framing's Introduction

framing

Framing provides a prefix length framed net.Conn connection. This is useful if you have connections that send packages that are prefixed with 1, 2 or 4 bytes of message length before the actual data.

Example

package main

import (
    "encoding/binary"
    "fmt"
    "log"
    "net"
    "strconv"

    "github.com/eproxus/framing"
)

const prefixLength = 4

var endianess = binary.BigEndian

func main() {
    message := "13 bytes long"

    l, err := net.Listen("tcp", ":0") // Listen on localhost, random port
    if err != nil {
        log.Fatal(err)
    }
    defer l.Close()

    port := l.Addr().(*net.TCPAddr).Port

    // Send message in a go routine
    go func() {
        conn, err := net.Dial("tcp", ":"+strconv.Itoa(port))
        if err != nil {
            log.Fatal(err)
        }

        framed, err := framing.NewConn(conn, prefixLength, endianess)
        if err != nil {
            log.Fatal(err)
        }
        defer framed.Close()

        if _, err := fmt.Fprintf(framed, message); err != nil {
            log.Fatal(err)
        }
    }()

    conn, err := l.Accept()
    if err != nil {
        log.Fatal(err)
    }

    framed, err := framing.NewConn(conn, prefixLength, endianess)
    if err != nil {
        log.Fatal(err)
    }
    defer framed.Close()

    // Receive message
    frame, err := framed.ReadFrame()
    if err != nil {
        log.Fatal(err)
    }

    fmt.Printf("Recieved \"%v\"\n", string(frame[:13]))
}

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