Go实战--实现简单的restful api(The way to go)

生命不止，继续 go go go !!!

介绍过net/http package：
http://blog.csdn.net/wangshubo1989/article/details/70147079

介绍过实现一个简单的tcp服务端/客户端：
http://blog.csdn.net/wangshubo1989/article/details/70147079

介绍过如何实现一个简单的聊天室：
http://blog.csdn.net/wangshubo1989/article/details/70668916

今天跟大家介绍一下如何使用go创建一套restful api，我们依托于开源库gorilla/mux。

let’s go~~

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

github地址：
https://github.com/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

而gorilla/mux是一个强大的路由，小巧但是稳定高效，不仅可以支持正则路由还可以按照Method，header，host等信息匹配，可以从我们设定的路由表达式中提取出参数方便上层应用，而且完全兼容http.ServerMux

设置好了go的环境变量，直接运行：

go get -u github.com/gorilla/mux

实现

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"`
}

接下来，定义一个全局变量，用于存储资源(数据)：

var people []Person

对这个变量进行赋值：

    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"}})

如果对go中的struct不够了解的可以看这里：
http://blog.csdn.net/wangshubo1989/article/details/70040022

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)
}

然后handle function:

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

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)
}

然后handle function:

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

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)
}

然后handle function:

router.HandleFunc("/people/{id}", DeletePerson).Methods("DELETE")

完整代码与运行结果

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

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)
}

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

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)
}

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() {
    router := mux.NewRouter()
    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"}})
    router.HandleFunc("/people", GetPeople).Methods("GET")
    router.HandleFunc("/people/{id}", GetPerson).Methods("GET")
    router.HandleFunc("/people/{id}", PostPerson).Methods("POST")
    router.HandleFunc("/people/{id}", DeletePerson).Methods("DELETE")
    log.Fatal(http.ListenAndServe(":12345", router))
}

运行结果：
Get People

package main

import (
    "fmt"
    "net/http"
    "io/ioutil"
)

func main() {

    url := "http://localhost:12345/people"

    req, _ := http.NewRequest("GET", url, nil)

    req.Header.Add("accept", "application/json")
    req.Header.Add("authorization", "Basic d2FuZ3NodWJvOndhbmdzaHVibw==")
    req.Header.Add("cache-control", "no-cache")
    req.Header.Add("postman-token", "18774413-0c11-e312-7ed6-7bc4f8151f5a")

    res, _ := http.DefaultClient.Do(req)

    defer res.Body.Close()
    body, _ := ioutil.ReadAll(res.Body)

    fmt.Println(res)
    fmt.Println(string(body))

}

Get Person

package main

import (
    "fmt"
    "strings"
    "net/http"
    "io/ioutil"
)

func main() {

    url := "http://localhost:12345/people/1"

    payload := strings.NewReader("{
  "firstname": "wang",
  "lastname": "shubo",
  "address": {
    "city": "Beijing",
    "state": "Beijng"
  }
}")

    req, _ := http.NewRequest("DELETE", url, payload)

    req.Header.Add("content-type", "application/json")
    req.Header.Add("cache-control", "no-cache")
    req.Header.Add("postman-token", "4a894ad6-2887-259a-c953-5d26fed70963")

    res, _ := http.DefaultClient.Do(req)

    defer res.Body.Close()
    body, _ := ioutil.ReadAll(res.Body)

    fmt.Println(res)
    fmt.Println(string(body))

}

Post Person

package main

import (
    "fmt"
    "strings"
    "net/http"
    "io/ioutil"
)

func main() {

    url := "http://localhost:12345/people/3"

    payload := strings.NewReader("{
  "firstname": "wang",
  "lastname": "shubo",
  "address": {
    "city": "Beijing",
    "state": "Beijng"
  }
}")

    req, _ := http.NewRequest("POST", url, payload)

    req.Header.Add("content-type", "application/json")
    req.Header.Add("cache-control", "no-cache")
    req.Header.Add("postman-token", "a9d590dd-1819-15f6-962e-0eabf4b7e707")

    res, _ := http.DefaultClient.Do(req)

    defer res.Body.Close()
    body, _ := ioutil.ReadAll(res.Body)

    fmt.Println(res)
    fmt.Println(string(body))

}

Delete Person

package main

import (
    "fmt"
    "strings"
    "net/http"
    "io/ioutil"
)

func main() {

    url := "http://localhost:12345/people/1"

    payload := strings.NewReader("{
  "firstname": "wang",
  "lastname": "shubo",
  "address": {
    "city": "Beijing",
    "state": "Beijng"
  }
}")

    req, _ := http.NewRequest("DELETE", url, payload)

    req.Header.Add("content-type", "application/json")
    req.Header.Add("cache-control", "no-cache")
    req.Header.Add("postman-token", "4c8d290e-4c6c-53f7-64e9-1d1f6ed19b09")

    res, _ := http.DefaultClient.Do(req)

    defer res.Body.Close()
    body, _ := ioutil.ReadAll(res.Body)

    fmt.Println(res)
    fmt.Println(string(body))

}