contents("php://input")),1).'</pre>';

In your code, you are indicating Content-Type:application/json, but you are not json-encoding all of the POST data -- only the value of the "customer" POST field. Instead, do something like this:

$ch = curl_init( $url );
# Setup request to send json via POST.
$payload = json_encode( array( "customer"=> $data ) );
curl_setopt( $ch, CURLOPT_POSTFIELDS, $payload );
curl_setopt( $ch, CURLOPT_HTTPHEADER, array('Content-Type:application/json'));
# Return response instead of printing.
curl_setopt( $ch, CURLOPT_RETURNTRANSFER, true );
# Send request.
$result = curl_exec($ch);
curl_close($ch);
# Print response.
echo "<pre>$result</pre>";

Sidenote: You might benefit from using a third-party library instead of interfacing with the Shopify API directly yourself.

$url = 'url_to_post';
$data = array("first_name" => "First name","last_name" => "last name","email"=>"[email protected]","addresses" => array ("address1" => "some address" ,"city" => "city","country" => "CA", "first_name" =>  "Mother","last_name" =>  "Lastnameson","phone" => "555-1212", "province" => "ON", "zip" => "123 ABC" ) );

$postdata = json_encode($data);

$ch = curl_init($url); 
curl_setopt($ch, CURLOPT_POST, 1);
curl_setopt($ch, CURLOPT_POSTFIELDS, $postdata);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1); 
curl_setopt($ch, CURLOPT_HTTPHEADER, array('Content-Type: application/json'));
$result = curl_exec($ch);
curl_close($ch);
print_r ($result);

This code worked for me. You can try...

Replace

curl_setopt($ch, CURLOPT_POSTFIELDS, array("customer"=>$data_string));

with:

$data_string = json_encode(array("customer"=>$data));
//Send blindly the json-encoded string.
//The server, IMO, expects the body of the HTTP request to be in JSON
curl_setopt($ch, CURLOPT_POSTFIELDS, $data_string);

I dont get what you meant by "other page", I hope it is the page at: 'url_to_post'. If that page is written in PHP, the JSON you just posted above will be read in the below way:

$jsonStr = file_get_contents("php://input"); //read the HTTP body.
$json = json_decode($jsonStr);

Please try this code:-

$url = 'url_to_post';

$data = array("first_name" => "First name","last_name" => "last name","email"=>"[email protected]","addresses" => array ("address1" => "some address" ,"city" => "city","country" => "CA", "first_name" =>  "Mother","last_name" =>  "Lastnameson","phone" => "555-1212", "province" => "ON", "zip" => "123 ABC" ) );

$data_string = json_encode(array("customer" =>$data));

$ch = curl_init($url);

curl_setopt($ch, CURLOPT_POSTFIELDS, $data_string);

curl_setopt($ch, CURLOPT_HTTPHEADER, array('Content-Type:application/json'));

curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);

$result = curl_exec($ch);

curl_close($ch);

echo "$result";

First,

1. always define certificates with CURLOPT_CAPATH option,

2. decide how your POSTed data will be transfered.

1 Certificates

By default:

• CURLOPT_SSL_VERIFYHOST == 2 which "checks the existence of a common name and also verify that it matches the hostname provided" and

• CURLOPT_VERIFYPEER == true which "verifies the peer's certificate".

So, all you have to do is:

const CAINFO = SERVER_ROOT . '/registry/cacert.pem';
...
\curl_setopt($ch, CURLOPT_CAINFO, self::CAINFO);

taken from a working class where SERVER_ROOT is a constant defined during application bootstraping like in a custom classloader, another class etc.

Forget things like \curl_setopt($handler, CURLOPT_SSL_VERIFYHOST, 0); or \curl_setopt($handler, CURLOPT_SSL_VERIFYPEER, 0);.

Find cacert.pem there as seen in this question.

2 POST modes

There are actually 2 modes when posting data:

• the data is transfered with Content-Type header set to multipart/form-data or,

• the data is a urlencoded string with application/x-www-form-urlencoded encoding.

In the first case you pass an array while in the second you pass a urlencoded string.

multipart/form-data ex.:

$fields = array('a' => 'sth', 'b' => 'else');
$ch = \curl_init();
\curl_setopt($ch, CURLOPT_POST, 1);
\curl_setopt($ch, CURLOPT_POSTFIELDS, $fields);

application/x-www-form-urlencoded ex.:

$fields = array('a' => 'sth', 'b' => 'else');
$ch = \curl_init();
\curl_setopt($ch, CURLOPT_POST, 1);
\curl_setopt($ch, CURLOPT_POSTFIELDS, \http_build_query($fields));

http_build_query:

Test it at your command line as

user@group:$ php -a
php > $fields = array('a' => 'sth', 'b' => 'else');
php > echo \http_build_query($fields);
a=sth&b=else

The other end of the POST request will define the appropriate mode of connection.

Try like this:

$url = 'url_to_post';
// this is only part of the data you need to sen
$customer_data = array("first_name" => "First name","last_name" => "last name","email"=>"[email protected]","addresses" => array ("address1" => "some address" ,"city" => "city","country" => "CA", "first_name" =>  "Mother","last_name" =>  "Lastnameson","phone" => "555-1212", "province" => "ON", "zip" => "123 ABC" ) );
// As per your API, the customer data should be structured this way
$data = array("customer" => $customer_data);
// And then encoded as a json string
$data_string = json_encode($data);
$ch=curl_init($url);

curl_setopt_array($ch, array(
    CURLOPT_POST => true,
    CURLOPT_POSTFIELDS => $data_string,
    CURLOPT_HEADER => true,
    CURLOPT_HTTPHEADER => array('Content-Type:application/json', 'Content-Length: ' . strlen($data_string)))
));

$result = curl_exec($ch);
curl_close($ch);

The key thing you've forgotten was to json_encode your data. But you also may find it convenient to use curl_setopt_array to set all curl options at once by passing an array.

Try this example.

<?php 
 $url = 'http://localhost/test/page2.php';
    $data = array("first_name" => "First name","last_name" => "last name","email"=>"[email protected]","addresses" => array ("address1" => "some address" ,"city" => "city","country" => "CA", "first_name" =>  "Mother","last_name" =>  "Lastnameson","phone" => "555-1212", "province" => "ON", "zip" => "123 ABC" ) );
    $ch=curl_init($url);
    $data_string = urlencode(json_encode($data));
    curl_setopt($ch, CURLOPT_CUSTOMREQUEST, "POST");
    curl_setopt($ch, CURLOPT_POSTFIELDS, array("customer"=>$data_string));


    $result = curl_exec($ch);
    curl_close($ch);

    echo $result;
?>

Your page2.php code

<?php
$datastring = $_POST['customer'];
$data = json_decode( urldecode( $datastring));

?>