using System.Threading.Tasks;
using Microsoft.AspNetCore.Http;

namespace Dpz.Core.Web.Library.Middleware
{
    /// <summary>
    /// 处理HTTP响应中间件
    /// </summary>
    public class HttpResponseHeaderHandel
    {
        private readonly RequestDelegate _next;

        /// <summary>
        /// 
        /// </summary>
        /// <param name="next"></param>
        public HttpResponseHeaderHandel(RequestDelegate next)
        {
            _next = next;
        }
        
        /// <summary>
        /// 
        /// </summary>
        /// <param name="httpContext"></param>
        /// <returns></returns>
        public async Task Invoke(HttpContext httpContext)
        {
            /*
             * from https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Access-Control-Expose-Headers
             * 列出哪些 http response headers 对外暴露
             * 这里设置为所有
             */
            httpContext.Response.Headers.Append("Access-Control-Expose-Headers","*");
            await _next.Invoke(httpContext);
        }
    }
}