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如何在httpwebrequest中混合压缩和缓存?

http-compression httpwebrequest caching c#

AngelBlaZe · 技术社区 · 15 年前

我有一个C客户机正在与一个Cherrypy(HTTP/REST)Web服务交谈。问题是我不能同时打开压缩和缓存。

request.AutomaticDecompression = DecompressionMethods.GZip | DecompressionMethods.Deflate;

通过去掉上面的行,我得到了正确的缓存头(如果没有数学,如果修改自),同时注释它得到了压缩头(accept encodig:gzip),但没有缓存头。在我看来,这就像一只虫子,但也许我做错了什么。

[完整代码]

        public static string GET(string URL)
    {
        string JSON;
        // Create the web request  
        HttpWebRequest request = WebRequest.Create(URL) as HttpWebRequest;
        HttpRequestCachePolicy cPolicy = new HttpRequestCachePolicy(HttpRequestCacheLevel.Revalidate);

        request.Accept = "application/json";            
        request.CachePolicy = cPolicy;
        request.AutomaticDecompression = DecompressionMethods.GZip | DecompressionMethods.Deflate;
        request.Pipelined = false;

        // Get response  
        using (HttpWebResponse response = request.GetResponse() as HttpWebResponse)
        {                
            // Get the response stream  
            StreamReader readerF = new StreamReader(response.GetResponseStream());

            JSON = readerF.ReadToEnd();
            // Console application output  
            //Console.WriteLine(JSON);
            if (response.IsFromCache )
                Console.WriteLine("Request not from cache");
        }

        return JSON;
    }

2 回复 | 直到 15 年前

AngelBlaZe 15 年前

我已经实现了一个变通方法,请参见下面的代码。我认为处理压缩比处理缓存更容易,所以我自己实现了压缩部分。非常简单,这要归功于博客: HttpWebRequest and GZip Http Responses 我仍然认为这是.NET中的一个bug。

        public static string GET(string URL)
    {
        string JSON;
        // Create the web request  
        HttpWebRequest request = WebRequest.Create(URL) as HttpWebRequest;
        HttpRequestCachePolicy cPolicy = new HttpRequestCachePolicy(HttpRequestCacheLevel.Revalidate);

        request.Accept = "application/json";
        request.Headers.Add(HttpRequestHeader.AcceptEncoding, "gzip,deflate");
        request.CachePolicy = cPolicy;
        request.Pipelined = false;

        // Get response  
        using (HttpWebResponse response = request.GetResponse() as HttpWebResponse)
        {
            //From http://www.west-wind.com/WebLog/posts/102969.aspx
            Stream responseStream = responseStream = response.GetResponseStream();
            if (response.ContentEncoding.ToLower().Contains("gzip"))
                responseStream = new GZipStream(responseStream, CompressionMode.Decompress);
            else if (response.ContentEncoding.ToLower().Contains("deflate"))
                responseStream = new DeflateStream(responseStream, CompressionMode.Decompress);


            // Get the response stream  
            StreamReader readerF = new StreamReader(responseStream);
            JSON = readerF.ReadToEnd();
        }

        return JSON;
    }

david valentine 15 年前

这是政策的副作用吗? 如果只使用默认策略或其他策略,会发生什么情况?

另一种选择是自己管理缓存。