proper conflict error handling

cmd/server/server.go

@@ -40,21 +40,37 @@ func main() {
 
 	r := mux.NewRouter()
 
-	r.HandleFunc("/", func(rw http.ResponseWriter, r *http.Request) {
-		rw.Write([]byte("welcome to underpass"))
-	}).Host(*host)
+	r.Handle("/", http.RedirectHandler("https://github.com/cjdenio/underpass", http.StatusTemporaryRedirect)).Host(*host)
 
 	r.HandleFunc("/start", func(rw http.ResponseWriter, r *http.Request) {
 		subdomain := r.URL.Query().Get("subdomain")
 		if subdomain == "" {
 			subdomain, _ = gonanoid.Generate("abcdefghijklmnopqrstuvwxyz0123456789", 5)
 		}
 
+		c, err := upgrader.Upgrade(rw, r, nil)
+		if err != nil {
+			rw.WriteHeader(http.StatusBadRequest)
+			rw.Write([]byte(err.Error()))
+			return
+		}
+
+		writeMutex := sync.Mutex{}
+
 		if _, ok := tunnels[subdomain]; ok {
 			// Tunnel already exists
 
-			rw.WriteHeader(http.StatusConflict)
-			rw.Write([]byte("Tunnel is already running"))
+			writeMutex.Lock()
+			err = util.WriteMsgPack(c, models.ServerMessage{
+				Type:  "error",
+				Error: fmt.Sprintf("Tunnel %s is already in use.", subdomain),
+			})
+			if err != nil {
+				log.Println(err)
+			}
+			writeMutex.Unlock()
+
+			c.Close()
 			return
 		}
 
@@ -66,15 +82,6 @@ func main() {
 
 		tunnels[subdomain] = &t
 
-		c, err := upgrader.Upgrade(rw, r, nil)
-		if err != nil {
-			rw.WriteHeader(http.StatusBadRequest)
-			rw.Write([]byte(err.Error()))
-			return
-		}
-
-		writeMutex := sync.Mutex{}
-
 		writeMutex.Lock()
 		err = util.WriteMsgPack(c, models.ServerMessage{
 			Type:      "subdomain",

pkg/client/cmd/root.go

@@ -39,6 +39,7 @@ var rootCmd = &cobra.Command{
 		t, err := tunnel.Connect(u.String(), fmt.Sprintf("http://localhost:%d", port))
 		if err != nil {
 			fmt.Println(err)
+			os.Exit(1)
 			return
 		}
 

pkg/client/tunnel/tunnel.go

@@ -1,6 +1,7 @@
 package tunnel
 
 import (
+	"errors"
 	"fmt"
 	"io"
 	"net/http"
@@ -42,6 +43,7 @@ func Connect(url, address string) (*Tunnel, error) {
 	writeMutex := sync.Mutex{}
 
 	go func() {
+	X:
 		for {
 			var msg models.ServerMessage
 
@@ -146,6 +148,10 @@ func Connect(url, address string) (*Tunnel, error) {
 				if v, ok := t.activeRequests[msg.RequestID]; ok {
 					v.Write(msg.Data)
 				}
+			case "error":
+				c.Close()
+				closeChan <- errors.New(msg.Error)
+				break X
 			}
 		}
 	}()

pkg/models/models.go

@@ -23,6 +23,7 @@ type ServerMessage struct {
 	Subdomain string  `msgpack:"subdomain"`
 	Request   Request `msgpack:"request"`
 	Data      []byte  `msgpack:"data"`
+	Error     string  `msg:"error"`
 }
 
 // Represents a message passed from the client to the server