/// <summary>
/// Asynchronously handles responding to a request.
/// </summary>
/// <param name="connection">The connection.</param>
/// <param name="request">A request message.</param>
/// <param name="responseHandler">A response handler.</param>
/// <param name="cancellationToken">A cancellation token.</param>
/// <returns>A task that represents the asynchronous operation.</returns>
/// <exception cref="ArgumentNullException">Thrown if <paramref name="connection" />
/// is <c>null</c>.</exception>
/// <exception cref="ArgumentNullException">Thrown if <paramref name="request" /> is <c>null</c>.</exception>
/// <exception cref="ArgumentNullException">Thrown if <paramref name="responseHandler" />
/// is <c>null</c>.</exception>
/// <exception cref="OperationCanceledException">Thrown if <paramref name="cancellationToken" />
/// is cancelled.</exception>
public async Task HandleResponseAsync(
IConnection connection,
Message request,
IResponseHandler responseHandler,
CancellationToken cancellationToken)
{
if (connection == null)
{
throw new ArgumentNullException(nameof(connection));
}
if (request == null)
{
throw new ArgumentNullException(nameof(request));
}
if (responseHandler == null)
{
throw new ArgumentNullException(nameof(responseHandler));
}
cancellationToken.ThrowIfCancellationRequested();
var response = _handshakeFailedResponse;
var handshakeRequest = MessageUtilities.DeserializePayload<HandshakeRequest>(request);
if (handshakeRequest != null)
{
if (!(handshakeRequest.MinimumProtocolVersion > handshakeRequest.ProtocolVersion ||
handshakeRequest.ProtocolVersion < _minimumProtocolVersion ||
handshakeRequest.MinimumProtocolVersion > _protocolVersion))
{
SemanticVersion negotiatedProtocolVersion;
if (_protocolVersion <= handshakeRequest.ProtocolVersion)
{
negotiatedProtocolVersion = _protocolVersion;
}
else
{
negotiatedProtocolVersion = handshakeRequest.ProtocolVersion;
}
response = new HandshakeResponse(MessageResponseCode.Success, negotiatedProtocolVersion);
}
}
await responseHandler.SendResponseAsync(request, response, cancellationToken)
.ContinueWith(task => _responseSentTaskCompletionSource.TrySetResult(0))
.ConfigureAwait(false);
}
/// <summary>
/// Initializes a new instance of the <see cref="SymmetricHandshake" /> class.
/// </summary>
/// <param name="connection">A connection.</param>
/// <param name="handshakeTimeout">The handshake timeout.</param>
/// <param name="protocolVersion">The handshaker's protocol version.</param>
/// <param name="minimumProtocolVersion">The handshaker's minimum protocol version.</param>
public SymmetricHandshake(
IConnection connection,
TimeSpan handshakeTimeout,
SemanticVersion protocolVersion,
SemanticVersion minimumProtocolVersion)
{
if (connection == null)
{
throw new ArgumentNullException(nameof(connection));
}
if (!TimeoutUtilities.IsValid(handshakeTimeout))
{
throw new ArgumentOutOfRangeException(
nameof(handshakeTimeout),
handshakeTimeout,
Strings.Plugin_TimeoutOutOfRange);
}
if (protocolVersion == null)
{
throw new ArgumentNullException(nameof(protocolVersion));
}
if (minimumProtocolVersion == null)
{
throw new ArgumentNullException(nameof(minimumProtocolVersion));
}
_connection = connection;
_handshakeTimeout = handshakeTimeout;
_protocolVersion = protocolVersion;
_minimumProtocolVersion = minimumProtocolVersion;
_handshakeFailedResponse = new HandshakeResponse(MessageResponseCode.Error, protocolVersion: null);
_responseSentTaskCompletionSource = new TaskCompletionSource <int>();
_timeoutCancellationTokenSource = new CancellationTokenSource(handshakeTimeout);
_timeoutCancellationTokenSource.Token.Register(() =>
{
_responseSentTaskCompletionSource.TrySetCanceled();
});
CancellationToken = _timeoutCancellationTokenSource.Token;
if (!_connection.MessageDispatcher.RequestHandlers.TryAdd(MessageMethod.Handshake, this))
{
throw new ArgumentException(Strings.Plugin_HandshakeRequestHandlerAlreadyExists, nameof(connection));
}
}