，一 go 实现的基于REST的Web服务

参考： 《Go Web 编程》

1. go 实现的基于REST的Web服务

// webserver project server.go
package main

import (
        "encoding/json"
        "fmt"
        "net/http"
        //"strconv"
)

type Post struct {
        Id      int    `json:"id"`
        Content string `jsong:"content"`
        Author  string
}

// 全局变量，用来保存post
var posts []Post

func (post *Post) create() (err error) {
        posts = append(posts, *post)
        return
}

func (post *Post) delete() (err error) {
        for pos, p := range posts {
                if p.Id == post.Id {
                        posts[pos] = posts[len(posts)-1]
                        posts = posts[:len(posts)-1]
                        return
                }
        }
        return
}

func main() {
        fmt.Print("start the web server")

        server := http.Server{
                Addr: "127.0.0.1:8080",
        }

        http.HandleFunc("/CRUD/", handleRequest)
        server.ListenAndServe()
}

func handleRequest(w http.ResponseWriter, r *http.Request) {
        var err error
        switch r.Method {
        case "GET":
                err = handleGet(w, r)
        case "POST":
                err = handlePost(w, r)
        case "PUT":
                err = handlePut(w, r)
        case "DELETE":
                err = handleDelete(w, r)
        }

        if err != nil {
                http.Error(w, err.Error(), http.StatusInternalServerError)
                return
        }
}

func handleGet(w http.ResponseWriter, r *http.Request) (err error) {
        // return posts value
        result, err := json.Marshal(posts)
        if err != nil {
                w.WriteHeader(201)
                return
        }
        w.Write([]byte(result))
        return
}

func handlePost(w http.ResponseWriter, r *http.Request) (err error) {
        // read post data
        len := r.ContentLength
        body := make([]byte, len)
        r.Body.Read(body)

        // parse body to post
        var post Post
        err = json.Unmarshal(body, &post)
        if err != nil {
                w.Write([]byte("parse json failed\n"))
                return
        }
        // save post value to database or somewhere.
        post.create()

        // return posts value
        result, err := json.Marshal(posts)
        if err != nil {
                w.WriteHeader(201)
                return
        }
        w.Write([]byte(result))

        w.WriteHeader(200)
        return
}

func handlePut(w http.ResponseWriter, r *http.Request) (err error) {
        w.Write([]byte("handlePut()"))
        return
}

func handleDelete(w http.ResponseWriter, r *http.Request) (err error) {
        // read post data
        len := r.ContentLength
        body := make([]byte, len)
        r.Body.Read(body)

        // parse body to post
        var post Post
        err = json.Unmarshal(body, &post)
        if err != nil {
                w.Write([]byte("parse json failed\n"))
                return
        }
        // save post value to database or somewhere.
        post.delete()

        // return posts value
        result, err := json.Marshal(posts)
        if err != nil {
                w.WriteHeader(201)
                return
        }
        w.Write([]byte(result))

        //      var result string
        //      result = strconv.Itoa(post.Id)
        //      w.Write([]byte(result))

        w.WriteHeader(200)
        return
}