netramesh

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// Copyright 2009 The Go 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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// +build ignore
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package main
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import (
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	"bytes"
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	"expvar"
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	"flag"
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	"fmt"
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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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	"strconv"
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	"sync"
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)
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// hello world, the web server
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var helloRequests = expvar.NewInt("hello-requests")
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func HelloServer(w http.ResponseWriter, req *http.Request) {
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	helloRequests.Add(1)
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	io.WriteString(w, "hello, world!\n")
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}
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// Simple counter server. POSTing to it will set the value.
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type Counter struct {
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	mu sync.Mutex // protects n
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	n  int
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}
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// This makes Counter satisfy the expvar.Var interface, so we can export
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// it directly.
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func (ctr *Counter) String() string {
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	ctr.mu.Lock()
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	defer ctr.mu.Unlock()
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	return fmt.Sprintf("%d", ctr.n)
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}
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func (ctr *Counter) ServeHTTP(w http.ResponseWriter, req *http.Request) {
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	ctr.mu.Lock()
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	defer ctr.mu.Unlock()
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	switch req.Method {
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	case "GET":
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		ctr.n++
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	case "POST":
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		buf := new(bytes.Buffer)
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		io.Copy(buf, req.Body)
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		body := buf.String()
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		if n, err := strconv.Atoi(body); err != nil {
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			fmt.Fprintf(w, "bad POST: %v\nbody: [%v]\n", err, body)
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		} else {
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			ctr.n = n
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			fmt.Fprint(w, "counter reset\n")
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		}
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	}
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	fmt.Fprintf(w, "counter = %d\n", ctr.n)
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}
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// simple flag server
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var booleanflag = flag.Bool("boolean", true, "another flag for testing")
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func FlagServer(w http.ResponseWriter, req *http.Request) {
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	w.Header().Set("Content-Type", "text/plain; charset=utf-8")
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	fmt.Fprint(w, "Flags:\n")
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	flag.VisitAll(func(f *flag.Flag) {
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		if f.Value.String() != f.DefValue {
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			fmt.Fprintf(w, "%s = %s [default = %s]\n", f.Name, f.Value.String(), f.DefValue)
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		} else {
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			fmt.Fprintf(w, "%s = %s\n", f.Name, f.Value.String())
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		}
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	})
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}
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// simple argument server
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func ArgServer(w http.ResponseWriter, req *http.Request) {
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	for _, s := range os.Args {
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		fmt.Fprint(w, s, " ")
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	}
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}
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// a channel (just for the fun of it)
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type Chan chan int
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func ChanCreate() Chan {
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	c := make(Chan)
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	go func(c Chan) {
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		for x := 0; ; x++ {
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			c <- x
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		}
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	}(c)
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	return c
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}
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func (ch Chan) ServeHTTP(w http.ResponseWriter, req *http.Request) {
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	io.WriteString(w, fmt.Sprintf("channel send #%d\n", <-ch))
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}
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// exec a program, redirecting output
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func DateServer(rw http.ResponseWriter, req *http.Request) {
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	rw.Header().Set("Content-Type", "text/plain; charset=utf-8")
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	date, err := exec.Command("/bin/date").Output()
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	if err != nil {
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		http.Error(rw, err.Error(), http.StatusInternalServerError)
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		return
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	}
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	rw.Write(date)
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}
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func Logger(w http.ResponseWriter, req *http.Request) {
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	log.Print(req.URL)
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	http.Error(w, "oops", http.StatusNotFound)
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}
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var webroot = flag.String("root", os.Getenv("HOME"), "web root directory")
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func main() {
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	flag.Parse()
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	// The counter is published as a variable directly.
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	ctr := new(Counter)
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	expvar.Publish("counter", ctr)
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	http.Handle("/counter", ctr)
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	http.Handle("/", http.HandlerFunc(Logger))
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	http.Handle("/go/", http.StripPrefix("/go/", http.FileServer(http.Dir(*webroot))))
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	http.Handle("/chan", ChanCreate())
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	http.HandleFunc("/flags", FlagServer)
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	http.HandleFunc("/args", ArgServer)
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	http.HandleFunc("/go/hello", HelloServer)
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	http.HandleFunc("/date", DateServer)
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	log.Fatal(http.ListenAndServe(":12345", nil))
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}
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