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