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.
$ 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
}Gin uses a custom version of HttpRouter
| 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.
- Download and install it:
go get github.com/gin-gonic/gin- Import it in your code:
import "github.com/gin-gonic/gin"##API Examples
func main() {
	// Creates a gin router with default middlewares:
	// logger and recovery (crash-free) middlewares
	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")
}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")
}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")
}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")
}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
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")
}Use
r := gin.New()instead of
r := gin.Default()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")
}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/loginfunc 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")
}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.
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")
}// 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 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")
}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")
}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()
}
