/// <summary>
/// This Service returns the Servers known to a Server or Discovery Server.
/// </summary>
/// <param name="request">a request.</param>
/// <returns>A <see cref="Task"/> representing the asynchronous operation.</returns>
public static async Task<FindServersResponse> FindServersAsync(FindServersRequest request)
{
if (request == null)
{
throw new ArgumentNullException("request");
}
var client = new UaTcpDiscoveryClient(
new EndpointDescription
{
EndpointUrl = request.EndpointUrl,
SecurityMode = MessageSecurityMode.None,
SecurityPolicyUri = SecurityPolicyUris.None
});
try
{
await client.OpenAsync().ConfigureAwait(false);
var response = await client.innerChannel.RequestAsync(request).ConfigureAwait(false);
await client.CloseAsync().ConfigureAwait(false);
return (FindServersResponse)response;
}
catch (Exception)
{
await client.AbortAsync().ConfigureAwait(false);
throw;
}
}
/// <summary>
/// This Service returns the Endpoints supported by a Server and all of the configuration information required to establish a SecureChannel and a Session.
/// </summary>
/// <param name="request">a request.</param>
/// <returns>A <see cref="Task"/> representing the asynchronous operation.</returns>
public static async Task <GetEndpointsResponse> GetEndpointsAsync(GetEndpointsRequest request)
{
if (request == null)
{
throw new ArgumentNullException("request");
}
var client = new UaTcpDiscoveryClient(
new EndpointDescription
{
EndpointUrl = request.EndpointUrl,
SecurityMode = MessageSecurityMode.None,
SecurityPolicyUri = SecurityPolicyUris.None
});
try
{
await client.OpenAsync().ConfigureAwait(false);
var response = await client.innerChannel.RequestAsync(request).ConfigureAwait(false);
await client.CloseAsync().ConfigureAwait(false);
return((GetEndpointsResponse)response);
}
catch (Exception)
{
await client.AbortAsync().ConfigureAwait(false);
throw;
}
}
/// <summary>
/// Opens a session with the remote endpoint.
/// </summary>
/// <param name="token">A cancellation token.</param>
/// <returns>A task.</returns>
private async Task OpenAsync(CancellationToken token = default(CancellationToken))
{
await this.semaphore.WaitAsync(token).ConfigureAwait(false);
try
{
if (this.RemoteEndpoint == null)
{
// If specific endpoint is not provided, use discovery to select endpoint with highest
// security level.
try
{
this.Logger?.LogInformation($"Discovering endpoints of '{this.discoveryUrl}'.");
var getEndpointsRequest = new GetEndpointsRequest
{
EndpointUrl = this.discoveryUrl,
ProfileUris = new[] { TransportProfileUris.UaTcpTransport }
};
var getEndpointsResponse = await UaTcpDiscoveryClient.GetEndpointsAsync(getEndpointsRequest).ConfigureAwait(false);
if (getEndpointsResponse.Endpoints == null || getEndpointsResponse.Endpoints.Length == 0)
{
throw new InvalidOperationException($"'{this.discoveryUrl}' returned no endpoints.");
}
this.RemoteEndpoint = getEndpointsResponse.Endpoints.OrderBy(e => e.SecurityLevel).Last();
this.Logger?.LogTrace($"Success discovering endpoints of '{this.discoveryUrl}'.");
}
catch (Exception ex)
{
this.Logger?.LogError($"Error discovering endpoints of '{this.discoveryUrl}'. {ex.Message}");
throw;
}
}
// throw here to exit state machine.
token.ThrowIfCancellationRequested();
// evaluate the user identity provider (may show a dialog).
var userIdentity = await this.UserIdentityProvider(this.RemoteEndpoint);
try
{
this.linkToken?.Dispose();
if (this.innerChannel != null && this.innerChannel.State != CommunicationState.Closed)
{
await this.innerChannel.AbortAsync();
}
this.innerChannel = new UaTcpSessionChannel(
this.LocalDescription,
this.CertificateStore,
userIdentity,
this.RemoteEndpoint,
this.loggerFactory,
this.SessionTimeout,
this.TimeoutHint,
this.DiagnosticsHint,
this.LocalReceiveBufferSize,
this.LocalSendBufferSize,
this.LocalMaxMessageSize,
this.LocalMaxChunkCount);
await this.innerChannel.OpenAsync(token).ConfigureAwait(false);
this.linkToken = this.pendingRequests.LinkTo(this.innerChannel);
//// create an internal subscription.
//var subscriptionRequest = new CreateSubscriptionRequest
//{
// RequestedPublishingInterval = DefaultPublishingInterval,
// RequestedMaxKeepAliveCount = DefaultKeepaliveCount,
// RequestedLifetimeCount = (uint)(this.SessionTimeout / DefaultPublishingInterval),
// PublishingEnabled = true,
// Priority = 0
//};
//var subscriptionResponse = await this.CreateSubscriptionAsync(subscriptionRequest).ConfigureAwait(false);
//this.subscriptionId = subscriptionResponse.SubscriptionId;
}
catch (Exception ex)
{
this.Logger?.LogError($"Error opening channel with endpoint '{this.RemoteEndpoint.EndpointUrl}'. {ex.Message}");
throw;
}
}
finally
{
this.semaphore.Release();
}
}
/// <summary>
/// Opens a session with the remote endpoint.
/// </summary>
/// <param name="token">A cancellation token.</param>
/// <returns>A task.</returns>
private async Task OpenAsync(CancellationToken token = default(CancellationToken))
{
await this.semaphore.WaitAsync(token).ConfigureAwait(false);
try
{
if (this.RemoteEndpoint == null)
{
// If specific endpoint is not provided, use discovery to select endpoint with highest
// security level.
try
{
Trace.TraceInformation($"UaTcpSessionClient discovering endpoints of '{this.discoveryUrl}'.");
var getEndpointsRequest = new GetEndpointsRequest
{
EndpointUrl = this.discoveryUrl,
ProfileUris = new[] { TransportProfileUris.UaTcpTransport }
};
var getEndpointsResponse = await UaTcpDiscoveryClient.GetEndpointsAsync(getEndpointsRequest).ConfigureAwait(false);
if (getEndpointsResponse.Endpoints == null || getEndpointsResponse.Endpoints.Length == 0)
{
throw new InvalidOperationException($"'{this.discoveryUrl}' returned no endpoints.");
}
this.RemoteEndpoint = getEndpointsResponse.Endpoints.OrderBy(e => e.SecurityLevel).Last();
}
catch (Exception ex)
{
Trace.TraceWarning($"UaTcpSessionClient error discovering endpoints of '{this.discoveryUrl}'. {ex.Message}");
throw;
}
}
// throw here to exit state machine.
token.ThrowIfCancellationRequested();
try
{
this.linkToken?.Dispose();
Trace.TraceInformation($"UaTcpSessionClient opening channel with endpoint '{this.RemoteEndpoint.EndpointUrl}'.");
this.innerChannel = new UaTcpSessionChannel(
this.LocalDescription,
this.LocalCertificate,
this.UserIdentity,
this.RemoteEndpoint,
this.SessionTimeout,
this.TimeoutHint,
this.DiagnosticsHint,
this.LocalReceiveBufferSize,
this.LocalSendBufferSize,
this.LocalMaxMessageSize,
this.LocalMaxChunkCount);
await this.innerChannel.OpenAsync(token).ConfigureAwait(false);
this.linkToken = this.pendingRequests.LinkTo(this.innerChannel);
// create an internal subscription.
this.publishEvent.Subscribe(this.OnPublishResponse, ThreadOption.PublisherThread, false);
var subscriptionRequest = new CreateSubscriptionRequest
{
RequestedPublishingInterval = DefaultPublishingInterval,
RequestedMaxKeepAliveCount = DefaultKeepaliveCount,
RequestedLifetimeCount = (uint)(this.SessionTimeout / DefaultPublishingInterval),
PublishingEnabled = true,
Priority = 0
};
var subscriptionResponse = await this.CreateSubscriptionAsync(subscriptionRequest).ConfigureAwait(false);
this.subscriptionId = subscriptionResponse.SubscriptionId;
}
catch (Exception ex)
{
Trace.TraceWarning($"UaTcpSessionClient error opening channel with endpoint '{this.RemoteEndpoint.EndpointUrl}'. {ex.Message}");
throw;
}
}
finally
{
this.semaphore.Release();
}
}
