gin 解决 Access-Control-Allow-Headers 错误

问题

前后端分离开发，前端添加新的请求头 "Access-Token"，发送请求时报错：
Access to XMLHttpRequest at 'http://localhost:8080/api' from origin 'http://localhost:5432' has been blocked by CORS policy: Request header field access-token is not allowed by Access-Control-Allow-Headers in preflight response.

解决方案

在cors的配置项AllowHeaders上添加需要的请求头 "Access-Token"

AllowHeaders: []string{"Origin", "Authorization", "Content-Type", "Access-Token"},

完整代码

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

engine := gin.Default()
allowCors(engine)

// 允许跨域访问，在前后端分开部署时必须启用
func allowCors(engine *gin.Engine) {
	engine.Use(cors.New(cors.Config{
		//准许跨域请求网站,多个使用,分开,限制使用*
		AllowOrigins: []string{"*"},
		//准许使用的请求方式
		AllowMethods: []string{"PUT", "PATCH", "POST", "GET", "DELETE"},
		//准许使用的请求表头
		AllowHeaders: []string{"Origin", "Authorization", "Content-Type", "Access-Token"},
		//显示的请求表头
		ExposeHeaders: []string{"Content-Type"},
		//凭证共享,确定共享
		AllowCredentials: true,
		//容许跨域的原点网站,可以直接return true就万事大吉了
		AllowOriginFunc: func(origin string) bool {
			return true
		},
		//超时时间设定
		MaxAge: 24 * time.Hour,
	}))
}