gocui_net.go

package main

import (
	"fmt"
	"io"
	"log"
	"net"
	"os"

	"github.com/jroimartin/gocui"
)

func main() {
	if len(os.Args) != 2 {
		fmt.Fprintln(os.Stderr, "usage: net addr:port")
		os.Exit(2)
	}
	addr := os.Args[1]

	g, err := gocui.NewGui(gocui.OutputNormal)
	if err != nil {
		log.Fatalln(err)
	}
	defer g.Close()

	g.SetManagerFunc(layout)

	if err := initKeybindings(g); err != nil {
		log.Fatalln(err)
	}

	go listenAndDump(g, addr)

	if err := g.MainLoop(); err != nil && err != gocui.ErrQuit {
		log.Panicln(err)
	}
}

func layout(g *gocui.Gui) error {
	maxX, maxY := g.Size()

	if v, err := g.SetView("legend", maxX-23, 0, maxX-1, 5); err != nil {
		if err != gocui.ErrUnknownView {
			return err
		}
		fmt.Fprintln(v, "KEYBINDINGS")
		fmt.Fprintln(v, "↑ ↓: Seek memory")
		fmt.Fprintln(v, "A: Enable autoscroll")
		fmt.Fprintln(v, "^C: Exit")
	}

	if v, err := g.SetView("net", 0, 0, maxX-24, maxY-1); err != nil {
		if err != gocui.ErrUnknownView {
			return err
		}
		if _, err := g.SetCurrentView("net"); err != nil {
			return err
		}
		v.Wrap = true
		v.Autoscroll = true
	}

	return nil
}

func initKeybindings(g *gocui.Gui) error {
	if err := g.SetKeybinding("", gocui.KeyCtrlC, gocui.ModNone,
		func(g *gocui.Gui, v *gocui.View) error {
			return gocui.ErrQuit
		}); err != nil {
		return err
	}
	if err := g.SetKeybinding("net", 'a', gocui.ModNone,
		func(g *gocui.Gui, v *gocui.View) error {
			v.Autoscroll = true
			return nil
		}); err != nil {
		return err
	}
	if err := g.SetKeybinding("net", gocui.KeyArrowUp, gocui.ModNone,
		func(g *gocui.Gui, v *gocui.View) error {
			scrollView(v, -1)
			return nil
		}); err != nil {
		return err
	}
	if err := g.SetKeybinding("net", gocui.KeyArrowDown, gocui.ModNone,
		func(g *gocui.Gui, v *gocui.View) error {
			scrollView(v, 1)
			return nil
		}); err != nil {
		return err
	}
	return nil
}

func scrollView(v *gocui.View, dy int) error {
	if v != nil {
		v.Autoscroll = false
		ox, oy := v.Origin()
		if err := v.SetOrigin(ox, oy+dy); err != nil {
			return err
		}
	}
	return nil
}

func listenAndDump(g *gocui.Gui, addr string) error {
	ln, err := net.Listen("tcp", addr)
	if err != nil {
		return err
	}
	for {
		conn, err := ln.Accept()
		if err != nil {
			return err
		}
		go g.Update(func(g *gocui.Gui) error {
			return handleConn(g, conn)
		})
	}
	return nil
}

func handleConn(g *gocui.Gui, conn net.Conn) error {
	defer conn.Close()

	v, err := g.View("net")
	if err != nil {
		return err
	}
	fmt.Fprintf(v, "Connection from %v:\n", conn.RemoteAddr())
	if _, err := io.Copy(v, conn); err != nil {
		return err
	}
	fmt.Fprintf(v, "---------\n")
	return nil
}