examples: Add chat example that also doesn't work properly yet

examples/chat/client/main.go

@@ -0,0 +1,102 @@
+package main
+
+import "os"
+import "fmt"
+import "time"
+import "bufio"
+import "context"
+import "crypto/tls"
+import "git.tebibyte.media/sashakoshka/hopp"
+import "git.tebibyte.media/sashakoshka/hopp/examples/chat"
+
+func main() {
+	name := os.Args[0]
+	if len(os.Args) != 3 && len(os.Args) != 4 {
+		fmt.Fprintf(os.Stderr, "Usage: %s HOST:PORT ROOM [NICKNAME]\n", name)
+		os.Exit(2)
+	}
+	address := os.Args[1]
+	room    := os.Args[2]
+	var nickname hopp.Option[string]; if len(os.Args) >= 4 {
+		nickname = hopp.O(os.Args[3])
+	}
+	trans, err := join(address, room, nickname)
+	handleErr(1, err)
+	go func() {
+		reader := bufio.NewReader(os.Stdin)
+		for {
+			line, err := reader.ReadString('\n')
+			if err != nil { break }
+			send(trans, line)
+		}
+	}()
+	for {
+		message, err := chat.Receive(trans)
+		handleErr(1, err)
+		switch message := message.(type) {
+		case *chat.MessageChat:
+			nickname := "Anonymous"
+			if value, ok := message.Nickname.Get(); ok {
+				nickname = value
+			}
+			fmt.Fprintf(os.Stdout, "%s: %s\n", nickname, message.Content)
+		case *chat.MessageJoinNotify:
+			fmt.Fprintf(os.Stdout, "(i) %s joined the room\n", message.Nickname)
+		case *chat.MessageLeaveNotify:
+			fmt.Fprintf(os.Stdout, "(i) %s left the room\n", message.Nickname)
+		}
+	}
+}
+
+func join(address string, room string, nickname hopp.Option[string]) (hopp.Trans, error) {
+	ctx, done := context.WithTimeout(context.Background(), 16 * time.Second)
+	defer done()
+	dialer := hopp.Dialer {
+		TLSConfig: &tls.Config {
+			// don't actually do this in real life
+			InsecureSkipVerify: true,
+		},
+	}
+	conn, err := dialer.Dial(ctx, "quic", address)
+	if err != nil { return nil, err }
+
+	err = updateProfile(conn, nickname)
+	if err != nil { return nil, err }
+	
+	transRoom, err := conn.OpenTrans()
+	if err != nil { return nil, err }
+	err = chat.Send(transRoom, &chat.MessageJoin {
+		Room: room,
+	})
+	if err != nil { return nil, err }
+	return transRoom, nil
+}
+
+func send(trans hopp.Trans, content string) error {
+	return chat.Send(trans, &chat.MessageChat {
+		Content: content,
+	})
+}
+
+func updateProfile(conn hopp.Conn, nickname hopp.Option[string]) error {
+	trans, err := conn.OpenTrans()
+	if err != nil { return err }
+	defer trans.Close()
+	err = chat.Send(trans, &chat.MessageUpdateProfile {
+		Nickname: nickname,
+	})
+	if err != nil { return err }
+	message, err := chat.Receive(trans)
+	if err != nil { return err }
+	switch message := message.(type) {
+	case *chat.MessageError: return message
+	default:                 return nil
+	}
+}
+
+func handleErr(code int, err error) {
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "%s: %v\n", os.Args[0], err)
+		os.Exit(code)
+	}
+}