github.com/Coccodrillo/gin/examples/app-engine

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.


License
MIT
Install
go get github.com/Coccodrillo/gin/examples/app-engine

Documentation

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

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")
}

JSON parsing and validation

type LoginJSON struct {
    User     string `json:"user" binding:"required"`
    Password string `json:"password" binding:"required"`
}

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

    r.POST("/login", func(c *gin.Context) {
        var json LoginJSON

        // If EnsureBody returns false, it will write automatically the error
        // in the HTTP stream and return a 400 error. If you want custom error
        // handling you should use: c.ParseBody(interface{}) error
        if c.EnsureBody(&json) {
            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"})
            }
        }
    })

    // 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")
}

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.Req.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.Req.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()
}