public virtual bool TestWebProxy(IActualProxy actualProxy)
{
// get test url specified in application config file
// (not in the settings file because this information is supposed to be set for site)
string targetUrl = SystemSettingsSwitcher.GetProxyTestUrl();
Debug.Assert(string.IsNullOrEmpty(targetUrl) == false);
Uri target = new Uri(targetUrl);
DnsEndPoint targetEndPoint = new DnsEndPoint(target.Host, target.Port);
WebClientForTest webClient = new WebClientForTest();
webClient.Timeout = 10 * 1000; // 10 seconds
// test each proxy candidate
CommandBase owner = this.Owner;
bool result = false;
IReadOnlyCollection <DnsEndPoint> endPoints = actualProxy.GetProxyEndPoints(target);
if (endPoints != null)
{
foreach (DnsEndPoint endPoint in endPoints)
{
owner.LogVerbose($"ActualProxy check: to {endPoint.Host}:{endPoint.Port}");
try {
webClient.Proxy = new WebProxy(endPoint.Host, endPoint.Port);
webClient.DownloadData(targetUrl); // an exception is thrown on error
result = true;
} catch (WebException exception) {
// Note that a protocol error indicates that the end point exists
result = (exception.Status == WebExceptionStatus.ProtocolError);
if (result)
{
owner.LogVerbose($"ActualProxy check: {exception.Status} -> OK");
}
else
{
owner.LogError($"ActualProxy check: {exception.Status} -> NG");
}
}
if (result)
{
// a valid proxy is found
break;
}
}
}
if (result)
{
owner.LogVerbose("ActualProxy check: OK - there is a valid actual proxy.");
}
else
{
owner.LogError("ActualProxy check: NG - no valid proxy.");
}
return(result);
}
public void Start(CommandSettings commandSettings, bool saveCredentials, bool checkPreviousBackup)
{
// argument checks
if (commandSettings == null)
{
throw new ArgumentNullException(nameof(commandSettings));
}
SystemSettingsSwitcherSettings systemSettingsSwitcherSettings = commandSettings.SystemSettingsSwitcher;
if (systemSettingsSwitcherSettings == null)
{
throw new ArgumentNullException(nameof(commandSettings.SystemSettingsSwitcher));
}
ProxySettings proxySettings = commandSettings.Proxy;
if (proxySettings == null)
{
throw new ArgumentNullException(nameof(commandSettings.Proxy));
}
// state checks
if (this.proxy != null)
{
throw new InvalidOperationException("The proxy is already started.");
}
Debug.Assert(this.switcher == null);
Debug.Assert(this.backup == null);
try {
ComponentFactory componentFactory = this.Owner.ComponentFactory;
// check the state of previous backup
if (checkPreviousBackup)
{
this.Owner.CheckPreviousBackup();
}
// create a system settings swither
SystemSettingsSwitcher switcher = componentFactory.CreateSystemSettingsSwitcher(this.Owner, systemSettingsSwitcherSettings);
this.switcher = switcher;
// setup credential dictionary
lock (this.credentialsLocker) {
IEnumerable <CredentialSettings> credentials = commandSettings.Credentials;
this.dictionary = (credentials == null)? new Dictionary <string, CredentialSettings>(): credentials.ToDictionary(c => c.EndPoint);
this.isCredentialsDirty = false;
}
// create a proxy
Proxy proxy = componentFactory.CreateProxy(proxySettings);
this.proxy = proxy;
// detect the current proxy
IActualProxy actualProxy = switcher.GetActualProxy();
if (actualProxy == null)
{
// no actual proxy to which it connects
throw new Exception(Resources.CommandBase_Message_NoActualProxy);
}
try {
// log
CommandBase owner = this.Owner;
if (owner.ShouldLog(TraceEventType.Verbose))
{
// log the actual proxy
owner.LogVerbose($"ActualProxy is '{actualProxy.Description}'");
// log whether system settings is being switched
string label = switcher.Enabled ? "enabled" : "disabled";
owner.LogVerbose($"SystemSettingsSwitch: {label}");
}
// test actual proxy
if (switcher.TestWebProxy(actualProxy) == false)
{
string message = string.Format(Resources.SystemSettingsSwitcher_Message_ProxyIsNotConnectable, actualProxy.Description);
throw new Exception(message);
}
// start the proxy
proxy.ActualProxy = actualProxy;
actualProxy = null; // its ownership has been moved to the proxy object.
proxy.Start(this);
this.saveCredentials = saveCredentials;
// switch system settings
this.backup = switcher.Switch(proxy);
if (this.backup != null)
{
// save backup settings
owner.SaveSystemSettingsBackup(this.backup);
}
this.commandSettings = commandSettings;
} catch {
DisposableUtil.ClearDisposableObject(ref actualProxy);
throw;
}
} catch {
Stop(systemSessionEnding: false);
throw;
}
return;
}