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gin-gonic/gin

5198

gin-gonic / gin

Go

Gin is a HTTP web framework written in Go (Golang). It features a Martini-like API with much better performance -- up to 40 times faster. If you need smashing performance, get yourself some Gin.


READ ME

Gin Web Framework

Build Status Coverage Status GoDoc Join the chat at https://gitter.im/gin-gonic/gin

Gin is a web framework written in Golang. It features a martini-like API with much better performance, up to 40 times faster thanks to httprouter. If you need performance and good productivity, you will love Gin.

Gin console logger

$ cat test.go
package main

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

func main() {
    r := gin.Default()
    r.GET("/ping", func(c *gin.Context) {
        c.String(200, "pong")
    })
    r.Run(":8080") // listen and serve on 0.0.0.0:8080
}

Benchmarks

Gin uses a custom version of HttpRouter

See all benchmarks

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): Total Repetitions
(2): Single Repetition Duration (ns/op)
(3): Heap Memory (B/op)
(4): Average Allocations per Repetition (allocs/op)

Gin v1. stable

  • Zero allocation router.
  • Still the fastest http router and framework. From routing to writing.
  • Complete suite of unit tests
  • Battle tested
  • API frozen, new releases will not break your code.

Start using it

  1. Download and install it:
go get github.com/gin-gonic/gin
  1. Import it in your code:
import "github.com/gin-gonic/gin"

API Examples

Using GET, POST, PUT, PATCH, DELETE and 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)

    // Listen and server on 0.0.0.0:8080
    router.Run(":8080")
}

Parameters in path

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/join/
    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")
}

Querystring parameters

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 Form

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,
        })
    })
    router.Run(":8080")
}

Another example: query + post form

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("id", "0")
        name := c.PostForm("name")
        message := c.PostForm("message")

        fmt.Println("id: %s; page: %s; name: %s; message: %s", id, page, name, message)
    })
    router.Run(":8080")
}
id: 1234; page: 0; name: manu; message: this_is_great

Grouping routes

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")
}

Blank Gin without middleware by default

Use

r := gin.New()

instead of

r := gin.Default()

Using middleware

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 than:
    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 and validation

To bind a request body into a type, use model binding. We currently support binding of JSON, XML and standard form values (foo=bar&boo=baz).

Note that you need to set the corresponding binding tag on all fields you want to bind. For example, when binding from JSON, set json:"fieldname".

When using the Bind-method, Gin tries to infer the binder depending on the Content-Type header. If you are sure what you are binding, you can use BindWith.

You can also specify that specific fields are required. If a field is decorated with binding:"required" and has a empty value when binding, the current request will fail with an error.

// 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 binding

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")
}

Test it with:

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

XML and JSON rendering

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")
}

Serving static files

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 rendering

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

You can also use your own html template render

import "html/template"

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

Redirects

Issuing a HTTP redirect is easy:

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

Both internal and external locations are supported.

Custom Middleware

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")
}

Using BasicAuth() middleware

// simulate some private data
var secrets = gin.H{
    "foo":    gin.H{"email": "foo@bar.com", "phone": "123433"},
    "austin": gin.H{"email": "austin@example.com", "phone": "666"},
    "lena":   gin.H{"email": "lena@guapa.com", "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 setted 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")
}

Goroutines inside a middleware

When starting inside a middleware or handler, you SHOULD NOT use the original context inside it, you have to use a read-only copy.

func main() {
    r := gin.Default()

    r.GET("/long_async", func(c *gin.Context) {
        // create copy to be used inside the goroutine
        c_cp := c.Copy()
        go func() {
            // simulate a long task with time.Sleep(). 5 seconds
            time.Sleep(5 * time.Second)

            // note than you are using the copied context "c_cp", IMPORTANT
            log.Println("Done! in path " + c_cp.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")
}

Custom HTTP configuration

Use http.ListenAndServe() directly, like this:

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

or

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()
}