diff --git a/cmd/web_server/handler/frontend.go b/cmd/web_server/handler/frontend.go
index 3fc83f7..4472dfb 100644
--- a/cmd/web_server/handler/frontend.go
+++ b/cmd/web_server/handler/frontend.go
@@ -16,6 +16,7 @@ func SetupFrontendRoute(baseRoute *gin.RouterGroup, frontendDist string) {
 		g.GET("/admin", RenderHTML)
 		g.GET("/admin/problem", RenderHTML)
 
+		// Static file routing
 		g.Static("manifest.json", fmt.Sprintf("%s/manifest.json", frontendDist))
 		g.Static("/assets", fmt.Sprintf("%s/assets", frontendDist))
 		g.Static("/avatars", fmt.Sprintf("%s/avatars", frontendDist))
diff --git a/cmd/web_server/handler/problem.go b/cmd/web_server/handler/problem.go
index 186bac6..e792762 100644
--- a/cmd/web_server/handler/problem.go
+++ b/cmd/web_server/handler/problem.go
@@ -2,7 +2,6 @@ package handler
 
 import (
 	"net/http"
-	"strconv"
 
 	"github.com/gin-gonic/gin"
 	judge_model "github.com/oj-lab/oj-lab-platform/models/judge"
@@ -95,20 +94,12 @@ func deleteProblem(ginCtx *gin.Context) {
 //	@Accept			json
 //	@Success		200
 func getProblemInfoList(ginCtx *gin.Context) {
-	limitStr := ginCtx.Query("limit")
-	offsetStr := ginCtx.Query("offset")
-	if limitStr == "" {
-		limitStr = "10"
-	}
-	if offsetStr == "" {
-		offsetStr = "0"
-	}
-	limit, err := strconv.Atoi(limitStr)
+	limit, err := gin_utils.QueryInt(ginCtx, "limit", 10)
 	if err != nil {
 		gin_utils.NewInvalidParamError(ginCtx, "limit", err.Error())
 		return
 	}
-	offset, err := strconv.Atoi(offsetStr)
+	offset, err := gin_utils.QueryInt(ginCtx, "offset", 0)
 	if err != nil {
 		gin_utils.NewInvalidParamError(ginCtx, "offset", err.Error())
 		return
diff --git a/cmd/web_server/handler/user.go b/cmd/web_server/handler/user.go
index 00b8e79..7748031 100644
--- a/cmd/web_server/handler/user.go
+++ b/cmd/web_server/handler/user.go
@@ -3,7 +3,6 @@ package handler
 import (
 	"fmt"
 	"net/http"
-	"strconv"
 	"strings"
 
 	"github.com/gin-gonic/gin"
@@ -52,21 +51,21 @@ func AddUserCasbinPolicies() error {
 }
 
 func GetUserList(ginCtx *gin.Context) {
-	options := user_model.GetUserOptions{}
-	limitStr := ginCtx.Query("limit")
-	offsetStr := ginCtx.Query("offset")
-	limit, err := strconv.Atoi(limitStr)
+	limit, err := gin_utils.QueryInt(ginCtx, "limit", 10)
 	if err != nil {
-		limit = 10
+		gin_utils.NewInvalidParamError(ginCtx, "limit", err.Error())
+		return
 	}
-	offset, err := strconv.Atoi(offsetStr)
+	offset, err := gin_utils.QueryInt(ginCtx, "offset", 0)
 	if err != nil {
-		offset = 0
+		gin_utils.NewInvalidParamError(ginCtx, "offset", err.Error())
+		return
 	}
-	options.Limit = func() *int { return &limit }()
-	options.Offset = func() *int { return &offset }()
 
-	users, total, err := user_service.GetUserList(ginCtx, options)
+	users, total, err := user_service.GetUserList(ginCtx, user_model.GetUserOptions{
+		Limit:  &limit,
+		Offset: &offset,
+	})
 	if err != nil {
 		gin_utils.NewInternalError(ginCtx, fmt.Sprintf("failed to get user list: %v", err))
 		return
diff --git a/modules/auth/github.go b/modules/auth/github.go
index 0c2406e..b905b0f 100644
--- a/modules/auth/github.go
+++ b/modules/auth/github.go
@@ -9,21 +9,24 @@ import (
 	config_module "github.com/oj-lab/oj-lab-platform/modules/config"
 )
 
-const githubOauthEntryURL = "https://github.com/login/oauth/authorize"
-const githubAccessTokenURL = "https://github.com/login/oauth/access_token"
-const githubApiUserURL = "https://api.github.com/user"
-
 const (
+	githubOauthEntryURL  = "https://github.com/login/oauth/authorize"
+	githubAccessTokenURL = "https://github.com/login/oauth/access_token"
+	githubApiUserURL     = "https://api.github.com/user"
+
 	servicePortProp       = "service.port"
 	serviceHostProp       = "service.host"
 	serviceSSLEnabledProp = "service.ssl_enabled"
 )
 
-var githubClientID string
-var githubClientSecret string
-var servicePort uint
-var serviceHost string
-var serviceSSLEnabled bool
+var (
+	githubClientID     string
+	githubClientSecret string
+
+	servicePort       uint
+	serviceHost       string
+	serviceSSLEnabled bool
+)
 
 func init() {
 	githubClientID = config_module.AppConfig().GetString("auth_modulegithub.client_id")
diff --git a/modules/auth/jwt.go b/modules/auth/jwt.go
index 7ca899e..fbb2ed2 100644
--- a/modules/auth/jwt.go
+++ b/modules/auth/jwt.go
@@ -8,8 +8,10 @@ import (
 	config_module "github.com/oj-lab/oj-lab-platform/modules/config"
 )
 
-var jwtSecret string
-var jwtDuration time.Duration
+var (
+	jwtSecret   string
+	jwtDuration time.Duration
+)
 
 func init() {
 	jwtSecret = config_module.AppConfig().GetString("jwt.secret")