package middleware

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

//Cors 跨域中间件
func Cors() gin.HandlerFunc {
	return func(c *gin.Context) {
		origin := c.Request.Header.Get("origin") //请求头部
		if len(origin) == 0 {
			origin = c.Request.Header.Get("Origin")
		}
		//接收客户端发送的origin （重要！）
		c.Writer.Header().Set("Access-Control-Allow-Origin", origin)
		//允许客户端传递校验信息比如 cookie (重要)
		c.Writer.Header().Set("Access-Control-Allow-Credentials", "true")
		c.Writer.Header().Set("Access-Control-Allow-Headers", "Content-Type, Content-Length, Accept-Encoding, X-CSRF-Token, Authorization, accept, origin, Cache-Control, X-Requested-With")
		//服务器支持的所有跨域请求的方法
		c.Writer.Header().Set("Access-Control-Allow-Methods", "OPTIONS, GET, POST, PUT, DELETE, UPDATE")
		c.Writer.Header().Set("Content-Type", "application/json; charset=utf-8")
		// 设置预验请求有效期为 86400 秒
		c.Writer.Header().Set("Access-Control-Max-Age", "86400")
		if c.Request.Method == "OPTIONS" {
			c.AbortWithStatus(200)
			return
		}
		c.Next()
	}
}