diff --git a/controllers/auth.go b/controllers/auth.go
index d87ba35..82a82e4 100644
--- a/controllers/auth.go
+++ b/controllers/auth.go
@@ -15,8 +15,8 @@ func AuthGet(c *gin.Context) {
 
 	session := sessions.Default(c)
 	uuid := helpers.UUID()
-	session.Delete(SESSION_GITHUB_STATE)
-	session.Set(SESSION_GITHUB_STATE, uuid)
+	session.Delete(SessionGithubState)
+	session.Set(SessionGithubState, uuid)
 	session.Save()
 
 	authurl := "/signin"
diff --git a/controllers/captcha.go b/controllers/captcha.go
index fad6e2c..34a52bc 100644
--- a/controllers/captcha.go
+++ b/controllers/captcha.go
@@ -9,8 +9,8 @@ import (
 func CaptchaGet(context *gin.Context) {
 	session := sessions.Default(context)
 	captchaId := captcha.NewLen(4)
-	session.Delete(SESSION_CAPTCHA)
-	session.Set(SESSION_CAPTCHA, captchaId)
+	session.Delete(SessionCaptcha)
+	session.Set(SessionCaptcha, captchaId)
 	session.Save()
 	captcha.WriteImage(context.Writer, captchaId, 100, 40)
 }
diff --git a/controllers/comment.go b/controllers/comment.go
index 5ea079e..476363e 100644
--- a/controllers/comment.go
+++ b/controllers/comment.go
@@ -19,12 +19,12 @@ func CommentPost(c *gin.Context) {
 	)
 	defer writeJSON(c, res)
 	s := sessions.Default(c)
-	sessionUserID := s.Get(SESSION_KEY)
+	sessionUserID := s.Get(SessionKey)
 	userId, _ := sessionUserID.(uint)
 
 	verifyCode := c.PostForm("verifyCode")
-	captchaId := s.Get(SESSION_CAPTCHA)
-	s.Delete(SESSION_CAPTCHA)
+	captchaId := s.Get(SessionCaptcha)
+	s.Delete(SessionCaptcha)
 	_captchaId, _ := captchaId.(string)
 	if !captcha.VerifyString(_captchaId, verifyCode) {
 		res["message"] = "error verifycode"
@@ -71,7 +71,7 @@ func CommentDelete(c *gin.Context) {
 	defer writeJSON(c, res)
 
 	s := sessions.Default(c)
-	sessionUserID := s.Get(SESSION_KEY)
+	sessionUserID := s.Get(SessionKey)
 	userId, _ := sessionUserID.(uint)
 
 	commentId := c.Param("id")
diff --git a/controllers/common.go b/controllers/common.go
index c159057..44040e7 100644
--- a/controllers/common.go
+++ b/controllers/common.go
@@ -17,10 +17,10 @@ import (
 )
 
 const (
-	SESSION_KEY          = "UserID"       // session key
-	CONTEXT_USER_KEY     = "User"         // context user key
-	SESSION_GITHUB_STATE = "GITHUB_STATE" // github state session key
-	SESSION_CAPTCHA      = "GIN_CAPTCHA"  // captcha session key
+	SessionKey         = "UserID"       // session key
+	ContextUserKey     = "User"         // context user key
+	SessionGithubState = "GITHUB_STATE" // GitHub state session key
+	SessionCaptcha     = "GIN_CAPTCHA"  // captcha session key
 )
 
 func Handle404(c *gin.Context) {
diff --git a/controllers/index.go b/controllers/index.go
index 54f416f..51eef1c 100644
--- a/controllers/index.go
+++ b/controllers/index.go
@@ -42,7 +42,7 @@ func IndexGet(c *gin.Context) {
 		post.Tags, _ = models.ListTagByPostId(strconv.FormatUint(uint64(post.ID), 10))
 		post.Body = policy.Sanitize(string(blackfriday.MarkdownCommon([]byte(post.Body))))
 	}
-	user, _ := c.Get(CONTEXT_USER_KEY)
+	user, _ := c.Get(ContextUserKey)
 	c.HTML(http.StatusOK, "index/index.html", gin.H{
 		"posts":           posts,
 		"tags":            models.MustListTag(),
@@ -58,7 +58,7 @@ func IndexGet(c *gin.Context) {
 }
 
 func AdminIndex(c *gin.Context) {
-	user, _ := c.Get(CONTEXT_USER_KEY)
+	user, _ := c.Get(ContextUserKey)
 	c.HTML(http.StatusOK, "admin/index.html", gin.H{
 		"pageCount":    models.CountPage(),
 		"postCount":    models.CountPost(),
diff --git a/controllers/link.go b/controllers/link.go
index 3ffbb35..e91883c 100644
--- a/controllers/link.go
+++ b/controllers/link.go
@@ -10,7 +10,7 @@ import (
 
 func LinkIndex(c *gin.Context) {
 	links, _ := models.ListLinks()
-	user, _ := c.Get(CONTEXT_USER_KEY)
+	user, _ := c.Get(ContextUserKey)
 	c.HTML(http.StatusOK, "admin/link.html", gin.H{
 		"links":    links,
 		"user":     user,
diff --git a/controllers/page.go b/controllers/page.go
index fed53d8..85c6f23 100644
--- a/controllers/page.go
+++ b/controllers/page.go
@@ -17,7 +17,7 @@ func PageGet(c *gin.Context) {
 	}
 	page.View++
 	page.UpdateView()
-	user, _ := c.Get(CONTEXT_USER_KEY)
+	user, _ := c.Get(ContextUserKey)
 	c.HTML(http.StatusOK, "page/display.html", gin.H{
 		"page": page,
 		"user": user,
@@ -25,7 +25,7 @@ func PageGet(c *gin.Context) {
 }
 
 func PageNew(c *gin.Context) {
-	user, _ := c.Get(CONTEXT_USER_KEY)
+	user, _ := c.Get(ContextUserKey)
 	c.HTML(http.StatusOK, "page/new.html", gin.H{
 		"user": user,
 	})
@@ -36,7 +36,7 @@ func PageCreate(c *gin.Context) {
 	body := c.PostForm("body")
 	isPublished := c.PostForm("isPublished")
 	published := "on" == isPublished
-	user, _ := c.Get(CONTEXT_USER_KEY)
+	user, _ := c.Get(ContextUserKey)
 
 	page := &models.Page{
 		Title:       title,
@@ -61,7 +61,7 @@ func PageEdit(c *gin.Context) {
 	if err != nil {
 		Handle404(c)
 	}
-	user, _ := c.Get(CONTEXT_USER_KEY)
+	user, _ := c.Get(ContextUserKey)
 	c.HTML(http.StatusOK, "page/modify.html", gin.H{
 		"page": page,
 		"user": user,
@@ -134,7 +134,7 @@ func PageDelete(c *gin.Context) {
 
 func PageIndex(c *gin.Context) {
 	pages, _ := models.ListAllPage()
-	user, _ := c.Get(CONTEXT_USER_KEY)
+	user, _ := c.Get(ContextUserKey)
 	c.HTML(http.StatusOK, "admin/page.html", gin.H{
 		"pages":    pages,
 		"user":     user,
diff --git a/controllers/post.go b/controllers/post.go
index 25b3805..b9486c1 100644
--- a/controllers/post.go
+++ b/controllers/post.go
@@ -20,7 +20,7 @@ func PostGet(c *gin.Context) {
 	post.UpdateView()
 	post.Tags, _ = models.ListTagByPostId(id)
 	post.Comments, _ = models.ListCommentByPostID(id)
-	user, _ := c.Get(CONTEXT_USER_KEY)
+	user, _ := c.Get(ContextUserKey)
 	c.HTML(http.StatusOK, "post/display.html", gin.H{
 		"post": post,
 		"user": user,
@@ -28,7 +28,7 @@ func PostGet(c *gin.Context) {
 }
 
 func PostNew(c *gin.Context) {
-	user, _ := c.Get(CONTEXT_USER_KEY)
+	user, _ := c.Get(ContextUserKey)
 	c.HTML(http.StatusOK, "post/new.html", gin.H{
 		"user": user,
 	})
@@ -40,7 +40,7 @@ func PostCreate(c *gin.Context) {
 	body := c.PostForm("body")
 	isPublished := c.PostForm("isPublished")
 	published := "on" == isPublished
-	user, _ := c.Get(CONTEXT_USER_KEY)
+	user, _ := c.Get(ContextUserKey)
 
 	post := &models.Post{
 		Title:       title,
@@ -83,7 +83,7 @@ func PostEdit(c *gin.Context) {
 		return
 	}
 	post.Tags, _ = models.ListTagByPostId(id)
-	user, _ := c.Get(CONTEXT_USER_KEY)
+	user, _ := c.Get(ContextUserKey)
 	c.HTML(http.StatusOK, "post/modify.html", gin.H{
 		"post": post,
 		"user": user,
@@ -97,7 +97,7 @@ func PostUpdate(c *gin.Context) {
 	body := c.PostForm("body")
 	isPublished := c.PostForm("isPublished")
 	published := "on" == isPublished
-	user, _ := c.Get(CONTEXT_USER_KEY)
+	user, _ := c.Get(ContextUserKey)
 
 	pid, err := strconv.ParseUint(id, 10, 64)
 	if err != nil {
@@ -187,7 +187,7 @@ func PostDelete(c *gin.Context) {
 
 func PostIndex(c *gin.Context) {
 	posts, _ := models.ListAllPost("")
-	user, _ := c.Get(CONTEXT_USER_KEY)
+	user, _ := c.Get(ContextUserKey)
 	c.HTML(http.StatusOK, "admin/post.html", gin.H{
 		"posts":    posts,
 		"Active":   "posts",
diff --git a/controllers/subscriber.go b/controllers/subscriber.go
index e6ca60a..636f26d 100644
--- a/controllers/subscriber.go
+++ b/controllers/subscriber.go
@@ -15,7 +15,7 @@ import (
 
 func SubscribeGet(c *gin.Context) {
 	count, _ := models.CountSubscriber()
-	user, _ := c.Get(CONTEXT_USER_KEY)
+	user, _ := c.Get(ContextUserKey)
 	c.HTML(http.StatusOK, "other/subscribe.html", gin.H{
 		"total": count,
 		"user":  user,
@@ -170,7 +170,7 @@ func sendEmailToSubscribers(subject, body string) (err error) {
 
 func SubscriberIndex(c *gin.Context) {
 	subscribers, _ := models.ListSubscriber(false)
-	user, _ := c.Get(CONTEXT_USER_KEY)
+	user, _ := c.Get(ContextUserKey)
 	c.HTML(http.StatusOK, "admin/subscriber.html", gin.H{
 		"subscribers": subscribers,
 		"user":        user,
diff --git a/controllers/user.go b/controllers/user.go
index eef0a46..f6a1d49 100644
--- a/controllers/user.go
+++ b/controllers/user.go
@@ -121,7 +121,7 @@ func SigninPost(c *gin.Context) {
 	}
 	s := sessions.Default(c)
 	s.Clear()
-	s.Set(SESSION_KEY, user.ID)
+	s.Set(SessionKey, user.ID)
 	s.Save()
 	if user.IsAdmin {
 		c.Redirect(http.StatusMovedPermanently, "/admin/index")
@@ -140,12 +140,12 @@ func Oauth2Callback(c *gin.Context) {
 
 	// validate state
 	session := sessions.Default(c)
-	if len(state) == 0 || state != session.Get(SESSION_GITHUB_STATE) {
+	if len(state) == 0 || state != session.Get(SessionGithubState) {
 		c.Abort()
 		return
 	}
 	// remove state from session
-	session.Delete(SESSION_GITHUB_STATE)
+	session.Delete(SessionGithubState)
 	session.Save()
 
 	// exchange accesstoken by code
@@ -164,7 +164,7 @@ func Oauth2Callback(c *gin.Context) {
 		return
 	}
 
-	sessionUser, exists := c.Get(CONTEXT_USER_KEY)
+	sessionUser, exists := c.Get(ContextUserKey)
 	if exists { // 已登录
 		user, _ = sessionUser.(*models.User)
 		_, err1 := models.IsGithubIdExists(userInfo.Login, user.ID)
@@ -197,7 +197,7 @@ func Oauth2Callback(c *gin.Context) {
 	if err == nil {
 		s := sessions.Default(c)
 		s.Clear()
-		s.Set(SESSION_KEY, user.ID)
+		s.Set(SessionKey, user.ID)
 		s.Save()
 		if user.IsAdmin {
 			c.Redirect(http.StatusMovedPermanently, "/admin/index")
@@ -254,7 +254,7 @@ func getGithubUserInfoByAccessToken(token string) (*GithubUserInfo, error) {
 }
 
 func ProfileGet(c *gin.Context) {
-	sessionUser, exists := c.Get(CONTEXT_USER_KEY)
+	sessionUser, exists := c.Get(ContextUserKey)
 	if exists {
 		c.HTML(http.StatusOK, "admin/profile.html", gin.H{
 			"user":     sessionUser,
@@ -271,7 +271,7 @@ func ProfileUpdate(c *gin.Context) {
 	defer writeJSON(c, res)
 	avatarUrl := c.PostForm("avatarUrl")
 	nickName := c.PostForm("nickName")
-	sessionUser, _ := c.Get(CONTEXT_USER_KEY)
+	sessionUser, _ := c.Get(ContextUserKey)
 	user, ok := sessionUser.(*models.User)
 	if !ok {
 		res["message"] = "server interval error"
@@ -293,7 +293,7 @@ func BindEmail(c *gin.Context) {
 	)
 	defer writeJSON(c, res)
 	email := c.PostForm("email")
-	sessionUser, _ := c.Get(CONTEXT_USER_KEY)
+	sessionUser, _ := c.Get(ContextUserKey)
 	user, ok := sessionUser.(*models.User)
 	if !ok {
 		res["message"] = "server interval error"
@@ -322,7 +322,7 @@ func UnbindEmail(c *gin.Context) {
 		res = gin.H{}
 	)
 	defer writeJSON(c, res)
-	sessionUser, _ := c.Get(CONTEXT_USER_KEY)
+	sessionUser, _ := c.Get(ContextUserKey)
 	user, ok := sessionUser.(*models.User)
 	if !ok {
 		res["message"] = "server interval error"
@@ -346,7 +346,7 @@ func UnbindGithub(c *gin.Context) {
 		res = gin.H{}
 	)
 	defer writeJSON(c, res)
-	sessionUser, _ := c.Get(CONTEXT_USER_KEY)
+	sessionUser, _ := c.Get(ContextUserKey)
 	user, ok := sessionUser.(*models.User)
 	if !ok {
 		res["message"] = "server interval error"
@@ -367,7 +367,7 @@ func UnbindGithub(c *gin.Context) {
 
 func UserIndex(c *gin.Context) {
 	users, _ := models.ListUsers()
-	user, _ := c.Get(CONTEXT_USER_KEY)
+	user, _ := c.Get(ContextUserKey)
 	c.HTML(http.StatusOK, "admin/user.html", gin.H{
 		"users":    users,
 		"user":     user,
diff --git a/main.go b/main.go
index 322f641..21fa392 100644
--- a/main.go
+++ b/main.go
@@ -183,7 +183,7 @@ func setTemplate(engine *gin.Engine) {
 	engine.LoadHTMLGlob(filepath.Join(getCurrentDirectory(), "./views/**/*"))
 }
 
-//setSessions initializes sessions & csrf middlewares
+// setSessions initializes sessions & csrf middlewares
 func setSessions(router *gin.Engine) {
 	config := system.GetConfiguration()
 	//https://github.com/gin-gonic/contrib/tree/master/sessions
@@ -202,14 +202,14 @@ func setSessions(router *gin.Engine) {
 
 //+++++++++++++ middlewares +++++++++++++++++++++++
 
-//SharedData fills in common data, such as user info, etc...
+// SharedData fills in common data, such as user info, etc...
 func SharedData() gin.HandlerFunc {
 	return func(c *gin.Context) {
 		session := sessions.Default(c)
-		if uID := session.Get(controllers.SESSION_KEY); uID != nil {
+		if uID := session.Get(controllers.SessionKey); uID != nil {
 			user, err := models.GetUser(uID)
 			if err == nil {
-				c.Set(controllers.CONTEXT_USER_KEY, user)
+				c.Set(controllers.ContextUserKey, user)
 			}
 		}
 		if system.GetConfiguration().SignupEnabled {
@@ -219,10 +219,10 @@ func SharedData() gin.HandlerFunc {
 	}
 }
 
-//AuthRequired grants access to authenticated users, requires SharedData middleware
+// AuthRequired grants access to authenticated users, requires SharedData middleware
 func AdminScopeRequired() gin.HandlerFunc {
 	return func(c *gin.Context) {
-		if user, _ := c.Get(controllers.CONTEXT_USER_KEY); user != nil {
+		if user, _ := c.Get(controllers.ContextUserKey); user != nil {
 			if u, ok := user.(*models.User); ok && u.IsAdmin {
 				c.Next()
 				return
@@ -238,7 +238,7 @@ func AdminScopeRequired() gin.HandlerFunc {
 
 func AuthRequired() gin.HandlerFunc {
 	return func(c *gin.Context) {
-		if user, _ := c.Get(controllers.CONTEXT_USER_KEY); user != nil {
+		if user, _ := c.Get(controllers.ContextUserKey); user != nil {
 			if _, ok := user.(*models.User); ok {
 				c.Next()
 				return
diff --git a/system/system.go b/system/system.go
index 943dc06..f24515c 100644
--- a/system/system.go
+++ b/system/system.go
@@ -33,7 +33,7 @@ type Configuration struct {
 }
 
 const (
-	DEFAULT_PAGESIZE = 10
+	DefaultPageSize = 10
 )
 
 var configuration *Configuration
@@ -49,7 +49,7 @@ func LoadConfiguration(path string) error {
 		return err
 	}
 	if config.PageSize <= 0 {
-		config.PageSize = DEFAULT_PAGESIZE
+		config.PageSize = DefaultPageSize
 	}
 	configuration = &config
 	return err