1 files changed, 64 insertions, 0 deletions
diff --git a/lib/http/callback_error_handler.go b/lib/http/callback_error_handler.go
new file mode 100644
index 00000000..199e1a12
--- /dev/null
+++ b/lib/http/callback_error_handler.go
@@ -0,0 +1,64 @@
+// Copyright 2020, Shulhan <ms@kilabit.info>. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package http
+
+import (
+	"encoding/json"
+	"errors"
+	"log"
+	"net/http"
+
+	liberrors "github.com/shuLhan/share/lib/errors"
+)
+
+//
+// CallbackErrorHandler define the function that can be used to handle an
+// error returned from Endpoint.Call.
+// By default, if Endpoint.Call is nil, it will use DefaultErrorHandler.
+//
+type CallbackErrorHandler func(http.ResponseWriter, *http.Request, error)
+
+//
+// DefaultErrorHandler define the default function that will called to handle
+// the error returned from Callback function, if the Endpoint.ErrorHandler is
+// not defined.
+//
+// First, it will check if error instance of errors.E. If its true, it will
+// use the Code value for HTTP status code, otherwise if its zero or invalid,
+// it will set to http.StatusInternalServerError.
+//
+// Second, it will set the HTTP content-type to "application/json" and write
+// the response body as JSON format,
+//
+//	{"code":<HTTP_STATUS_CODE>, "message":<err.Error()>}
+//
+func DefaultErrorHandler(res http.ResponseWriter, req *http.Request, err error) {
+	errInternal := &liberrors.E{}
+	if errors.As(err, &errInternal) {
+		if errInternal.Code <= 0 || errInternal.Code >= 512 {
+			errInternal.Code = http.StatusInternalServerError
+		}
+	} else {
+		log.Printf("DefaultErrorHandler: %d %s %s %s\n",
+			http.StatusInternalServerError,
+			req.Method, req.URL.Path, err)
+
+		errInternal = liberrors.Internal(err)
+	}
+
+	res.Header().Set(HeaderContentType, ContentTypeJSON)
+	res.WriteHeader(errInternal.Code)
+
+	rsp, err := json.Marshal(errInternal)
+	if err != nil {
+		log.Println("DefaultErrorHandler: " + err.Error())
+		return
+	}
+
+	_, err = res.Write(rsp)
+	if err != nil {
+		log.Println("DefaultErrorHandler: " + err.Error())
+	}
+}