Throw if file was declared but not uploaded

Fixes #26

Author: PowerKiKi

src/UploadMiddleware.php

@@ -47,6 +47,7 @@ private function parseUploadedFiles(ServerRequestInterface $request): ServerRequ
         $map = $this->decodeArray($bodyParams, 'map');
         $result = $this->decodeArray($bodyParams, 'operations');
 
+        $uploadedFiles = $request->getUploadedFiles();
         foreach ($map as $fileKey => $locations) {
             foreach ($locations as $location) {
                 $items = &$result;
@@ -57,7 +58,13 @@ private function parseUploadedFiles(ServerRequestInterface $request): ServerRequ
                     $items = &$items[$key];
                 }
 
-                $items = $request->getUploadedFiles()[$fileKey];
+                if (!array_key_exists($fileKey, $uploadedFiles)) {
+                    throw new RequestError(
+                        "GraphQL query declared an upload in `$location`, but no corresponding file were actually uploaded"
+                    );
+                }
+
+                $items = $uploadedFiles[$fileKey];
             }
         }
 

tests/UploadMiddlewareTest.php

@@ -201,6 +201,32 @@ public function testRequestWithMapThatIsNotValidJsonShouldThrows(): void
         $this->middleware->processRequest($request);
     }
 
+    public function testMissingUploadedFileShouldThrow(): void
+    {
+        $query = '{my query}';
+        $variables = [
+            'uploads' => [
+                0 => null,
+                1 => null,
+            ],
+        ];
+        $map = [
+            1 => ['variables.uploads.0'],
+            2 => ['variables.uploads.1'],
+        ];
+
+        $file1 = new PsrUploadedFileStub('image.jpg', 'image/jpeg');
+        $files = [
+            1 => $file1,
+        ];
+
+        $request = $this->createRequest($query, $variables, $map, $files, 'op');
+
+        $this->expectException(RequestError::class);
+        $this->expectExceptionMessage('GraphQL query declared an upload in `variables.uploads.1`, but no corresponding file were actually uploaded');
+        $this->middleware->processRequest($request);
+    }
+
     public function testCanUploadFileWithStandardServer(): void
     {
         $query = 'mutation TestUpload($text: String, $file: Upload) {