GIN框架解决跨域问题

package main
import (

    "github.com/gin-gonic/gin"

    "strings"

    "fmt"

    "net/http"

)

func main() {
        r := gin.Default()
        r.Use(Cors()) //开启中间件 允许使用跨域请求
        r.run()
}

func Cors() gin.HandlerFunc {
    return func(c *gin.Context) {
        method := c.Request.Method
        origin := c.Request.Header.Get("Origin") //请求头部
        if origin != "" {
            //接收客户端发送的origin （重要！）
            c.Writer.Header().Set("Access-Control-Allow-Origin", origin) 
            //服务器支持的所有跨域请求的方法
            c.Header("Access-Control-Allow-Methods", "POST, GET, OPTIONS, PUT, DELETE,UPDATE") 
            //允许跨域设置可以返回其他子段，可以自定义字段
            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")
            // 允许浏览器（客户端）可以解析的头部 （重要）
            c.Header("Access-Control-Expose-Headers", "Content-Length, Access-Control-Allow-Origin, Access-Control-Allow-Headers") 
            //设置缓存时间
            c.Header("Access-Control-Max-Age", "172800") 
            //允许客户端传递校验信息比如 cookie (重要)
            c.Header("Access-Control-Allow-Credentials", "true")                                                                            
        }

        //允许类型校验 
        if method == "OPTIONS" {
            c.JSON(http.StatusOK, "ok!")
        }

        defer func() {
            if err := recover(); err != nil {
                log.Printf("Panic info is: %v", err)
            }
        }()
        c.Next()
    }
}