Refactor API handlers

views/auth.go

@@ -15,22 +15,24 @@ import (
 
 const TOKEN_LIFETIME_IN_SECONDS = 60 * 60 * 24 * 30
 
-func ShowRegistrationForm(c *gin.Context, db *gorm.DB) {
-	if database.CountAdmins(db) > 0 {
-		ShowError(c, errors.New("At least 1 user already exists"))
-		return
-	}
+func ShowRegistrationForm(db *gorm.DB) gin.HandlerFunc {
+	return func(ctx *gin.Context) {
+		if database.CountAdmins(db) > 0 {
+			ShowError(ctx, errors.New("At least 1 user already exists"))
+			return
+		}
 
-	c.HTML(http.StatusOK, "auth.html.tmpl", gin.H{
-		"title":       "Create an account",
-		"description": "To prevent other people from seeing your links, create an account.",
-		"button":      "Create",
-		"formAction":  "/api/users",
-	})
+		ctx.HTML(http.StatusOK, "auth.html.tmpl", gin.H{
+			"title":       "Create an account",
+			"description": "To prevent other people from seeing your links, create an account.",
+			"button":      "Create",
+			"formAction":  "/api/users",
+		})
+	}
 }
 
-func ShowLoginForm(c *gin.Context) {
-	c.HTML(http.StatusOK, "auth.html.tmpl", gin.H{
+func ShowLoginForm(ctx *gin.Context) {
+	ctx.HTML(http.StatusOK, "auth.html.tmpl", gin.H{
 		"title":       "Sign in",
 		"description": "Authorization is required to view this page.",
 		"button":      "Sign in",
@@ -69,37 +71,39 @@ func RequireAuth(c *gin.Context, cfg *config.Config) (*jwt.RegisteredClaims, err
 	return claims, nil
 }
 
-func AuthMiddleware(c *gin.Context, db *gorm.DB, cfg *config.Config) {
-	claims, err := RequireAuth(c, cfg)
-	if err != nil {
-		if cfg.HeaderAuth && c.Request.Header.Get("Remote-User") != "" {
-			// Generate access token.
-			token, err := GetJWTToken(cfg)
-			if err != nil {
-				ShowError(c, err)
+func AuthMiddleware(db *gorm.DB, cfg *config.Config) gin.HandlerFunc {
+	return func(ctx *gin.Context) {
+		claims, err := RequireAuth(ctx, cfg)
+		if err != nil {
+			if cfg.HeaderAuth && ctx.Request.Header.Get("Remote-User") != "" {
+				// Generate access token.
+				token, err := GetJWTToken(cfg)
+				if err != nil {
+					ShowError(ctx, err)
+					return
+				}
+				SetTokenCookie(ctx, token, cfg)
 				return
 			}
-			SetTokenCookie(c, token, cfg)
+
+			if database.CountAdmins(db) < 1 {
+				ctx.Redirect(http.StatusFound, "/registration")
+			} else {
+				ctx.Redirect(http.StatusFound, "/signin")
+			}
+			ctx.Abort()
 			return
 		}
 
-		if database.CountAdmins(db) < 1 {
-			c.Redirect(http.StatusFound, "/registration")
-		} else {
-			c.Redirect(http.StatusFound, "/signin")
+		// Create a new token if the old one is about to expire
+		if time.Now().Add(time.Second * (TOKEN_LIFETIME_IN_SECONDS / 2)).After(claims.ExpiresAt.Time) {
+			newToken, err := GetJWTToken(cfg)
+			if err != nil {
+				ShowError(ctx, err)
+				return
+			}
+			SetTokenCookie(ctx, newToken, cfg)
 		}
-		c.Abort()
-		return
-	}
-
-	// Create a new token if the old one is about to expire
-	if time.Now().Add(time.Second * (TOKEN_LIFETIME_IN_SECONDS / 2)).After(claims.ExpiresAt.Time) {
-		newToken, err := GetJWTToken(cfg)
-		if err != nil {
-			ShowError(c, err)
-			return
-		}
-		SetTokenCookie(c, newToken, cfg)
 	}
 }
 
@@ -111,53 +115,57 @@ func GetJWTToken(cfg *config.Config) (string, error) {
 	return token.SignedString([]byte(cfg.SecretKey))
 }
 
-func CreateUser(c *gin.Context, db *gorm.DB, cfg *config.Config) {
-	if database.CountAdmins(db) > 0 {
-		ShowError(c, errors.New("At least 1 user already exists"))
-		return
-	}
+func CreateUser(db *gorm.DB, cfg *config.Config) gin.HandlerFunc {
+	return func(ctx *gin.Context) {
+		if database.CountAdmins(db) > 0 {
+			ShowError(ctx, errors.New("At least 1 user already exists"))
+			return
+		}
 
-	// Try to create a user.
-	username := c.PostForm("username")
-	password := c.PostForm("password")
-	_, err := database.CreateAdmin(db, username, password)
-	if err != nil {
-		ShowError(c, err)
-		return
-	}
+		// Try to create a user.
+		username := ctx.PostForm("username")
+		password := ctx.PostForm("password")
+		_, err := database.CreateAdmin(db, username, password)
+		if err != nil {
+			ShowError(ctx, err)
+			return
+		}
 
-	// Generate access token.
-	token, err := GetJWTToken(cfg)
-	if err != nil {
-		ShowError(c, err)
-		return
-	}
-	SetTokenCookie(c, token, cfg)
+		// Generate access token.
+		token, err := GetJWTToken(cfg)
+		if err != nil {
+			ShowError(ctx, err)
+			return
+		}
+		SetTokenCookie(ctx, token, cfg)
 
-	// Redirect to homepage.
-	c.Redirect(http.StatusFound, "/")
+		// Redirect to homepage.
+		ctx.Redirect(http.StatusFound, "/")
+	}
 }
 
-func AuthorizeUser(c *gin.Context, db *gorm.DB, cfg *config.Config) {
-	// Check credentials.
-	username := c.PostForm("username")
-	password := c.PostForm("password")
-	_, err := database.AuthorizeAdmin(db, username, password)
-	if err != nil {
-		ShowError(c, err)
-		return
-	}
+func AuthorizeUser(db *gorm.DB, cfg *config.Config) gin.HandlerFunc {
+	return func(ctx *gin.Context) {
+		// Check credentials.
+		username := ctx.PostForm("username")
+		password := ctx.PostForm("password")
+		_, err := database.AuthorizeAdmin(db, username, password)
+		if err != nil {
+			ShowError(ctx, err)
+			return
+		}
 
-	// Generate an access token.
-	token, err := GetJWTToken(cfg)
-	if err != nil {
-		ShowError(c, err)
-		return
-	}
-	SetTokenCookie(c, token, cfg)
+		// Generate an access token.
+		token, err := GetJWTToken(cfg)
+		if err != nil {
+			ShowError(ctx, err)
+			return
+		}
+		SetTokenCookie(ctx, token, cfg)
 
-	// Redirect to homepage.
-	c.Redirect(http.StatusFound, "/")
+		// Redirect to homepage.
+		ctx.Redirect(http.StatusFound, "/")
+	}
 }
 
 // Save token in cookies

views/errors.go

@@ -5,13 +5,13 @@ import (
 	"net/http"
 )
 
-func ShowError(c *gin.Context, err error) {
-	c.HTML(
+func ShowError(ctx *gin.Context, err error) {
+	ctx.HTML(
 		http.StatusBadRequest,
 		"error.html.tmpl",
 		gin.H{
 			"error": err.Error(),
 		},
 	)
-	c.Abort()
+	ctx.Abort()
 }

views/groups.go

@@ -8,55 +8,61 @@ import (
 	"strconv"
 )
 
-func CreateGroup(c *gin.Context, db *gorm.DB) {
-	// Save new group to the database.
-	group := database.Group{
-		Name: c.PostForm("groupName"),
-	}
-	if result := db.Create(&group); result.Error != nil {
-		ShowError(c, result.Error)
-		return
-	}
+func CreateGroup(db *gorm.DB) gin.HandlerFunc {
+	return func(ctx *gin.Context) {
+		// Save new group to the database.
+		group := database.Group{
+			Name: ctx.PostForm("groupName"),
+		}
+		if result := db.Create(&group); result.Error != nil {
+			ShowError(ctx, result.Error)
+			return
+		}
 
-	// This page is called from the settings, return the user back.
-	c.Redirect(http.StatusFound, "/settings")
+		// This page is called from the settings, return the user back.
+		ctx.Redirect(http.StatusFound, "/settings")
+	}
 }
 
-func UpdateGroup(c *gin.Context, db *gorm.DB) {
-	id, err := strconv.ParseUint(c.Param("id"), 10, 64)
-	if err != nil {
-		ShowError(c, err)
-		return
-	}
+func UpdateGroup(db *gorm.DB) gin.HandlerFunc {
+	return func(ctx *gin.Context) {
+		id, err := strconv.ParseUint(ctx.Param("id"), 10, 64)
+		if err != nil {
+			ShowError(ctx, err)
+			return
+		}
 
-	var group database.Group
-	if result := db.First(&group, id); result.Error != nil {
-		ShowError(c, result.Error)
-		return
-	}
+		var group database.Group
+		if result := db.First(&group, id); result.Error != nil {
+			ShowError(ctx, result.Error)
+			return
+		}
 
-	group.Name = c.PostForm("groupName")
-	if result := db.Save(&group); result.Error != nil {
-		ShowError(c, result.Error)
-		return
-	}
+		group.Name = ctx.PostForm("groupName")
+		if result := db.Save(&group); result.Error != nil {
+			ShowError(ctx, result.Error)
+			return
+		}
 
-	// This page is called from the settings, return the user back.
-	c.Redirect(http.StatusFound, "/settings")
+		// This page is called from the settings, return the user back.
+		ctx.Redirect(http.StatusFound, "/settings")
+	}
 }
 
-func DeleteGroup(c *gin.Context, db *gorm.DB) {
-	id, err := strconv.ParseUint(c.Param("id"), 10, 64)
-	if err != nil {
-		ShowError(c, err)
-		return
-	}
+func DeleteGroup(db *gorm.DB) gin.HandlerFunc {
+	return func(ctx *gin.Context) {
+		id, err := strconv.ParseUint(ctx.Param("id"), 10, 64)
+		if err != nil {
+			ShowError(ctx, err)
+			return
+		}
 
-	if result := db.Delete(&database.Group{}, id); result.Error != nil {
-		ShowError(c, result.Error)
-		return
-	}
+		if result := db.Delete(&database.Group{}, id); result.Error != nil {
+			ShowError(ctx, result.Error)
+			return
+		}
 
-	// Redirect to settings.
-	c.Redirect(http.StatusFound, "/settings")
+		// Redirect to settings.
+		ctx.Redirect(http.StatusFound, "/settings")
+	}
 }

views/index.go

@@ -7,20 +7,22 @@ import (
 	"net/http"
 )
 
-func ShowMainPage(c *gin.Context, db *gorm.DB) {
-	// Get a list of groups with links
-	var groups []database.Group
-	result := db.
-		Model(&database.Group{}).
-		Preload("Links").
-		Find(&groups)
+func ShowMainPage(db *gorm.DB) gin.HandlerFunc {
+	return func(ctx *gin.Context) {
+		// Get a list of groups with links
+		var groups []database.Group
+		result := db.
+			Model(&database.Group{}).
+			Preload("Links").
+			Find(&groups)
 
-	if result.Error != nil {
-		ShowError(c, result.Error)
-		return
+		if result.Error != nil {
+			ShowError(ctx, result.Error)
+			return
+		}
+
+		ctx.HTML(http.StatusOK, "index.html.tmpl", gin.H{
+			"groups": groups,
+		})
 	}
-
-	c.HTML(http.StatusOK, "index.html.tmpl", gin.H{
-		"groups": groups,
-	})
 }

views/links.go

@@ -8,75 +8,81 @@ import (
 	"strconv"
 )
 
-func CreateLink(c *gin.Context, db *gorm.DB) {
-	groupID, err := strconv.ParseUint(c.PostForm("groupID"), 10, 32)
-	if err != nil {
-		ShowError(c, err)
-		return
-	}
+func CreateLink(db *gorm.DB) gin.HandlerFunc {
+	return func(ctx *gin.Context) {
+		groupID, err := strconv.ParseUint(ctx.PostForm("groupID"), 10, 32)
+		if err != nil {
+			ShowError(ctx, err)
+			return
+		}
 
-	link := database.Link{
-		Name:    c.PostForm("linkName"),
-		Href:    c.PostForm("href"),
-		GroupID: groupID,
-	}
-	icon := c.PostForm("icon")
-	if icon == "" {
-		link.Icon = nil
-	} else {
-		link.Icon = &icon
-	}
-	if result := db.Create(&link); result.Error != nil {
-		ShowError(c, result.Error)
-		return
-	}
+		link := database.Link{
+			Name:    ctx.PostForm("linkName"),
+			Href:    ctx.PostForm("href"),
+			GroupID: groupID,
+		}
+		icon := ctx.PostForm("icon")
+		if icon == "" {
+			link.Icon = nil
+		} else {
+			link.Icon = &icon
+		}
+		if result := db.Create(&link); result.Error != nil {
+			ShowError(ctx, result.Error)
+			return
+		}
 
-	// Redirect to settings.
-	c.Redirect(http.StatusFound, "/settings")
+		// Redirect to settings.
+		ctx.Redirect(http.StatusFound, "/settings")
+	}
 }
 
-func UpdateLink(c *gin.Context, db *gorm.DB) {
-	id, err := strconv.ParseUint(c.Param("id"), 10, 64)
-	if err != nil {
-		ShowError(c, err)
-		return
-	}
+func UpdateLink(db *gorm.DB) gin.HandlerFunc {
+	return func(ctx *gin.Context) {
+		id, err := strconv.ParseUint(ctx.Param("id"), 10, 64)
+		if err != nil {
+			ShowError(ctx, err)
+			return
+		}
 
-	var link database.Link
-	if result := db.First(&link, id); result.Error != nil {
-		ShowError(c, err)
-		return
-	}
+		var link database.Link
+		if result := db.First(&link, id); result.Error != nil {
+			ShowError(ctx, err)
+			return
+		}
 
-	link.Name = c.PostForm("linkName")
-	link.Href = c.PostForm("href")
-	icon := c.PostForm("icon")
-	if icon == "" {
-		link.Icon = nil
-	} else {
-		link.Icon = &icon
-	}
-	if result := db.Save(&link); result.Error != nil {
-		ShowError(c, result.Error)
-		return
-	}
+		link.Name = ctx.PostForm("linkName")
+		link.Href = ctx.PostForm("href")
+		icon := ctx.PostForm("icon")
+		if icon == "" {
+			link.Icon = nil
+		} else {
+			link.Icon = &icon
+		}
+		if result := db.Save(&link); result.Error != nil {
+			ShowError(ctx, result.Error)
+			return
+		}
 
-	// Redirect to settings.
-	c.Redirect(http.StatusFound, "/settings")
+		// Redirect to settings.
+		ctx.Redirect(http.StatusFound, "/settings")
+	}
 }
 
-func DeleteLink(c *gin.Context, db *gorm.DB) {
-	id, err := strconv.ParseUint(c.Param("id"), 10, 64)
-	if err != nil {
-		ShowError(c, err)
-		return
-	}
+func DeleteLink(db *gorm.DB) gin.HandlerFunc {
+	return func(ctx *gin.Context) {
+		id, err := strconv.ParseUint(ctx.Param("id"), 10, 64)
+		if err != nil {
+			ShowError(ctx, err)
+			return
+		}
 
-	if result := db.Delete(&database.Link{}, id); result.Error != nil {
-		ShowError(c, result.Error)
-		return
-	}
+		if result := db.Delete(&database.Link{}, id); result.Error != nil {
+			ShowError(ctx, result.Error)
+			return
+		}
 
-	// Redirect to settings.
-	c.Redirect(http.StatusFound, "/settings")
+		// Redirect to settings.
+		ctx.Redirect(http.StatusFound, "/settings")
+	}
 }

views/main.go

@@ -22,68 +22,42 @@ func GetGinEngine(cfg *config.Config, db *gorm.DB) *gin.Engine {
 
 	engine.Use(SecurityHeadersMiddleware)
 
-	engine.GET("/signin", func(c *gin.Context) {
-		ShowLoginForm(c)
-	})
-	engine.POST("/api/users/signin", func(c *gin.Context) {
-		AuthorizeUser(c, db, cfg)
-	})
+	engine.GET("/signin", ShowLoginForm)
+	engine.POST("/api/users/signin", AuthorizeUser(db, cfg))
 
-	engine.GET("/registration", func(c *gin.Context) {
-		ShowRegistrationForm(c, db)
-	})
-	engine.POST("/api/users", func(c *gin.Context) {
-		CreateUser(c, db, cfg)
-	})
+	engine.GET("/registration", ShowRegistrationForm(db))
+	engine.POST("/api/users", CreateUser(db, cfg))
 
 	// This group requires authorization before viewing.
 	protected := engine.Group("/")
-	protected.Use(func(c *gin.Context) {
-		AuthMiddleware(c, db, cfg)
-	})
+	protected.Use(AuthMiddleware(db, cfg))
 
 	// Main page
-	protected.GET("/", func(c *gin.Context) {
-		ShowMainPage(c, db)
-	})
+	protected.GET("/", ShowMainPage(db))
 
-	protected.GET("/settings", func(c *gin.Context) {
-		ShowSettings(c, db)
-	})
+	protected.GET("/settings", ShowSettings(db))
 
 	// Create new group
-	protected.POST("/api/groups", func(c *gin.Context) {
-		CreateGroup(c, db)
-	})
+	protected.POST("/api/groups", CreateGroup(db))
 
 	// Update group
 	// HTML forms cannot be submitted using PUT or PATCH methods without javascript.
-	protected.POST("/api/groups/:id/put", func(c *gin.Context) {
-		UpdateGroup(c, db)
-	})
+	protected.POST("/api/groups/:id/put", UpdateGroup(db))
 
 	// Delete group
 	// HTML forms cannot be submitted using the DELETE method without javascript.
-	protected.POST("/api/groups/:id/delete", func(c *gin.Context) {
-		DeleteGroup(c, db)
-	})
+	protected.POST("/api/groups/:id/delete", DeleteGroup(db))
 
 	// Create new link
-	protected.POST("/api/links", func(c *gin.Context) {
-		CreateLink(c, db)
-	})
+	protected.POST("/api/links", CreateLink(db))
 
 	// Update link.
 	// HTML forms cannot be submitted using PUT or PATCH methods without javascript.
-	protected.POST("/api/links/:id/put", func(c *gin.Context) {
-		UpdateLink(c, db)
-	})
+	protected.POST("/api/links/:id/put", UpdateLink(db))
 
 	// Delete link
 	// HTML forms cannot be submitted using the DELETE method without javascript.
-	protected.POST("/api/links/:id/delete", func(c *gin.Context) {
-		DeleteLink(c, db)
-	})
+	protected.POST("/api/links/:id/delete", DeleteLink(db))
 
 	return engine
 }

views/settings.go

@@ -7,20 +7,22 @@ import (
 	"net/http"
 )
 
-func ShowSettings(c *gin.Context, db *gorm.DB) {
-	// Get a list of groups with links
-	var groups []database.Group
-	result := db.
-		Model(&database.Group{}).
-		Preload("Links").
-		Find(&groups)
+func ShowSettings(db *gorm.DB) gin.HandlerFunc {
+	return func(ctx *gin.Context) {
+		// Get a list of groups with links
+		var groups []database.Group
+		result := db.
+			Model(&database.Group{}).
+			Preload("Links").
+			Find(&groups)
 
-	if result.Error != nil {
-		ShowError(c, result.Error)
-		return
+		if result.Error != nil {
+			ShowError(ctx, result.Error)
+			return
+		}
+
+		ctx.HTML(http.StatusOK, "settings.html.tmpl", gin.H{
+			"groups": groups,
+		})
 	}
-
-	c.HTML(http.StatusOK, "settings.html.tmpl", gin.H{
-		"groups": groups,
-	})
 }