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Gin is a web framework written in Go (Golang). It features a martini-like API with performance that is 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
- [Gin Web Framework](#gin-web-framework)
- [Contents](#contents)
- [Installation](#installation)
- [Quick start](#quick-start)
- [Benchmarks](#benchmarks)
- [Gin v1. stable](#gin-v1-stable)
- [Build with jsoniter/go-json](#build-with-json-replacement)
- [Build without `MsgPack` rendering feature](#build-without-msgpack-rendering-feature)
- [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)
- [Single file](#single-file)
- [Multiple files](#multiple-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)
- [Custom Log Format](#custom-log-format)
- [Controlling Log output coloring](#controlling-log-output-coloring)
- [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 Uri](#bind-uri)
- [Bind Header](#bind-header)
- [Bind HTML checkboxes](#bind-html-checkboxes)
- [Multipart/Urlencoded binding](#multiparturlencoded-binding)
- [XML, JSON, YAML and ProtoBuf rendering](#xml-json-yaml-and-protobuf-rendering)
- [SecureJSON](#securejson)
- [JSONP](#jsonp)
- [AsciiJSON](#asciijson)
- [PureJSON](#purejson)
- [Serving static files](#serving-static-files)
- [Serving data from file](#serving-data-from-file)
- [Serving data from reader](#serving-data-from-reader)
- [HTML rendering](#html-rendering)
- [Custom Template renderer](#custom-template-renderer)
- [Custom Delimiters](#custom-delimiters)
- [Custom Template Funcs](#custom-template-funcs)
- [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 shutdown or restart](#graceful-shutdown-or-restart)
- [Third-party packages](#third-party-packages)
- [Manually](#manually)
- [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)
- [Define format for the log of routes](#define-format-for-the-log-of-routes)
- [Set and get a cookie](#set-and-get-a-cookie)
- [Don't trust all proxies](#dont-trust-all-proxies)
- [Testing](#testing)
- [Users](#users)
## Installation
To install Gin package, you need to install Go and set your Go workspace first.
1. The first need [Go](https://golang.org/) installed (**version 1.13+ is required**), then you can use the below Go command to install Gin.
```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"
```
## 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 (for windows "localhost:8080")
}
```
```
# run example.go and visit 0.0.0.0:8080/ping (for windows "localhost: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 | **43550** | **27364 ns/op** | **0 B/op** | **0 allocs/op** |
| BenchmarkAce_GithubAll | 40543 | 29670 ns/op | 0 B/op | 0 allocs/op |
| BenchmarkAero_GithubAll | 57632 | 20648 ns/op | 0 B/op | 0 allocs/op |
| BenchmarkBear_GithubAll | 9234 | 216179 ns/op | 86448 B/op | 943 allocs/op |
| BenchmarkBeego_GithubAll | 7407 | 243496 ns/op | 71456 B/op | 609 allocs/op |
| BenchmarkBone_GithubAll | 420 | 2922835 ns/op | 720160 B/op | 8620 allocs/op |
| BenchmarkChi_GithubAll | 7620 | 238331 ns/op | 87696 B/op | 609 allocs/op |
| BenchmarkDenco_GithubAll | 18355 | 64494 ns/op | 20224 B/op | 167 allocs/op |
| BenchmarkEcho_GithubAll | 31251 | 38479 ns/op | 0 B/op | 0 allocs/op |
| BenchmarkGocraftWeb_GithubAll | 4117 | 300062 ns/op | 131656 B/op | 1686 allocs/op |
| BenchmarkGoji_GithubAll | 3274 | 416158 ns/op | 56112 B/op | 334 allocs/op |
| BenchmarkGojiv2_GithubAll | 1402 | 870518 ns/op | 352720 B/op | 4321 allocs/op |
| BenchmarkGoJsonRest_GithubAll | 2976 | 401507 ns/op | 134371 B/op | 2737 allocs/op |
| BenchmarkGoRestful_GithubAll | 410 | 2913158 ns/op | 910144 B/op | 2938 allocs/op |
| BenchmarkGorillaMux_GithubAll | 346 | 3384987 ns/op | 251650 B/op | 1994 allocs/op |
| BenchmarkGowwwRouter_GithubAll | 10000 | 143025 ns/op | 72144 B/op | 501 allocs/op |
| BenchmarkHttpRouter_GithubAll | 55938 | 21360 ns/op | 0 B/op | 0 allocs/op |
| BenchmarkHttpTreeMux_GithubAll | 10000 | 153944 ns/op | 65856 B/op | 671 allocs/op |
| BenchmarkKocha_GithubAll | 10000 | 106315 ns/op | 23304 B/op | 843 allocs/op |
| BenchmarkLARS_GithubAll | 47779 | 25084 ns/op | 0 B/op | 0 allocs/op |
| BenchmarkMacaron_GithubAll | 3266 | 371907 ns/op | 149409 B/op | 1624 allocs/op |
| BenchmarkMartini_GithubAll | 331 | 3444706 ns/op | 226551 B/op | 2325 allocs/op |
| BenchmarkPat_GithubAll | 273 | 4381818 ns/op | 1483152 B/op | 26963 allocs/op |
| BenchmarkPossum_GithubAll | 10000 | 164367 ns/op | 84448 B/op | 609 allocs/op |
| BenchmarkR2router_GithubAll | 10000 | 160220 ns/op | 77328 B/op | 979 allocs/op |
| BenchmarkRivet_GithubAll | 14625 | 82453 ns/op | 16272 B/op | 167 allocs/op |
| BenchmarkTango_GithubAll | 6255 | 279611 ns/op | 63826 B/op | 1618 allocs/op |
| BenchmarkTigerTonic_GithubAll | 2008 | 687874 ns/op | 193856 B/op | 4474 allocs/op |
| BenchmarkTraffic_GithubAll | 355 | 3478508 ns/op | 820744 B/op | 14114 allocs/op |
| BenchmarkVulcan_GithubAll | 6885 | 193333 ns/op | 19894 B/op | 609 allocs/op |
- (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 json replacement
Gin uses `encoding/json` as default json package but you can change it by build from other tags.
[jsoniter](https://github.com/json-iterator/go)
```sh
$ go build -tags=jsoniter .
```
[go-json](https://github.com/goccy/go-json)
```sh
$ go build -tags=go_json .
```
## Build without `MsgPack` rendering feature
Gin enables `MsgPack` rendering feature by default. But you can disable this feature by specifying `nomsgpack` build tag.
```sh
$ go build -tags=nomsgpack .
```
This is useful to reduce the binary size of executable files. See the [detail information](https://github.com/gin-gonic/gin/pull/1852).
## API Examples
You can find a number of ready-to-run examples at [Gin examples repository](https://github.com/gin-gonic/examples).
### Using GET, POST, PUT, PATCH, DELETE and OPTIONS
```go
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
```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)
})
// For each matched request Context will hold the route definition
router.POST("/user/:name/*action", func(c *gin.Context) {
b := c.FullPath() == "/user/:name/*action" // true
c.String(http.StatusOK, "%t", b)
})
// This handler will add a new router for /user/groups.
// Exact routes are resolved before param routes, regardless of the order they were defined.
// Routes starting with /user/groups are never interpreted as /user/:name/... routes
router.GET("/user/groups", func(c *gin.Context) {
c.String(http.StatusOK, "The available groups are [...]")
})
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](https://github.com/gin-gonic/examples/tree/master/upload-file/single).
`file.Filename` **SHOULD NOT** be trusted. See [`Content-Disposition` on MDN](https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Content-Disposition#Directives) and [#1693](https://github.com/gin-gonic/gin/issues/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.
```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("Filename")
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](https://github.com/gin-gonic/examples/tree/master/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")
}
```
### Custom Recovery behavior
```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.CustomRecovery(func(c *gin.Context, recovered interface{}) {
if err, ok := recovered.(string); ok {
c.String(http.StatusInternalServerError, fmt.Sprintf("error: %s", err))
}
c.AbortWithStatus(http.StatusInternalServerError)
}))
r.GET("/panic", func(c *gin.Context) {
// panic with a string -- the custom middleware could save this to a database or report it to the user
panic("foo")
})
r.GET("/", func(c *gin.Context) {
c.String(http.StatusOK, "ohai")
})
// 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")
}
```
### Custom Log Format
```go
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:
```go
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:
```go
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/v10**](https://github.com/go-playground/validator) for validation. Check the full docs on tags usage [here](https://godoc.org/github.com/go-playground/validator#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`, `BindXML`, `BindQuery`, `BindYAML`, `BindHeader`
- **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`, `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.
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" 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 (
//
// 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](https://github.com/gin-gonic/examples/tree/master/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", gin.H{ "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 HTTP redirect from POST. Refer to issue: [#444](https://github.com/gin-gonic/gin/issues/444) ```go r.POST("/test", func(c *gin.Context) { c.Redirect(http.StatusFound, "/foo") }) ``` 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. ```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. ```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: ```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 { err := server01.ListenAndServe() if err != nil && err != http.ErrServerClosed { log.Fatal(err) } return err }) g.Go(func() error { err := server02.ListenAndServe() if err != nil && err != http.ErrServerClosed { log.Fatal(err) } return err }) if err := g.Wait(); err != nil { log.Fatal(err) } } ``` ### Graceful shutdown or restart There are a few approaches you can use to perform a graceful shutdown or restart. You can make use of third-party packages specifically built for that, or you can manually do the same with the functions and methods from the built-in packages. #### Third-party packages We can use [fvbock/endless](https://github.com/fvbock/endless) to replace the default `ListenAndServe`. Refer to issue [#296](https://github.com/gin-gonic/gin/issues/296) for more details. ```go router := gin.Default() router.GET("/", handler) // [...] endless.ListenAndServe(":4242", router) ``` Alternatives: * [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. #### Manually In case you are using Go 1.8 or a later version, you may not need to use those libraries. Consider using `http.Server`'s built-in [Shutdown()](https://golang.org/pkg/net/http/#Server.Shutdown) method for graceful shutdowns. The example below describes its usage, and we've got more examples using gin [here](https://github.com/gin-gonic/examples/tree/master/graceful-shutdown). ```go // +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, } // Initializing the server in a goroutine so that // it won't block the graceful shutdown handling below go func() { if err := srv.ListenAndServe(); err != nil && errors.Is(err, http.ErrServerClosed) { log.Printf("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 caught, so don't need to add it signal.Notify(quit, syscall.SIGINT, syscall.SIGTERM) <-quit log.Println("Shutting down server...") // The context is used to inform the server it has 5 seconds to finish // the request it is currently handling ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second) defer cancel() if err := srv.Shutdown(ctx); err != nil { log.Fatal("Server forced to 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 { defer file.Close() 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: ```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"}} ``` ### 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.Form); 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)). ### Bind form-data request with custom struct and custom tag ```go const ( customerTag = "url" defaultMemory = 32 << 20 ) type customerBinding struct {} func (customerBinding) Name() string { return "form" } func (customerBinding) Bind(req *http.Request, obj interface{}) error { if err := req.ParseForm(); err != nil { return err } if err := req.ParseMultipartForm(defaultMemory); err != nil { if err != http.ErrNotMultipart { return err } } if err := binding.MapFormWithTag(obj, req.Form, customerTag); err != nil { return err } return validate(obj) } func validate(obj interface{}) error { if binding.Validator == nil { return nil } return binding.Validator.ValidateStruct(obj) } // Now we can do this!!! // FormA is a external type that we can't modify it's tag type FormA struct { FieldA string `url:"field_a"` } func ListHandler(s *Service) func(ctx *gin.Context) { return func(ctx *gin.Context) { var urlBinding = customerBinding{} var opt FormA err := ctx.MustBindWith(&opt, urlBinding) if err != nil { ... } ... } } ``` ### http2 server push http.Pusher is supported only **go1.8+**. See the [golang blog](https://blog.golang.org/h2push) for detail information. ```go package main import ( "html/template" "log" "github.com/gin-gonic/gin" ) var html = template.Must(template.New("https").Parse(`