/// <summary>
/// Invokes an operation method.
/// </summary>
/// <typeparam name="TT">The task return type.</typeparam>
/// <param name="method">The method.</param>
/// <param name="args">The arguments.</param>
/// <param name="returnType">The real return type.</param>
/// <returns></returns>
protected virtual async Task <TT> InvokeOperationAsync <TT>(MethodInfo method, object[] args, Type returnType)
{
// build arguments
Dictionary <string, object> argsPayload = new Dictionary <string, object>();
ParameterInfo[] argsMethod = method.GetParameters();
for (int i = 0; i < args.Length; i++)
{
argsPayload[argsMethod[i].Name] = args[i];
}
// create request
RpcRequest req = new RpcRequest(_contractAttr.Name != null ? _contractAttr.Name : _typeInfo.Name, method.Name, argsPayload);
// serialize
byte[] requestBody = new ProtobufRpcSerializer().SerializeRequest(req);
RpcHeader header = new RpcHeader(RpcHeader.HEADER_VERSION, ProtobufRpcSerializer.SerializerName, RpcMessageType.Single);
// create headers
IDictionary <string, object> headers = new Dictionary <string, object>()
{
{ RpcHeader.HEADER_NAME, header.ToString() }
};
// ask or send
if (method.GetCustomAttribute <RpcOperationAttribute>().NoReply)
{
// send operation
await _channel.SendAsync(requestBody, headers);
return(default(TT));
}
else
{
Envelope res = await _channel.AskAsync(requestBody, _configuration.Timeout, headers);
// transform response
byte[] responseBody = res.Body;
// try and get response header
if (!res.Headers.TryGetValue(RpcHeader.HEADER_NAME, out object resHeaderData))
{
throw new InvalidOperationException("The response envelope is not a valid RPC message");
}
RpcHeader resHeader = new RpcHeader(Encoding.UTF8.GetString(resHeaderData as byte[]));
// deserialize response
if (!RpcSerializer.Serializers.TryGetValue(resHeader.Serializer, out IRpcSerializer deserializer))
{
throw new NotSupportedException("The response serializer is not supported");
}
// deserialize
RpcResponse resPayload = null;
if (method.ReturnType == typeof(Task))
{
// deserialize
resPayload = deserializer.DeserializeResponse(responseBody, typeof(void));
// return result
if (resPayload.IsSuccess)
{
return((TT)(object)true);
}
}
else
{
// deserialize
Type taskType = method.ReturnType.GetGenericArguments()[0];
resPayload = deserializer.DeserializeResponse(responseBody, taskType);
// return result
if (resPayload.IsSuccess)
{
return((TT)resPayload.Data);
}
}
// throw error
throw new RpcException(resPayload.Error);
}
}
/// <summary>
/// Takes the parsed header and envelope and applies correct type handler.
/// </summary>
/// <param name="header">The header.</param>
/// <param name="envelope">The envelope.</param>
/// <returns></returns>
private async Task ApplyAsync(RpcHeader header, Envelope envelope)
{
if (header.Type == RpcMessageType.Single)
{
// find serializer for this request
RpcRequest req = null;
IRpcSerializer serializer = null;
if (!RpcSerializer.Serializers.TryGetValue(header.Serializer, out serializer))
{
throw new NotSupportedException("The serializer is not supported by RPC");
}
// deserialize into a request
RpcResponse res = null;
try {
req = serializer.DeserializeRequest(envelope.Body, (i, o) => RpcArgument.FromMember(GetMember(i, o)));
} catch (KeyNotFoundException) {
res = new RpcResponse("InterfaceNotFound", "The interface or operation could not be found", null);
} catch (Exception ex) {
res = new RpcResponse("ArgumentInvalid", string.Format("The request format is invalid: {0}", ex.Message), null);
}
// apply single request
MemberInfo memberInfo = null;
try {
if (req != null)
{
memberInfo = GetMember(req.Interface, req.Operation);
}
} catch (KeyNotFoundException) {
res = new RpcResponse("OperationNotFound", "The interface or operation could not be found", null);
}
// get operation information
RpcOperationAttribute opAttr = null;
if (memberInfo != null)
{
Type interfaceType = GetInterface(req.Interface);
MemberInfo[] interfaceMember = interfaceType.GetMember(req.Operation);
opAttr = interfaceMember[0].GetCustomAttribute <RpcOperationAttribute>();
}
// get if no reply is enabled
bool noReply = opAttr != null && opAttr.NoReply;
// check if they have a response ID if no reply isn't enabled
if (!noReply && envelope.ID == Guid.Empty)
{
res = new RpcResponse("InvalidOperation", "The envelope does not specify a correlation ID", null);
}
// apply request if we don't have a response already, typically an error
if (res == null)
{
// setup context
RpcContext.Current = new RpcContext()
{
Envelope = envelope
};
// apply request
res = await ApplyRequestAsync(req, memberInfo).ConfigureAwait(false);
// destroy context
RpcContext.Current = null;
}
// send response unless no-reply
if (!noReply)
{
// serialize response
byte[] resBody = serializer.SerializeResponse(res);
// send reply
string rpcHeader = new RpcHeader(RpcHeader.HEADER_VERSION, serializer.Name, RpcMessageType.Single).ToString();
Dictionary <string, object> headers = new Dictionary <string, object>(StringComparer.CurrentCultureIgnoreCase)
{
{ RpcHeader.HEADER_NAME, rpcHeader },
{ RpcHeader.HEADER_NAME_LEGACY, rpcHeader }
};
// reply
await envelope.ReplyAsync(resBody, headers).ConfigureAwait(false);
}
// throw exceptions
}
else
{
throw new NotImplementedException("Batched RPC is not supported currently");
}
}