This is a binding for ZMQ. Tested with Delphi7, BDS2006, and FPC 2.6.0. (Just in Windows for now).
The package contains a wrapper (zmq.pas) for the dll, and a higher level api (zmqapi.pas). It should work with ZMQ 2.2.0, and with 3.2.0 rc1 (experimental). To use the v3.2 dll, in zmq.inc define zmq3 (($define zmq3}). The dll's come from the official distro
You should use the higher level api, which'll save you a lot of time, and incidentally the code'll be easier to read.
First, you need to create a context
context := TZMQContext.Create;
There are various socket types, see the Guide, each has a constant. To create for example a REP socket, just write this:
socket := context.Socket( stRep );
// binding the socket
socket.bind( 'tcp://*:5555' );
// connecting the socket
socket.connect( 'tcp://localhost:5555' );
To send messages the api has several methods. You can send single, or Multipart messages, in blocking or nonblocking (in the v3 it's called dontwait) mode.
// sending a string in blocking mode(default) is just as easy as this:
socket.send( 'Hello' );
// or in non-blocking mode
socket.send( 'Hello', [rsfNoBlock] );
// in this case if the message cannot be queued an EZMQException is raised,
// with a value EAGAIN.
// sending data from a stream (don't forget to set the position of the stream, to read to)
socket.send( stream, size );
// sending multipart messages.
// strings:
socket.send( ['Hello','World'] );
//this is equivalent to:
socket.send( 'Hello', [rsfSndMore] );
socket.send( 'World' );
// or use TStrings.
tsl := TStringList.Create;
tsl.Add( 'Hello' );
tsl.Add( 'World' );
socket.send( tsl );
tsl.Free;
Receiving messages is as easy as
msize := socket.recv( msg );
// the new message is in the msg, and msize holds the length of the message
// to a Stream
msize := socket.recv( stream );
// read multipart message
tsl := TStringList.Create;
mcount := socket.recv( tsl );
// this will add message parts to the stringlist, and returns
// the count of the messages received.
Monitoring Sockets ( just available in v3.2)
// define a callback like this.
procedure TMyClass.MonitorCallback( event: TZMQEvent );
begin
// do something.
end;
// Register the callback
socket.RegisterMonitor( MonitorCallback, cZMQMonitorEventsAll );
// The `MonitorCallback` is called from a separate thread, created by `RegisterMonitor`
// you can deregister the monitoring with calling.
socket.DeRegisterMonitor;
in the examples directory there are some examples translated from the guide.
-
poll function of TZMQPoller has a new optional parameter "pollCount".
-
Upgrade dll-s to v3.2.2 RC2
-
New monitoring logic implemented.
-
Default ZMQ version for the binding is now 3.2 ( can switch back to 2.2 by not defining
zmq3in thezmq.incfile )
- if poll returns ETERM the socket with the terminated context should be removed from the poll, and closed;
- zmq_stopwatch_stop returns the correct value, but on program exit there's an exception.
- if recv(string) recieves not a valid string ,but a binary data convert it to Hex.(not trivial, because String definition changes through delphi versions) (the identity.dpr is a test case)
- Decide the need of the zhelpers.h
- beter CTRL+C handling
- improve lruqueue2.dpr ( in client task CTRL+C handling)
The following people have contributed to the project:
Balazs Varga bb.varga@gmail.com Stathis Gkotsis stathis.gkotsis@gmail.com Stephane Carre scarre.lu@gmail.com
Free use of this software is granted under the terms of the GNU Lesser General
Public License (LGPL). For details see the files COPYING.LESSER included with
the distribution.