| // 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. |
| |
| package main |
| |
| import ( |
| "bytes" |
| "expvar" |
| "flag" |
| "fmt" |
| "http" |
| "io" |
| "log" |
| "os" |
| "strconv" |
| ) |
| |
| |
| // 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 { |
| n int |
| } |
| |
| // This makes Counter satisfy the expvar.Var interface, so we can export |
| // it directly. |
| func (ctr *Counter) String() string { return fmt.Sprintf("%d", ctr.n) } |
| |
| func (ctr *Counter) ServeHTTP(w http.ResponseWriter, req *http.Request) { |
| switch req.Method { |
| case "GET": |
| ctr.n++ |
| case "POST": |
| buf := new(bytes.Buffer) |
| 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.SetHeader("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.SetHeader("content-type", "text/plain; charset=utf-8") |
| r, w, err := os.Pipe() |
| if err != nil { |
| fmt.Fprintf(rw, "pipe: %s\n", err) |
| return |
| } |
| pid, err := os.ForkExec("/bin/date", []string{"date"}, os.Environ(), "", []*os.File{nil, w, w}) |
| defer r.Close() |
| w.Close() |
| if err != nil { |
| fmt.Fprintf(rw, "fork/exec: %s\n", err) |
| return |
| } |
| io.Copy(rw, r) |
| wait, err := os.Wait(pid, 0) |
| if err != nil { |
| fmt.Fprintf(rw, "wait: %s\n", err) |
| return |
| } |
| if !wait.Exited() || wait.ExitStatus() != 0 { |
| fmt.Fprintf(rw, "date: %v\n", wait) |
| return |
| } |
| } |
| |
| func Logger(w http.ResponseWriter, req *http.Request) { |
| log.Print(req.URL.Raw) |
| w.WriteHeader(404) |
| w.Write([]byte("oops")) |
| } |
| |
| |
| var webroot = flag.String("root", "/home/rsc", "web root directory") |
| |
| func main() { |
| flag.Parse() |
| |
| // The counter is published as a variable directly. |
| ctr := new(Counter) |
| http.Handle("/counter", ctr) |
| expvar.Publish("counter", ctr) |
| |
| http.Handle("/", http.HandlerFunc(Logger)) |
| http.Handle("/go/", http.FileServer(*webroot, "/go/")) |
| http.Handle("/flags", http.HandlerFunc(FlagServer)) |
| http.Handle("/args", http.HandlerFunc(ArgServer)) |
| http.Handle("/go/hello", http.HandlerFunc(HelloServer)) |
| http.Handle("/chan", ChanCreate()) |
| http.Handle("/date", http.HandlerFunc(DateServer)) |
| err := http.ListenAndServe(":12345", nil) |
| if err != nil { |
| log.Panicln("ListenAndServe:", err) |
| } |
| } |