Use vanilla HTTP handlers (refactoring)

http/response/html/html.go

@@ -0,0 +1,57 @@
+// Copyright 2018 Frédéric Guillot. All rights reserved.
+// Use of this source code is governed by the Apache 2.0
+// license that can be found in the LICENSE file.
+
+package html
+
+import (
+	"net/http"
+
+	"github.com/miniflux/miniflux/logger"
+)
+
+// OK writes a standard HTML response.
+func OK(w http.ResponseWriter, b []byte) {
+	w.Header().Set("Content-Type", "text/html; charset=utf-8")
+	w.Write(b)
+}
+
+// ServerError sends a 500 error to the browser.
+func ServerError(w http.ResponseWriter, err error) {
+	w.Header().Set("Content-Type", "text/plain; charset=utf-8")
+	w.WriteHeader(http.StatusInternalServerError)
+
+	if err != nil {
+		logger.Error("[Internal Server Error] %v", err)
+		w.Write([]byte("Internal Server Error: " + err.Error()))
+	} else {
+		w.Write([]byte("Internal Server Error"))
+	}
+}
+
+// BadRequest sends a 400 error to the browser.
+func BadRequest(w http.ResponseWriter, err error) {
+	w.Header().Set("Content-Type", "text/plain; charset=utf-8")
+	w.WriteHeader(http.StatusBadRequest)
+
+	if err != nil {
+		logger.Error("[Bad Request] %v", err)
+		w.Write([]byte("Bad Request: " + err.Error()))
+	} else {
+		w.Write([]byte("Bad Request"))
+	}
+}
+
+// NotFound sends a 404 error to the browser.
+func NotFound(w http.ResponseWriter) {
+	w.Header().Set("Content-Type", "text/plain; charset=utf-8")
+	w.WriteHeader(http.StatusNotFound)
+	w.Write([]byte("Page Not Found"))
+}
+
+// Forbidden sends a 403 error to the browser.
+func Forbidden(w http.ResponseWriter) {
+	w.Header().Set("Content-Type", "text/plain; charset=utf-8")
+	w.WriteHeader(http.StatusForbidden)
+	w.Write([]byte("Access Forbidden"))
+}