improve logging, add X-Forwarded-User header

cmd/go-matrix-webhook/cmd.go

@@ -4,7 +4,6 @@ import (
 	"fmt"
 	"net/http"
 
-	"github.com/gorilla/mux"
 	"github.com/mazzz1y/go-matrix-webhook/internal/handler"
 	"github.com/mazzz1y/go-matrix-webhook/internal/matrix"
 	"github.com/rs/zerolog/log"
@@ -28,12 +27,9 @@ func run(c *cli.Context) error {
 	if err != nil {
 		panic(err)
 	}
-	h := handler.NewHandler(*m, secretHeader)
-
-	router := mux.NewRouter().StrictSlash(true)
-	router.HandleFunc(listenPath, h).Methods("POST")
+	http.HandleFunc(listenPath, handler.NewHandler(*m, secretHeader))
 
 	listen := fmt.Sprintf("%s:%d", listenAddr, listenPort)
 	log.Info().Err(err).Msgf("listen on: %s", listen)
-	return http.ListenAndServe(listen, router)
+	return http.ListenAndServe(listen, nil)
 }

cmd/go-matrix-webhook/main.go

@@ -36,10 +36,9 @@ func main() {
 				Value:   "/",
 			},
 			&cli.StringFlag{
-				Name:     "secret-header",
-				Usage:    "secret header",
-				EnvVars:  []string{"SECRET_HEADER"},
-				Required: true,
+				Name:    "secret-header",
+				Usage:   "secret header",
+				EnvVars: []string{"SECRET_HEADER"},
 			},
 			&cli.StringFlag{
 				Name:     "matrix-access-token",

go.mod

@@ -3,7 +3,6 @@ module github.com/mazzz1y/go-matrix-webhook
 go 1.20
 
 require (
-	github.com/gorilla/mux v1.8.0
 	github.com/rs/zerolog v1.29.1
 	github.com/urfave/cli/v2 v2.25.1
 	maunium.net/go/mautrix v0.15.1

go.sum

@@ -3,8 +3,6 @@ github.com/cpuguy83/go-md2man/v2 v2.0.2 h1:p1EgwI/C7NhT0JmVkwCD2ZBK8j4aeHQX2pMHH
 github.com/cpuguy83/go-md2man/v2 v2.0.2/go.mod h1:tgQtvFlXSQOSOSIRvRPT7W67SCa46tRHOmNcaadrF8o=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/godbus/dbus/v5 v5.0.4/go.mod h1:xhWf0FNVPg57R7Z0UbKHbJfkEywrmjJnf7w5xrFpKfA=
-github.com/gorilla/mux v1.8.0 h1:i40aqfkR1h2SlN9hojwV5ZA91wcXFOvkdNIeFDP5koI=
-github.com/gorilla/mux v1.8.0/go.mod h1:DVbg23sWSpFRCP0SfiEN6jmj59UnW/n46BH5rLB71So=
 github.com/mattn/go-colorable v0.1.12 h1:jF+Du6AlPIjs2BiUiQlKOX0rt3SujHxPnksPKZbaA40=
 github.com/mattn/go-colorable v0.1.12/go.mod h1:u5H1YNBxpqRaxsYJYSkiCWKzEfiAb1Gb520KVy5xxl4=
 github.com/mattn/go-isatty v0.0.14 h1:yVuAays6BHfxijgZPzw+3Zlu5yQgKGP2/hcQbHb7S9Y=

internal/handler/handler.go

@@ -3,10 +3,13 @@ package handler
 import (
 	"encoding/json"
 	"errors"
+	"io"
+	"net"
 	"net/http"
+	"strings"
 
 	"github.com/mazzz1y/go-matrix-webhook/internal/matrix"
-	"github.com/rs/zerolog/log"
+	zerolog "github.com/rs/zerolog/log"
 )
 
 type WebhookPayload struct {
@@ -19,54 +22,90 @@ type ResponseData struct {
 	Message string `json:"message"`
 }
 
-func NewHandler(m matrix.Matrix, s string) func(http.ResponseWriter, *http.Request) {
+const (
+	successSent         = "message sent"
+	errInvalidSecret    = "invalid secret header"
+	errParseBodyError   = "parse body error"
+	errJoinRoomError    = "join room error"
+	errSendMessageError = "send message error"
+	errEmptyMessage     = "empty message"
+)
+
+func NewHandler(m matrix.Matrix, secret string) func(http.ResponseWriter, *http.Request) {
 	return func(w http.ResponseWriter, r *http.Request) {
-		if r.Header.Get("X-Secret") != s {
-			response(w, http.StatusBadRequest, "invalid secret header")
+		secretHeader := r.Header.Get("X-Secret")
+		userHeader := r.Header.Get("X-Forwarded-User")
+		reqIP := getIP(r)
+
+		if secret != "" && secretHeader != secret {
+			sendResponse(w, http.StatusBadRequest, errInvalidSecret)
 			return
 		}
 
-		payload, err := parsePayload(r)
+		log := zerolog.With().Str("ip", reqIP).Str("path", r.URL.Path).Logger()
+		if userHeader != "" {
+			log = log.With().Str("user", userHeader).Logger()
+		}
+
+		payload, err := parsePayload(r.Body)
 		if err != nil {
-			log.Error().Err(err).Msg("")
-			response(w, http.StatusBadRequest, "parse body error")
+			log.Error().Err(err).Msg(errParseBodyError)
+			sendResponse(w, http.StatusBadRequest, errParseBodyError)
 			return
 		}
 
 		err = m.JoinRoom(payload.RoomID)
 		if err != nil {
-			log.Error().Str("room_id", payload.RoomID).Err(err).Msg("")
-			response(w, http.StatusInternalServerError, "join room error")
+			log.Error().Str("room_id", payload.RoomID).Err(err).Msg(errJoinRoomError)
+			sendResponse(w, http.StatusInternalServerError, errJoinRoomError)
 			return
 		}
 
 		err = m.SendMessage(payload.RoomID, payload.Message)
 		if err != nil {
-			log.Error().Str("room_id", payload.RoomID).Err(err).Msg("")
-			response(w, http.StatusOK, "send message error")
+			log.Error().Str("room_id", payload.RoomID).Err(err).Msg(errSendMessageError)
+			sendResponse(w, http.StatusOK, errSendMessageError)
 			return
 		}
 
-		log.Debug().Str("room_id", payload.RoomID).Msg("message sent")
-		response(w, http.StatusOK, "")
+		log.Debug().Str("room_id", payload.RoomID).Msg(successSent)
+		sendResponse(w, http.StatusOK, "")
 	}
 }
 
-func parsePayload(r *http.Request) (*WebhookPayload, error) {
+func parsePayload(body io.ReadCloser) (*WebhookPayload, error) {
 	var payload WebhookPayload
-	err := json.NewDecoder(r.Body).Decode(&payload)
+	err := json.NewDecoder(body).Decode(&payload)
 	if err != nil {
 		return nil, err
 	}
 
 	if payload.Message == "" {
-		return nil, errors.New("empty message")
+		return nil, errors.New(errEmptyMessage)
 	}
 
 	return &payload, nil
 }
 
-func response(w http.ResponseWriter, code int, msg string) {
+func getIP(r *http.Request) string {
+	if xff := r.Header.Get("X-Forwarded-For"); xff != "" {
+		ipParts := strings.Split(xff, ",")
+		return strings.TrimSpace(ipParts[0])
+	}
+
+	if xri := r.Header.Get("X-Real-IP"); xri != "" {
+		return xri
+	}
+
+	if cf := r.Header.Get("CF-Connecting-IP"); cf != "" {
+		return cf
+	}
+
+	ip, _, _ := net.SplitHostPort(r.RemoteAddr)
+	return ip
+}
+
+func sendResponse(w http.ResponseWriter, code int, msg string) {
 	if msg == "" {
 		msg = http.StatusText(code)
 	}