Use http_build_multi_query() to build POST data string containing multiple values for the same key

Curl.class.php

@@ -23,7 +23,7 @@ class Curl {
     function post($url, $data=array()) {
         $this->setopt(CURLOPT_URL, $url);
         $this->setopt(CURLOPT_POST, TRUE);
-        $this->setopt(CURLOPT_POSTFIELDS, $data);
+        $this->setopt(CURLOPT_POSTFIELDS, $this->_postfields($data));
         $this->_exec();
     }
 
@@ -81,6 +81,31 @@ class Curl {
         curl_close($this->curl);
     }
 
+    function http_build_multi_query($data, $key=NULL) {
+        $query = array();
+
+        foreach ($data as $k => $value) {
+            if (is_string($value)) {
+                $query[] = urlencode(is_null($key) ? $k : $key) . '=' . urlencode($value);
+            }
+            else if (is_array($value)) {
+                $query[] = $this->http_build_multi_query($value, $k . '[]');
+            }
+        }
+
+        return implode('&', $query);
+    }
+
+    function _postfields($data) {
+        $multidimensional = !(count($data) === count($data, COUNT_RECURSIVE));
+
+        if ($multidimensional) {
+            $data = $this->http_build_multi_query($data);
+        }
+
+        return $data;
+    }
+
     function _exec() {
         $this->response = curl_exec($this->curl);
         $this->curl_error_code = curl_errno($this->curl);

tests/run.php

@@ -53,7 +53,7 @@ class CurlTest extends PHPUnit_Framework_TestCase {
                 'wubble',
                 'wobble',
             ),
-        )) === '{"test":"post_multidimensional","key":"file","file":["wibble","wubble","wobble"]}');
+        )) === 'test=post_multidimensional&key=file&file%5B%5D=wibble&file%5B%5D=wubble&file%5B%5D=wobble');
     }
 
     public function testPostFilePathUpload() {

tests/server.php

@@ -20,7 +20,8 @@ if ($test == 'http_basic_auth') {
     exit;
 }
 else if ($test === 'post_multidimensional') {
-    echo json_encode($_POST);
+    $http_raw_post_data = file_get_contents('php://input');
+    echo $http_raw_post_data;
     exit;
 }
 else if ($test === 'post_file_path_upload') {