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GoLang-Gin框架入门

Posted Jan 25, 2024
By shigophilo
8 min read

入门

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func main() {
	r := gin.Default()
	r.GET("/hello", func(ctx *gin.Context) {
		ctx.JSON(200, gin.H{
			"name": "zhangsan",
		})
	})
	err := r.Run(":8080")
	if err != nil {

	}
}

路由

  • 路由uri到函数得映射

RESTful API规范

请求方法

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//get请求
r.GET("/hello", func(ctx *gin.Context) {
		ctx.JSON(200, gin.H{
			"name": "zhangsan",
		})
	})
//post请求
r.POST("/save", func(ctx *gin.Context) {
		ctx.JSON(200, "post")
	})
	
//Any 接受所有请求
r.Any("/save", func(ctx *gin.Context) {
		ctx.JSON(200, "post")
	})

URI

  • 静态url

    比如 /he1lo ， /user/find

  • 路径参数，

    比如 /user/find/:id

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	//http://ip:8080/hello/aaa
	//获取路径的值
	r.GET("/hello/:id", func(ctx *gin.Context) {
		ctx.JSON(200, ctx.Param("id"))
	})

  • 模糊匹配

    比如 /user/*path , 比如 /user/*

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//http://ip:8080/hello/aaa/aaaaaaaaaa
//会匹配出/aaa/aaaaaaaaaa
	r.GET("/hello/*path", func(ctx *gin.Context) {
		ctx.JSON(200, ctx.Param("path"))
	})

处理函数

  • 通过上下文的参数，获取http的请求参数，响应http请求等
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type HandlerFunc func(*Context)

分组路由

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	//http://ip:8080/v1/save
	v1 := r.Group("/v1")
	{
		v1.Any("/save", func(ctx *gin.Context) {
			ctx.JSON(200, "v1 post")
		})
	}
	//http://ip:8080/v2/save
	v2 := r.Group("/v2")
	{
		v2.Any("/save", func(ctx *gin.Context) {
			ctx.JSON(200, "v2 post")
		})
	}

获取参数

GET

http://ip:8080/hello?id=123&name=zhangsan&address2=tianjing&address=beijing

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	r.GET("/hello", func(ctx *gin.Context) {
		//Query : 获取确认存在的参数
		id := ctx.Query("id")
		name := ctx.Query("name")
		//GetQuery : 不确认是否存在的参数, 如果存在 ok 返回ture
		address, ok := ctx.GetQuery("address")
		//DefaultQuery : 如果参数不存在,给它一个默认的值
		address2 := ctx.DefaultQuery("address2", "北京")
		ctx.JSON(200, gin.H{
			"id":       id,
			"name":     name,
			"address":  address,
			"ok":       ok,
			"address2": address2,
		})
	})

上面的GetQuery,DefaultQuery,Query返回string类型, 但是如上面的例子id是int, 所以返回的值也会变成string, 如果想返回原格式类型

解决方法

http://ip:8080/hello?id=123&name=zhangsan

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type User struct {
	Id   int64  `form:"id"`
	Name string `form:"name"`
	//ShouldBindQuery() 必须的参数
	//如果使用ShouldBindQuery(),无Address参数会会报错
	Address string `form:"address binding:"required"`
}

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

	r.GET("/hello", func(ctx *gin.Context) {
		var user User
		err := ctx.BindQuery(&user)
		if err != nil {
		}

		ctx.JSON(200, user)
	})

数组参数

多个相同参数名的参数: http://ip:8080/hello?name=123&name=zhangsan

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	r.GET("/hello", func(ctx *gin.Context) {
	//QueryArray()  确定有的参数
	//如果不确定是否有参数,使用GetQueryArray()
		name := ctx.QueryArray("name")
		ctx.JSON(200, name)
	})
  • 绑定的
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type User struct {
	Id   int64  `form:"id"`
	Name string `form:"name"`
	//ShouldBindQuery() 必须的参数
	//如果使用ShouldBindQuery(),无Address参数会会报错
	Address []string `form:"address binding:"required"`
}

	r.GET("/hello", func(ctx *gin.Context) {
	    var user User
		ctx.ShouBindQuery(&user)
		ctx.JSON(200, user)
	})

map参数

http://ip:8080/hello?name[home]=Beijing&name[company]=shanghai

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	r.GET("/hello", func(ctx *gin.Context) {
		name := ctx.QueryMap("name")
		ctx.JSON(200, name)
	})
	
	//返回
	{"company":"shanghai","home":"Beijing"}

POST

表单参数

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POST /hello HTTP/1.1

id=123&name=zhangsan&address=shanghai&address=beijing&addressmap[map1]=map1&addressmap[map2]=map2

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	r.POST("/hello", func(ctx *gin.Context) {
		id := ctx.PostForm("id")
		name := ctx.PostForm("name")
		address := ctx.PostFormArray("address")
		addressMap := ctx.PostFormMap("addressmap")
		ctx.JSON(200, gin.H{
			"id":         id,
			"name":       name,
			"address":    address,
			"addressmap": addressMap,
		})
	})

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//返回
{"address":["shanghai","beijing"],"addressmap":{"map1":"map1","map2":"map2"},"id":"123","name":"zhangsan"}
  • 也支持绑定

JSON

  • ShouldBindJSON()
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type User struct {
	Id         int64             `json:"id"`
	Name       string            `json:"name"`
	Address    []string          `json:"address" binding:"required"`
	AddressMap map[string]string `json:"addressMap"`
}

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

	r.POST("/hello", func(ctx *gin.Context) {
		var user User
		ctx.ShouldBindJSON(&user)
		ctx.JSON(200, user)
	})

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//request
POST /hello HTTP/1.1
Content-Type: application/json;charset=UTF-8

{"address":["shanghai","beijing"],"addressmap":{"map1":"map1","map2":"map2"},"id":123,"name":"zhangsan"}

//response
{"id":123,"name":"zhangsan","address":["shanghai","beijing"],"addressMap":{"map1":"map1","map2":"map2"}}

XML

  • ShouldBindXML()

路径参数

http://ip:8080/hello/aaa/bbb

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	r.POST("/hello/:id/:name", func(ctx *gin.Context) {
		id := ctx.Param("id")
		name := ctx.Param("name")
		ctx.JSON(200, gin.H{
			"id":   id,
			"name": name,
		})
	})
  • ShouldBindUri()
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type User struct {
	Id         string             `json:"id" uri:"id"`
	Name       string            `json:"name" uri:"name"`
}

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

	r.POST("/hello/:id/:name", func(ctx *gin.Context) {
		var user User
		ctx.ShouldBindUri(&user)
		ctx.JSON(200, user)
	})


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//response
{"id":"aaa","name":"bbb"}

文件参数(文件上传)

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//request

POST /hello HTTP/1.1
Content-Type: multipart/form-data; boundary=----WebKitFormBoundaryQit2QsPnj7R0enz7

------WebKitFormBoundaryQit2QsPnj7R0enz7
Content-Disposition: form-data; name="file"; filename="at.aspx"
Content-Type: image/jpeg

11111111111
------WebKitFormBoundaryQit2QsPnj7R0enz7--
  • 一次上传多个文件
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	r.POST("/hello", func(ctx *gin.Context) {
		form, err := ctx.MultipartForm()
		if err != nil {

		}
		value := form.Value
		files := form.File
		for _, fileArray := range files {
			for _, v := range fileArray {
				ctx.SaveUploadedFile(v, "/tmp/"+v.Filename)
			}
		}
		ctx.JSON(200, value)
	})
  • 单个文件上传
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	r.POST("/hello", func(ctx *gin.Context) {
		file, err := ctx.FormFile("file")
		if err != nil {
			ctx.String(http.StatusInternalServerError, "读取file失败: "+err.Error())
			return
		}
		ctx.SaveUploadedFile(file, "/tmp/"+file.Filename)
		ctx.String(http.StatusOK, "上传成功！")

		ctx.JSON(200, file.Filename)
	})

响应

字符串

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	r.Any("/hello", func(ctx *gin.Context) {
		ctx.String(200, "ok")
	})

JSON

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	r.Any("/hello", func(ctx *gin.Context) {
		ctx.JSON(200, gin.H{
			"json": "json",
		})

XML

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	r.Any("/hello", func(ctx *gin.Context) {
		ctx.XML(200, gin.H{
			"json": "json",
		})

文件格式(下载)

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	r.Any("/hello", func(ctx *gin.Context) {
		ctx.File("./1.png")
		//下载文件重名名
		ctx.FileAttachment("./1.png","保存的名字.png")
	})

设置相应头

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	r.Any("/hello", func(ctx *gin.Context) {
		ctx.Header("test","test" )

重定向

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	r.Any("/hello", func(ctx *gin.Context) {
		ctx.Redirect(301,"http://www.baidu.com" )

YAML

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	r.Any("/hello", func(ctx *gin.Context) {
		ctx.YAML(200, gin.H{
			"json": "json",
		})

模板渲染

基本使用

  • 占位符
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//	/templates/index.tmpl
<!DOCTYPE html>
<html lang="en">
	<head>
	<meta charset="UTF-8"><title>Title</title>
</head>
<body>
	
</body>
</html>

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	//读取模板文件
	r.LoadHTMLFiles("./templates/index.tmpl")
	r.Any("/hello", func(ctx *gin.Context) {
	//使用模板
		ctx.HTML(200, "index.tmpl", gin.H{
			"title": "hello template",
		})
	})

多个模板渲染

  • LoadHTMLFiles
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	//读取模板文件
	r.LoadHTMLFiles("./templates/index.tmpl","./templates/index1.tmpl","./templates/index2.tmpl")
	r.Any("/hello", func(ctx *gin.Context) {
	//使用模板
		ctx.HTML(200, "index.tmpl", gin.H{
			"title": "hello template",
		})
	})
  • LoadHTMLGlob
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	//解析templates目录下的所有模板文件
	r.LoadHTMLGlob("./templates/**")
	r.Any("/hello", func(ctx *gin.Context) {
	//使用模板
		ctx.HTML(200, "index.tmpl", gin.H{
			"title": "hello template",
		})
	})

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// **/* 代表所有子目录下的所有文件
	r.LoadHTMLGlob("./templates/**/*")
	r.Any("/hello", func(ctx *gin.Context) {
	//使用模板
		ctx.HTML(200, "index.tmpl", gin.H{
			"title": "hello template",
		})
	})

自定义模板函数

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	import "html/template"
	
	r.SetFuncMap(template.FuncMap{
		"safe": func(str string) template.HTML {
			return template.HTML(str)
		},
	})

静态文件处理

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r.Static("/css", "服务器中静态文件所在的文件夹")

会话

  • 设置cookie
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func (c *Context) SetCookie(name, value string, maxAge int, path, domain string, secure, httpOnly bool)

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	r.Any("/hello", func(ctx *gin.Context) {
		ctx.SetCookie("user", "admin", 3600, "/", "129.150.46.86", false, false)
		ctx.String(200, "index.tmpl")
	})
  • 读取cookie
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	r.Any("/h", func(ctx *gin.Context) {
		user, _ := ctx.Cookie("user")
		ctx.String(200, user)
	})
  • 删除cookie

将maxAge设置为-1,达到删除cookie的目的

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func (c *Context) SetCookie(name, value string, maxAge int, path, domain string, secure, httpOnly bool)

session

在Gin框架中，我们可以依赖gin-contrib/sessions中间件处理session

中间件

  • Use()
Program
Program golang
This post is licensed under CC BY 4.0 by the author.
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