chore: refactroing of code

Commenting code for enhancing readability

internal/middlewares/error_interceptor.go

@@ -0,0 +1,74 @@
+package middlewares
+
+/*
+ * Copyright 2024 Jonas Kaninda
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+import (
+	"bytes"
+	"github.com/jkaninda/goma-gateway/pkg/logger"
+	"io"
+	"net/http"
+	"slices"
+)
+
+func newResponseRecorder(w http.ResponseWriter) *responseRecorder {
+	return &responseRecorder{
+		ResponseWriter: w,
+		statusCode:     http.StatusOK,
+		body:           &bytes.Buffer{},
+	}
+}
+
+func (rec *responseRecorder) WriteHeader(code int) {
+	rec.statusCode = code
+}
+
+func (rec *responseRecorder) Write(data []byte) (int, error) {
+	return rec.body.Write(data)
+}
+
+// ErrorInterceptor Middleware intercepts backend errors
+func (intercept InterceptErrors) ErrorInterceptor(next http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		// Check if the connection is a WebSocket
+		if isWebSocketRequest(r) {
+			next.ServeHTTP(w, r)
+			return
+		}
+		rec := newResponseRecorder(w)
+		next.ServeHTTP(rec, r)
+		if canIntercept(rec.statusCode, intercept.Errors) {
+			logger.Error("Request to %s resulted in error with status code %d\n", r.URL.Path, rec.statusCode)
+			RespondWithError(w, rec.statusCode, http.StatusText(rec.statusCode))
+			return
+		} else {
+			// No error: write buffered response to client
+			w.WriteHeader(rec.statusCode)
+			_, err := io.Copy(w, rec.body)
+			if err != nil {
+				return
+			}
+
+		}
+
+	})
+}
+func isWebSocketRequest(r *http.Request) bool {
+	return r.Header.Get("Upgrade") == "websocket" && r.Header.Get("Connection") == "Upgrade"
+}
+func canIntercept(code int, errors []int) bool {
+	return slices.Contains(errors, code)
+}