Added auth opportunity for VK callback API

vk/handlers.go

@@ -7,12 +7,15 @@ import (
 )
 
 func HandleMessage(c *gin.Context) {
-	defer c.String(http.StatusOK, "ok")
 	var req MessageRequest
 	c.BindJSON(&req)
+	if (req.Type == "confirmation") && (req.GroupId == GROUPID) {
+		c.String(http.StatusOK, CONFIRMATION_STRING)
+	}
 	if req.Secret != SECRET_KEY {
 		return
 	}
 	cardName := cardsinfo.GetOriginalName(req.Object.Body)
 	Message(req.Object.UserId, cardName)
+	c.String(http.StatusOK, "ok")
 }

vk/structs.go

@@ -1,8 +1,10 @@
 package vk
 
 type MessageRequest struct {
-	Object UserMessage `json:"object"`
-	Secret string      `json:"secret"`
+	Type    string      `json:"type"`
+	GroupId int64       `json:"group_id"`
+	Object  UserMessage `json:"object"`
+	Secret  string      `json:"secret"`
 }
 
 type UserMessage struct {