Chinese document of Gin framework

Chinese document of Gin framework

Gin is a go written web framework, which has the advantages of high performance.
Official address: https://github.com/gin-gonic/gin

install

To install the Gin package, you first need to install Go and set up the Go workspace

1. Download and install

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

2. Import it in code

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

Using the package management tool Govendor to install

1. Go get vendor (install)

$ go get github.com/kardianos/govendor

2. Create project folder and enter folder

GOPATH/src/github.com/myusername/project && cd "$_"

3. Initialize project and add gin

$ govendor init
$ govendor fetch github.com/gin-gonic/gin@v1.3

4. Copy a template to your project

$ curl https://raw.githubusercontent.com/gin-gonic/gin/master/examples/basic/main.go > main.go

5. Running the project

$ go run main.go

premise

Using gin requires Go version number 1.6 or higher

quick get start

Run this code and visit http://localhost:8080 in the browser

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
}

Code example

Use GET, POST, PUT, PATCH, DELETE, OPTIONS

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

    // Create a gin router using the 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)

    // The default boot port is port 8080, or you can define your own boot port
    router.Run()
    // router.Run(":3000") for a hard coded port
}

Get parameters in path

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

    // This rule can match the format of / user/john, but cannot match the format of / user / or / user
    router.GET("/user/:name", func(c *gin.Context) {
        name := c.Param("name")
        c.String(http.StatusOK, "Hello %s", name)
    })

    // However, this rule can match both the / user/john / format and the / user/john/send format
    // If no other router matches / 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")
}

Get get parameter

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

    // Matching url format: / welcome? Firstname = Jane & LastName = doe
    router.GET("/welcome", func(c *gin.Context) {
        firstname := c.DefaultQuery("firstname", "Guest")
        lastname := c.Query("lastname") // Short for c.Request.URL.Query().Get("lastname")

        c.String(http.StatusOK, "Hello %s %s", firstname, lastname)
    })
    router.Run(":8080")
}

Get Post parameters

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

    router.POST("/form_post", func(c *gin.Context) {
        message := c.PostForm("message")
        nick := c.DefaultPostForm("nick", "anonymous") // This method can set the default value

        c.JSON(200, gin.H{
            "status":  "posted",
            "message": message,
            "nick":    nick,
        })
    })
    router.Run(":8080")
}

Get + Post mix

Example:
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")
}

//Results: id: 1234; page: 1; name: manu; message: this_is_great

Upload files

Single file upload

Use file.Filename carefully, refer to Content-Disposition on MDN and #1693

The file name of the uploaded file can be customized by the user, so it may contain illegal strings. For security reasons, the server should unify the file name rules

func main() {
    router := gin.Default()
    // Limit the upload size of the form (32 MIB by default)
    // router.MaxMultipartMemory = 8 << 20  // 8 MiB
    router.POST("/upload", func(c *gin.Context) {
        // Single file
        file, _ := c.FormFile("file")
        log.Println(file.Filename)

        // Upload the file to the specified path
        // c.SaveUploadedFile(file, dst)

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

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

Multi file upload

func main() {
    router := gin.Default()
    // Limit the upload size of the form (32 MIB by default)
    // router.MaxMultipartMemory = 8 << 20  // 8 MiB
    router.POST("/upload", func(c *gin.Context) {
        // Multiple files
        form, _ := c.MultipartForm()
        files := form.File["upload[]"]

        for _, file := range files {
            log.Println(file.Filename)

            // Upload the file to the specified path
            // c.SaveUploadedFile(file, dst)
        }
        c.String(http.StatusOK, fmt.Sprintf("%d files uploaded!", len(files)))
    })
    router.Run(":8080")
}

curl Test:
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"

Routing packet

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")
}

Start without Middleware

Use

r := gin.New()

replace

// Default startup mode, including Logger and Recovery Middleware
r := gin.Default()

Using middleware

func main() {
    // Create a router without Middleware
    r := gin.New()

    // Global Middleware
    // Using Logger Middleware
    r.Use(gin.Logger())

    // Using Recovery Middleware
    r.Use(gin.Recovery())

    // Routing add middleware, you can add as many as you want
    r.GET("/benchmark", MyBenchLogger(), benchEndpoint)

    // Add middleware to routing 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")
}

Write log file

func main() {
    // Disable console color
    gin.DisableConsoleColor()

    // Create a log file
    f, _ := os.Create("gin.log")
    gin.DefaultWriter = io.MultiWriter(f)

    // If you need to write logs to both the file and the console, use the following code
    // gin.DefaultWriter = io.MultiWriter(f, os.Stdout)

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

    router.Run(":8080")
}

Custom log format

func main() {
    router := gin.New()

    // LoggerWithFormatter middleware will write log to gin.DefaultWriter
    // By default gin.DefaultWriter = os.Stdout
    router.Use(gin.LoggerWithFormatter(func(param gin.LogFormatterParams) string {

        // Your custom format
        return fmt.Sprintf("%s - [%s] \"%s %s %s %d %s \"%s\" %s\"\n",
                param.ClientIP,
                param.TimeStamp.Format(time.RFC1123),
                param.Method,
                param.Path,
                param.Request.Proto,
                param.StatusCode,
                param.Latency,
                param.Request.UserAgent(),
                param.ErrorMessage,
        )
    }))
    router.Use(gin.Recovery())

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

    router.Run(":8080")
}

//Output example:
::1 - [Fri, 07 Dec 2018 17:04:38 JST] "GET /ping HTTP/1.1 200 122.767µs "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_11_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/71.0.3578.80 Safari/537.36" "

Model binding and validation

To bind the request body to the structure, use model binding, which currently supports JSON, XML, YAML, and standard form values (foo = Bar & boo = Baz).
Gin use go-playground/validator.v8 Validation parameters, viewing Complete document.
You need to set the tag on the bound field. For example, if the binding format is json, you need to set json:"fieldname".

In addition, Gin provides two sets of binding methods:

  • Must bind

    1. Methods - Bind, BindJSON, BindXML, BindQuery, BindYAML

    2. Behavior - the underlying use of these methods is MustBindWith. If there is a binding error, the request will be aborted by the following instructions
      c.AbortWithError(400,err).SetType(ErrorTypeBind), the response status code will be set to 400, and the request header content type will be set to text/plain; charset=utf-8. Note that if you try to set the response code after this, a warning [gin debug] [warning] headers were already written. Wanted to override status code 400 with 422 will be issued. If you want to better control the behavior, please use ShouldBind related methods

  • Should bind

    1. Methods - ShouldBind, ShouldBindJSON, ShouldBindXML, ShouldBindQuery, ShouldBindYAML

    2. Behavior - the bottom layer of these methods uses ShouldBindWith. If there is a binding error, it will return an error, and the developer can handle the request and error correctly.

When we use the binding method, Gin will infer which binder to use based on the content type. If you are sure what you are binding, you can use MustBindWith or BindingWith.

You can also specify a modifier for a specific rule for a field. If a field is decorated with binding:"required", and the value of the field is empty when binding, an error will be returned.

// Bind as json
type Login struct {
    User     string `form:"user" json:"user" xml:"user"  binding:"required"`
    Password string `form:"password" json:"password" xml:"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 err := c.ShouldBindJSON(&json); err != nil {
            c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
            return
        }
        
        if json.User != "manu" || json.Password != "123" {
            c.JSON(http.StatusUnauthorized, gin.H{"status": "unauthorized"})
            return
        } 
        
        c.JSON(http.StatusOK, gin.H{"status": "you are logged in"})
    })

    // Example for binding XML (
    //  <?xml version="1.0" encoding="UTF-8"?>
    //  <root>
    //      <user>user</user>
    //      <password>123</password>
    //  </root>)
    router.POST("/loginXML", func(c *gin.Context) {
        var xml Login
        if err := c.ShouldBindXML(&xml); err != nil {
            c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
            return
        }
        
        if xml.User != "manu" || xml.Password != "123" {
            c.JSON(http.StatusUnauthorized, gin.H{"status": "unauthorized"})
            return
        } 
        
        c.JSON(http.StatusOK, gin.H{"status": "you are logged in"})
    })

    // 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 err := c.ShouldBind(&form); err != nil {
            c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
            return
        }
        
        if form.User != "manu" || form.Password != "123" {
            c.JSON(http.StatusUnauthorized, gin.H{"status": "unauthorized"})
            return
        } 
        
        c.JSON(http.StatusOK, gin.H{"status": "you are logged in"})
    })

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

//Request example:
$ curl -v -X POST \
  http://localhost:8080/loginJSON \
  -H 'content-type: application/json' \
  -d '{ "user": "manu" }'
> POST /loginJSON HTTP/1.1
> Host: localhost:8080
> User-Agent: curl/7.51.0
> Accept: */*
> content-type: application/json
> Content-Length: 18
>
* upload completely sent off: 18 out of 18 bytes
< HTTP/1.1 400 Bad Request
< Content-Type: application/json; charset=utf-8
< Date: Fri, 04 Aug 2017 03:51:31 GMT
< Content-Length: 100
<
{"error":"Key: 'Login.Password' Error:Field validation for 'Password' failed on the 'required' tag"}

Skip validation:

When running the above example with the curl command above, an error is returned because the Password field in the example uses binding:"required". If we use binding: "-", then it will not report an error.

Custom validator

Gin allows us to customize parameter validators, Reference resources

package main

import (
    "net/http"
    "reflect"
    "time"

    "github.com/gin-gonic/gin"
    "github.com/gin-gonic/gin/binding"
    "gopkg.in/go-playground/validator.v8"
)

// Booking contains binded and validated data.
type Booking struct {
    CheckIn  time.Time `form:"check_in" binding:"required,bookabledate" time_format:"2006-01-02"`
    CheckOut time.Time `form:"check_out" binding:"required,gtfield=CheckIn" time_format:"2006-01-02"`
}

func bookableDate(
    v *validator.Validate, topStruct reflect.Value, currentStructOrField reflect.Value,
    field reflect.Value, fieldType reflect.Type, fieldKind reflect.Kind, param string,
) bool {
    if date, ok := field.Interface().(time.Time); ok {
        today := time.Now()
        if today.Year() > date.Year() || today.YearDay() > date.YearDay() {
            return false
        }
    }
    return true
}

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

    if v, ok := binding.Validator.Engine().(*validator.Validate); ok {
        v.RegisterValidation("bookabledate", bookableDate)
    }

    route.GET("/bookable", getBookable)
    route.Run(":8085")
}

func getBookable(c *gin.Context) {
    var b Booking
    if err := c.ShouldBindWith(&b, binding.Query); err == nil {
        c.JSON(http.StatusOK, gin.H{"message": "Booking dates are valid!"})
    } else {
        c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
    }
}

$ curl "localhost:8085/bookable?check_in=2018-04-16&check_out=2018-04-17"
{"message":"Booking dates are valid!"}

$ curl "localhost:8085/bookable?check_in=2018-03-08&check_out=2018-03-09"
{"error":"Key: 'Booking.CheckIn' Error:Field validation for 'CheckIn' failed on the 'bookabledate' tag"}

Bind only Get parameters

ShouldBindQuery function only binds Get parameter, not post data. View detailed information

package main

import (
    "log"

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

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

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

func startPage(c *gin.Context) {
    var person Person
    if c.ShouldBindQuery(&person) == nil {
        log.Println("====== Only Bind By Query String ======")
        log.Println(person.Name)
        log.Println(person.Address)
    }
    c.String(200, "Success")
}

Bind Get parameter or Post parameter

View details , this example is very useful, you can practice it yourself

package main

import (
    "log"
    "time"

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

type Person struct {
    Name     string    `form:"name"`
    Address  string    `form:"address"`
    Birthday time.Time `form:"birthday" time_format:"2006-01-02" time_utc:"1"`
}

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 it is Get, the data of Post in the request cannot be received??
    // If it is Post, first determine the type 'JSON' or 'XML' of 'content type', and then use the corresponding binder to get the data
    // See more at https://github.com/gin-gonic/gin/blob/master/binding/binding.go#L48
    if c.ShouldBind(&person) == nil {
        log.Println(person.Name)
        log.Println(person.Address)
        log.Println(person.Birthday)
    }

    c.String(200, "Success")
}

Binding uri

View details

package main

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

type Person struct {
    ID string `uri:"id" binding:"required,uuid"`
    Name string `uri:"name" binding:"required"`
}

func main() {
    route := gin.Default()
    route.GET("/:name/:id", func(c *gin.Context) {
        var person Person
        if err := c.ShouldBindUri(&person); err != nil {
            c.JSON(400, gin.H{"msg": err})
            return
        }
        c.JSON(200, gin.H{"name": person.Name, "uuid": person.ID})
    })
    route.Run(":8088")
}

//Test case:
$ curl -v localhost:8088/thinkerou/987fbc97-4bed-5078-9f07-9141ba07c9f3
$ curl -v localhost:8088/thinkerou/not-uuid

Bind HTML check box

View details

main.go
...

type myForm struct {
    Colors []string `form:"colors[]"`
}

...

func formHandler(c *gin.Context) {
    var fakeForm myForm
    c.ShouldBind(&fakeForm)
    c.JSON(200, gin.H{"color": fakeForm.Colors})
}

...

form.html
<form action="/" method="POST">
    <p>Check some colors</p>
    <label for="red">Red</label>
    <input type="checkbox" name="colors[]" value="red" id="red">
    <label for="green">Green</label>
    <input type="checkbox" name="colors[]" value="green" id="green">
    <label for="blue">Blue</label>
    <input type="checkbox" name="colors[]" value="blue" id="blue">
    <input type="submit">
</form>

result:
{"color":["red","green","blue"]}

Bind Post parameter

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.ShouldBindWith(&form, binding.Form)
        // or you can simply use autobinding with ShouldBind method:
        var form LoginForm
        // in this case proper binding will be automatically selected
        if c.ShouldBind(&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 case:
$ curl -v --form user=user --form password=password http://localhost:8080/login

XML, JSON, YAML, and ProtoBuf rendering (output format)

That is, the data format returned by the interface

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})
    })

    r.GET("/someProtoBuf", func(c *gin.Context) {
        reps := []int64{int64(1), int64(2)}
        label := "test"
        // The specific definition of protobuf is written in the testdata/protoexample file.
        data := &protoexample.Test{
            Label: &label,
            Reps:  reps,
        }
        // Note that data becomes binary data in the response
        // Will output protoexample.Test protobuf serialized data
        c.ProtoBuf(http.StatusOK, data)
    })

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

SecureJSON

Using SecureJSON can prevent json hijacking. If the returned data is an array, the "while(1)" will be added before the returned value by default

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

    // You can customize the json data prefix returned
    // r.SecureJsonPrefix(")]}',\n")

    r.GET("/someJSON", func(c *gin.Context) {
        names := []string{"lena", "austin", "foo"}

        // Will output: while(1);["lena","austin","foo"]
        c.SecureJSON(http.StatusOK, names)
    })

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

JSONP

JSONP can be used for cross domain transmission. If there is a callback parameter in the parameter, the returned parameter will be in the form of a callback function

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

    r.GET("/JSONP", func(c *gin.Context) {
        data := map[string]interface{}{
            "foo": "bar",
        }
        
        // Visit http://localhost:8080/JSONP?callback=call
        // Will output: call({foo:"bar"})
        c.JSONP(http.StatusOK, data)
    })

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

AsciiJSON

Using ASCII JSON will encode special characters

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

    r.GET("/someJSON", func(c *gin.Context) {
        data := map[string]interface{}{
            "lang": "GO language",
            "tag":  "<br>",
        }

        // Output: {"lang":"GO\u8bed\u8a00","tag":"\u003cbr\u003e"}
        c.AsciiJSON(http.StatusOK, data)
    })

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

PureJSON

In general, JSON will replace special HTML characters with corresponding unicode characters, such as < replace with \ u003c. If you want to output HTML as is, use PureJSON. This feature cannot be used in Go 1.6 and below.

func main() {
    r := gin.Default()
    
    // Serves unicode entities
    r.GET("/json", func(c *gin.Context) {
        c.JSON(200, gin.H{
            "html": "<b>Hello, world!</b>",
        })
    })
    
    // Serves literal characters
    r.GET("/purejson", func(c *gin.Context) {
        c.PureJSON(200, gin.H{
            "html": "<b>Hello, world!</b>",
        })
    })
    
    // listen and serve on 0.0.0.0:8080
    r.Run(":8080")
}

Set static file path

Path setting is required to access 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")
}

Return the data acquired by the third party

func main() {
    router := gin.Default()
    router.GET("/someDataFromReader", func(c *gin.Context) {
        response, err := http.Get("https://raw.githubusercontent.com/gin-gonic/logo/master/color.png")
        if err != nil || response.StatusCode != http.StatusOK {
            c.Status(http.StatusServiceUnavailable)
            return
        }

        reader := response.Body
        contentLength := response.ContentLength
        contentType := response.Header.Get("Content-Type")

        extraHeaders := map[string]string{
            "Content-Disposition": `attachment; filename="gopher.png"`,
        }

        c.DataFromReader(http.StatusOK, contentLength, contentType, reader, extraHeaders)
    })
    router.Run(":8080")
}

HTML rendering

Use loadhtmlglobal() 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>

Use a template with the 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 }}

Custom template renderer

import "html/template"

func main() {
    router := gin.Default()
    html := template.Must(template.ParseFiles("file1", "file2"))
    router.SetHTMLTemplate(html)
    router.Run(":8080")
}

Custom render separator

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

Custom template functions

main.go
import (
    "fmt"
    "html/template"
    "net/http"
    "time"

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

func formatAsDate(t time.Time) string {
    year, month, day := t.Date()
    return fmt.Sprintf("%d%02d/%02d", year, month, day)
}

func main() {
    router := gin.Default()
    router.Delims("{[{", "}]}")
    router.SetFuncMap(template.FuncMap{
        "formatAsDate": formatAsDate,
    })
    router.LoadHTMLFiles("./testdata/template/raw.tmpl")

    router.GET("/raw", func(c *gin.Context) {
        c.HTML(http.StatusOK, "raw.tmpl", map[string]interface{}{
            "now": time.Date(2017, 07, 01, 0, 0, 0, 0, time.UTC),
        })
    })

    router.Run(":8080")
}

raw.tmpl
//Then you can use the formatAsDate function directly in html
Date: {[{.now | formatAsDate}]}

Result:
Date: 2017/07/01

Multiple template files

Gin only allows one html template file by default (that is, multiple template files can be loaded at a time), click here View implementation cases

redirect

It's easy to publish HTTP redirects, supporting internal and external links

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

For Gin route redirection, use the following HandleContext

r.GET("/test", func(c *gin.Context) {
    c.Request.URL.Path = "/test2"
    r.HandleContext(c)
})
r.GET("/test2", func(c *gin.Context) {
    c.JSON(200, gin.H{"hello": "world"})
})

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() (authentication) 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")
}

Using Goroutines in middleware

When starting a new Goroutines in middleware or handler, you should not use its original context. You must use a read-only copy (c.Copy())

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

    r.GET("/long_async", func(c *gin.Context) {
        // Create a replica to use in goroutine
        cCp := c.Copy()
        go func() {
            // simulate a long task with time.Sleep(). 5 seconds
            time.Sleep(5 * time.Second)

            // Use the copy you created here
            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)

        // goroutine is not used here, so no replica is used
        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 directly like this`http.ListenAndServe()`
func main() {
    router := gin.Default()
    http.ListenAndServe(":8080", router)
}

//perhaps
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 for Let's Encrypt certificates

1 line of code to implement LetsEncrypt HTTPS server

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"))
}

An example of customizing the 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))
}

Gin runs multiple services

please Refer to questions And try the following example

package main

import (
    "log"
    "net/http"
    "time"

    "github.com/gin-gonic/gin"
    "golang.org/x/sync/errgroup"
)

var (
    g errgroup.Group
)

func router01() http.Handler {
    e := gin.New()
    e.Use(gin.Recovery())
    e.GET("/", func(c *gin.Context) {
        c.JSON(
            http.StatusOK,
            gin.H{
                "code":  http.StatusOK,
                "error": "Welcome server 01",
            },
        )
    })

    return e
}

func router02() http.Handler {
    e := gin.New()
    e.Use(gin.Recovery())
    e.GET("/", func(c *gin.Context) {
        c.JSON(
            http.StatusOK,
            gin.H{
                "code":  http.StatusOK,
                "error": "Welcome server 02",
            },
        )
    })

    return e
}

func main() {
    server01 := &http.Server{
        Addr:         ":8080",
        Handler:      router01(),
        ReadTimeout:  5 * time.Second,
        WriteTimeout: 10 * time.Second,
    }

    server02 := &http.Server{
        Addr:         ":8081",
        Handler:      router02(),
        ReadTimeout:  5 * time.Second,
        WriteTimeout: 10 * time.Second,
    }

    g.Go(func() error {
        return server01.ListenAndServe()
    })

    g.Go(func() error {
        return server02.ListenAndServe()
    })

    if err := g.Wait(); err != nil {
        log.Fatal(err)
    }
}

Graceful restart or stop

To gracefully restart or stop your Web server, use the following methods
We can use fvblock / endless to replace the default ListenAndServe. For more information, see the question #296

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

An alternative

  • manners : a Go HTTP server that can be shut down gracefully
  • graceful : Graceful is a go package that supports Graceful shutdown of the http.Handler server
  • grace : elegant restart and zero downtime deployment of Go server

If your Go version is 1.8, you may not need to use this library. Consider using http.Server's built-in Shutdown() method for graceful shutdown

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 && err != http.ErrServerClosed {
            log.Fatalf("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 exiting")
}

Building binaries with templates

You can use go-assets Build the server as a binary with templates

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

    t, err := loadTemplate()
    if err != nil {
        panic(err)
    }
    r.SetHTMLTemplate(t)

    r.GET("/", func(c *gin.Context) {
        c.HTML(http.StatusOK, "/html/index.tmpl",nil)
    })
    r.Run(":8080")
}

// loadTemplate loads templates embedded by go-assets-builder
func loadTemplate() (*template.Template, error) {
    t := template.New("")
    for name, file := range Assets.Files {
        if file.IsDir() || !strings.HasSuffix(name, ".tmpl") {
            continue
        }
        h, err := ioutil.ReadAll(file)
        if err != nil {
            return nil, err
        }
        t, err = t.New(name).Parse(string(h))
        if err != nil {
            return nil, err
        }
    }
    return t, nil
}

See examples in the examples / assets in binary directory

Binding form data with a custom structure

The following example uses a custom structure

type StructA struct {
    FieldA string `form:"field_a"`
}

type StructB struct {
    NestedStruct StructA
    FieldB string `form:"field_b"`
}

type StructC struct {
    NestedStructPointer *StructA
    FieldC string `form:"field_c"`
}

type StructD struct {
    NestedAnonyStruct struct {
        FieldX string `form:"field_x"`
    }
    FieldD string `form:"field_d"`
}

func GetDataB(c *gin.Context) {
    var b StructB
    c.Bind(&b)
    c.JSON(200, gin.H{
        "a": b.NestedStruct,
        "b": b.FieldB,
    })
}

func GetDataC(c *gin.Context) {
    var b StructC
    c.Bind(&b)
    c.JSON(200, gin.H{
        "a": b.NestedStructPointer,
        "c": b.FieldC,
    })
}

func GetDataD(c *gin.Context) {
    var b StructD
    c.Bind(&b)
    c.JSON(200, gin.H{
        "x": b.NestedAnonyStruct,
        "d": b.FieldD,
    })
}

func main() {
    r := gin.Default()
    r.GET("/getb", GetDataB)
    r.GET("/getc", GetDataC)
    r.GET("/getd", GetDataD)

    r.Run()
}

//Running example:
$ curl "http://localhost:8080/getb?field_a=hello&field_b=world"
{"a":{"FieldA":"hello"},"b":"world"}
$ curl "http://localhost:8080/getc?field_a=hello&field_c=world"
{"a":{"FieldA":"hello"},"c":"world"}
$ curl "http://localhost:8080/getd?field_x=hello&field_d=world"
{"d":"world","x":{"FieldX":"hello"}}

//Note: the following style structures are not supported
type StructX struct {
    X struct {} `form:"name_x"` // HERE have form
}

type StructY struct {
    Y StructX `form:"name_y"` // HERE have form
}

type StructZ struct {
    Z *StructZ `form:"name_z"` // HERE have form
}

All in all, now only the custom structure without form label is supported

Bind the request body to a different structure

The general method of binding request body uses c.Request.Body and cannot be called more than once

type formA struct {
  Foo string `json:"foo" xml:"foo" binding:"required"`
}

type formB struct {
  Bar string `json:"bar" xml:"bar" binding:"required"`
}

func SomeHandler(c *gin.Context) {
  objA := formA{}
  objB := formB{}
  // This c.ShouldBind consumes c.Request.Body and it cannot be reused.
  if errA := c.ShouldBind(&objA); errA == nil {
    c.String(http.StatusOK, `the body should be formA`)
  // Always an error is occurred by this because c.Request.Body is EOF now.
  } else if errB := c.ShouldBind(&objB); errB == nil {
    c.String(http.StatusOK, `the body should be formB`)
  } else {
    ...
  }
}

Also, you can use c.ShouldBindBodyWith

func SomeHandler(c *gin.Context) {
  objA := formA{}
  objB := formB{}
  // This reads c.Request.Body and stores the result into the context.
  if errA := c.ShouldBindBodyWith(&objA, binding.JSON); errA == nil {
    c.String(http.StatusOK, `the body should be formA`)
  // At this time, it reuses body stored in the context.
  } else if errB := c.ShouldBindBodyWith(&objB, binding.JSON); errB == nil {
    c.String(http.StatusOK, `the body should be formB JSON`)
  // And it can accepts other formats
  } else if errB2 := c.ShouldBindBodyWith(&objB, binding.XML); errB2 == nil {
    c.String(http.StatusOK, `the body should be formB XML`)
  } else {
    ...
  }
}

c.ShouldBindBodyWith stores the body in the context before binding, which has a slight performance impact, so you should not use this method if you want to call immediately
This function only applies to these formats – JSON, XML, MsgPack,ProtoBuf. For other formats, Query, Form, FormPost, FormMultipart can be called multiple times by c.ShouldBind() without affecting performance( Reference #1341)

HTTP/2 server push

http.Pusher only supports Go 1.8 or later

package main

import (
    "html/template"
    "log"

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

var html = template.Must(template.New("https").Parse(`
<html>
<head>
  <title>Https Test</title>
  <script src="/assets/app.js"></script>
</head>
<body>
  <h1 style="color:red;">Welcome, Ginner!</h1>
</body>
</html>
`))

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

    r.GET("/", func(c *gin.Context) {
        if pusher := c.Writer.Pusher(); pusher != nil {
            // use pusher.Push() to do server push
            if err := pusher.Push("/assets/app.js", nil); err != nil {
                log.Printf("Failed to push: %v", err)
            }
        }
        c.HTML(200, "https", gin.H{
            "status": "success",
        })
    })

    // Listen and Server in https://127.0.0.1:8080
    r.RunTLS(":8080", "./testdata/server.pem", "./testdata/server.key")
}

Format of custom routing log

The default routing log is as follows:

[GIN-debug] POST   /foo                      --> main.main.func1 (3 handlers)
[GIN-debug] GET    /bar                      --> main.main.func2 (3 handlers)
[GIN-debug] GET    /status                   --> main.main.func3 (3 handlers)

If you want to record these information in a given format (such as JSON, key value pair or other formats), you can use gin.DebugPrintRouteFunc to define the format. In the following example, we use standard log packet to record routing logs, and you can use other logging tools that are suitable for your needs

import (
    "log"
    "net/http"

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

func main() {
    r := gin.Default()
    gin.DebugPrintRouteFunc = func(httpMethod, absolutePath, handlerName string, nuHandlers int) {
        log.Printf("endpoint %v %v %v %v\n", httpMethod, absolutePath, handlerName, nuHandlers)
    }

    r.POST("/foo", func(c *gin.Context) {
        c.JSON(http.StatusOK, "foo")
    })

    r.GET("/bar", func(c *gin.Context) {
        c.JSON(http.StatusOK, "bar")
    })

    r.GET("/status", func(c *gin.Context) {
        c.JSON(http.StatusOK, "ok")
    })

    // Listen and Server in http://0.0.0.0:8080
    r.Run()
}

Set and get cookie s

import (
    "fmt"

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

func main() {

    router := gin.Default()

    router.GET("/cookie", func(c *gin.Context) {

        cookie, err := c.Cookie("gin_cookie")

        if err != nil {
            cookie = "NotSet"
            c.SetCookie("gin_cookie", "test", 3600, "/", "localhost", false, true)
        }

        fmt.Printf("Cookie value: %s \n", cookie)
    })

    router.Run()
}

test

net/http/httptest package is the preferred way of http testing

package main

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

func main() {
    r := setupRouter()
    r.Run(":8080")
}

Test the sample code above

package main

import (
    "net/http"
    "net/http/httptest"
    "testing"

    "github.com/stretchr/testify/assert"
)

func TestPingRoute(t *testing.T) {
    router := setupRouter()

    w := httptest.NewRecorder()
    req, _ := http.NewRequest("GET", "/ping", nil)
    router.ServeHTTP(w, req)

    assert.Equal(t, 200, w.Code)
    assert.Equal(t, "pong", w.Body.String())
}

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Tags: JSON github xml curl

Posted on Tue, 25 Feb 2020 22:01:43 -0800 by uniboy86