private async Task<ConnectionDescriptor> EnsureConnectionAsync(ClientActionContext context, SessionDescriptor sessionDescriptor)
{
if (sessionDescriptor.State == ProxyState.Open)
{
context.ActionResult = sessionDescriptor.InitSessionResult;
return sessionDescriptor.ServerConnection;
}
if (sessionDescriptor.State == ProxyState.Closed)
{
throw new ProxyClosedException();
}
using (await sessionDescriptor.LockAsync())
{
// check connections tate again when under lock
if (sessionDescriptor.State == ProxyState.Open)
{
context.ActionResult = sessionDescriptor.InitSessionResult;
return sessionDescriptor.ServerConnection;
}
if (sessionDescriptor.State == ProxyState.Closed)
{
throw new ProxyClosedException();
}
ClientActionContext initSessionContext = context;
if (context.Action != sessionDescriptor.Contract.InitSession)
{
// we are not initializaing proxy explicitely, so we need to check whether proxy has been initalized before
if (sessionDescriptor.RequiresInitParameters)
{
if (sessionDescriptor.InitSessionParameters == null)
{
// we can not reuse initialization parameters, so throw
throw new BoltClientException(
"Proxy need to be initialized before it can be used.",
ClientErrorCode.ProxyNotInitialized,
context.Action,
null);
}
}
// create init session context and reuse init parameters
initSessionContext = new ClientActionContext(
context.Proxy,
context.Contract,
sessionDescriptor.Contract.InitSession,
sessionDescriptor.InitSessionParameters);
}
else if (sessionDescriptor.RequiresInitParameters)
{
try
{
BoltFramework.ValidateParameters(sessionDescriptor.Contract.InitSession, initSessionContext.Parameters);
}
catch (Exception e)
{
// we can not reuse initialization parameters, so throw
throw new BoltClientException(
$"Proxy is beeing initialized with invalid parameters. If session initialization has non empty parameters you should initialize it first by calling '{initSessionContext.Action.Name}' with proper parameters.",
ClientErrorCode.InvalidInitSessionParameters,
context.Action,
e);
}
}
try
{
// execute whole pipeline
await Next(initSessionContext);
// extract connection and session id from response
string sessionId = ClientSessionHandler.GetSessionIdentifier(initSessionContext.Response);
if (sessionId == null)
{
throw new BoltServerException(
ServerErrorCode.SessionIdNotReceived,
sessionDescriptor.Contract.InitSession,
initSessionContext.Request?.RequestUri?.ToString());
}
if (initSessionContext.ServerConnection == null)
{
throw new BoltClientException(ClientErrorCode.ConnectionUnavailable, initSessionContext.Action);
}
sessionDescriptor.InitSessionResult = initSessionContext.ActionResult;
sessionDescriptor.InitSessionParameters = initSessionContext.Parameters;
sessionDescriptor.SessionId = sessionId;
sessionDescriptor.ServerConnection = initSessionContext.ServerConnection;
sessionDescriptor.ChangeState(context.Proxy, ProxyState.Open);
}
catch (Exception e)
{
Exception handled = HandleOpenConnectionError(initSessionContext, e, sessionDescriptor);
if (handled == e)
{
throw;
}
if (handled != null)
{
throw handled;
}
throw;
}
finally
{
// we should not dispose original context
if (context.Action != sessionDescriptor.Contract.InitSession)
{
initSessionContext.Dispose();
}
}
return sessionDescriptor.ServerConnection;
}
}
protected virtual Exception HandleOpenConnectionError(ClientActionContext context, Exception error, SessionDescriptor session)
{
session.ClearSession();
ErrorHandlingResult handlingResult = ErrorHandling.Handle(context, error);
switch (handlingResult)
{
case ErrorHandlingResult.Close:
session.ChangeState(context.Proxy, ProxyState.Closed);
break;
case ErrorHandlingResult.Recover:
case ErrorHandlingResult.Rethrow:
session.ChangeState(context.Proxy, ProxyState.Ready);
break;
default:
throw new ArgumentOutOfRangeException();
}
return error;
}