Go Client Connect to an URL with Socket

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I'm newbie in Go. I have a server run FastAPI Python. I have already run websocket request in 127.0.0.1:8000/register.

@app.websocket("/register")
async def websocket_endpoint(websocket: WebSocket):
    await websocket.accept()
    while True:
        data = await websocket.receive_text()
        await websocket.send_text(f"Message text was: {data}")

I want to create an app work as a client by Go. This app use socket connect to this URL and send info to create account. But when I try to use example code in google:

package main

import "net"
import "fmt"
import "bufio"
import "os"
import "log"

func main() {
  // connect to server
  conn, err := net.Dial("tcp", "127.0.0.1:8000/register")
  if err != nil {
    log.Println(err)
}
  for { 
    // what to send?
    reader := bufio.NewReader(os.Stdin)
    fmt.Print("Text to send: ")
    text, err := reader.ReadString('\n')
    if err != nil {
        log.Println(err)
    }
    // send to server
    fmt.Fprintf(conn, text + "\n")
    // wait for reply
    message, err := bufio.NewReader(conn).ReadString('\n')
    if err != nil {
        log.Println(err)
    }
    fmt.Print("Message from server: "+message)
  }
}

It's not working because of dial tcp: lookup tcp/8000/register: getaddrinfow: The specified class was not found

As I understand that it cannot lookup for this link, it only lookups when it's a IP Address. How can I create a Socket request to an URL?

fastapi go sockets websocket python
1 Answers

use github.com/gorilla/websocket example:

package main

import (
    "flag"
    "log"
    "net/url"
    "os"
    "os/signal"
    "time"

    "github.com/gorilla/websocket"
)

var addr = flag.String("addr", "127.0.0.1:8080", "http service address")

func main() {
    flag.Parse()
    log.SetFlags(0)

    interrupt := make(chan os.Signal, 1)
    signal.Notify(interrupt, os.Interrupt)

    u := url.URL{Scheme: "ws", Host: *addr, Path: "/register"}
    log.Printf("connecting to %s", u.String())

    c, _, err := websocket.DefaultDialer.Dial(u.String(), nil)
    if err != nil {
        log.Fatal("dial:", err)
    }
    defer c.Close()

    done := make(chan struct{})

    go func() {
        defer close(done)
        for {
            _, message, err := c.ReadMessage()
            if err != nil {
                log.Println("read:", err)
                return
            }
            log.Printf("recv: %s", message)
        }
    }()

    ticker := time.NewTicker(time.Second)
    defer ticker.Stop()

    for {
        select {
        case <-done:
            return
        case t := <-ticker.C:
            err := c.WriteMessage(websocket.TextMessage, []byte(t.String()))
            if err != nil {
                log.Println("write:", err)
                return
            }
        case <-interrupt:
            log.Println("interrupt")

            // Cleanly close the connection by sending a close message and then
            // waiting (with timeout) for the server to close the connection.
            err := c.WriteMessage(websocket.CloseMessage, websocket.FormatCloseMessage(websocket.CloseNormalClosure, ""))
            if err != nil {
                log.Println("write close:", err)
                return
            }
            select {
            case <-done:
            case <-time.After(time.Second):
            }
            return
        }
    }
}

or nhooyr.io/websocket - is a minimal and idiomatic WebSocket library for Go https://github.com/nhooyr/websocket

ctx, cancel := context.WithTimeout(context.Background(), time.Minute)
defer cancel()

c, _, err := websocket.Dial(ctx, "ws://localhost:8080/register", nil)
if err != nil {
    // ...
}
defer c.Close(websocket.StatusInternalError, "the sky is falling")
user_77948400
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