Gin is a web framework written in 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.
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README.md

Gin Web Framework

GoDoc Build Status

Gin is a web framework written in Golang. It features a martini-like API with much better performance, up to 40 times faster. 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() {
    router := gin.Default()
    router.GET("/", func(c *gin.Context) {
        c.String(200, "hello world")
    })
    router.GET("/ping", func(c *gin.Context) {
        c.String(200, "pong")
    })
    router.POST("/submit", func(c *gin.Context) {
        c.String(401, "not authorized")
    })
    router.PUT("/error", func(c *gin.Context) {
        c.String(500, "and error hapenned :(")
    })
    router.Run(":8080")
}

Gin is new, will it be supported?

Yes, Gin is an internal project of my upcoming startup. We developed it and we are going to continue using and improve it.

Roadmap for v1.0

  • Performance improments, reduce allocation and garbage collection overhead
  • Fix bugs
  • Stable API
  • Ask our designer for a cool logo
  • Add tons of unit tests
  • Add internal benchmarks suite
  • Improve logging system
  • Improve JSON/XML validation using bindings
  • Improve XML support
  • Flexible rendering system
  • More powerful validation API
  • Improve documentation
  • Add more cool middlewares, for example redis caching (this also helps developers to understand the framework).
  • Continuous integration

Start using it

Obviously, you need to have Git and Go already installed to run Gin.
Run this in your terminal

go get github.com/gin-gonic/gin

Then import it in your Go code:

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

Community

If you'd like to help out with the project, there's a mailing list and IRC channel where Gin discussions normally happen.

API Examples

Create most basic PING/PONG HTTP endpoint

package main

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

func main() {
    r := gin.Default()
    r.GET("/ping", func(c *gin.Context) {
        c.String(200, "pong")
    })

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

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

func main() {
    // Creates a gin router + logger and recovery (crash-free) middlewares
    r := gin.Default()

    r.GET("/someGet", getting)
    r.POST("/somePost", posting)
    r.PUT("/somePut", putting)
    r.DELETE("/someDelete", deleting)
    r.PATCH("/somePatch", patching)
    r.HEAD("/someHead", head)
    r.OPTIONS("/someOptions", options)

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

Parameters in path

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

    // This handler will match /user/john but will not match neither /user/ or /user
    r.GET("/user/:name", func(c *gin.Context) {
        name := c.Params.ByName("name")
        message := "Hello "+name
        c.String(200, message)
    })

    // However, this one will match /user/john and also /user/john/send
    r.GET("/user/:name/*action", func(c *gin.Context) {
        name := c.Params.ByName("name")
        action := c.Params.ByName("action")
        message := name + " is " + action
        c.String(200, message)
    })

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

Grouping routes

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

    // Simple group: v1
    v1 := r.Group("/v1")
    {
        v1.POST("/login", loginEndpoint)
        v1.POST("/submit", submitEndpoint)
        v1.POST("/read", readEndpoint)
    }

    // Simple group: v2
    v2 := r.Group("/v2")
    {
        v2.POST("/login", loginEndpoint)
        v2.POST("/submit", submitEndpoint)
        v2.POST("/read", readEndpoint)
    }

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

Blank Gin without middlewares by default

Use

r := gin.New()

instead of

r := gin.Default()

Using middlewares

func main() {
    // Creates a router without any middleware by default
    r := gin.New()

    // Global middlewares
    r.Use(gin.Logger())
    r.Use(gin.Recovery())

    // Per route middlewares, 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 middlewares! 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 LoginJSON struct {
    User     string `json:"user" binding:"required"`
    Password string `json:"password" binding:"required"`
}

// Binding from form values
type LoginForm struct {
    User     string `form:"user" binding:"required"`
    Password string `form:"password" binding:"required"`   
}

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

    // Example for binding JSON ({"user": "manu", "password": "123"})
    r.POST("/login", func(c *gin.Context) {
        var json LoginJSON

        c.Bind(&json) // This will infer what binder to use depending on the content-type header.
        if json.User == "manu" && json.Password == "123" {
            c.JSON(200, gin.H{"status": "you are logged in"})
        } else {
            c.JSON(401, gin.H{"status": "unauthorized"})
        }
    })

    // Example for binding a HTML form (user=manu&password=123)
    r.POST("/login", func(c *gin.Context) {
        var form LoginForm

        c.BindWith(&form, binding.Form) // You can also specify which binder to use. We support binding.Form, binding.JSON and binding.XML.
        if form.User == "manu" && form.Password == "123" {
            c.JSON(200, gin.H{"status": "you are logged in"})
        } else {
            c.JSON(401, gin.H{"status": "unauthorized"})
        }
    })

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

XML and JSON rendering

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

    // gin.H is a shortcup for map[string]interface{}
    r.GET("/someJSON", func(c *gin.Context) {
        c.JSON(200, gin.H{"message": "hey", "status": 200})
    })

    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(200, msg)
    })

    r.GET("/someXML", func(c *gin.Context) {
        c.XML(200, gin.H{"message": "hey", "status": 200})
    })

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

HTML rendering

Using LoadHTMLTemplates()

func main() {
    r := gin.Default()
    r.LoadHTMLTemplates("templates/*")
    r.GET("/index", func(c *gin.Context) {
        obj := gin.H{"title": "Main website"}
        c.HTML(200, "index.tmpl", obj)
    })

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

You can also use your own html template render

import "html/template"

func main() {
    r := gin.Default()
    html := template.Must(template.ParseFiles("file1", "file2"))
    r.HTMLTemplates = html

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

Redirects

Issuing a HTTP redirect is easy:

r.GET("/test", func(c *gin.Context) {
    c.Redirect(301, "http://www.google.com/")
})

Both internal and external locations are supported.

Custom Middlewares

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

// similate 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.Get(gin.AuthUserKey).(string)
        if secret, ok := secrets[user]; ok {
            c.JSON(200, gin.H{"user": user, "secret": secret})
        } else {
            c.JSON(200, 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()
}