Abp.core中在应用层获取HttpContext对象

实际IHttpContextAccessor对象已经在底层实现了自动的依赖注入，只需要在应用层引入Microsoft.AspNetCore.Http，然后在构造函数中依赖注入即可。

/// <summary>
    /// 应用服务父类
    /// </summary>
    public abstract class AppServiceBase : ApplicationService
    {
        protected IHttpContextAccessor httpContext;

        /// <summary>
        /// 客户端域名
        /// </summary>
        protected string origin;

        protected AppServiceBase (IHttpContextAccessor httpContextAccessor)
        {
            LocalizationSourceName = FakaConsts.LocalizationSourceName;
            httpContext = httpContextAccessor;
            origin = httpContextAccessor.HttpContext.Request.Headers["Origin"].ToString();
        }
   }