Introduce middleware for parsing ID from URI

api/application.go

@@ -40,7 +40,7 @@ func (h *ApplicationHandler) applicationExists(token string) bool {
 func (h *ApplicationHandler) CreateApplication(ctx *gin.Context) {
 	var createApplication model.CreateApplication
 
-	if success := successOrAbort(ctx, http.StatusBadRequest, ctx.Bind(&createApplication)); !success {
+	if err := ctx.Bind(&createApplication); err != nil {
 		return
 	}
 
@@ -69,13 +69,12 @@ func (h *ApplicationHandler) CreateApplication(ctx *gin.Context) {
 
 // DeleteApplication deletes an application with a certain ID.
 func (h *ApplicationHandler) DeleteApplication(ctx *gin.Context) {
-	var deleteApplication model.DeleteApplication
+	id, err := getID(ctx)
-
+	if err != nil {
-	if success := successOrAbort(ctx, http.StatusBadRequest, ctx.BindUri(&deleteApplication)); !success {
 		return
 	}
 
-	application, err := h.DB.GetApplicationByID(deleteApplication.ID)
+	application, err := h.DB.GetApplicationByID(id)
 	if success := successOrAbort(ctx, http.StatusNotFound, err); !success {
 		return
 	}
@@ -99,13 +98,12 @@ func (h *ApplicationHandler) DeleteApplication(ctx *gin.Context) {
 
 // UpdateApplication updates an application with a certain ID.
 func (h *ApplicationHandler) UpdateApplication(ctx *gin.Context) {
-	var updateApplication model.UpdateApplication
+	id, err := getID(ctx)
-
+	if err != nil {
-	if success := successOrAbort(ctx, http.StatusBadRequest, ctx.BindUri(&updateApplication)); !success {
 		return
 	}
 
-	application, err := h.DB.GetApplicationByID(updateApplication.ID)
+	application, err := h.DB.GetApplicationByID(id)
 	if success := successOrAbort(ctx, http.StatusNotFound, err); !success {
 		return
 	}
@@ -114,6 +112,12 @@ func (h *ApplicationHandler) UpdateApplication(ctx *gin.Context) {
 		return
 	}
 
+	var updateApplication model.UpdateApplication
+
+	if err := ctx.BindUri(&updateApplication); err != nil {
+		return
+	}
+
 	log.Printf("Updating application %s.\n", application.Name)
 
 	// TODO: Handle unbound members.

api/middleware.go

@@ -0,0 +1,36 @@
+package api
+
+import (
+	"errors"
+	"net/http"
+
+	"github.com/gin-gonic/gin"
+)
+
+type idInURI struct {
+	ID uint `uri:"id" binding:"required"`
+}
+
+// RequireIDInURI returns a Gin middleware which requires an ID to be supplied in the URI of the request.
+func RequireIDInURI() gin.HandlerFunc {
+	return func(ctx *gin.Context) {
+		var requestModel idInURI
+
+		if err := ctx.BindUri(&requestModel); err != nil {
+			return
+		}
+
+		ctx.Set("id", requestModel.ID)
+	}
+}
+
+func getID(ctx *gin.Context) (uint, error) {
+	id, ok := ctx.MustGet("user").(uint)
+	if !ok {
+		err := errors.New("an error occured while retrieving ID from context")
+		ctx.AbortWithError(http.StatusInternalServerError, err)
+		return 0, err
+	}
+
+	return id, nil
+}

api/notification.go

@@ -31,7 +31,7 @@ type NotificationHandler struct {
 func (h *NotificationHandler) CreateNotification(ctx *gin.Context) {
 	var notification model.Notification
 
-	if success := successOrAbort(ctx, http.StatusBadRequest, ctx.Bind(&notification)); !success {
+	if err := ctx.Bind(&notification); err != nil {
 		return
 	}
 

api/user.go

@@ -13,7 +13,7 @@ import (
 
 // The UserDatabase interface for encapsulating database access.
 type UserDatabase interface {
-	CreateUser(user model.ExternalUserWithCredentials) (*model.User, error)
+	CreateUser(user model.CreateUser) (*model.User, error)
 	DeleteUser(user *model.User) error
 	UpdateUser(user *model.User) error
 	GetUserByID(ID uint) (*model.User, error)
@@ -57,9 +57,9 @@ func (h *UserHandler) ensureIsNotLastAdmin(ctx *gin.Context) (int, error) {
 // CreateUser creates a new user.
 // This method assumes that the requesting user has privileges.
 func (h *UserHandler) CreateUser(ctx *gin.Context) {
-	var externalUser model.ExternalUserWithCredentials
+	var externalUser model.CreateUser
 
-	if success := successOrAbort(ctx, http.StatusBadRequest, ctx.Bind(&externalUser)); !success {
+	if err := ctx.Bind(&externalUser); err != nil {
 		return
 	}
 
@@ -81,13 +81,12 @@ func (h *UserHandler) CreateUser(ctx *gin.Context) {
 //
 // This method assumes that the requesting user has privileges.
 func (h *UserHandler) DeleteUser(ctx *gin.Context) {
-	var deleteUser model.DeleteUser
+	id, err := getID(ctx)
-
+	if err != nil {
-	if success := successOrAbort(ctx, http.StatusBadRequest, ctx.BindUri(&deleteUser)); !success {
 		return
 	}
 
-	user, err := h.DB.GetUserByID(deleteUser.ID)
+	user, err := h.DB.GetUserByID(id)
 	if success := successOrAbort(ctx, http.StatusNotFound, err); !success {
 		return
 	}
@@ -125,17 +124,22 @@ func (h *UserHandler) DeleteUser(ctx *gin.Context) {
 // This method assumes that the requesting user has privileges. If users can later update their own user, make sure they
 // cannot give themselves privileges.
 func (h *UserHandler) UpdateUser(ctx *gin.Context) {
-	var updateUser model.UpdateUser
+	id, err := getID(ctx)
-
+	if err != nil {
-	if success := successOrAbort(ctx, http.StatusBadRequest, ctx.BindUri(&updateUser)); !success {
 		return
 	}
 
-	user, err := h.DB.GetUserByID(updateUser.ID)
+	user, err := h.DB.GetUserByID(id)
 	if success := successOrAbort(ctx, http.StatusNotFound, err); !success {
 		return
 	}
 
+	var updateUser model.UpdateUser
+
+	if err := ctx.BindUri(&updateUser); err != nil {
+		return
+	}
+
 	currentUser := authentication.GetUser(ctx)
 
 	// Last privileged user must not be taken privileges. Assumes that the current user has privileges.

database/user.go

@@ -10,7 +10,7 @@ import (
 )
 
 // CreateUser creates a user.
-func (d *Database) CreateUser(externalUser model.ExternalUserWithCredentials) (*model.User, error) {
+func (d *Database) CreateUser(externalUser model.CreateUser) (*model.User, error) {
 	user := externalUser.IntoInternalUser(d.credentialsManager)
 
 	return user, d.gormdb.Create(user).Error

model/application.go

@@ -14,17 +14,7 @@ type CreateApplication struct {
 	Name string `form:"name" query:"name" json:"name" binding:"required"`
 }
 
-type applicationIdentification struct {
-	ID uint `uri:"id" binding:"required"`
-}
-
-// DeleteApplication is used to process queries for deleting applications.
-type DeleteApplication struct {
-	applicationIdentification
-}
-
 // UpdateApplication is used to process queries for updating applications.
 type UpdateApplication struct {
-	applicationIdentification
 	Name string `json:"name"`
 }

model/user.go

@@ -29,8 +29,8 @@ type UserCredentials struct {
 	Password string `json:"password,omitempty" form:"password" query:"password" binding:"required"`
 }
 
-// ExternalUserWithCredentials represents a user for external purposes and includes the user's credentials in plaintext.
+// CreateUser is used to process queries for creating users.
-type ExternalUserWithCredentials struct {
+type CreateUser struct {
 	ExternalUser
 	UserCredentials
 }
@@ -47,8 +47,8 @@ func NewUser(cm *credentials.Manager, name, password string, isAdmin bool, matri
 	}
 }
 
-// IntoInternalUser converts a ExternalUserWithCredentials into a User.
+// IntoInternalUser converts a CreateUser into a User.
-func (u *ExternalUserWithCredentials) IntoInternalUser(cm *credentials.Manager) *User {
+func (u *CreateUser) IntoInternalUser(cm *credentials.Manager) *User {
 	return &User{
 		Name:         u.Name,
 		PasswordHash: cm.CreatePasswordHash(u.Password),
@@ -67,18 +67,8 @@ func (u *User) IntoExternalUser() *ExternalUser {
 	}
 }
 
-type userIdentification struct {
-	ID uint `uri:"id" binding:"required"`
-}
-
-// DeleteUser is used to process queries for deleting users.
-type DeleteUser struct {
-	userIdentification
-}
-
 // UpdateUser is used to process queries for updating users.
 type UpdateUser struct {
-	userIdentification
 	Name     string `json:"name"`
 	Password string `json:"password"`
 	IsAdmin  bool   `json:"is_admin"`

router/router.go

@@ -35,8 +35,8 @@ func Create(debug bool, cm *credentials.Manager, db *database.Database, dp *disp
 	applicationGroup.Use(auth.RequireUser())
 	{
 		applicationGroup.POST("", applicationHandler.CreateApplication)
-		applicationGroup.DELETE("/:id", applicationHandler.DeleteApplication)
+		applicationGroup.DELETE("/:id", api.RequireIDInURI(), applicationHandler.DeleteApplication)
-		applicationGroup.PUT("/:id", applicationHandler.UpdateApplication)
+		applicationGroup.PUT("/:id", api.RequireIDInURI(), applicationHandler.UpdateApplication)
 	}
 
 	r.POST("/message", auth.RequireApplicationToken(), notificationHandler.CreateNotification)
@@ -45,8 +45,8 @@ func Create(debug bool, cm *credentials.Manager, db *database.Database, dp *disp
 	userGroup.Use(auth.RequireAdmin())
 	{
 		userGroup.POST("", userHandler.CreateUser)
-		userGroup.DELETE("/:id", userHandler.DeleteUser)
+		userGroup.DELETE("/:id", api.RequireIDInURI(), userHandler.DeleteUser)
-		userGroup.PUT("/:id", userHandler.UpdateUser)
+		userGroup.PUT("/:id", api.RequireIDInURI(), userHandler.UpdateUser)
 	}
 
 	return r