Trouble POSTing using cURL, PHP, and Basic Authentication - php

Question

I made a similar post last week, which can be found here. I was having problems with authentication, which I believe I've solved. The error message is different, at least.
I'm trying to recreate a successful POST I made to our vendor via POSTman by executing cURL commands in PHP.
Here is the example cURL command from their documentation:
curl -i -k -u '<api_key>': -XPOST --data-urlencode assessment_data#/path/to/test/file.json "https://<your_subdomain>.vendor.org/api/v1/import"; echo ""
This is my PHP code, which does not work:
<?php session_start();
include('../connect.php');
include('../functions.php');
function curlPost($url, $headers, $username, $password, $post) {
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, $url);
curl_setopt($ch, CURLOPT_CAINFO, 'certificate.pem');
curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, true);
curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, 2);
curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);
curl_setopt($ch, CURLINFO_HEADER_OUT, true);
curl_setopt($ch, CURLOPT_HTTPAUTH, CURLAUTH_BASIC);
curl_setopt($ch, CURLOPT_USERPWD, $username . ":" . $password);
curl_setopt($ch, CURLOPT_TIMEOUT, 30);
curl_setopt($ch, CURLOPT_POST, 1);
curl_setopt($ch, CURLOPT_POSTFIELDS, $post);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, TRUE);
echo '<pre>';
echo curl_exec($ch) . '<br><br>';
echo print_r(curl_getinfo($ch)) . '<br><br>';
echo curl_error($ch) . '<br><br>';
echo '</pre>';
curl_close($ch);
}
$data = 'JSON_object={"JSON_key":"JSON_value"}';
curlPost('https://company.vendor.org/api/v1/import',
['Content-Type: multipart/form-data'],
'api-key',
'',
$data
);
and instead produces this output:
{"success":false,"errors":["500 Internal Server Error"],"warnings":[],"info":[],"meta":[],"results":[]}
Array
(
[url] => https://company.vendor.org/api/v1/import
[content_type] => application/json; charset=utf-8
[http_code] => 500
[header_size] => 547
[request_size] => 248
[filetime] => -1
[ssl_verify_result] => 0
[redirect_count] => 0
[total_time] => 1.586493
[namelookup_time] => 0.135777
[connect_time] => 0.177182
[pretransfer_time] => 0.286958
[size_upload] => 1999
[size_download] => 103
[speed_download] => 64
[speed_upload] => 1260
[download_content_length] => 103
[upload_content_length] => 1999
[starttransfer_time] => 0.345878
[redirect_time] => 0
[redirect_url] =>
[primary_ip] => xx.xxx.xx.xxx
[certinfo] => Array
(
'This array is actually empty, I didn't delete anything.'
)
[primary_port] => 443
[local_ip] => xxx.xxx.xx.xxx
[local_port] => 60532
[request_header] => POST /api/v1/import HTTP/1.1
Authorization: Basic xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Host: company.vendor.org
Accept: */*
Content-Type: multipart/form-data
Content-Length: 1999
Expect: 100-continue
)
1
For good measure, here is a screenshot of a successful POST using POSTman (It's censored a little differently, but I'm passing in the exact same information):
Their documentation contains an example JSON object, which they save as a file and send as form-data. I've managed to recreate the object with live data, output it to a properly formatted string, and send that as the value instead. This works in POSTman, but not in my PHP, so I suspect the problem lies there somehow. CURLOPT_POSTFIELDS requires a string (tried an array - it got mad), and I've tried formatting it every way I can think of. Any help would be greatly appreciated.