Re: [Quickfix-developers] empty sequence number on sequence reset message

[Oren M. <or...@qu...>]

Well, when a sequence reset is sent in reset mode (123=3DN) the spec =
says=20
that you should ignore the MsgSeqNum.  I guess Appia took this to mean=20=

that they can choose to just not send it, even though it is listed as a=20=

required field (not conditionally required) in the standard header.

First thing that we should do is have QF gracefully handle rejecting a=20=

message without a sequence number.  This should be accomplished easily=20=

enough by replacing that line with this:

   if( message.getHeader().isSetField( msgSeqNum ) )
     message.getHeader().getField( msgSeqNum );

This will essentially cause the reject message to say it is rejecting=20
the message with sequence number 0, which I think is a reasonable thing=20=

to say if there is no sequence number.

Now the question is do we want to make an exception for this message=20
type and process the message that doesn't contain this required field. =20=

I would say since it is our job to "ignore" it, than yes, we should=20
probably allow it.  To accomplish this we will need to allow the=20
nextSequenceReset method to specify that the validate method should=20
ignore sequence numbers.  We can probably do this by rewriting the=20
method like so:

bool Session::verify( const Message& msg, bool checkTooHigh,
                       bool checkTooLow, bool checkSequenceNumber )
{ QF_STACK_PUSH(Session::verify)

   SenderCompID senderCompID;
   TargetCompID targetCompID;
   SendingTime sendingTime;
   MsgType msgType;
   MsgSeqNum msgSeqNum;

   try
   {
     const Header& header =3D msg.getHeader();
     header.getField( senderCompID );
     header.getField( targetCompID );
     header.getField( sendingTime );
     header.getField( msgType );
     if( checkSequenceNumber )
       header.getField( msgSeqNum );

     if ( !validLogonState( msgType ) )
       throw std::logic_error( "Logon state is not valid for message" );

     if ( !isGoodTime( sendingTime ) )
     {
       doBadTime( msg );
       return false;
     }
     if ( !isCorrectCompID( senderCompID, targetCompID ) )
     {
       doBadCompID( msg );
       return false;
     }
     if ( checkSequenceNumber && checkTooHigh && isTargetTooHigh(=20
msgSeqNum ) )
     {
       doTargetTooHigh( msg );
       return false;
     }
     else if ( checkSequenceNumber && checkTooLow && isTargetTooLow(=20
msgSeqNum ) )
     {
       doTargetTooLow( msg );
       return false;
     }

     UtcTimeStamp now;
     m_state.lastReceivedTime( now );
     m_state.testRequest( 0 );
   }
   catch ( std::exception& e )
   {
     m_state.onEvent( e.what() );
     disconnect();
     return false;
   }

   fromCallback( msgType, msg, m_sessionID );
   return true;

   QF_STACK_POP
}

On Nov 4, 2004, at 8:33 AM, Michael Raykh wrote:

> In our test of quickFix against Appia fix engine the following =
happens:
>
> - Appia sends sequence reset request msg
> - for some reason sequence number field is not populated on this reset=20=

> request
> - quickFix decides to reject this
> - crashes in generateReject in
> =A0=A0=A0=A0=A0=A0=A0 =A0 message.getHeader().getField( msgSeqNum );
> =A0=A0 'cause message seq number is not set...
>
>
>
> Is this proper behaviour? Any suggestions how to handle this?
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