Go实现简单的RESTful_API

何为RESTful API

A RESTful API is an application program interface (API) that uses HTTP requests to GET, PUT, POST and DELETE data.

A RESTful API – also referred to as a RESTful web service – is based on representational state transfer (REST) technology, an architectural style and approach to communications often used in web services development.

Wikipedia: 表征性状态传输（英文：Representational State Transfer，简称REST）是Roy Fielding博士于2000年在他的博士论文中提出来的一种软件架构风格。
Roy Fielding是HTTP协议（1.0版和1.1版）的主要设计者，事实上HTTP 1.1规范正是基于REST架构风格的指导原理来设计的。需要注意的是，REST是一种设计风格而不是标准，如果一个架构符合REST原则，我们就称它为RESTful架构。

gorilla/mux

golang自带的http.SeverMux路由实现简单,本质是一个map[string]Handler,是请求路径与该路径对应的处理函数的映射关系。实现简单功能也比较单一：

1. 不支持正则路由， 这个是比较致命的
2. 只支持路径匹配，不支持按照Method，header，host等信息匹配，所以也就没法实现RESTful架构

安装第三方安装包

go get -u github.com/gorilla/mux

实现

1. 定义结构体，用户构造json

type Person struct {
    ID        string   `json:"id,omitemty"`
    Firstname string   `json:"firstname,omitempty"`
    Lastname  string   `json:"lastname,omitempty"`
    Address   *Address `json:"address,omitempty"`
}

type Address struct {
    City     string `json:"city,omitempty"`
    Province string `json:"province,omitempty"`
}

1. 接下来，定义一个全局变量，用于存储资源(数据)：

var people []Person

1. Get

获取所有person，这里我们叫people：

func GetPeople(w http.ResponseWriter, req *http.Request) {
    json.NewEncoder(w).Encode(people)
}

根据id获取person：

func GetPerson(w http.ResponseWriter, req *http.Request) {
    params := mux.Vars(req)
    for _, item := range people {
        if item.ID == params["id"] {
            json.NewEncoder(w).Encode(item)
            return
        }
    }
    json.NewEncoder(w).Encode(people)
}

1. post

同样可以，通过post操作向服务器添加数据：

func PostPerson(w http.ResponseWriter, req *http.Request) {
    params := mux.Vars(req)
    var person Person
    _ = json.NewDecoder(req.Body).Decode(&person)
    person.ID = params["id"]
    people = append(people, person)
    json.NewEncoder(w).Encode(people)
}

1. Delete

func DeletePerson(w http.ResponseWriter, req *http.Request) {
    params := mux.Vars(req)
    for index, item := range people {
        if item.ID == params["id"] {
            people = append(people[:index], people[index+1:]...)
            break
        }
    }
    json.NewEncoder(w).Encode(people)
}

完整代码

package main

import (
    "encoding/json"
    "log"
    "net/http"

    "github.com/gorilla/mux"
)

type Person struct {
    ID        string   `json:"id,omitemty"`
    Firstname string   `json:"firstname,omitempty"`
    Lastname  string   `json:"lastname,omitempty"`
    Address   *Address `json:"address,omitempty"`
}

type Address struct {
    City     string `json:"city,omitempty"`
    Province string `json:"province,omitempty"`
}

var people []Person

// *******************************************************************>>
// Get
// 获取所有person
func GetPeople(w http.ResponseWriter, req *http.Request) {
    json.NewEncoder(w).Encode(people)
}

// 根据id获取person
func GetPerson(w http.ResponseWriter, req *http.Request) {
    params := mux.Vars(req)
    for _, item := range people {
        if item.ID == params["id"] {
            json.NewEncoder(w).Encode(item)
            return
        }
    }
    json.NewEncoder(w).Encode(people)
}

// <<*******************************************************************

// *******************************************************************>>
// Post
// 通过post操作向服务器添加数据
func PostPerson(w http.ResponseWriter, req *http.Request) {
    params := mux.Vars(req)
    var person Person
    _ = json.NewDecoder(req.Body).Decode(&person)
    person.ID = params["id"]
    people = append(people, person)
    json.NewEncoder(w).Encode(people)
}

// <<*******************************************************************

// *******************************************************************>>
// Delete
// 根据id进行删除操作
func DeletePerson(w http.ResponseWriter, req *http.Request) {
    params := mux.Vars(req)
    for index, item := range people {
        if item.ID == params["id"] {
            people = append(people[:index], people[index+1:]...)
            break
        }
    }
    json.NewEncoder(w).Encode(people)
}

// <<*******************************************************************

func main() {
    people = append(people, Person{ID: "1", Firstname: "xi", Lastname: "dada", Address: &Address{City: "Shenyang", Province: "Liaoning"}})
    people = append(people, Person{ID: "2", Firstname: "li", Lastname: "xiansheng", Address: &Address{City: "Changchun", Province: "Jinlin"}})

    // Get handle function:
    router := mux.NewRouter()
    router.HandleFunc("/people", GetPeople).Methods("GET")
    router.HandleFunc("/people/{id}", GetPerson).Methods("GET")

    // Post handle function
    router.HandleFunc("/people/{id}", PostPerson).Methods("POST")

    // Delete handle function:
    router.HandleFunc("/people/{id}", DeletePerson).Methods("DELETE")
    // 启动 API端口9899
    log.Fatal(http.ListenAndServe(":9899", router))
}

运行：

go run ***.go

或者编译成二进制运行

go build ***.go

然后在浏览器中测试

http://localhost:9899/people

[
    {
      "id":"1",
      "firstname":"xi",
      "lastname":"dada",
      "address":{"city":"Shenyang","province":"Liaoning"}
    },
    {
      "id":"2",
      "firstname":"li",
      "lastname":"xiansheng",
      "address":{"city":"Changchun","province":"Jinlin"}
    }
]