My PHP curl Post request didnt work as expected - php

Question

I try to send a post request to another php page with the following code:
$vars = ['val1' => 'myval'];
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, $url);
curl_setopt($ch, CURLOPT_POSTFIELDS, $vars);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, TRUE);
curl_setopt($ch, CURLOPT_REFERER, $_SERVER['REQUEST_URI']);
curl_setopt($ch, CURLOPT_VERBOSE, TRUE);
curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, TRUE);
curl_setopt($ch, CURLOPT_FOLLOWLOCATION, TRUE);
curl_setopt($ch, CURLOPT_MAXREDIRS, 4);
curl_setopt($ch, CURLOPT_POST, TRUE);
curl_setopt($ch, CURLOPT_USERPWD, "username:password");
$data = curl_exec($ch);
curl_close($ch);
But on the target page, var_dump($_POST); will output only "1". I had expected something like:
array(val1 = myval) or something similar. So that i can check with isset($_POST["val1"]) if this exists and contains "myval".
Any ideas whats wrong with the request?
Edit:
I have now changed my code to the following:
<?php
$data = array(
'foo'=>'bar',
'baz'=>'boom',
'cow'=>'milk',
'php'=>'hypertext processor');
$ch=curl_init();
curl_setopt($ch, CURLOPT_POST, true);
curl_setopt($ch, CURLOPT_POSTFIELDS, http_build_query($data));
curl_setopt($ch, CURLOPT_HTTPHEADER, array('Content-Type: application/x-www-form-urlencoded'));
curl_setopt($ch, CURLOPT_URL, "target.php");
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
$response = curl_exec($ch);
curl_close($ch);
echo $response;
?>
And in target.php:
<?php
echo print_r($_POST, true));
?>
But there is no response. Both files are in the same dir at the server.

Answer 1

That's because curl_setopt() doesn't accept such complext types as array ;) You need to present your data in form of a query string: "postvar1=value1&postvar2=value2&postvar3=value3".
$format = http_build_query($vars);
curl_setopt($ch, CURLOPT_POSTFIELDS, $format);
or
$format = "val1=my-value"; // be careful to create proper encoding
curl_setopt($ch, CURLOPT_POSTFIELDS, $format);

Answer 2

If you're using CURLOPT_POSTFIELDS, you don't need to set CURLOPT_POST as well. In fact, setting it after will result in a potentially incorrect header being sent.
CURLOPT_POSTFIELDS accepts an array, and will set the Content-Type header to multipart/form-data if one is provided. Later, setting CURLOPT_POST will overwrite this to application/x-www-form-urlencoded, and means that the PHP script at the other end will expect data encoded as an HTTP query-string. This is why you're having problems.
You can fix this either by encoding $vars correctly before sending (using http_build_query, as in the other answer), or just remove the call to set CURLOPT_POST. I'd recommend the latter.

Answer 3

I think, i got it. When i set as target something like "target.php", data was not send. But when i use a complete URL, like https://myserver.com/target.php, this will work as expected. Sometimes, its to easy... sorry for stealing your time.