package main

import (
	"fmt"
	"github.com/gin-gonic/gin"
	"net/http"
	"strings"
)

// 跨域中間件
func Cors() gin.HandlerFunc {
	return func(c *gin.Context) {
		method := c.Request.Method // 請求方法
		origin := c.Request.Header.Get("Origin") // 請求頭部
		var headerKeys []string // 聲明請求頭keys
		for k, _ := range c.Request.Header {
			headerKeys = append(headerKeys, k)
		}
		headerStr := strings.Join(headerKeys, ", ")
		if headerStr != "" {
			headerStr = fmt.Sprintf("access-control-allow-origin, access-control-allow-headers, %s", headerStr)
		} else {
			headerStr = "access-control-allow-origin, access-control-allow-headers"
		}
		if origin != "" {
			c.Writer.Header().Set("Access-Control-Allow-Origin", "*")
			c.Header("Access-Control-Allow-Origin", "*") // 允許訪問所有域
			c.Header("Access-Control-Allow-Methods", "POST, GET, OPTIONS, PUT, DELETE, UPDATE") // 服務器支持的所有跨域請求的方法
			c.Header("Access-Control-Allow-Headers", "Authorization, Content-Length, X-CSRF-Token, Token, session, X_Requested_With, Accept, Origin, Host, Connection, Accept-Encoding, Accept-Language, DNT, X-CustomHeader, Keep-Alive, User-Agent, X-Requested-With, If-Modified-Since, Cache-Control, Content-Type, Pragma") // 允許的頭類型
			c.Header("Access-Control-Expose-Headers", "Content-Length, Access-Control-Allow-Origin, Access-Control-Allow-Headers, Cache-Control, Content-Language, Content-Type, Expires, Last-Modified, Pragma, FooBar") // 允許跨域設置，可以返回其他子段
			c.Header("Access-Control-Max-Age", "172800") // 緩存請求信息，單位為秒
			c.Header("Access-Control-Allow-Credentials", "false") // 跨域請求是否需要帶cookie信息，默認設置為true
			c.Set("content-type", "application/json") // 設置返回格式是json
		}
		// 放行所有OPTIONS方法
		if method == "OPTIONS" {
			c.JSON(http.StatusOK, "Options Request!")
		}
		// 處理請求
		c.Next()
	}
}

func main() {
	engine := gin.Default()
	// 允許使用跨域請求，全局中間件
	engine.Use(Cors())
	engine.Run(":11000") // 運行啟動端口
}

go get -u github.com/gin-contrib/cors

package conf

import (
    "github.com/gin-contrib/cors"
    "time"
)

var CorsConfig = cors.Config{
    AllowAllOrigins:  false,
    AllowOrigins:     []string{"http://localhost:3000"}, // 允許的源，生產(chǎn)環(huán)境中應替換為具體的允許域名
    AllowOriginFunc:  func(origin string) bool { return true }, // 自定義函數(shù)來判斷源是否允許
    AllowMethods:     []string{"GET", "POST", "PUT", "PATCH", "DELETE", "HEAD", "OPTIONS"}, // 允許的HTTP方法列表
    AllowHeaders:     []string{"Origin", "Content-Length", "Content-Type", "Authorization"}, // 允許的HTTP頭部列表
    AllowCredentials: true,                             // 是否允許瀏覽器發(fā)送Cookie
    MaxAge:           10 * time.Minute,                 // 預檢請求（OPTIONS）的緩存時間（秒）
}

package main

import (
    "github.com/gin-contrib/cors"
    "github.com/gin-gonic/gin"
    "goproject/conf" // 引入CORS配置
)

func main() {
    router := gin.Default()
    // 使用配置好的CORS規(guī)則
    router.Use(cors.New(conf.CorsConfig))

    // 定義路由
    router.GET("/ping", func(c *gin.Context) {
        c.JSON(200, gin.H{
            "message": "pong",
        })
    })

    router.Run(":8080") // 啟動服務器
}

package main

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

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

	// JSONP請求處理
	router.GET("/jsonp", func(c *gin.Context) {
		callback := c.Query("callback")
		data := map[string]interface{}{
			"title": "標題-jsonp",
			"desc":  "說明-jsonp",
			"content": "內容-jsonp",
		}
		c.JSONP(200, data)
	})

	router.Run(":8080")
}