streamline response handling and logging

Signed-off-by: Tobias Erbshäußer <tobias@tesoft.dev>

backend/api.go

@@ -23,7 +23,7 @@ func (h *ApiHandler) ServeLoginPost(writer http.ResponseWriter, request *http.Re
 	body, err := io.ReadAll(bodyReader)
 	_ = bodyReader.Close()
 	if err != nil {
-		http.Error(writer, err.Error(), http.StatusBadRequest)
+		WriteError(writer, http.StatusBadRequest, "failed to read body", err)
 		return
 	}
 
@@ -34,19 +34,19 @@ func (h *ApiHandler) ServeLoginPost(writer http.ResponseWriter, request *http.Re
 	loginBody := LoginBody{}
 	err = json.Unmarshal(body, &loginBody)
 	if err != nil {
-		http.Error(writer, err.Error(), http.StatusBadRequest)
+		WriteError(writer, http.StatusBadRequest, "failed to read body", err)
 		return
 	}
 
 	success, err := h.db.ValidateRootPassword(loginBody.Password)
 	if err != nil {
-		log.Println("Error logging in:", err)
-		http.Error(writer, "failed to read database", http.StatusInternalServerError)
+		WriteError(writer, http.StatusInternalServerError, "failed to read database", err)
 		return
 	}
 
 	if !success {
-		http.Error(writer, "invalid password", http.StatusUnauthorized)
+		log.Printf("failed login from '%s'", request.RemoteAddr)
+		WriteError(writer, http.StatusUnauthorized, "invalid password", nil)
 		return
 	}
 
@@ -62,14 +62,9 @@ func (h *ApiHandler) ServeLoginPost(writer http.ResponseWriter, request *http.Re
 	cookie.HttpOnly = true
 	http.SetCookie(writer, &cookie)
 
-	writer.Header().Set("Content-Type", "application/json")
-	writer.WriteHeader(http.StatusOK)
-	err = json.NewEncoder(writer).Encode(map[string]interface{}{})
-	if err != nil {
-		http.Error(writer, "failed to serialize results", http.StatusInternalServerError)
-		return
-	}
+	WriteResponse(writer, http.StatusOK, map[string]interface{}{})
 
+	log.Printf("successful login from '%s'", request.RemoteAddr)
 }
 
 func (h *ApiHandler) ServeLogoutPost(writer http.ResponseWriter, request *http.Request) {
@@ -85,13 +80,9 @@ func (h *ApiHandler) ServeLogoutPost(writer http.ResponseWriter, request *http.R
 
 	h.authToken = nil
 
-	writer.Header().Set("Content-Type", "application/json")
-	writer.WriteHeader(http.StatusOK)
-	err := json.NewEncoder(writer).Encode(map[string]interface{}{})
-	if err != nil {
-		http.Error(writer, "failed to serialize results", http.StatusInternalServerError)
-		return
-	}
+	WriteResponse(writer, http.StatusOK, map[string]interface{}{})
+
+	log.Printf("successful logout from '%s'", request.RemoteAddr)
 }
 
 func (h *ApiHandler) ProcessAuth(next http.Handler, required bool) http.Handler {
@@ -103,7 +94,7 @@ func (h *ApiHandler) ProcessAuth(next http.Handler, required bool) http.Handler
 		}
 
 		if !isAuthorized && required {
-			http.Error(writer, "authentication required", http.StatusUnauthorized)
+			WriteError(writer, http.StatusUnauthorized, "authentication required", nil)
 			return
 		}
 
@@ -115,3 +106,19 @@ func IsAuthorized(request *http.Request) bool {
 	value := request.Context().Value(isAuthorizedContextKey)
 	return value != nil && value.(bool)
 }
+
+func WriteResponse(writer http.ResponseWriter, code int, body any) {
+	writer.Header().Set("Content-Type", "application/json")
+	writer.WriteHeader(code)
+	_ = json.NewEncoder(writer).Encode(body)
+}
+
+func WriteError(writer http.ResponseWriter, code int, message string, err error) {
+	if err != nil {
+		log.Println(err)
+	}
+
+	WriteResponse(writer, code, map[string]interface{}{
+		"message": message,
+	})
+}