In this post, we will not only cover how to use Go to create a RESTful JSON API, but we will also talk about good RESTful design.
部分内容删减调整，原文请查看： Making a RESTful JSON API in Go,2014Nov
Author:CORY LANOU:a full stack technologist who has specialized in start-ups for the last 17 years. I'm currently working at InfluxDB on their core data team. I also help lead and organizer several community technology meetups and do Go training.
What is a JSON API?
JSON API 是数据交互规范，用以定义客户端如何获取与修改资源，以及服务器如何响应对应请求。JSON API设计用来最小化请求的数量，以及客户端与服务器间传输的数据量。通过遵循共同的约定，可以提高开发效率，利用更普遍的工具,基于 JSON API 的客户端还能够充分利用缓存，以提升性能。(更多：http://jsonapi.org.cn/format/)。
示例：
{
"links": {
"posts.author": {
"href": "http://example.com/people/{posts.author}",
"type": "people"
},
"posts.comments": {
"href": "http://example.com/comments/{posts.comments}",
"type": "comments"
}
},
"posts": [{
"id": "1",
"title": "Rails is Omakase",
"links": {
"author": "9",
"comments": [ "5", "12", "17", "20" ]
}
}]
}
启动一个RESTful服务
$ go run main.go
$ curl http://localhost:8080
Hello,"/"
package main
import (
"fmt"
"html"
"log"
"net/http"
)
func main() {
http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
fmt.Fprintf(w, "Hello, %q", html.EscapeString(r.URL.Path))
})
log.Fatal(http.ListenAndServe(":8080", nil))
}
增加路径分发功能
路径又称"终点"（endpoint），表示API的具体网址。在RESTful架构中，每个网址代表一种资源（resource）。 第三方组件（Gorilla Mux package）： “github.com/gorilla/mux”
package main
import (
"fmt"
"log"
"net/http"
"github.com/gorilla/mux"
)
func main() {
router := mux.NewRouter().StrictSlash(true)
router.HandleFunc("/", Index)
router.HandleFunc("/todos", TodoIndex)
router.HandleFunc("/todos/{todoId}", TodoShow)
log.Fatal(http.ListenAndServe(":8080", router))
}
func Index(w http.ResponseWriter, r *http.Request) {
fmt.Fprintln(w, "Welcome!")
}
func TodoIndex(w http.ResponseWriter, r *http.Request) {
fmt.Fprintln(w, "Todo Index!")
}
func TodoShow(w http.ResponseWriter, r *http.Request) {
vars := mux.Vars(r)
todoId := vars["todoId"]
fmt.Fprintln(w, "Todo show:", todoId)
}
访问测试：
$ curl http://localhost:8080/todo
404 page not found
$ curl http://localhost:8080/todos
Todo Index! ,"/todos"
$ curl http://localhost:8080/todos/{123}
TodoShow: ,"123"
抽象数据模型
创建一个数据模型“Todo”、“Routes”。在其它语言中，使用类（class）实现。 在Go语言中，没有class，必须使用结构(struct)。
Todo.go
package main
import "time"
type Todo struct {
Id int `json:"id"`
Name string `json:"name"`
Completed bool `json:"completed"`
Due time.Time `json:"due"`
}
type Todos []Todo
Routes.go
package main
import (
"net/http"
"github.com/gorilla/mux"
)
type Route struct {
Name string
Method string
Pattern string
HandlerFunc http.HandlerFunc
}
type Routes []Route
重构：Handlers & Router
Handlers.go
package main
import (
"encoding/json"
"fmt"
"net/http"
"github.com/gorilla/mux"
)
func Index(w http.ResponseWriter, r *http.Request) {
fmt.Fprintln(w, "Welcome!")
}
func TodoIndex(w http.ResponseWriter, r *http.Request) {
todos := Todos{
Todo{Name: "Write presentation"},
Todo{Name: "Host meetup"},
}
if err := json.NewEncoder(w).Encode(todos); err != nil {
panic(err)
}
}
func TodoShow(w http.ResponseWriter, r *http.Request) {
vars := mux.Vars(r)
todoId := vars["todoId"]
fmt.Fprintln(w, "Todo show:", todoId)
}
Router.go
package main
import (
"net/http"
"github.com/gorilla/mux"
)
func NewRouter() *mux.Router {
router := mux.NewRouter().StrictSlash(true)
for _, route := range routes {
var handler http.Handler
handler = route.HandlerFunc
handler = Logger(handler, route.Name)
router.
Methods(route.Method).
Path(route.Pattern).
Name(route.Name).
Handler(handler)
}
return router
}
启动入口是不是清爽很多！
Main.go
Main.go
package main
import (
"log"
"net/http"
)
func main() {
router := NewRouter()
log.Fatal(http.ListenAndServe(":8080", router))
}
web access:http://localhost:8080/todos
Todo Index! ,"/todos" [ { "id":0, "name":"Write sth ....", "completed":false, "due":"0001-01-01T00:00:00 }, { "id":1, "name":"Host meetup ....", "completed":false, "due":"0001-01-01T00:00:00Z" } ]
增强功能：持久化
func TodoCreate(w http.ResponseWriter, r *http.Request) {
var todo Todo
//add Todo instance
}
增强功能：日志
2017/05/23 15:57:23 http: multiple response.WriteHeader calls
2017/05/23 15:57:23 GET /todos TodoIndex 6.945807ms
2017/05/23 16:18:40 http: multiple response.WriteHeader calls
2017/05/23 16:18:40 GET /todos TodoIndex 2.127435ms
Things We Didn’t Do
-
版本控制 API版本迭代 & 跨版本资源访问。常用做法是将版本号放在URL，较为简洁，例如：https://localhost:8080/v1/ 另一种做法是将版本号放在HTTP头信息中。
-
授权验证：涉及到OAuth和JWT。 （1）OAuth 2.0，OAuth2 is an authentication framework,RFC 6749 OAuth2是一种授权框架，提供了一套详细的、可供实践的指导性解决方案。OAuth 2.0定义了四种授权方式。授权码模式（authorization code）、简化模式（implicit）、密码模式（resource owner password credentials）、客户端模式（client credentials）。
(2)JSON web tokens,JWT is an authentication protocol,RFC 7519 JWT是一种安全协议。基本思路就是用户提供用户名和密码给认证服务器，服务器验证用户提交信息信息的合法性；如果验证成功，会产生并返回一个Token（令牌），用户可以使用这个token访问服务器上受保护的资源。
eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJzdWIiOiIxMjM0NTY3ODkwIiwibmFtZSI6IkpvaG4gRG9lIiwiYWRtaW4iOnRydWV9.TJVA95OrM7E2cBab30RMHrHDcEfxjoYZgeFONFh7HgQ
header:定义算法(alg:ALGORITHM)和TOKEN TYPE（typ）
{
"alg": "HS256",
"typ": "JWT"
}
Data:
{
"sub": "1234567890",
"name": "John Doe",
"admin": true
}
- eTags：关于缓存、性能和用户标识和追踪。
https://my.oschina.net/zijingshanke/blog/907955