Gin Web框架简介

翻译自: https://github.com/gin-gonic/gin/blob/develop/README.md

Gin Web框架

Gin是用Golang实现的一种Web框架。基于 httprouter，它提供了类似martini但更好性能(路由性能约快40倍)的API服务. 如果你希望构建一个高性能的生产环境，你会喜欢上使用 Gin。

$ cat test.go

package mainimport "github.com/gin-gonic/gin"func main() {    r := gin.Default()    r.GET("/ping", func(c *gin.Context) {        c.JSON(200, gin.H{            "message": "pong",        })    })    r.Run() // listen and server on 0.0.0.0:8080}

基准测试

Gin基于HttpRouter的这个定制版本来构建。

查看全部测试

Benchmark name (1) (2) (3) (4) BenchmarkAce_GithubAll 10000 109482 13792 167 BenchmarkBear_GithubAll 10000 287490 79952 943 BenchmarkBeego_GithubAll 3000 562184 146272 2092 BenchmarkBone_GithubAll 500 2578716 648016 8119 BenchmarkDenco_GithubAll 20000 94955 20224 167 BenchmarkEcho_GithubAll 30000 58705 0 0 BenchmarkGin_GithubAll 30000 50991 0 0 BenchmarkGocraftWeb_GithubAll 5000 449648 133280 1889 BenchmarkGoji_GithubAll 2000 689748 56113 334 BenchmarkGoJsonRest_GithubAll 5000 537769 135995 2940 BenchmarkGoRestful_GithubAll 100 18410628 797236 7725 BenchmarkGorillaMux_GithubAll 200 8036360 153137 1791 BenchmarkHttpRouter_GithubAll 20000 63506 13792 167 BenchmarkHttpTreeMux_GithubAll 10000 165927 56112 334 BenchmarkKocha_GithubAll 10000 171362 23304 843 BenchmarkMacaron_GithubAll 2000 817008 224960 2315 BenchmarkMartini_GithubAll 100 12609209 237952 2686 BenchmarkPat_GithubAll 300 4830398 1504101 32222 BenchmarkPossum_GithubAll 10000 301716 97440 812 BenchmarkR2router_GithubAll 10000 270691 77328 1182 BenchmarkRevel_GithubAll 1000 1491919 345553 5918 BenchmarkRivet_GithubAll 10000 283860 84272 1079 BenchmarkTango_GithubAll 5000 473821 87078 2470 BenchmarkTigerTonic_GithubAll 2000 1120131 241088 6052 BenchmarkTraffic_GithubAll 200 8708979 2664762 22390 BenchmarkVulcan_GithubAll 5000 353392 19894 609 BenchmarkZeus_GithubAll 2000 944234 300688 2648

(1): 总重复次数
(2): 单次请求耗时 (ns/op)
(3): 堆内存大小 (B/op)
(4): 单次请求内存分配数 (allocs/op)

Gin v1. stable

• [x] 零分配路由.
• [x] 从路由到写请求, 依然为最快的路由器和框架.
• [x] 完备的单元测试套件.
• [x] Battle tested.(?)
• [x] API冻结, 新的release版不会影响现有的代码.

快速开始

1. 下载并安装Gin:

   $ go get github.com/gin-gonic/gin

2. 在代码中import进来:

   import "github.com/gin-gonic/gin"

3. (可选) Import net/http. 如果用到诸如 http.StatusOK的常量, 需要引入该包:

   import "net/http"

API示例

使用 GET, POST, PUT, PATCH, DELETE 以及 OPTIONS

func main() {    // Creates a gin router with default middleware:    // logger and recovery (crash-free) middleware    router := gin.Default()    router.GET("/someGet", getting)    router.POST("/somePost", posting)    router.PUT("/somePut", putting)    router.DELETE("/someDelete", deleting)    router.PATCH("/somePatch", patching)    router.HEAD("/someHead", head)    router.OPTIONS("/someOptions", options)    // By default it serves on :8080 unless a    // PORT environment variable was defined.    router.Run()    // router.Run(":3000") for a hard coded port}

路径参数

func main() {    router := gin.Default()    // This handler will match /user/john but will not match neither /user/ or /user    router.GET("/user/:name", func(c *gin.Context) {        name := c.Param("name")        c.String(http.StatusOK, "Hello %s", name)    })    // However, this one will match /user/john/ and also /user/john/send    // If no other routers match /user/john, it will redirect to /user/john/    router.GET("/user/:name/*action", func(c *gin.Context) {        name := c.Param("name")        action := c.Param("action")        message := name + " is " + action        c.String(http.StatusOK, message)    })    router.Run(":8080")}

查询字符串参数

func main() {    router := gin.Default()    // Query string parameters are parsed using the existing underlying request object.    // The request responds to a url matching:  /welcome?firstname=Jane&lastname=Doe    router.GET("/welcome", func(c *gin.Context) {        firstname := c.DefaultQuery("firstname", "Guest")        lastname := c.Query("lastname") // shortcut for c.Request.URL.Query().Get("lastname")        c.String(http.StatusOK, "Hello %s %s", firstname, lastname)    })    router.Run(":8080")}

Multipart/Urlencoded表单提交

func main() {    router := gin.Default()    router.POST("/form_post", func(c *gin.Context) {        message := c.PostForm("message")        nick := c.DefaultPostForm("nick", "anonymous")        c.JSON(200, gin.H{            "status":  "posted",            "message": message,            "nick":    nick,        })    })    router.Run(":8080")}

更多示例: 查询参数 + POST表单提交

POST /post?id=1234&page=1 HTTP/1.1Content-Type: application/x-www-form-urlencodedname=manu&message=this_is_great

func main() {    router := gin.Default()    router.POST("/post", func(c *gin.Context) {        id := c.Query("id")        page := c.DefaultQuery("page", "0")        name := c.PostForm("name")        message := c.PostForm("message")        fmt.Printf("id: %s; page: %s; name: %s; message: %s", id, page, name, message)    })    router.Run(":8080")}

id: 1234; page: 1; name: manu; message: this_is_great

更多示例: 上传文件

参考问题 #548.

func main() {    router := gin.Default()    router.POST("/upload", func(c *gin.Context) {            file, header , err := c.Request.FormFile("upload")            filename := header.Filename            fmt.Println(header.Filename)            out, err := os.Create("./tmp/"+filename+".png")            if err != nil {                log.Fatal(err)            }            defer out.Close()            _, err = io.Copy(out, file)            if err != nil {                log.Fatal(err)            }    })    router.Run(":8080")}

分组路由

func main() {    router := gin.Default()    // Simple group: v1    v1 := router.Group("/v1")    {        v1.POST("/login", loginEndpoint)        v1.POST("/submit", submitEndpoint)        v1.POST("/read", readEndpoint)    }    // Simple group: v2    v2 := router.Group("/v2")    {        v2.POST("/login", loginEndpoint)        v2.POST("/submit", submitEndpoint)        v2.POST("/read", readEndpoint)    }    router.Run(":8080")}

不使用中间件, 使用Gin默认配置

使用

r := gin.New()

来代替

r := gin.Default()

使用中间件

func main() {    // Creates a router without any middleware by default    r := gin.New()    // Global middleware    r.Use(gin.Logger())    r.Use(gin.Recovery())    // Per route middleware, you can add as many as you desire.    r.GET("/benchmark", MyBenchLogger(), benchEndpoint)    // Authorization group    // authorized := r.Group("/", AuthRequired())    // exactly the same as:    authorized := r.Group("/")    // per group middleware! in this case we use the custom created    // AuthRequired() middleware just in the "authorized" group.    authorized.Use(AuthRequired())    {        authorized.POST("/login", loginEndpoint)        authorized.POST("/submit", submitEndpoint)        authorized.POST("/read", readEndpoint)        // nested group        testing := authorized.Group("testing")        testing.GET("/analytics", analyticsEndpoint)    }    // Listen and server on 0.0.0.0:8080    r.Run(":8080")}

model binding与验证

要绑定一个请求body到某个类型, 可以使用model binding。 目前支持JSON, XML 以及标准from格式 (foo=bar&boo=baz)的绑定。

所有你想要绑定的域(field)， 需要你设置对应的绑定标识。 例如, 要绑定到JSON, 则这样声明json:"fieldname"。

使用Bind方法时, Gin会尝试通过Content-Type头部来推定绑定的类型(如json还是form)。而如果你明确知道要绑定的类型, 可以使用BindWith方法。

你也可以指定哪些filed需要绑定。 如果某个filed像这样声明: binding:"required", 那么在进行绑定时如果发现是空值(注: 是请求中不存在该field名?), 当前的请求会失败并收到错误提示。

// Binding from JSONtype Login struct {    User     string `form:"user" json:"user" binding:"required"`    Password string `form:"password" json:"password" binding:"required"`}func main() {    router := gin.Default()    // Example for binding JSON ({"user": "manu", "password": "123"})    router.POST("/loginJSON", func(c *gin.Context) {        var json Login        if c.BindJSON(&json) == nil {            if json.User == "manu" && json.Password == "123" {                c.JSON(http.StatusOK, gin.H{"status": "you are logged in"})            } else {                c.JSON(http.StatusUnauthorized, gin.H{"status": "unauthorized"})            }        }    })    // Example for binding a HTML form (user=manu&password=123)    router.POST("/loginForm", func(c *gin.Context) {        var form Login        // This will infer what binder to use depending on the content-type header.        if c.Bind(&form) == nil {            if form.User == "manu" && form.Password == "123" {                c.JSON(http.StatusOK, gin.H{"status": "you are logged in"})            } else {                c.JSON(http.StatusUnauthorized, gin.H{"status": "unauthorized"})            }        }    })    // Listen and server on 0.0.0.0:8080    router.Run(":8080")}

Multipart/Urlencoded表单请求方式的绑定

package mainimport (    "github.com/gin-gonic/gin"    "github.com/gin-gonic/gin/binding")type LoginForm struct {    User     string `form:"user" binding:"required"`    Password string `form:"password" binding:"required"`}func main() {    router := gin.Default()    router.POST("/login", func(c *gin.Context) {        // you can bind multipart form with explicit binding declaration:        // c.BindWith(&form, binding.Form)        // or you can simply use autobinding with Bind method:        var form LoginForm        // in this case proper binding will be automatically selected        if c.Bind(&form) == nil {            if form.User == "user" && form.Password == "password" {                c.JSON(200, gin.H{"status": "you are logged in"})            } else {                c.JSON(401, gin.H{"status": "unauthorized"})            }        }    })    router.Run(":8080")}

使用以下命令测试:

$ curl -v --form user=user --form password=password http://localhost:8080/login

XML和JSON的渲染

func main() {    r := gin.Default()    // gin.H is a shortcut for map[string]interface{}    r.GET("/someJSON", func(c *gin.Context) {        c.JSON(http.StatusOK, gin.H{"message": "hey", "status": http.StatusOK})    })    r.GET("/moreJSON", func(c *gin.Context) {        // You also can use a struct        var msg struct {            Name    string `json:"user"`            Message string            Number  int        }        msg.Name = "Lena"        msg.Message = "hey"        msg.Number = 123        // Note that msg.Name becomes "user" in the JSON        // Will output  :   {"user": "Lena", "Message": "hey", "Number": 123}        c.JSON(http.StatusOK, msg)    })    r.GET("/someXML", func(c *gin.Context) {        c.XML(http.StatusOK, gin.H{"message": "hey", "status": http.StatusOK})    })    // Listen and server on 0.0.0.0:8080    r.Run(":8080")}

处理静态文件的请求

func main() {    router := gin.Default()    router.Static("/assets", "./assets")    router.StaticFS("/more_static", http.Dir("my_file_system"))    router.StaticFile("/favicon.ico", "./resources/favicon.ico")    // Listen and server on 0.0.0.0:8080    router.Run(":8080")}

HTML模板渲染

Using LoadHTMLTemplates()

func main() {    router := gin.Default()    router.LoadHTMLGlob("templates/*")    //router.LoadHTMLFiles("templates/template1.html", "templates/template2.html")    router.GET("/index", func(c *gin.Context) {        c.HTML(http.StatusOK, "index.tmpl", gin.H{            "title": "Main website",        })    })    router.Run(":8080")}

templates/index.tmpl

<html>    <h1>        {{ .title }}    </h1></html>

使用不同路径下但相同文件名的模板

func main() {    router := gin.Default()    router.LoadHTMLGlob("templates/**/*")    router.GET("/posts/index", func(c *gin.Context) {        c.HTML(http.StatusOK, "posts/index.tmpl", gin.H{            "title": "Posts",        })    })    router.GET("/users/index", func(c *gin.Context) {        c.HTML(http.StatusOK, "users/index.tmpl", gin.H{            "title": "Users",        })    })    router.Run(":8080")}

templates/posts/index.tmpl

{{ define "posts/index.tmpl" }}<html><h1>    {{ .title }}</h1><p>Using posts/index.tmpl</p></html>{{ end }}

templates/users/index.tmpl

{{ define "users/index.tmpl" }}<html><h1>    {{ .title }}</h1><p>Using users/index.tmpl</p></html>{{ end }}

你也可以使用自己的渲染模板

import "html/template"func main() {    router := gin.Default()    html := template.Must(template.ParseFiles("file1", "file2"))    router.SetHTMLTemplate(html)    router.Run(":8080")}

重定向

实现HTTP重定向并不麻烦:

r.GET("/test", func(c *gin.Context) {    c.Redirect(http.StatusMovedPermanently, "http://www.google.com/")})

内部或外部的地址都是支持的。

定制中间件

func Logger() gin.HandlerFunc {    return func(c *gin.Context) {        t := time.Now()        // Set example variable        c.Set("example", "12345")        // before request        c.Next()        // after request        latency := time.Since(t)        log.Print(latency)        // access the status we are sending        status := c.Writer.Status()        log.Println(status)    }}func main() {    r := gin.New()    r.Use(Logger())    r.GET("/test", func(c *gin.Context) {        example := c.MustGet("example").(string)        // it would print: "12345"        log.Println(example)    })    // Listen and server on 0.0.0.0:8080    r.Run(":8080")}

使用 BasicAuth() 中间件

// simulate some private datavar secrets = gin.H{    "foo":    gin.H{"email": "[e-mail]", "phone": "123433"},    "austin": gin.H{"email": "[e-mail]", "phone": "666"},    "lena":   gin.H{"email": "[e-mail]", "phone": "523443"},}func main() {    r := gin.Default()    // Group using gin.BasicAuth() middleware    // gin.Accounts is a shortcut for map[string]string    authorized := r.Group("/admin", gin.BasicAuth(gin.Accounts{        "foo":    "bar",        "austin": "1234",        "lena":   "hello2",        "manu":   "4321",    }))    // /admin/secrets endpoint    // hit "localhost:8080/admin/secrets    authorized.GET("/secrets", func(c *gin.Context) {        // get user, it was set by the BasicAuth middleware        user := c.MustGet(gin.AuthUserKey).(string)        if secret, ok := secrets[user]; ok {            c.JSON(http.StatusOK, gin.H{"user": user, "secret": secret})        } else {            c.JSON(http.StatusOK, gin.H{"user": user, "secret": "NO SECRET :("})        }    })    // Listen and server on 0.0.0.0:8080    r.Run(":8080")}

中间件中的Goroutines

在一个middleware或handler中使用goroutine时, 你不能直接使用源gin.Context, 而只能使用它的一份只读拷贝。

func main() {    r := gin.Default()    r.GET("/long_async", func(c *gin.Context) {        // create copy to be used inside the goroutine        cCp := c.Copy()        go func() {            // simulate a long task with time.Sleep(). 5 seconds            time.Sleep(5 * time.Second)            // note that you are using the copied context "cCp", IMPORTANT            log.Println("Done! in path " + cCp.Request.URL.Path)        }()    })    r.GET("/long_sync", func(c *gin.Context) {        // simulate a long task with time.Sleep(). 5 seconds        time.Sleep(5 * time.Second)        // since we are NOT using a goroutine, we do not have to copy the context        log.Println("Done! in path " + c.Request.URL.Path)    })    // Listen and server on 0.0.0.0:8080    r.Run(":8080")}

自定义HTTP配置

直接使用http.ListenAndServe()， 示例:

func main() {    router := gin.Default()    http.ListenAndServe(":8080", router)}

或者

func main() {    router := gin.Default()    s := &http.Server{        Addr:           ":8080",        Handler:        router,        ReadTimeout:    10 * time.Second,        WriteTimeout:   10 * time.Second,        MaxHeaderBytes: 1 << 20,    }    s.ListenAndServe()}

平滑重启或关闭

是否需要平滑重启或关闭你的服务?有以下这些方式可以实现。

我们可以用 fvbock/endless来替换默认的方法 ListenAndServe，详情请参考#296。

router := gin.Default()router.GET("/", handler)// [...]endless.ListenAndServe(":4242", router)

或者, 除使用endless之外的方法:

• manners: 一种平滑关闭自己的Go HTTP服务。