用golang写一个restful api。如果您不知道什么是restful,可以看阮一峰老师的教程。
首先，我们需要解决的是路由的问题，也就是如何将不同的url映射到不同的处理函数。
router.GET("/api/todo/:todoid", getTodoById)
router.POST("/api/todo/", addTodo)
router.DELETE("/api/todo/:todoid", deleteTodo)
router.PUT("/api/todo/:todoid", modifyTodo)
作为一个初学者，我马上打开github,找到了awesome-go,经过一番调研，我感觉有几个http router的库比较适合：bone, httprouter, mux。
最终我选择了httprouter这个库。因为它真的很像express。
基本框架
首先，我们设计了四个路由，分别为根据Id获得todo，增加todo，修改todo，删除todo。这里关于解析路由参数，我们使用了httprouter.Params的ByName函数。
package main
import (
"fmt"
"github.com/julienschmidt/httprouter"
"net/http"
"log"
"io"
"io/ioutil"
)
func getTodoById(w http.ResponseWriter, r *http.Request, params httprouter.Params){
todoid := params.ByName("todoid")
fmt.Fprintf(w, "getTodo %s\n", todoid)
}
func addTodo(w http.ResponseWriter, r *http.Request, _ httprouter.Params){
body, _ := ioutil.ReadAll(io.LimitReader(r.Body, 1048576))
fmt.Fprintf(w, "addTodo! %s\n",body)
}
func deleteTodo(w http.ResponseWriter, r *http.Request, params httprouter.Params){
todoid := params.ByName("todoid")
fmt.Fprintf(w, "deleteTodo %s\n", todoid)
}
func modifyTodo(w http.ResponseWriter, r *http.Request, params httprouter.Params){
todoid := params.ByName("todoid")
body, _ := ioutil.ReadAll(io.LimitReader(r.Body, 1048576))
fmt.Fprintf(w, "modifyTodo %s to %s\n", todoid, body)
}
func main() {
router := httprouter.New()
router.GET("/api/todo/:todoid", getTodoById)
router.POST("/api/todo/", addTodo)
router.DELETE("/api/todo/:todoid", deleteTodo)
router.PUT("/api/todo/:todoid", modifyTodo)
log.Fatal(http.ListenAndServe(":8080", router))
}
我们可以用curl来测试一下我们的api,以put为例
curl --data "content=shopping&time=tomorrow" http://127.0.0.1:8080/api/todo/123 -X PUT
// modifyTodo 123 to content=shopping&time=tomorrow
json的解析
我们在使用restful api的时候，常常需要给后台传递数据。从上面可以看到，我们通过http.Request的Body属性可以获得数据
body, _ := ioutil.ReadAll(io.LimitReader(r.Body, 1048576))
从上面，我们读出的数据是[]byte，但是我们希望将其解析为对象，那么在这之前，我们需要先定义我们的struct。假设我们的todo只有一个字段，就是Name
type Todo struct {
Name string
}
现在我们可以这样解析
var todo Todo;
json.Unmarshal(body, &todo);
model层设计
package main
import (
"gopkg.in/mgo.v2"
"fmt"
"log"
"gopkg.in/mgo.v2/bson"
)
var session *mgo.Session
func init(){
session,_ = mgo.Dial("mongodb://127.0.0.1")
}
type Todo struct {
Name string
}
func createTodo(t Todo){
c := session.DB("test").C("todo")
c.Insert(&t)
}
func queryTodoById(id string){
c := session.DB("test").C("todo")
result := Todo{}
err := c.Find(bson.M{"_id": bson.ObjectIdHex(id)}).One(&result)
if err != nil {
log.Fatal(err)
}
fmt.Println("Todo:", result.Name)
}
func removeTodo(id string){
c := session.DB("test").C("todo")
err := c.Remove(bson.M{"_id": bson.ObjectIdHex(id)})
if err != nil{
log.Fatal(err)
}
}
func updateTodo(id string, update interface{}){
//change := bson.M{"$set": bson.M{"name": "hahaha"}}
c := session.DB("test").C("todo")
err := c.Update(bson.M{"_id": bson.ObjectIdHex(id)}, update)
if err != nil{
log.Fatal(err)
}
}
我们定义了Todo的struct,并添加了几种函数。
main
package main
import (
"fmt"
"github.com/julienschmidt/httprouter"
"net/http"
"log"
"io"
"io/ioutil"
"encoding/json"
"gopkg.in/mgo.v2/bson"
)
func getTodoById(w http.ResponseWriter, r *http.Request, params httprouter.Params){
todoid := params.ByName("todoid")
queryTodoById(todoid)
fmt.Fprintf(w, "getUser %s\n", todoid)
}
func addTodo(w http.ResponseWriter, r *http.Request, _ httprouter.Params){
body, _ := ioutil.ReadAll(io.LimitReader(r.Body, 1048576))
var todo Todo;
json.Unmarshal(body, &todo);
createTodo(todo)
fmt.Fprintf(w, "addUser! %s\n",body)
}
func deleteTodo(w http.ResponseWriter, r *http.Request, params httprouter.Params){
todoid := params.ByName("todoid")
removeTodo(todoid)
fmt.Fprintf(w, "deleteUser %s\n", todoid)
}
func modifyTodo(w http.ResponseWriter, r *http.Request, params httprouter.Params){
todoid := params.ByName("todoid")
body, _ := ioutil.ReadAll(io.LimitReader(r.Body, 1048576))
var todo Todo
json.Unmarshal(body, &todo);
change := bson.M{"$set": bson.M{"name": todo.Name}}
updateTodo(todoid,change)
fmt.Fprintf(w, "modifyUser %s to %s\n", todoid, body)
}
func main() {
router := httprouter.New()
router.GET("/api/todo/:todoid", getTodoById)
router.POST("/api/todo/", addTodo)
router.DELETE("/api/todo/:todoid", deleteTodo)
router.PUT("/api/todo/:todoid", modifyTodo)
log.Fatal(http.ListenAndServe(":8080", router))
}
