HttpClient返回特殊字符但没有可读性

Question

我正在尝试使用async和await和HttpClient下载一个网页,但我只得到一个充满特殊字符的字符串...代码就像..

static async void DownloadPageAsync(string url)
{
    HttpClient client = new HttpClient();
    client.DefaultRequestHeaders.TryAddWithoutValidation("Accept", "text/html,application/xhtml+xml,application/xml");
    client.DefaultRequestHeaders.TryAddWithoutValidation("Accept-Encoding", "gzip, deflate");
    client.DefaultRequestHeaders.TryAddWithoutValidation("User-Agent", "Mozilla/5.0 (Windows NT 6.2; WOW64; rv:19.0) Gecko/20100101 Firefox/19.0");
    client.DefaultRequestHeaders.TryAddWithoutValidation("Accept-Charset", "ISO-8859-1");
    HttpResponseMessage response = await client.GetAsync(url);
    response.EnsureSuccessStatusCode();
    var responseStream = await response.Content.ReadAsStreamAsync();
    var streamReader = new StreamReader(responseStream);
    var str = streamReader.ReadToEnd();

}

和网址是

url = @"http://www.nseindia.com/live_market/dynaContent/live_watch/live_index_watch.htm";

当我做的时候

client.DefaultRequestHeaders.Add("User-Agent",
                                 "Mozilla/5.0 (compatible; MSIE 10.0; Windows NT 6.2; 
                                  WOW64; Trident/6.0)");

代替那四个DefaultRequestHeaders,我得到403错误,但这是nse网站,并且对所有人都是免费的.请各位朋友帮我们正确回复..问候

斯里瓦斯塔瓦

Answer 1

client.DefaultRequestHeaders.TryAddWithoutValidation("Accept-Encoding", "gzip, deflate");

有了这个,你告诉服务器你允许它压缩响应gzip/deflate.所以响应实际上是压缩的,这解释了为什么你会得到你得到的那种响应文本.

如果您想要纯文本,则不应添加标头,因此服务器不会压缩响应.如果删除上一行,则会获得正常的HTML响应文本.

或者,您当然可以保留该标头,并在收到后使用GZipStream解压缩响应.这将是这样的:

using (var responseStream = await response.Content.ReadAsStreamAsync())
using (var deflateStream = new GZipStream(responseStream, CompressionMode.Decompress))
using (var streamReader = new StreamReader(deflateStream))
{
    var str = streamReader.ReadToEnd();
    Console.WriteLine(str);
}

理想情况下,您应该检查值response.Content.Headers.GetValues("Content-Encoding")以确保编码gzip.既然您也接受deflate了可能的编码,那么您可以使用DeflateStream来解码它; 或者在Content-Encoding标头丢失的情况下不解码任何内容.