2018-04-17 18:04:36 +08:00

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Gin Web Framework

Gin is a web framework written in Go (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.JSON(200, gin.H{
			"message": "pong",
		})
	})
	r.Run() // 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

Download and install it:

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

Import it in your code:

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

(Optional) Import net/http. This is required for example if using constants such as http.StatusOK.

import "net/http"

API Examples

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

func main() {
	// Disable Console Color
	// gin.DisableConsoleColor()

	// 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
}

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/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")
}

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,
			"nick":    nick,
		})
	})
	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("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

Upload files

Single file

References issue #774 and detail example code.

func main() {
	router := gin.Default()
	router.POST("/upload", func(c *gin.Context) {
		// single file
		file, _ := c.FormFile("file")
		log.Println(file.Filename)

		c.String(http.StatusOK, fmt.Printf("'%s' uploaded!", file.Filename))
	})
	router.Run(":8080")
}

How to curl:

curl -X POST http://localhost:8080/upload \
  -F "file=@/Users/appleboy/test.zip" \
  -H "Content-Type: multipart/form-data"

Multiple files

See the detail example code.

func main() {
	router := gin.Default()
	router.POST("/upload", func(c *gin.Context) {
		// Multipart form
		form, _ := c.MultipartForm()
		files := form.File["upload[]"]

		for _, file := range files {
			log.Println(file.Filename)
		}
		c.String(http.StatusOK, fmt.Printf("%d files uploaded!", len(files)))
	})
	router.Run(":8080")
}

How to curl:

curl -X POST http://localhost:8080/upload \
  -F "upload[]=@/Users/appleboy/test1.zip" \
  -F "upload[]=@/Users/appleboy/test2.zip" \
  -H "Content-Type: multipart/form-data"

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 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 serve 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 serve on 0.0.0.0:8080
	router.Run(":8080")
}

Bind Query String

See the detail information.

package main

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

type Person struct {
	Name    string `form:"name"`
	Address string `form:"address"`
}

func main() {
	route := gin.Default()
	route.GET("/testing", startPage)
	route.Run(":8085")
}

func startPage(c *gin.Context) {
	var person Person
	// If `GET`, only `Form` binding engine (`query`) used.
	// If `POST`, first checks the `content-type` for `JSON` or `XML`, then uses `Form` (`form-data`).
	// See more at https://github.com/gin-gonic/gin/blob/develop/binding/binding.go#L45
	if c.Bind(&person) == nil {
		log.Println(person.Name)
		log.Println(person.Address)
	}

	c.String(200, "Success")
}

Multipart/Urlencoded binding

package main

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

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.MustBindWith(&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, JSON and YAML 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})
	})

	r.GET("/someYAML", func(c *gin.Context) {
		c.YAML(http.StatusOK, gin.H{"message": "hey", "status": http.StatusOK})
	})

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

HTML rendering

Using LoadHTMLGlob() or LoadHTMLFiles()

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>

Using templates with same name in different directories

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 }}

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")
}

You may use custom delims

	r := gin.Default()
	r.Delims("{[{", "}]}")
	r.LoadHTMLGlob("/path/to/templates"))

Add custom template funcs

main.go

	...
	
	func formatAsDate(t time.Time) string {
		year, month, day := t.Date()
		return fmt.Sprintf("%d/%02d/%02d", year, month, day)
	}
	
	...
	
	router.SetFuncMap(template.FuncMap{
		"formatAsDate": formatAsDate,
	})
	
	...
	
	router.GET("/raw", func(c *Context) {
		c.HTML(http.StatusOK, "raw.tmpl", map[string]interface{}{
			"now": time.Date(2017, 07, 01, 0, 0, 0, 0, time.UTC),
		})
	})
	
	...

raw.tmpl

Date: {[{.now | formatAsDate}]}

Result:

Date: 2017/07/01

Multitemplate

Gin allow by default use only one html.Template. Check a multitemplate render for using features like go 1.6 block template.

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 serve 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 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 serve 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
		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 serve 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)
}

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()
}

Support Let's Encrypt

example for 1-line LetsEncrypt HTTPS servers.

package main

import (
	"log"

	"github.com/gin-gonic/autotls"
	"github.com/gin-gonic/gin"
)

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

	// Ping handler
	r.GET("/ping", func(c *gin.Context) {
		c.String(200, "pong")
	})

	log.Fatal(autotls.Run(r, "example1.com", "example2.com"))
}

example for custom autocert manager.

package main

import (
	"log"

	"github.com/gin-gonic/autotls"
	"github.com/gin-gonic/gin"
	"golang.org/x/crypto/acme/autocert"
)

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

	// Ping handler
	r.GET("/ping", func(c *gin.Context) {
		c.String(200, "pong")
	})

	m := autocert.Manager{
		Prompt:     autocert.AcceptTOS,
		HostPolicy: autocert.HostWhitelist("example1.com", "example2.com"),
		Cache:      autocert.DirCache("/var/www/.cache"),
	}

	log.Fatal(autotls.RunWithManager(r, m))
}

Graceful restart or stop

Do you want to graceful restart or stop your web server? There are some ways this can be done.

We can use fvbock/endless to replace the default ListenAndServe. Refer issue #296 for more details.

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

An alternative to endless:

manners: A polite Go HTTP server that shuts down gracefully.
graceful: Graceful is a Go package enabling graceful shutdown of an http.Handler server.
grace: Graceful restart & zero downtime deploy for Go servers.

If you are using Go 1.8, you may not need to use this library! Consider using http.Server's built-in Shutdown() method for graceful shutdowns. See the full graceful-shutdown example with gin.

// +build go1.8

package main

import (
	"context"
	"log"
	"net/http"
	"os"
	"os/signal"
	"time"

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

func main() {
	router := gin.Default()
	router.GET("/", func(c *gin.Context) {
		time.Sleep(5 * time.Second)
		c.String(http.StatusOK, "Welcome Gin Server")
	})

	srv := &http.Server{
		Addr:    ":8080",
		Handler: router,
	}

	go func() {
		// service connections
		if err := srv.ListenAndServe(); err != nil {
			log.Printf("listen: %s\n", err)
		}
	}()

	// Wait for interrupt signal to gracefully shutdown the server with
	// a timeout of 5 seconds.
	quit := make(chan os.Signal)
	signal.Notify(quit, os.Interrupt)
	<-quit
	log.Println("Shutdown Server ...")

	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
	defer cancel()
	if err := srv.Shutdown(ctx); err != nil {
		log.Fatal("Server Shutdown:", err)
	}
	log.Println("Server exist")
}

Contributing

With issues:
- Use the search tool before opening a new issue.
- Please provide source code and commit sha if you found a bug.
- Review existing issues and provide feedback or react to them.
With pull requests:
- Open your pull request against develop
- Your pull request should have no more than two commits, if not you should squash them.
- It should pass all tests in the available continuous integrations systems such as TravisCI.
- You should add/modify tests to cover your proposed code changes.
- If your pull request contains a new feature, please document it on the README.

Users

Awesome project lists using Gin web framework.

drone: Drone is a Continuous Delivery platform built on Docker, written in Go
gorush: A push notification server written in Go.

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