asp.net – 如果内容是静态的,那么对于带有“If-Modified-Since

是否可以在没有实际检查给定日期的情况下始终为具有“If-Modified-Since”标头的请求返回http状态代码304？
原因是浏览器必须已经拥有该映像的副本(因为它提供了modified-since标头).

这将使生活更轻松,因为我们(尚未)跟踪图像创建日期.

这是实际代码(更新：我现在在Aristos推荐的服务器响应中包含了if-modified标头)：

public void ProcessRequest(HttpContext context)
{
    if (!String.IsNullOrEmpty(context.Request.Headers["If-Modified-Since"])) {
        //Is this okay?
        context.Response.StatusCode = 304;
        context.Response.StatusDescription = "Not Modified";
        return;
    }
    var thumbnailId = context.Request.QueryString["thumbnail"];
    using (var thumbnailCache = new CThumbnailCache()) {
        var imageBytes = thumbnailCache.GetImageById(thumbnailId);

        context.Response.ContentType = "image/png";
        var outputStream = context.Response.OutputStream;
        outputStream.Write(imageBytes,imageBytes.Count());
        context.Response.Cache.SetCacheability(HttpCacheability.Public);
        context.Response.Cache.SetLastModified(DateTime.UtcNow);
        // added after Aristos post
        context.Response.AddHeader("If-Modified-Since",DateTime.UtcNow.ToString("r"));

        const int maxAge = 86400 * 14; // 14 Tage
        context.Response.Cache.SetExpires(DateTime.Now.AddSeconds(maxAge));
        context.Response.Cache.SetMaxAge(new TimeSpan(0,maxAge));
        context.Response.CacheControl = "private";
        context.Response.Cache.SetValidUntilExpires(true);

    }
}