triv.go

Documentation: net/http

     1  // Copyright 2009 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  //go:build ignore
     6  // +build ignore
     7  
     8  package main
     9  
    10  import (
    11  	"bytes"
    12  	"expvar"
    13  	"flag"
    14  	"fmt"
    15  	"io"
    16  	"log"
    17  	"net/http"
    18  	"os"
    19  	"os/exec"
    20  	"strconv"
    21  	"sync"
    22  )
    23  
    24  // hello world, the web server
    25  var helloRequests = expvar.NewInt("hello-requests")
    26  
    27  func HelloServer(w http.ResponseWriter, req *http.Request) {
    28  	helloRequests.Add(1)
    29  	io.WriteString(w, "hello, world!\n")
    30  }
    31  
    32  // Simple counter server. POSTing to it will set the value.
    33  type Counter struct {
    34  	mu sync.Mutex // protects n
    35  	n  int
    36  }
    37  
    38  // This makes Counter satisfy the expvar.Var interface, so we can export
    39  // it directly.
    40  func (ctr *Counter) String() string {
    41  	ctr.mu.Lock()
    42  	defer ctr.mu.Unlock()
    43  	return fmt.Sprintf("%d", ctr.n)
    44  }
    45  
    46  func (ctr *Counter) ServeHTTP(w http.ResponseWriter, req *http.Request) {
    47  	ctr.mu.Lock()
    48  	defer ctr.mu.Unlock()
    49  	switch req.Method {
    50  	case "GET":
    51  		ctr.n++
    52  	case "POST":
    53  		buf := new(bytes.Buffer)
    54  		io.Copy(buf, req.Body)
    55  		body := buf.String()
    56  		if n, err := strconv.Atoi(body); err != nil {
    57  			fmt.Fprintf(w, "bad POST: %v\nbody: [%v]\n", err, body)
    58  		} else {
    59  			ctr.n = n
    60  			fmt.Fprint(w, "counter reset\n")
    61  		}
    62  	}
    63  	fmt.Fprintf(w, "counter = %d\n", ctr.n)
    64  }
    65  
    66  // simple flag server
    67  var booleanflag = flag.Bool("boolean", true, "another flag for testing")
    68  
    69  func FlagServer(w http.ResponseWriter, req *http.Request) {
    70  	w.Header().Set("Content-Type", "text/plain; charset=utf-8")
    71  	fmt.Fprint(w, "Flags:\n")
    72  	flag.VisitAll(func(f *flag.Flag) {
    73  		if f.Value.String() != f.DefValue {
    74  			fmt.Fprintf(w, "%s = %s [default = %s]\n", f.Name, f.Value.String(), f.DefValue)
    75  		} else {
    76  			fmt.Fprintf(w, "%s = %s\n", f.Name, f.Value.String())
    77  		}
    78  	})
    79  }
    80  
    81  // simple argument server
    82  func ArgServer(w http.ResponseWriter, req *http.Request) {
    83  	for _, s := range os.Args {
    84  		fmt.Fprint(w, s, " ")
    85  	}
    86  }
    87  
    88  // a channel (just for the fun of it)
    89  type Chan chan int
    90  
    91  func ChanCreate() Chan {
    92  	c := make(Chan)
    93  	go func(c Chan) {
    94  		for x := 0; ; x++ {
    95  			c <- x
    96  		}
    97  	}(c)
    98  	return c
    99  }
   100  
   101  func (ch Chan) ServeHTTP(w http.ResponseWriter, req *http.Request) {
   102  	io.WriteString(w, fmt.Sprintf("channel send #%d\n", <-ch))
   103  }
   104  
   105  // exec a program, redirecting output
   106  func DateServer(rw http.ResponseWriter, req *http.Request) {
   107  	rw.Header().Set("Content-Type", "text/plain; charset=utf-8")
   108  
   109  	date, err := exec.Command("/bin/date").Output()
   110  	if err != nil {
   111  		http.Error(rw, err.Error(), http.StatusInternalServerError)
   112  		return
   113  	}
   114  	rw.Write(date)
   115  }
   116  
   117  func Logger(w http.ResponseWriter, req *http.Request) {
   118  	log.Print(req.URL)
   119  	http.Error(w, "oops", http.StatusNotFound)
   120  }
   121  
   122  var webroot = flag.String("root", os.Getenv("HOME"), "web root directory")
   123  
   124  func main() {
   125  	flag.Parse()
   126  
   127  	// The counter is published as a variable directly.
   128  	ctr := new(Counter)
   129  	expvar.Publish("counter", ctr)
   130  	http.Handle("/counter", ctr)
   131  	http.Handle("/", http.HandlerFunc(Logger))
   132  	http.Handle("/go/", http.StripPrefix("/go/", http.FileServer(http.Dir(*webroot))))
   133  	http.Handle("/chan", ChanCreate())
   134  	http.HandleFunc("/flags", FlagServer)
   135  	http.HandleFunc("/args", ArgServer)
   136  	http.HandleFunc("/go/hello", HelloServer)
   137  	http.HandleFunc("/date", DateServer)
   138  	log.Fatal(http.ListenAndServe(":12345", nil))
   139  }
   140
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