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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](https://github.com/julienschmidt/httprouter). If you need performance and good productivity, you will love Gin.
## Contents
- [Installation](#installation)
- [Prerequisite](#prerequisite)
- [Quick start](#quick-start)
- [Benchmarks](#benchmarks)
- [Gin v1.stable](#gin-v1-stable)
- [Build with jsoniter](#build-with-jsoniter)
- [API Examples](#api-examples)
- [Using GET,POST,PUT,PATCH,DELETE and OPTIONS](#using-get-post-put-patch-delete-and-options)
- [Parameters in path](#parameters-in-path)
- [Querystring parameters](#querystring-parameters)
- [Multipart/Urlencoded Form](#multiparturlencoded-form)
- [Another example: query + post form](#another-example-query--post-form)
- [Map as querystring or postform parameters](#map-as-querystring-or-postform-parameters)
- [Upload files](#upload-files)
- [Grouping routes](#grouping-routes)
- [Blank Gin without middleware by default](#blank-gin-without-middleware-by-default)
- [Using middleware](#using-middleware)
- [How to write log file](#how-to-write-log-file)
- [Model binding and validation](#model-binding-and-validation)
- [Custom Validators](#custom-validators)
- [Only Bind Query String](#only-bind-query-string)
- [Bind Query String or Post Data](#bind-query-string-or-post-data)
- [Bind HTML checkboxes](#bind-html-checkboxes)
- [Multipart/Urlencoded binding](#multiparturlencoded-binding)
- [XML, JSON and YAML rendering](#xml-json-and-yaml-rendering)
- [JSONP rendering](#jsonp)
- [Serving static files](#serving-static-files)
- [Serving data from reader](#serving-data-from-reader)
- [HTML rendering](#html-rendering)
- [Multitemplate](#multitemplate)
- [Redirects](#redirects)
- [Custom Middleware](#custom-middleware)
- [Using BasicAuth() middleware](#using-basicauth-middleware)
- [Goroutines inside a middleware](#goroutines-inside-a-middleware)
- [Custom HTTP configuration](#custom-http-configuration)
- [Support Let's Encrypt](#support-lets-encrypt)
- [Run multiple service using Gin](#run-multiple-service-using-gin)
- [Graceful restart or stop](#graceful-restart-or-stop)
- [Build a single binary with templates](#build-a-single-binary-with-templates)
- [Bind form-data request with custom struct](#bind-form-data-request-with-custom-struct)
- [Try to bind body into different structs](#try-to-bind-body-into-different-structs)
- [http2 server push](#http2-server-push)
- [Testing](#testing)
- [Users](#users--)
## Installation
To install Gin package, you need to install Go and set your Go workspace first.
1. Download and install it:
```sh
$ go get -u github.com/gin-gonic/gin
```
2. Import it in your code:
```go
import "github.com/gin-gonic/gin"
```
3. (Optional) Import `net/http`. This is required for example if using constants such as `http.StatusOK`.
```go
import "net/http"
```
### Use a vendor tool like [Govendor](https://github.com/kardianos/govendor)
1. `go get` govendor
```sh
$ go get github.com/kardianos/govendor
```
2. Create your project folder and `cd` inside
```sh
$ mkdir -p $GOPATH/src/github.com/myusername/project && cd "$_"
```
3. Vendor init your project and add gin
```sh
$ govendor init
$ govendor fetch github.com/gin-gonic/gin@v1.2
```
4. Copy a starting template inside your project
```sh
$ curl https://raw.githubusercontent.com/gin-gonic/gin/master/examples/basic/main.go > main.go
```
5. Run your project
```sh
$ go run main.go
```
## Prerequisite
Now Gin requires Go 1.6 or later and Go 1.7 will be required soon.
## Quick start
```sh
# assume the following codes in example.go file
$ cat example.go
```
```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](https://github.com/julienschmidt/httprouter)
[See all benchmarks](/BENCHMARKS.md)
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
- [x] Zero allocation router.
- [x] Still the fastest http router and framework. From routing to writing.
- [x] Complete suite of unit tests
- [x] Battle tested
- [x] API frozen, new releases will not break your code.
## Build with [jsoniter](https://github.com/json-iterator/go)
Gin use `encoding/json` as default json package but you can change to [jsoniter](https://github.com/json-iterator/go) by build from other tags.
```sh
$ go build -tags=jsoniter .
```
## API Examples
### Using GET, POST, PUT, PATCH, DELETE and OPTIONS
```go
func main() {
// Disable Console Color
// gin.DisableConsoleColor()
// Creates a gin router with default middleware:
// logger and recovery (crash-free) middleware
router := gin.Default()
router.GET("/someGet", getting)
router.POST("/somePost", posting)
router.PUT("/somePut", putting)
router.DELETE("/someDelete", deleting)
router.PATCH("/somePatch", patching)
router.HEAD("/someHead", head)
router.OPTIONS("/someOptions", options)
// By default it serves on :8080 unless a
// PORT environment variable was defined.
router.Run()
// router.Run(":3000") for a hard coded port
}
```
### Parameters in path
```go
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)
})
router.Run(":8080")
}
```
### Querystring parameters
```go
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
```go
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
```
```go
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
```
```go
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](https://github.com/gin-gonic/gin/issues/774) and detail [example code](examples/upload-file/single).
```go
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`:
```bash
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](examples/upload-file/multiple).
```go
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`:
```bash
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
```go
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
```go
r := gin.New()
```
instead of
```go
// Default With the Logger and Recovery middleware already attached
r := gin.Default()
```
### Using middleware
```go
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
```go
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")
}
```
### Model binding and validation
To bind a request body into a type, use model binding. We currently support binding of JSON, XML and standard form values (foo=bar&boo=baz).
Gin uses [**go-playground/validator.v8**](https://github.com/go-playground/validator) for validation. Check the full docs on tags usage [here](http://godoc.org/gopkg.in/go-playground/validator.v8#hdr-Baked_In_Validators_and_Tags).
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`, `BindQuery`
- **Behavior** - These methods use `MustBindWith` under the hood. If there is a binding error, the request is aborted with `c.AbortWithError(400, err).SetType(ErrorTypeBind)`. This sets the response status code to 400 and the `Content-Type` header is set to `text/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 the `ShouldBind` equivalent method.
- **Type** - Should bind
- **Methods** - `ShouldBind`, `ShouldBindJSON`, `ShouldBindQuery`
- **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.
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.
```go
// Binding from JSON
type Login struct {
User string `form:"user" json:"user" binding:"required"`
Password string `form:"password" json:"password" binding:"required"`
}
func main() {
router := gin.Default()
// Example for binding JSON ({"user": "manu", "password": "123"})
router.POST("/loginJSON", func(c *gin.Context) {
var json Login
if err := c.ShouldBindJSON(&json); err == nil {
if json.User == "manu" && json.Password == "123" {
c.JSON(http.StatusOK, gin.H{"status": "you are logged in"})
} else {
c.JSON(http.StatusUnauthorized, gin.H{"status": "unauthorized"})
}
} else {
c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
}
})
// 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 {
if form.User == "manu" && form.Password == "123" {
c.JSON(http.StatusOK, gin.H{"status": "you are logged in"})
} else {
c.JSON(http.StatusUnauthorized, gin.H{"status": "unauthorized"})
}
} else {
c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
}
})
// Listen and serve on 0.0.0.0:8080
router.Run(":8080")
}
```
**Sample request**
```shell
$ 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](examples/custom-validation/server.go).
[embedmd]:# (examples/custom-validation/server.go go)
```go
package main
import (
"net/http"
"reflect"
"time"
"github.com/gin-gonic/gin"
"github.com/gin-gonic/gin/binding"
"gopkg.in/go-playground/validator.v8"
)
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()})
}
}
```
```console
$ 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](https://github.com/go-playground/validator/releases/tag/v8.7) can also be registed this way.
See the [struct-lvl-validation example](examples/struct-lvl-validations) to learn more.
### Only Bind Query String
`ShouldBindQuery` function only binds the query params and not the post data. See the [detail information](https://github.com/gin-gonic/gin/issues/742#issuecomment-315953017).
```go
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](https://github.com/gin-gonic/gin/issues/742#issuecomment-264681292).
```go
package main
import "log"
import "github.com/gin-gonic/gin"
import "time"
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 `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)
}
c.String(200, "Success")
}
```
Test it with:
```sh
$ curl -X GET "localhost:8085/testing?name=appleboy&address=xyz&birthday=1992-03-15"
```
### Bind HTML checkboxes
See the [detail information](https://github.com/gin-gonic/gin/issues/129#issuecomment-124260092)
main.go
```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
```html
```
result:
```
{"color":["red","green","blue"]}
```
### Multipart/Urlencoded binding
```go
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 it with:
```sh
$ curl -v --form user=user --form password=password http://localhost:8080/login
```
### XML, JSON and YAML rendering
```go
func main() {
r := gin.Default()
// gin.H is a shortcut for map[string]interface{}
r.GET("/someJSON", func(c *gin.Context) {
c.JSON(http.StatusOK, gin.H{"message": "hey", "status": http.StatusOK})
})
r.GET("/moreJSON", func(c *gin.Context) {
// You also can use a struct
var msg struct {
Name string `json:"user"`
Message string
Number int
}
msg.Name = "Lena"
msg.Message = "hey"
msg.Number = 123
// Note that msg.Name becomes "user" in the JSON
// Will output : {"user": "Lena", "Message": "hey", "Number": 123}
c.JSON(http.StatusOK, msg)
})
r.GET("/someXML", func(c *gin.Context) {
c.XML(http.StatusOK, gin.H{"message": "hey", "status": http.StatusOK})
})
r.GET("/someYAML", func(c *gin.Context) {
c.YAML(http.StatusOK, gin.H{"message": "hey", "status": http.StatusOK})
})
// Listen and serve on 0.0.0.0:8080
r.Run(":8080")
}
```
#### SecureJSON
Using SecureJSON to prevent json hijacking. Default prepends `"while(1),"` to response body if the given struct is array values.
```go
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.
```go
func main() {
r := gin.Default()
r.GET("/JSONP?callback=x", func(c *gin.Context) {
data := map[string]interface{}{
"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")
}
```
#### AsciiJSON
Using AsciiJSON to Generates ASCII-only JSON with escaped non-ASCII chracters.
```go
func main() {
r := gin.Default()
r.GET("/someJSON", func(c *gin.Context) {
data := map[string]interface{}{
"lang": "GO语言",
"tag": "Using posts/index.tmpl
{{ end }} ``` templates/users/index.tmpl ```html {{ define "users/index.tmpl" }}Using users/index.tmpl
{{ end }} ``` #### Custom Template renderer You can also use your own html template render ```go 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 ```go r := gin.Default() r.Delims("{[{", "}]}") r.LoadHTMLGlob("/path/to/templates")) ``` #### Custom Template Funcs See the detail [example code](examples/template). main.go ```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 ```html Date: {[{.now | formatAsDate}]} ``` Result: ``` Date: 2017/07/01 ``` ### Multitemplate Gin allow by default use only one html.Template. Check [a multitemplate render](https://github.com/gin-contrib/multitemplate) for using features like go 1.6 `block template`. ### Redirects Issuing a HTTP redirect is easy. Both internal and external locations are supported. ```go r.GET("/test", func(c *gin.Context) { c.Redirect(http.StatusMovedPermanently, "http://www.google.com/") }) ``` Issuing a Router redirect, use `HandleContext` like below. ``` go 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 ```go 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 ```go // 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. ```go 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: ```go func main() { router := gin.Default() http.ListenAndServe(":8080", router) } ``` or ```go 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. [embedmd]:# (examples/auto-tls/example1/main.go go) ```go 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. [embedmd]:# (examples/auto-tls/example2/main.go go) ```go 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](https://github.com/gin-gonic/gin/issues/346) and try the following example: [embedmd]:# (examples/multiple-service/main.go go) ```go 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](https://github.com/fvbock/endless) to replace the default `ListenAndServe`. Refer issue [#296](https://github.com/gin-gonic/gin/issues/296) for more details. ```go router := gin.Default() router.GET("/", handler) // [...] endless.ListenAndServe(":4242", router) ``` An alternative to endless: * [manners](https://github.com/braintree/manners): A polite Go HTTP server that shuts down gracefully. * [graceful](https://github.com/tylerb/graceful): Graceful is a Go package enabling graceful shutdown of an http.Handler server. * [grace](https://github.com/facebookgo/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()](https://golang.org/pkg/net/http/#Server.Shutdown) method for graceful shutdowns. See the full [graceful-shutdown](./examples/graceful-shutdown) example with gin. [embedmd]:# (examples/graceful-shutdown/graceful-shutdown/server.go go) ```go // +build go1.8 package main import ( "context" "log" "net/http" "os" "os/signal" "time" "github.com/gin-gonic/gin" ) func main() { router := gin.Default() router.GET("/", func(c *gin.Context) { time.Sleep(5 * time.Second) c.String(http.StatusOK, "Welcome Gin Server") }) srv := &http.Server{ Addr: ":8080", Handler: router, } go func() { // service connections if err := srv.ListenAndServe(); err != nil && 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") } ``` ### Build a single binary with templates You can build a server into a single binary containing templates by using [go-assets][]. [go-assets]: https://github.com/jessevdk/go-assets ```go 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 `examples/assets-in-binary` directory. ### Bind form-data request with custom struct The follow example using custom struct: ```go 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"}} ``` **NOTE**: NOT support the follow style struct: ```go type StructX struct { X struct {} `form:"name_x"` // HERE have form } type StructY struct { Y StructX `form:"name_y"` // HERE hava form } type StructZ struct { Z *StructZ `form:"name_z"` // HERE hava form } ``` In a word, only support nested custom struct which have no `form` now. ### 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. ```go 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`. ```go 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 by `c.ShouldBind()` multiple times without any damage to performance (See [#1341](https://github.com/gin-gonic/gin/pull/1341)). ### http2 server push http.Pusher is supported only **go1.8+**. See the [golang blog](https://blog.golang.org/h2push) for detail information. [embedmd]:# (examples/http-pusher/main.go go) ```go package main import ( "html/template" "log" "github.com/gin-gonic/gin" ) var html = template.Must(template.New("https").Parse(`