Eventually solved it with cURL after 2 days' fumbling. I guess this is the first time a piece of ready-made PHP code for digest auth is posted, hopefully it can help someone who are in the same ditch as I was in.
Code:
<?php
error_reporting(E_ALL);
ini_set( 'display_errors','1');
$url = "https://api.example.com/ws.asmx/do";
$username = "username";
$password = "pwd";
$post_data = array(
'fieldname1' => 'value1',
'fieldname2' => 'value2'
);
$options = array(
CURLOPT_URL => $url,
CURLOPT_HEADER => true,
CURLOPT_VERBOSE => true,
CURLOPT_RETURNTRANSFER => true,
CURLOPT_FOLLOWLOCATION => true,
CURLOPT_SSL_VERIFYPEER => false, // for https
CURLOPT_USERPWD => $username . ":" . $password,
CURLOPT_HTTPAUTH => CURLAUTH_DIGEST,
CURLOPT_POST => true,
CURLOPT_POSTFIELDS => http_build_query($post_data)
);
$ch = curl_init();
curl_setopt_array( $ch, $options );
try {
$raw_response = curl_exec( $ch );
// validate CURL status
if(curl_errno($ch))
throw new Exception(curl_error($ch), 500);
// validate HTTP status code (user/password credential issues)
$status_code = curl_getinfo($ch, CURLINFO_HTTP_CODE);
if ($status_code != 200)
throw new Exception("Response with Status Code [" . $status_code . "].", 500);
} catch(Exception $ex) {
if ($ch != null) curl_close($ch);
throw new Exception($ex);
}
if ($ch != null) curl_close($ch);
echo "raw response: " . $raw_response;
?>