[PHP] Fix converting objects to formdata

Author: jtreminio

modules/openapi-generator/src/main/resources/php/ObjectSerializer.mustache

@@ -321,15 +321,28 @@ class ObjectSerializer
      *
      * @param string|\SplFileObject $value the value of the form parameter
      *
-     * @return string the form string
+     * @return array
      */
-    public static function toFormValue($value)
+    public static function toFormValue(string $key, mixed $value)
     {
-        if ($value instanceof \SplFileObject) {
-            return $value->getRealPath();
-        } else {
-            return self::toString($value);
+        $stringable = self::toString($value);
+
+        if ($stringable !== null) {
+            return [$key => $stringable];
+        } elseif ($value instanceof \SplFileObject) {
+            return [$key => $value->getRealPath()];
+        }
+
+        $flattened = [];
+        $result = [];
+
+        self::flatten_array(json_decode(json_encode($value), true), $flattened);
+
+        foreach ($flattened as $k => $v) {
+            $result["{$key}{$k}"] = self::toString($v);
         }
+
+        return $result;
     }
 
     /**
@@ -340,12 +353,14 @@ class ObjectSerializer
      *
      * @param float|int|bool|\DateTime $value the value of the parameter
      *
-     * @return string the header string
+     * @return string|null the header string
      */
     public static function toString($value)
     {
         if ($value instanceof \DateTime) { // datetime in ISO8601 format
             return $value->format(self::$dateTimeFormat);
+        } elseif (!is_scalar($value) && $value !== null) {
+            return null;
         } elseif (is_bool($value)) {
             return $value ? 'true' : 'false';
         } else {

modules/openapi-generator/src/main/resources/php/api.mustache

@@ -677,13 +677,13 @@ use {{invokerPackage}}\ObjectSerializer;
             $paramFiles = is_array(${{paramName}}) ? ${{paramName}} : [${{paramName}}];
             foreach ($paramFiles as $paramFile) {
                 $formParams['{{baseName}}'][] = \GuzzleHttp\Psr7\Utils::tryFopen(
-                    ObjectSerializer::toFormValue($paramFile),
+                    ObjectSerializer::toFormValue('{{baseName}}', $paramFile)['{{baseName}}'],
                     'rb'
                 );
             }
             {{/isFile}}
             {{^isFile}}
-            $formParams['{{baseName}}'] = ObjectSerializer::toFormValue(${{paramName}});
+            $formParams = array_merge($formParams, ObjectSerializer::toFormValue('{{baseName}}', ${{paramName}}));
             {{/isFile}}
         }
         {{/formParams}}