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blog.go
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blog.go
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package main
import (
"encoding/json"
"github.com/simonz05/godis"
"html/template"
"log"
"net/http"
"strconv"
"time"
)
type BlogEntry struct {
Title string
Body []byte
Date int64
}
type BlogStruct struct {
Name string
Author string
Email string
Entries []BlogEntry
}
var (
client *godis.Client
blog BlogStruct = BlogStruct{Name: "Stanley's Blog", Author: "stanley", Email: "stanley.w.cai@gmail.com"}
)
const (
blogPrefix = "/blog/view/"
)
func (b *BlogStruct) add(entry BlogEntry) error {
key := strconv.FormatInt(time.Now().Unix(), 10)
value, err := json.Marshal(entry)
// log.Printf("entry %v value %v\n", entry, value)
if err != nil {
return err
}
if ok, err := client.Hset("blog", key, value); !ok && err != nil {
return err
}
// TODO This implementation is dirty. Optimize this.
// reload all blog entries
return b.loadAll()
}
func (b *BlogStruct) addNewEntries() error {
// clean up the database at first
client.Flushdb()
entry := BlogEntry{"hello, world", []byte("hello, go world"), time.Now().Unix()}
if err := b.add(entry); err != nil {
return err
}
// sleep 2 seconds to make sure two different items are added
time.Sleep(1 * 1e9)
entry = BlogEntry{"hello again", []byte("hello, GO world"), time.Now().Unix()}
if err := b.add(entry); err != nil {
return err
}
return nil
}
func (b *BlogStruct) loadAll() error {
actual, err := client.Hkeys("blog")
if err != nil {
// log error msg and return
// log.Printf("failed to invoke Hkeys(blog) %v\n", actual)
return err
}
keys := make([]int64, len(actual))
for i, key := range actual {
keys[i], err = strconv.ParseInt(key, 10, 0)
if err != nil {
// log err message and continue
log.Printf("failed to convert key(%v) into int64\n", key)
keys[i] = 0
}
}
// TODO: need sort the keys at first
b.Entries = make([]BlogEntry, len(keys))
for i, strKey := range actual {
// JSON string to blogStruct
value, err := client.Hget("blog", strKey)
if err != nil {
// log error message and continue
log.Printf("failed to hget(blog, %v)\n", strKey)
continue
}
err = json.Unmarshal(value.Bytes(), &b.Entries[i])
if err != nil {
// log error message and continue
log.Printf("failed to unmarshal JSON %v\n", value)
}
}
// Done
return nil
}
func blogIndex(w http.ResponseWriter, r *http.Request) error {
defer func() {
if _, ok := recover().(error); ok {
// go error.html
log.Println("failed")
}
}()
if blog.Entries == nil {
if err := blog.loadAll(); err != nil {
return err
}
}
t, err := template.ParseFiles("template/index.tmpl")
if err != nil {
return err
}
return t.Execute(w, blog)
}
func viewBlogEntry(w http.ResponseWriter, r *http.Request) error {
id := r.URL.Path[len(blogPrefix):]
if blog.Entries == nil {
if err := blog.loadAll(); err != nil {
return err
}
}
p, err := strconv.ParseInt(id, 10, 0)
if err != nil {
p = 0
return err
}
var entry BlogEntry
for _, e := range blog.Entries {
if e.Date == p {
entry = e
break
}
}
t, err := template.ParseFiles("template/view.tmpl")
if err != nil {
return err
}
return t.Execute(w, entry)
}
func editBlogEntry(w http.ResponseWriter, r *http.Request) error {
http.Error(w, "not implemented", 500)
return nil
}
// A method's receiver is a function. This implementation is confusing
// changed to a closure.
/*
func (fn appHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
if err := fn(w, r); err != nil {
http.Error(w, err.Error(), 500)
}
}
*/
type appHandler func(http.ResponseWriter, *http.Request) error
func ServeHTTP(fn appHandler) func(http.ResponseWriter, *http.Request) {
return func(w http.ResponseWriter, r *http.Request) {
if err := fn(w, r); err != nil {
http.Error(w, err.Error(), 500)
}
}
}
func main() {
client = godis.New("", 0, "")
blog.addNewEntries()
http.Handle("/", http.FileServer(http.Dir("www")))
http.Handle("/static", http.FileServer(http.Dir("static")))
http.HandleFunc("/blog/", ServeHTTP(blogIndex))
http.HandleFunc("/blog/view/", ServeHTTP(viewBlogEntry))
http.HandleFunc("/blog/edit/", ServeHTTP(editBlogEntry))
http.ListenAndServe(":8080", nil)
}