Implement offset exceeded handling

src/http/handler.go

@@ -139,7 +139,18 @@ func (h *Handler) patchFile(w http.ResponseWriter, r *http.Request, id string) {
 		return
 	}
 
-	// @TODO Reject if offset > current offset
+	info, err := h.store.GetInfo(id)
+	if err != nil {
+		h.err(err, w, http.StatusInternalServerError)
+		return
+	}
+
+	if offset > info.Offset {
+		err = fmt.Errorf("Offset: %d exceeds current offset: %d", offset, info.Offset)
+		h.err(err, w, http.StatusForbidden)
+		return
+	}
+
 	// @TODO Test offset < current offset
 
 	err = h.store.WriteFileChunk(id, offset, r.Body)

src/http/handler_test.go

@@ -177,7 +177,7 @@ var Protocol_Core_Tests = []struct {
 		},
 	},
 	{
-		Description:       "Resume",
+		Description:       "Simple Resume",
 		FinalLength:       11,
 		ExpectFileContent: "hello world",
 		Requests: []TestRequest{
@@ -200,7 +200,20 @@ var Protocol_Core_Tests = []struct {
 			},
 		},
 	},
-	// @TODO Test applying PATCH at offset > current offset (error)
+	{
+		Description: "Offset exceeded",
+		FinalLength: 5,
+		Requests: []TestRequest{
+			{
+				Method:  "PATCH",
+				Headers: map[string]string{"Offset": "1"},
+				// Not sure if this is the right status to use. Once the parallel
+				// chunks protocol spec is done, we can use NotImplemented as a
+				// status until we implement support for this.
+				ExpectStatusCode: http.StatusForbidden,
+			},
+		},
+	},
 }
 
 func TestProtocol_Core(t *testing.T) {