kataras / Neffos

Server

import (
    // [...]
    "github.com/kataras/neffos"
    "github.com/kataras/neffos/gorilla"
)

func runServer() {
    events := make(neffos.Namespaces)
    events.On("/v1", "workday", func(ns *neffos.NSConn, msg neffos.Message) error {
        date := string(msg.Body)

        t, err := time.Parse("01-02-2006", date)
        if err != nil {
            if n := ns.Conn.Increment("tries"); n >= 3 && n%3 == 0 {
                // Return custom error text to the client.
                return fmt.Errorf("Why not try this one? 06-24-2019")
            } else if n >= 6 && n%2 == 0 {
                // Fire the "notify" client event.
                ns.Emit("notify", []byte("What are you doing?"))
            }
            // Return the parse error back to the client.
            return err
        }

        weekday := t.Weekday()

        if weekday == time.Saturday || weekday == time.Sunday {
            return neffos.Reply([]byte("day off"))
        }

        // Reply back to the client.
        responseText := fmt.Sprintf("it's %s, do your job.", weekday)
        return neffos.Reply([]byte(responseText))
    })

    websocketServer := neffos.New(gorilla.DefaultUpgrader, events)

    // Fire the "/v1:notify" event to all clients after server's 1 minute.
    time.AfterFunc(1*time.Minute, func() {
        websocketServer.Broadcast(nil, neffos.Message{
            Namespace: "/v1",
            Event:     "notify",
            Body:      []byte("server is up and running for 1 minute"),
        })
    })

    router := http.NewServeMux()
    router.Handle("/", websocketServer)

    log.Println("Serving websockets on localhost:8080")
    log.Fatal(http.ListenAndServe(":8080", router))
}

Go Client

func runClient() {
    ctx := context.TODO()
    events := make(neffos.Namespaces)
    events.On("/v1", "notify", func(c *neffos.NSConn, msg neffos.Message) error {
        log.Printf("Server says: %s\n", string(msg.Body))
        return nil
    })

    // Connect to the server.
    client, err := neffos.Dial(ctx,
        gorilla.DefaultDialer,
        "ws://localhost:8080",
        events)
    if err != nil {
        panic(err)
    }

    // Connect to a namespace.
    c, err := client.Connect(ctx, "/v1")
    if err != nil {
        panic(err)
    }

    fmt.Println("Please specify a date of format: mm-dd-yyyy")

    for {
        fmt.Print(">> ")
        var date string
        fmt.Scanf("%s", &date)

        // Send to the server and wait reply to this message.
        response, err := c.Ask(ctx, "workday", []byte(date))
        if err != nil {
            if neffos.IsCloseError(err) {
                // Check if the error is a close signal,
                // or make use of the `<- client.NotifyClose`
                // read-only channel instead.
                break
            }

            // >> 13-29-2019
            // error received: parsing time "13-29-2019": month out of range
            fmt.Printf("error received: %v\n", err)
            continue
        }

        // >> 06-29-2019
        // it's a day off!
        //
        // >> 06-24-2019
        // it's Monday, do your job.
        fmt.Println(string(response.Body))
    }
}

Javascript Client

Navigate to: https://github.com/kataras/neffos.js