ZMQ::Handler

The ZMQ::Pollitem instance wrapped by this handler.

A ZMQ::Pollitem instance is compulsary on init, with support for optional arguments if a subclasses do require them.

pub = ctx.bind(:PUB, “tcp://127.0.0.1:5000”) # lower level API item = ZMQ::Pollitem.new(pub) item.handler = ZMQ::Handler.new(pub)

class ProducerHandler < ZMQ::Handler

def initialize(item, producer)
  super
  @producer = producer
end

def on_writable
  @producer.work
end

end

ZMQ::Loop.bind(:PUB, "tcp://127.0.0.1:5000", ProducerHandler, producer) # higher level API

# File lib/zmq/handler.rb, line 26
def initialize(pollitem, *args)
  raise TypeError.new("#{pollitem.inspect} is not a valid ZMQ::Pollitem instance") unless ZMQ::Pollitem === pollitem
  @pollitem = pollitem
end

Callback for error conditions such as pollable item errors on poll and exceptions raised in callbacks. Receives an exception instance as argument and raises by default.

handler.on_error(err) => raise

# File lib/zmq/handler.rb, line 60
def on_error(exception)
  raise exception
end

Callback invoked from ZMQ::Loop handlers when the pollable item is ready for reading. Subclasses are expected to implement this contract as the default just raises NotImplementedError. It’s reccommended to read in a non-blocking manner from within this callback.

def on_readable

msgs << recv

end

# File lib/zmq/handler.rb, line 39
def on_readable
  raise NotImplementedError, "ZMQ handlers are expected to implement an #on_readable contract"
end

Callback invoked from ZMQ::Loop handlers when the pollable item is ready for writing. Subclasses are expected to implement this contract as the default just raises NotImplementedError. It’s reccommended to write data out as fast as possible from within this callback.

def on_writable

send buffer.shift

end

# File lib/zmq/handler.rb, line 51
def on_writable
  raise NotImplementedError, "ZMQ handlers are expected to implement an #on_writable contract"
end

API that allows handlers to receive data regardless of the underlying pollable item type (ZMQ::Socket or IO).

# File lib/zmq/handler.rb, line 72
def recv
  pollitem.recv
end

API that allows handlers to send data regardless of the underlying pollable item type (ZMQ::Socket or IO).

# File lib/zmq/handler.rb, line 66
def send(*args)
  pollitem.send(*args)
end