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 main

import "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/1.1
Content-Type: application/x-www-form-urlencoded

name=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 JSON
type 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 main

import (
    "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 data
var secrets = gin.H{
    "foo":    gin.H{"email": "[email protected]", "phone": "123433"},
    "austin": gin.H{"email": "[email protected]", "phone": "666"},
    "lena":   gin.H{"email": "[email protected]", "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。