gin/README.md at 63503bf682ca0baf48b2900e6d608d0ecf5e7675

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#Gin Web Framework

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() {
	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 tool of Manu and Javi for many of our projects/start-ups. We developed it and we are going to continue using and improve it.

##Roadmap for v1.0

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

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 serve 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
	// If no other routers match /user/john, it will redirect to /user/join/
	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")
}

###Form parameters

func main() {
	r := gin.Default()
	
	// This will respond to urls like search?firstname=Jane&lastname=Doe
	r.GET("/search", func(c *gin.Context) {
		// You need to call ParseForm() on the request to receive url and form params first
		c.Request.ParseForm()
		
		firstname := c.Request.Form.Get("firstname")
		lastname := c.Request.Form.get("lastname")

		message := "Hello "+ firstname + lastname
		c.String(200, message)
	})
	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("/loginJSON", 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("/loginHTML", 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 shortcut 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")
}

####Serving static files

Use Engine.ServeFiles(path string, root http.FileSystem):

func main() {
    r := gin.Default()
    r.Static("/assets", "./assets")

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

Note: this will use httpNotFound instead of the Router's NotFound handler.

####HTML rendering

Using LoadHTMLTemplates()

func main() {
	r := gin.Default()
	r.LoadHTMLGlob("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")
}

<h1>
	{{ .title }}
</h1>

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.SetHTMLTemplate(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.MustGet(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)
}

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()
}

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