C＃HttpWebRequest从美国IP超时，在浏览器中很好

Question

I am struggling with web requests to some websites like (mrporter.com or size.co.uk). Outside USA (so no USA IPs), I can make requests just fine. However once I am behind USA IP, requests either time out or end up with "A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond" exception. I have tried all kind of headers combinations, still no luck. I need to note, that those websites are opening in browsers just fine.

This is my implementation that works with non-USA ips.

var _request = (HttpWebRequest)WebRequest.Create("https://www.mrporter.com");                
_request.CookieContainer = new CookieContainer();
_request.UserAgent = "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/55.0.2883.87 Safari/537.36";
_request.KeepAlive = true;
_request.AutomaticDecompression = (DecompressionMethods.GZip | DecompressionMethods.Deflate);
_request.Headers.Add("Accept-Encoding", "gzip, deflate");
_request.Headers.Add("Accept-Language", "en-GB, en-US; q=0.9, en; q=0.8");
_request.Headers.Add("Upgrade-Insecure-Requests", "1");

var _srr = "";
using (var response = _request.GetResponse())
{
var httpWebResponse = response.GetResponseStream();
using (var sr = new StreamReader(httpWebResponse))
{
_srr = sr.ReadToEnd();
}
}

Anybody can help? I seriously wasted hours with it with no result ...

Answer 1

This is the procedure used test the Server you mentioned ( https://www.mrporter.com/ )

The main method can be called this way:
(The StreamObject class returns a number of informations about the Server, including the Html of the landing page. (Also its Cookies, IP Address etc.)

public async void SomeMethodAsync()
{
    StreamObject _streamObj = new StreamObject()
    {
        ResourceURI = new Uri(@"https://www.mrporter.com/"),
        ProcessStream = true
    };
    _streamObj = await HTTP_GetStreamAsync(_streamObj);
}

I had to cut out the Proxy setup (it's inititialized if needed in the same method that initializes the WebRequest Headers). Anyway, it should looks like this:

if ([UseProxy])
    if ([ProxyHost] != null) {
        WebRequest.Proxy = new WebProxy([ProxyHost], [ProxyPort]);

        if ([Credentials] != null)
            WebRequest.Proxy.Credentials = new NetworkCredential([Credentials].UserID, [Credentials].Password);
    } else {
        WebRequest.Proxy = WebRequest.GetSystemWebProxy();
    }
}

If you plan on using a Proxy, you should also insert this parameter in your app.config file:

<system.net>
    <defaultProxy useDefaultCredentials="true" />
</system.net>

When the main method ( HTTP_GetStreamAsync() ) returns, StreamObject.Payload will contain the decoded Html Page of the Site you connected to.

There are a number of sub-utilities and it might look complicated, but everything should work fine. You just need to insert all of the code inside a class and modify the calling method ( SomeMethodAsync() ) accordingly.

(I'll edit this when I have a moment).

using System;
using System.Collections.Generic;
using System.IO;
using System.IO.Compression;
using System.Linq;
using System.Net;
using System.Net.NetworkInformation;
using System.Net.Security;
using System.Net.Sockets;
using System.Security.Cryptography;
using System.Security.Cryptography.X509Certificates;
using System.Text;
using System.Text.RegularExpressions;
using System.Threading.Tasks;

private const uint COR_E_INVALIDOPERATION = 0x80131509;

public class StreamObject
{
    public Stream ContentStream { get; set; }
    public bool ProcessStream { get; set; }
    public Uri ResourceURI { get; set; }
    public Uri ResponseURI { get; set; }
    public string Referer { get; set; }
    public string Payload { get; set; }
    public string ServerType { get; set; }
    public string ServerName { get; set; }
    public IPAddress[] ServerIP { get; set; }
    public string ContentName { get; set; }
    public string ContentType { get; set; }
    public string ContentCharSet { get; set; }
    public string ContentLanguage { get; set; }
    public long ContentLenght { get; set; }
    public HttpStatusCode StatusCode { get; set; }
    public string StatusDescription { get; set; }
    public WebExceptionStatus WebException { get; set; }
    public string WebExceptionDescription { get; set; }
    public CookieContainer Cookies { get; set; }
}

public async Task<StreamObject> HTTP_GetStreamAsync(StreamObject RequestObject)
{
    if (string.IsNullOrEmpty(RequestObject.ResourceURI.ToString().Trim()))
        return null;

    MemoryStream _memstream = new MemoryStream();
    HttpWebRequest httpRequest;
    CookieContainer _cookiejar = new CookieContainer();
    HttpStatusCode _StatusCode = HttpStatusCode.OK;

    ServicePointManager.SecurityProtocol = SecurityProtocolType.Ssl3 |
                                           SecurityProtocolType.Tls |
                                           SecurityProtocolType.Tls11 |
                                           SecurityProtocolType.Tls12;
    ServicePointManager.ServerCertificateValidationCallback += TlsValidationCallback;

    if (RequestObject.Cookies != null && RequestObject.Cookies.Count > 0)
        _cookiejar = RequestObject.Cookies;

    httpRequest = WebRequest.CreateHttp(RequestObject.ResourceURI);

    try
    {
        HTTP_RequestHeadersInit(ref httpRequest, _cookiejar, null);
        httpRequest.Referer = RequestObject.Referer;
        using (HttpWebResponse httpResponse = (HttpWebResponse)await httpRequest.GetResponseAsync())
        {
            Stream ResponseStream = httpResponse.GetResponseStream();

            if (_StatusCode == HttpStatusCode.OK)
            {
                await ResponseStream.CopyToAsync(_memstream);
                RequestObject.ContentStream = _memstream;
                RequestObject.ResponseURI = httpResponse.ResponseUri;
                RequestObject.ContentLenght = _memstream.Length;
                RequestObject.ContentCharSet = httpResponse.CharacterSet ?? string.Empty;
                RequestObject.ContentLanguage = httpResponse.Headers["Content-Language"] ?? string.Empty;
                RequestObject.ContentType = httpResponse.ContentType.ToLower();
                if (RequestObject.ContentType.IndexOf(@"/") > -1)
                {
                    do
                    {
                        RequestObject.ContentType = RequestObject.ContentType.Substring(RequestObject.ContentType.IndexOf(@"/") + 1);
                        if (RequestObject.ContentType.IndexOf(@"/") < 0)
                            break;
                    } while (true);
                    if (RequestObject.ContentType.IndexOf(";") > -1)
                        RequestObject.ContentType = RequestObject.ContentType.Substring(0, RequestObject.ContentType.IndexOf(@";"));
                    RequestObject.ContentType = "." + RequestObject.ContentType;
                }
                RequestObject.ContentName = httpResponse.Headers["Content-Disposition"] ?? string.Empty;
                if (RequestObject.ContentName.Length == 0)
                    RequestObject.ContentName = RequestObject.ResourceURI.Segments.Last();
                RequestObject.ServerType = httpResponse.Server;
                RequestObject.ServerName = RequestObject.ResponseURI.DnsSafeHost;
                RequestObject.ServerIP = await Dns.GetHostAddressesAsync(RequestObject.ServerName);
                RequestObject.StatusCode = _StatusCode;
                RequestObject.StatusDescription = httpResponse.StatusDescription;
                if (RequestObject.ProcessStream)
                    RequestObject.Payload = ProcessResponse(RequestObject.ContentStream,
                                                            Encoding.GetEncoding(RequestObject.ContentCharSet),
                                                            httpResponse.ContentEncoding);
            }
        }
    }
    catch (WebException exW)
    {
        if (exW.Response != null)
        {
            RequestObject.StatusCode = ((HttpWebResponse)exW.Response).StatusCode;
            RequestObject.StatusDescription = ((HttpWebResponse)exW.Response).StatusDescription;
        }
        RequestObject.WebException = exW.Status;
        RequestObject.WebExceptionDescription = exW.Message;

    }
    catch (System.Exception exS)
    {
        if ((uint)exS.HResult == COR_E_INVALIDOPERATION)
        {
            RequestObject.WebException = await PingHostAddressAsync("8.8.8.8", 500) > 0
                                       ? WebExceptionStatus.NameResolutionFailure
                                       : WebExceptionStatus.ConnectFailure;
            RequestObject.WebExceptionDescription = RequestObject.WebException.ToString();
        }
        else
        {
            RequestObject.WebException = WebExceptionStatus.RequestCanceled;
            RequestObject.WebExceptionDescription = RequestObject.WebException.ToString();
        }
    }
    finally
    {
        ServicePointManager.ServerCertificateValidationCallback -= TlsValidationCallback;
    }

    RequestObject.Cookies = httpRequest.CookieContainer;
    RequestObject.StatusCode = _StatusCode;
    return RequestObject;

}   //HTTP_GetStream

private bool TlsValidationCallback(object sender, X509Certificate CACert, X509Chain CAChain, SslPolicyErrors sslPolicyErrors)
{
    X509Certificate2 _Certificate = new X509Certificate2(CACert);
    //ADD A CERIFICATE HERE IF NEEDED
    //X509Certificate2 _CACert = new X509Certificate2(@"[localstorage]/ca.cert");
    //CAChain.ChainPolicy.ExtraStore.Add(_CACert);

    X509Certificate2 cert = (X509Certificate2)CACert;

    CAChain.Build(_Certificate);
    foreach (X509ChainStatus CACStatus in CAChain.ChainStatus)
    {
        if ((CACStatus.Status != X509ChainStatusFlags.NoError) &
            (CACStatus.Status != X509ChainStatusFlags.UntrustedRoot))
            return false;
    }
    return true;
}

private void HTTP_RequestHeadersInit(ref HttpWebRequest _httpreq, CookieContainer _cookiecontainer, StreamObject sObject)
{
    _httpreq.Date = DateTime.Now;
    _httpreq.Timeout = 30000;
    _httpreq.ReadWriteTimeout = 30000;
    _httpreq.CookieContainer = _cookiecontainer;
    _httpreq.KeepAlive = true;
    _httpreq.ConnectionGroupName = Guid.NewGuid().ToString();
    _httpreq.AllowAutoRedirect = true;
    _httpreq.AutomaticDecompression = DecompressionMethods.GZip | DecompressionMethods.Deflate;
    _httpreq.ServicePoint.MaxIdleTime = 30000;
    _httpreq.ServicePoint.Expect100Continue = false;
    _httpreq.Referer = sObject.Referer ?? string.Empty;
    _httpreq.UserAgent = "Mozilla/5.0 (Windows NT 10; Win64; x64; rv:56.0) Gecko/20100101 Firefox/56.0";
    _httpreq.Accept = "ext/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8";
    _httpreq.Headers.Add(HttpRequestHeader.AcceptLanguage, "en-US;q=0.8,en-GB;q=0.5,en;q=0.3");
    _httpreq.Headers.Add(HttpRequestHeader.AcceptEncoding, "gzip, deflate;q=0.8");
    _httpreq.Headers.Add(HttpRequestHeader.CacheControl, "no-cache");

    //I had to cut out the WebRequest Proxy setup here
}

private string ProcessResponse(Stream stream, Encoding encoding, string ContentEncoding)
{
    string html = string.Empty;
    stream.Position = 0;
    try
    {
        using (MemoryStream _memStream = new MemoryStream())
        {
            if (ContentEncoding.Contains("gzip"))
            {
                using (GZipStream _gzipStream = new GZipStream(stream, System.IO.Compression.CompressionMode.Decompress))
                {
                    _gzipStream.CopyTo(_memStream);
                };
            }
            else if (ContentEncoding.Contains("deflate"))
            {
                using (DeflateStream _deflStream = new DeflateStream(stream, System.IO.Compression.CompressionMode.Decompress))
                {
                    _deflStream.CopyTo(_memStream);
                };
            }
            else
            {
                stream.CopyTo(_memStream);
            }

            _memStream.Position = 0;
            using (StreamReader _reader = new StreamReader(_memStream, encoding))
            {
                html = _reader.ReadToEnd().Trim();
                html = DecodeMetaCharSetEncoding(_memStream, html, encoding);
            };
        };
    }
    catch (Exception)
    {
        return string.Empty;
    }
    return html;
}

private string DecodeMetaCharSetEncoding(Stream memStream, string _html, Encoding _encode)
{
    Match _match = new Regex("<meta\\s+.*?charset\\s*=\\s*\"?(?<charset>[A-Za-z0-9_-]+)\"?",
                                        RegexOptions.Singleline |
                                        RegexOptions.IgnoreCase).Match(_html);
    if (_match.Success)
    {
        string charset = _match.Groups["charset"].Value.ToLower() ?? "utf-8";
        if ((charset == "unicode") | (charset == "utf-7") | (charset == "utf-16"))
            charset = "utf-8";

        try
        {
            Encoding metaEncoding = Encoding.GetEncoding(charset);
            if (_encode.WebName != metaEncoding.WebName)
            {
                memStream.Position = 0L;
                using (StreamReader recodeReader = new StreamReader(memStream, metaEncoding))
                { _html = recodeReader.ReadToEnd().Trim(); }
            }
        }
        catch (ArgumentException)
        {
            _html = string.Empty;
        }
        catch (Exception)
        {
            _html = string.Empty;
        }
    }
    return _html;
}

public async Task<IPStatus> PingHostAddressAsync(string HostAddress, int timeout)
{
    if (string.IsNullOrEmpty(HostAddress.Trim()))
        return IPStatus.BadDestination;

    byte[] buffer = new byte[32];
    PingReply iReplay = null;
    IPStatus ipStatus;
    using (Ping iPing = new Ping())
    {
        try
        {
            IPAddress _IPAddress = IPAddress.Parse(HostAddress);
            iReplay = await iPing.SendPingAsync(_IPAddress, timeout, buffer, new PingOptions(64, false));
            return iReplay.Status;
        }
        catch (FormatException)
        {
            return IPStatus.BadDestination;
        }
        catch (NotSupportedException nsex)
        {
            ipStatus = (IPStatus)nsex.HResult;
            ipStatus = IPStatus.DestinationProtocolUnreachable;
        }
        catch (PingException pex)
        {
            ipStatus = (IPStatus)pex.HResult;
        }
        catch (SocketException soex)
        {
            ipStatus = (IPStatus)soex.HResult;
        }
        catch (Exception ex)
        {
            //Log ex
            ipStatus = (IPStatus)ex.HResult;
        }
        return (iReplay != null) ? iReplay.Status : ipStatus;
    }
}