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@@ -0,0 +1,156 @@
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+// Copyright 2015 The Gorilla WebSocket Authors. All rights reserved.
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+// Use of this source code is governed by a BSD-style
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+// license that can be found in the LICENSE file.
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+
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+package main
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+
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+import (
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+ "bufio"
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+ "flag"
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+ "io"
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+ "log"
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+ "net/http"
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+ "os"
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+ "os/exec"
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+ "text/template"
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+ "time"
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+
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+ "github.com/gorilla/websocket"
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+)
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+
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+var (
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+ addr = flag.String("addr", "127.0.0.1:8080", "http service address")
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+ homeTempl = template.Must(template.ParseFiles("home.html"))
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+)
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+
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+const (
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+ // Time allowed to write a message to the peer.
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+ writeWait = 10 * time.Second
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+
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+ // Maximum message size allowed from peer.
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+ maxMessageSize = 8192
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+)
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+
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+// connection is an middleman between the websocket connection and the command.
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+type connection struct {
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+ ws *websocket.Conn
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+ stdout io.ReadCloser
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+ stdin io.WriteCloser
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+ cmd *exec.Cmd
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+}
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+
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+func (c *connection) pumpStdin() {
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+ defer c.ws.Close()
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+ c.ws.SetReadLimit(maxMessageSize)
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+ for {
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+ _, message, err := c.ws.ReadMessage()
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+ if err != nil {
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+ break
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+ }
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+ message = append(message, '\n')
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+ if _, err := c.stdin.Write(message); err != nil {
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+ break
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+ }
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+ }
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+ c.stdin.Close()
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+ log.Println("exit stdin pump")
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+}
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+
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+func (c *connection) pumpStdout() {
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+ defer c.ws.Close()
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+ s := bufio.NewScanner(c.stdout)
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+ for s.Scan() {
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+ c.ws.SetWriteDeadline(time.Now().Add(writeWait))
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+ if err := c.ws.WriteMessage(websocket.TextMessage, s.Bytes()); err != nil {
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+ break
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+ }
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+ }
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+ if s.Err() != nil {
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+ log.Println("scan:", s.Err())
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+ }
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+ c.stdout.Close()
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+ log.Println("exit stdout pump")
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+}
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+
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+func internalError(ws *websocket.Conn, fmt string, err error) {
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+ log.Println(fmt, err)
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+ ws.WriteMessage(websocket.TextMessage, []byte("Internal server error."))
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+}
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+
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+var upgrader = websocket.Upgrader{}
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+
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+func serveWs(w http.ResponseWriter, r *http.Request) {
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+ if r.Method != "GET" {
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+ http.Error(w, "Method not allowed", http.StatusMethodNotAllowed)
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+ return
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+ }
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+
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+ ws, err := upgrader.Upgrade(w, r, nil)
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+ if err != nil {
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+ log.Println(err)
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+ return
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+ }
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+
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+ c := &connection{
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+ cmd: exec.Command(flag.Args()[0], flag.Args()[1:]...),
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+ ws: ws,
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+ }
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+
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+ c.stdout, err = c.cmd.StdoutPipe()
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+ if err != nil {
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+ internalError(ws, "stdout: %v", err)
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+ ws.Close()
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+ return
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+ }
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+
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+ c.stdin, err = c.cmd.StdinPipe()
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+ if err != nil {
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+ internalError(ws, "stdin: %v", err)
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+ c.stdout.Close()
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+ if closer, ok := c.cmd.Stdout.(io.Closer); ok {
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+ closer.Close()
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+ }
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+ ws.Close()
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+ return
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+ }
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+
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+ if err := c.cmd.Start(); err != nil {
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+ internalError(ws, "start: %v", err)
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+ c.stdout.Close()
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+ c.stdin.Close()
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+ ws.Close()
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+ return
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+ }
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+
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+ go c.pumpStdout()
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+ c.pumpStdin()
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+
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+ c.cmd.Process.Signal(os.Interrupt)
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+ if err := c.cmd.Wait(); err != nil {
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+ log.Println("wait:", err)
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+ }
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+ log.Println("exit serveWs")
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+}
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+
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+func serveHome(w http.ResponseWriter, r *http.Request) {
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+ if r.URL.Path != "/" {
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+ http.Error(w, "Not found", 404)
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+ return
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+ }
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+ if r.Method != "GET" {
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+ http.Error(w, "Method not allowed", 405)
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+ return
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+ }
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+ w.Header().Set("Content-Type", "text/html; charset=utf-8")
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+ homeTempl.Execute(w, r.Host)
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+}
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+
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+func main() {
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+ flag.Parse()
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+ if len(flag.Args()) < 1 {
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+ log.Fatal("must specify at least one argument")
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+ }
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+ http.HandleFunc("/", serveHome)
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+ http.HandleFunc("/ws", serveWs)
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+ log.Fatal(http.ListenAndServe(*addr, nil))
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+}
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Gary Burd