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go/doc/codelab/wiki/final-parsetemplate.go
Rob Pike f56db6f534 text/template: new, simpler API
The Set type is gone. Instead, templates are automatically associated by
being parsed together; nested definitions implicitly create associations.
Only associated templates can invoke one another.

This approach dramatically reduces the breadth of the construction API.

For now, html/template is deleted from src/pkg/Makefile, so this can
be checked in. Nothing in the tree depends on it. It will be updated next.

R=dsymonds, adg, rsc, r, gri, mikesamuel, nigeltao
CC=golang-dev
https://golang.org/cl/5415060
2011-11-23 20:17:22 -08:00

90 lines
2.0 KiB
Go

package main
import (
"io/ioutil"
"net/http"
"regexp"
"text/template"
)
type Page struct {
Title string
Body []byte
}
func (p *Page) save() error {
filename := p.Title + ".txt"
return ioutil.WriteFile(filename, p.Body, 0600)
}
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 viewHandler(w http.ResponseWriter, r *http.Request, title string) {
p, err := loadPage(title)
if err != nil {
http.Redirect(w, r, "/edit/"+title, http.StatusFound)
return
}
renderTemplate(w, "view", p)
}
func editHandler(w http.ResponseWriter, r *http.Request, title string) {
p, err := loadPage(title)
if err != nil {
p = &Page{Title: title}
}
renderTemplate(w, "edit", p)
}
func saveHandler(w http.ResponseWriter, r *http.Request, title string) {
body := r.FormValue("body")
p := &Page{Title: title, Body: []byte(body)}
err := p.save()
if err != nil {
http.Error(w, err.Error(), http.StatusInternalServerError)
return
}
http.Redirect(w, r, "/view/"+title, http.StatusFound)
}
func renderTemplate(w http.ResponseWriter, tmpl string, p *Page) {
t, err := template.ParseFiles(tmpl+".html", nil)
if err != nil {
http.Error(w, err.Error(), http.StatusInternalServerError)
return
}
err = t.Execute(w, p)
if err != nil {
http.Error(w, err.Error(), http.StatusInternalServerError)
}
}
const lenPath = len("/view/")
var titleValidator = regexp.MustCompile("^[a-zA-Z0-9]+$")
func makeHandler(fn func(http.ResponseWriter, *http.Request, string)) http.HandlerFunc {
return func(w http.ResponseWriter, r *http.Request) {
title := r.URL.Path[lenPath:]
if !titleValidator.MatchString(title) {
http.NotFound(w, r)
return
}
fn(w, r, title)
}
}
func main() {
http.HandleFunc("/view/", makeHandler(viewHandler))
http.HandleFunc("/edit/", makeHandler(editHandler))
http.HandleFunc("/save/", makeHandler(saveHandler))
http.ListenAndServe(":8080", nil)
}