fix "invalid session"

router/init.go

@@ -49,6 +49,7 @@ func InitRouters(router *gin.Engine, db *gorm.DB, meta *ServerMeta, skinRootUrl
 	textureRouter := NewTextureRouter(textureService)
 
 	router.GET("/", homeRouter.Home)
+	router.HEAD("/", homeRouter.Home)
 	authserver := router.Group("/authserver")
 	{
 		authserver.POST("/register", userRouter.Register)

router/session_router.go

@@ -68,8 +68,7 @@ func (s *sessionRouterImpl) JoinServer(c *gin.Context) {
 func (s *sessionRouterImpl) HasJoinedServer(c *gin.Context) {
 	username := c.Query("username")
 	serverId := c.Query("serverId")
-	ip := c.DefaultQuery("ip",
-		c.Request.RemoteAddr[:strings.LastIndexByte(c.Request.RemoteAddr, ':')])
+	ip := c.Query("ip")
 	var textureBaseUrl string
 	if len(s.skinRootUrl) > 0 {
 		textureBaseUrl = strings.TrimRight(s.skinRootUrl, "/") + "/textures"