.NETCore3.1允许跨域

 

1.新建跨域类【CorsMiddleware】

    /// <summary>
    /// 跨域帮助类
    /// </summary>
    public class CorsMiddleware
    {
        private readonly RequestDelegate next;

        public CorsMiddleware(RequestDelegate next)
        {
            this.next = next;
        }
        public async Task Invoke(HttpContext context)
        {
            if (context.Request.Headers.ContainsKey(CorsConstants.Origin))
            {
                context.Response.Headers.Add("Access-Control-Allow-Origin", context.Request.Headers["Origin"]);
                context.Response.Headers.Add("Access-Control-Allow-Methods", "PUT,POST,GET,DELETE,OPTIONS,HEAD,PATCH");
                context.Response.Headers.Add("Access-Control-Allow-Headers", context.Request.Headers["Access-Control-Request-Headers"]);
                context.Response.Headers.Add("Access-Control-Allow-Credentials", "true");

                if (context.Request.Method.Equals("OPTIONS"))
                {
                    context.Response.StatusCode = StatusCodes.Status200OK;
                    return;
                }
            }

            await next(context);
        }
    }

2.在Startup.cs的【Configure】里引用，注意要放到【app.UseMvc()】之后

//跨域
app.UseMiddleware<CorsMiddleware>();

3.还有几种以供参考（我这边是部署到CentOS7上，发现错误就换掉了，后面发现是端口被占用了）

 

 

 

感谢：https://www.cnblogs.com/linyijia/p/12981830.html