HTTPサーバーの写経// http://www.slideshare.net/yasi_life/goweb-16448500

src__server.go

package main

import (
  "fmt"
  "net/http"
  "io/ioutil"
  "html/template"
)

type Page struct {
  Title string
  Body  []byte
}

func ( p *Page ) save() error {
  filename := p.Title + ".txt"
  fmt.Println( "Save", "Title:", p.Title, "filename:", filename, "Body:", string( p.Body ) )
  err := ioutil.WriteFile( filename, p.Body, 0600 )

  if err != nil {
    fmt.Println( err )
  }

  return err
}

func detectTitle( r *http.Request, path string ) string {
  title := r.URL.Path[ len( path ) : ]

  if title == "" {
    title = "index"
  }

  fmt.Println( "Title:", title )

  return title
}

func loadPage( title string ) ( *Page, error ) {
  filename := title + ".txt"
  body, err := ioutil.ReadFile( filename )

  if err != nil {
    return nil, err
  }

  return &Page{ Title: title, Body: body }, nil
}

func viewHandlerWithPath( w http.ResponseWriter, r *http.Request ) {
  viewHandler( w, r, "/view/" )
}

func viewHandlerWithoutPath( w http.ResponseWriter, r *http.Request ) {
  viewHandler( w, r, "/" )
}

func viewHandler( w http.ResponseWriter, r *http.Request, path string ) {
  title := detectTitle( r, path )
  p, err := loadPage( title )

  if err != nil {
    p = &Page{ Title: title, Body: []byte( "no content" ) }
  }

  t, err := template.ParseFiles( "views/view.html" )
  t.Execute( w, p )
}

func editHandler( w http.ResponseWriter, r *http.Request ) {
  title := detectTitle( r, "/edit/" )
  p, err := loadPage( title )

  if err != nil {
    p = &Page{ Title: title }
  }

  t, err := template.ParseFiles( "views/edit.html" )
  t.Execute( w, p )
}

func saveHandler( w http.ResponseWriter, r *http.Request ) {
  title := detectTitle( r, "/save/" )
  body  := r.FormValue( "body" )
  p := &Page{ Title: title, Body: []byte( body ) }
  p.save()
  http.Redirect( w, r, "/view/" + title, http.StatusFound )
}

func main() {
  http.HandleFunc( "/edit/", editHandler )
  http.HandleFunc( "/save/", saveHandler )
  http.HandleFunc( "/view/", viewHandlerWithPath )
  http.HandleFunc( "/",      viewHandlerWithoutPath )
  http.ListenAndServe( "localhost:8080", nil )
}

views__edit.html

<h1>Editing {{ .Title }}</h1>
<form action="/save/{{ .Title }}" method="POST">
  <div>
    <textarea name="body" rows="50" cols="80">{{ printf "%s" .Body }}</textarea>
  </div>
  <div>
    <input type="submit" value="Save" />
  </div>
</form>

views__view.html

<h1>{{ .Title }}</h1>
<p>[<a href="/edit/{{ .Title }}">edit</a>]</p>
<div><pre>{{ printf "%s" .Body }}</pre></div>