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.
Contents
- Installation
- Prerequisite
- Quick start
- Benchmarks
- Gin v1.stable
- Build with jsoniter
- API Examples
- Using GET,POST,PUT,PATCH,DELETE and OPTIONS
- Parameters in path
- Querystring parameters
- Multipart/Urlencoded Form
- Another example: query + post form
- Map as querystring or postform parameters
- Upload files
- Grouping routes
- Blank Gin without middleware by default
- Using middleware
- How to write log file
- Custom Log Format
- Model binding and validation
- Custom Validators
- Only Bind Query String
- Bind Query String or Post Data
- Bind Uri
- Bind Header
- Bind HTML checkboxes
- Multipart/Urlencoded binding
- XML, JSON, YAML and ProtoBuf rendering
- JSONP rendering
- Serving static files
- Serving data from reader
- HTML rendering
- Multitemplate
- Redirects
- Custom Middleware
- Using BasicAuth() middleware
- Goroutines inside a middleware
- Custom HTTP configuration
- Support Let's Encrypt
- Run multiple service using Gin
- Graceful restart or stop
- Build a single binary with templates
- Bind form-data request with custom struct
- Try to bind body into different structs
- http2 server push
- Define format for the log of routes
- Set and get a cookie
- Testing
- Users
Installation
To install Gin package, you need to install Go and set your Go workspace first.
- The first need Go installed (version 1.10+ is required), then you can use the below Go command to install Gin.
$ go get -u 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 ashttp.StatusOK
.
import "net/http"
Govendor
Use a vendor tool likego get
govendor
$ go get github.com/kardianos/govendor
- Create your project folder and
cd
inside
$ mkdir -p $GOPATH/src/github.com/myusername/project && cd "$_"
- Vendor init your project and add gin
$ govendor init
$ govendor fetch github.com/gin-gonic/gin@v1.3
- Copy a starting template inside your project
$ curl https://raw.githubusercontent.com/gin-gonic/examples/master/basic/main.go > main.go
- Run your project
$ go run main.go
Quick start
# assume the following codes in example.go file
$ cat example.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
}
# run example.go and visit 0.0.0.0:8080/ping on browser
$ go run example.go
Benchmarks
Gin uses a custom version of HttpRouter
Benchmark name | (1) | (2) | (3) | (4) |
---|---|---|---|---|
BenchmarkGin_GithubAll | 30000 | 48375 | 0 | 0 |
BenchmarkAce_GithubAll | 10000 | 134059 | 13792 | 167 |
BenchmarkBear_GithubAll | 5000 | 534445 | 86448 | 943 |
BenchmarkBeego_GithubAll | 3000 | 592444 | 74705 | 812 |
BenchmarkBone_GithubAll | 200 | 6957308 | 698784 | 8453 |
BenchmarkDenco_GithubAll | 10000 | 158819 | 20224 | 167 |
BenchmarkEcho_GithubAll | 10000 | 154700 | 6496 | 203 |
BenchmarkGocraftWeb_GithubAll | 3000 | 570806 | 131656 | 1686 |
BenchmarkGoji_GithubAll | 2000 | 818034 | 56112 | 334 |
BenchmarkGojiv2_GithubAll | 2000 | 1213973 | 274768 | 3712 |
BenchmarkGoJsonRest_GithubAll | 2000 | 785796 | 134371 | 2737 |
BenchmarkGoRestful_GithubAll | 300 | 5238188 | 689672 | 4519 |
BenchmarkGorillaMux_GithubAll | 100 | 10257726 | 211840 | 2272 |
BenchmarkHttpRouter_GithubAll | 20000 | 105414 | 13792 | 167 |
BenchmarkHttpTreeMux_GithubAll | 10000 | 319934 | 65856 | 671 |
BenchmarkKocha_GithubAll | 10000 | 209442 | 23304 | 843 |
BenchmarkLARS_GithubAll | 20000 | 62565 | 0 | 0 |
BenchmarkMacaron_GithubAll | 2000 | 1161270 | 204194 | 2000 |
BenchmarkMartini_GithubAll | 200 | 9991713 | 226549 | 2325 |
BenchmarkPat_GithubAll | 200 | 5590793 | 1499568 | 27435 |
BenchmarkPossum_GithubAll | 10000 | 319768 | 84448 | 609 |
BenchmarkR2router_GithubAll | 10000 | 305134 | 77328 | 979 |
BenchmarkRivet_GithubAll | 10000 | 132134 | 16272 | 167 |
BenchmarkTango_GithubAll | 3000 | 552754 | 63826 | 1618 |
BenchmarkTigerTonic_GithubAll | 1000 | 1439483 | 239104 | 5374 |
BenchmarkTraffic_GithubAll | 100 | 11383067 | 2659329 | 21848 |
BenchmarkVulcan_GithubAll | 5000 | 394253 | 19894 | 609 |
- (1): Total Repetitions achieved in constant time, higher means more confident result
- (2): Single Repetition Duration (ns/op), lower is better
- (3): Heap Memory (B/op), lower is better
- (4): Average Allocations per Repetition (allocs/op), lower is better
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.
jsoniter
Build withGin uses encoding/json
as default json package but you can change to jsoniter by build from other tags.
$ go build -tags=jsoniter .
API Examples
You can find a number of ready-to-run examples at Gin examples repository.
Using GET, POST, PUT, PATCH, DELETE and OPTIONS
func main() {
// 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 /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)
})
// For each matched request Context will hold the route definition
router.POST("/user/:name/*action", func(c *gin.Context) {
c.FullPath() == "/user/:name/*action" // true
})
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
Map as querystring or postform parameters
POST /post?ids[a]=1234&ids[b]=hello HTTP/1.1
Content-Type: application/x-www-form-urlencoded
names[first]=thinkerou&names[second]=tianou
func main() {
router := gin.Default()
router.POST("/post", func(c *gin.Context) {
ids := c.QueryMap("ids")
names := c.PostFormMap("names")
fmt.Printf("ids: %v; names: %v", ids, names)
})
router.Run(":8080")
}
ids: map[b:hello a:1234], names: map[second:tianou first:thinkerou]
Upload files
Single file
References issue #774 and detail example code.
file.Filename
SHOULD NOT be trusted. See Content-Disposition
on MDN and #1693
The filename is always optional and must not be used blindly by the application: path information should be stripped, and conversion to the server file system rules should be done.
func main() {
router := gin.Default()
// Set a lower memory limit for multipart forms (default is 32 MiB)
// 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 specific dst.
// c.SaveUploadedFile(file, dst)
c.String(http.StatusOK, fmt.Sprintf("'%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()
// Set a lower memory limit for multipart forms (default is 32 MiB)
// router.MaxMultipartMemory = 8 << 20 // 8 MiB
router.POST("/upload", func(c *gin.Context) {
// Multipart form
form, _ := c.MultipartForm()
files := form.File["upload[]"]
for _, file := range files {
log.Println(file.Filename)
// Upload the file to specific dst.
// c.SaveUploadedFile(file, dst)
}
c.String(http.StatusOK, fmt.Sprintf("%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
// Default With the Logger and Recovery middleware already attached
r := gin.Default()
Using middleware
func main() {
// Creates a router without any middleware by default
r := gin.New()
// Global middleware
// Logger middleware will write the logs to gin.DefaultWriter even if you set with GIN_MODE=release.
// By default gin.DefaultWriter = os.Stdout
r.Use(gin.Logger())
// Recovery middleware recovers from any panics and writes a 500 if there was one.
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")
}
How to write log file
func main() {
// Disable Console Color, you don't need console color when writing the logs to file.
gin.DisableConsoleColor()
// Logging to a file.
f, _ := os.Create("gin.log")
gin.DefaultWriter = io.MultiWriter(f)
// Use the following code if you need to write the logs to file and console at the same time.
// 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 the logs 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")
}
Sample Output
::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" "
Controlling Log output coloring
By default, logs output on console should be colorized depending on the detected TTY.
Never colorize logs:
func main() {
// Disable log's color
gin.DisableConsoleColor()
// Creates a gin router with default middleware:
// logger and recovery (crash-free) middleware
router := gin.Default()
router.GET("/ping", func(c *gin.Context) {
c.String(200, "pong")
})
router.Run(":8080")
}
Always colorize logs:
func main() {
// Force log's color
gin.ForceConsoleColor()
// Creates a gin router with default middleware:
// logger and recovery (crash-free) middleware
router := gin.Default()
router.GET("/ping", func(c *gin.Context) {
c.String(200, "pong")
})
router.Run(":8080")
}
Model binding and validation
To bind a request body into a type, use model binding. We currently support binding of JSON, XML, YAML and standard form values (foo=bar&boo=baz).
Gin uses go-playground/validator.v8 for validation. Check the full docs on tags usage here.
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"
.
Also, Gin provides two sets of methods for binding:
- Type - Must bind
- Methods -
Bind
,BindJSON
,BindXML
,BindQuery
,BindYAML
,BindHeader
- Behavior - These methods use
MustBindWith
under the hood. If there is a binding error, the request is aborted withc.AbortWithError(400, err).SetType(ErrorTypeBind)
. This sets the response status code to 400 and theContent-Type
header is set totext/plain; charset=utf-8
. Note that if you try to set the response code after this, it will result in a warning[GIN-debug] [WARNING] Headers were already written. Wanted to override status code 400 with 422
. If you wish to have greater control over the behavior, consider using theShouldBind
equivalent method.
- Methods -
- Type - Should bind
- Methods -
ShouldBind
,ShouldBindJSON
,ShouldBindXML
,ShouldBindQuery
,ShouldBindYAML
,ShouldBindHeader
- Behavior - These methods use
ShouldBindWith
under the hood. If there is a binding error, the error is returned and it is the developer's responsibility to handle the request and error appropriately.
- Methods -
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 MustBindWith
or ShouldBindWith
.
You can also specify that specific fields are required. If a field is decorated with binding:"required"
and has a empty value when binding, an error will be returned.
// Binding from 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")
}
Sample request
$ 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 validate
When running the above example using the above the curl
command, it returns error. Because the example use binding:"required"
for Password
. If use binding:"-"
for Password
, then it will not return error when running the above example again.
Custom Validators
It is also possible to register custom validators. See the example code.
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.After(date) {
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"}
Struct level validations can also be registered this way. See the struct-lvl-validation example to learn more.
Only Bind Query String
ShouldBindQuery
function only binds the query params and not the post data. See the detail 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 Query String or Post Data
See the detail information.
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"`
CreateTime time.Time `form:"createTime" time_format:"unixNano"`
UnixTime time.Time `form:"unixTime" time_format:"unix"`
}
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/master/binding/binding.go#L48
if c.ShouldBind(&person) == nil {
log.Println(person.Name)
log.Println(person.Address)
log.Println(person.Birthday)
log.Println(person.CreateTime)
log.Println(person.UnixTime)
}
c.String(200, "Success")
}
Test it with:
$ curl -X GET "localhost:8085/testing?name=appleboy&address=xyz&birthday=1992-03-15&createTime=1562400033000000123&unixTime=1562400033"
Bind Uri
See the detail information.
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 it with:
$ curl -v localhost:8088/thinkerou/987fbc97-4bed-5078-9f07-9141ba07c9f3
$ curl -v localhost:8088/thinkerou/not-uuid
Bind Header
package main
import (
"fmt"
"github.com/gin-gonic/gin"
)
type testHeader struct {
Rate int `header:"Rate"`
Domain string `header:"Domain"`
}
func main() {
r := gin.Default()
r.GET("/", func(c *gin.Context) {
h := testHeader{}
if err := c.ShouldBindHeader(&h); err != nil {
c.JSON(200, err)
}
fmt.Printf("%#v\n", h)
c.JSON(200, gin.H{"Rate": h.Rate, "Domain": h.Domain})
})
r.Run()
// client
// curl -H "rate:300" -H "domain:music" 127.0.0.1:8080/
// output
// {"Domain":"music","Rate":300}
}
Bind HTML checkboxes
See the detail information
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"]}
Multipart/Urlencoded binding
type ProfileForm struct {
Name string `form:"name" binding:"required"`
Avatar *multipart.FileHeader `form:"avatar" binding:"required"`
// or for multiple files
// Avatars []*multipart.FileHeader `form:"avatar" binding:"required"`
}
func main() {
router := gin.Default()
router.POST("/profile", 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 ProfileForm
// in this case proper binding will be automatically selected
if err := c.ShouldBind(&form); err != nil {
c.String(http.StatusBadRequest, "bad request")
return
}
err := c.SaveUploadedFile(form.Avatar, form.Avatar.Filename)
if err != nil {
c.String(http.StatusInternalServerError, "unknown error")
return
}
// db.Save(&form)
c.String(http.StatusOK, "ok")
})
router.Run(":8080")
}
Test it with:
$ curl -X POST -v --form name=user --form "avatar=@./avatar.png" http://localhost:8080/profile
XML, JSON, YAML and ProtoBuf 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})
})
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 to prevent json hijacking. Default prepends "while(1),"
to response body if the given struct is array values.
func main() {
r := gin.Default()
// You can also use your own secure json prefix
// 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
Using JSONP to request data from a server in a different domain. Add callback to response body if the query parameter callback exists.
func main() {
r := gin.Default()
r.GET("/JSONP", func(c *gin.Context) {
data := gin.H{
"foo": "bar",
}
//callback is x
// Will output : x({\"foo\":\"bar\"})
c.JSONP(http.StatusOK, data)
})
// Listen and serve on 0.0.0.0:8080
r.Run(":8080")
// client
// curl http://127.0.0.1:8080/JSONP?callback=x
}
AsciiJSON
Using AsciiJSON to Generates ASCII-only JSON with escaped non-ASCII chracters.
func main() {
r := gin.Default()
r.GET("/someJSON", func(c *gin.Context) {
data := gin.H{
"lang": "GOčŻč¨€",
"tag": "<br>",
}
// will 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
Normally, JSON replaces special HTML characters with their unicode entities, e.g. <
becomes \u003c
. If you want to encode such characters literally, you can use PureJSON instead.
This feature is unavailable in Go 1.6 and lower.
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")
}
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")
}
Serving data from reader
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
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 }}
Custom Template renderer
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")
}
Custom Delimiters
You may use custom delims
r := gin.Default()
r.Delims("{[{", "}]}")
r.LoadHTMLGlob("/path/to/templates")
Custom Template Funcs
See the detail example code.
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", gin.H{
"now": time.Date(2017, 07, 01, 0, 0, 0, 0, time.UTC),
})
})
router.Run(":8080")
}
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. Both internal and external locations are supported.
r.GET("/test", func(c *gin.Context) {
c.Redirect(http.StatusMovedPermanently, "http://www.google.com/")
})
Issuing a Router redirect, use HandleContext
like below.
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() 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 new Goroutines 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)
}
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()
}
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))
}
Run multiple service using Gin
See the question 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
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"
"syscall"
"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)
// kill (no param) default send syscall.SIGTERM
// kill -2 is syscall.SIGINT
// kill -9 is syscall.SIGKILL but can't be catch, so don't need add it
signal.Notify(quit, syscall.SIGINT, syscall.SIGTERM)
<-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)
}
// catching ctx.Done(). timeout of 5 seconds.
select {
case <-ctx.Done():
log.Println("timeout of 5 seconds.")
}
log.Println("Server exiting")
}
Build a single binary with templates
You can build a server into a single binary containing templates by using go-assets.
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 a complete example in the https://github.com/gin-gonic/examples/tree/master/assets-in-binary
directory.
Bind form-data request with custom struct
The follow example using custom struct:
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()
}
Using the command curl
command result:
$ 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"}}
Try to bind body into different structs
The normal methods for binding request body consumes c.Request.Body
and they
cannot be called multiple times.
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 {
...
}
}
For this, 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 body into the context before binding. This has a slight impact to performance, so you should not use this method if you are enough to call binding at once.- This feature is only needed for some formats --
JSON
,XML
,MsgPack
,ProtoBuf
. For other formats,Query
,Form
,FormPost
,FormMultipart
, can be called byc.ShouldBind()
multiple times without any damage to performance (See #1341).
http2 server push
http.Pusher is supported only go1.8+. See the golang blog for detail information.
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")
}
Define format for the log of routes
The default log of routes is:
[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 log this information in given format (e.g. JSON, key values or something else), then you can define this format with gin.DebugPrintRouteFunc
.
In the example below, we log all routes with standard log package but you can use another log tools that suits of 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 a cookie
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()
}
Testing
The net/http/httptest
package is preferable way for 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 for code example 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())
}
Users
Awesome project lists using Gin web framework.
- gorush: A push notification server written in Go.
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- photoprism: Personal photo management powered by Go and Google TensorFlow.
- krakend: Ultra performant API Gateway with middlewares.
- picfit: An image resizing server written in Go.
- brigade: Event-based Scripting for Kubernetes.