UWP 解压 GZIP

准备工作：

通过 NUGET 安装 Microsoft.Bcl.Compression ;

使用命名空间

using System.IO.Compression ;

        public static async Task<string> Get(string url)
        {
            WebRequest request = WebRequest.CreateHttp(new Uri(url)); //创建WebRequest对象
            request.Method = "GET";    //设置请求方式为GET
            request.Headers[HttpRequestHeader.UserAgent] = "Mozilla/5.0 (Windows NT 10.0; WOW64; rv:44.0) Gecko/20100101 Firefox/44.0";
            request.Headers[HttpRequestHeader.AcceptEncoding] = "gzip, deflate"; //设置接收的编码 可以接受 gzip

            var response = await request.GetResponseAsync();
            Stream stream = null;
            stream = response.Headers[HttpRequestHeader.ContentEncoding].Equals("gzip",
                StringComparison.CurrentCultureIgnoreCase) ? new GZipStream(response.GetResponseStream(), CompressionMode.Decompress) : response.GetResponseStream();
            var ms = new MemoryStream();
            var buffer = new byte[];
            while (true)
            {
                if (stream == null) continue;
                var sz = stream.Read(buffer, , );
                if (sz == ) break;
                ms.Write(buffer, , sz);
            }
            var bytes = ms.ToArray();
            var html = GetEncoding(bytes, response.Headers[HttpRequestHeader.ContentType]).GetString(bytes);
            await stream.FlushAsync();
            return html;

        }       

获取编码：

public static Encoding GetEncoding(byte[] bytes, string charSet)
{
    var html = Encoding.UTF8.GetString(bytes);
    var regCharset = new Regex(@"charset\b\s*=\s*""*(?<charset>[^""]*)");
    if (regCharset.IsMatch(html))
    {
        return Encoding.GetEncoding(regCharset.Match(html).Groups["charset"].Value);
    }
    if (string.IsNullOrEmpty(charSet))
    {
        return Encoding.UTF8;
    }
    try
    {
        // 解决 gbk gb2312
        Encoding.RegisterProvider(CodePagesEncodingProvider.Instance);
        return Encoding.GetEncoding(charSet);
    }
    catch (Exception)
    {
        return Encoding.UTF8;
    }
}

虽然使用 HttpClient 更简单

            var http = new HttpClient();
            http.DefaultRequestHeaders.Add("user-agent", "Mozilla/5.0 (Windows NT 10.0; WOW64; rv:44.0) Gecko/20100101 Firefox/44.0");
            http.DefaultRequestHeaders.Add("accept-encoding", "gzip, deflate");
            var response = await http.GetAsync(new Uri(url));
            response.EnsureSuccessStatusCode();//确保请求成功    

但是它的响应头并没有 “Content-Encoding” ，所以无法直接判断需不需要 Gzip 解压。