2010/09/23

Perl - IO::Async - version 0.30

Yesterday, I put the next version of IO::Async on CPAN; version 0.30. This was primarily an update to add some new features, though also a few minor bugfixes and documentation updates were included too. Here I want to focus on a few of these new features.

The first of these new features is nothing groundbreaking in itself, but feeds into the others. It's simply the addition of IO::Async::Socket, a notifier subclass to contain a socket that isn't necessarily a stream (primarily SOCK_DGRAM or SOCK_RAW sockets such as UDP, PF_PACKET or PF_NETLINK). This neatens up a few rough edges with trying to put such sockets directly in IO::Async::Handle objects.

The second main new feature is the creation of the IO::Async::Protocol class, and IO::Async::Protocol::Stream subclass. These derive directly from IO::Async::Notifier rather than IO::Async::Handle, and are intended to be abstract containers of code, and not perform any IO operations directly. Instead, they contain a Handle or Stream object as a child notifier. By exposing an API identical to IO::Async::Stream, the IO::Async::Protocol::Stream should be a drop-in replacement for any modules trying to implement a network protocol.

With the addition of IO::Async::SSL, not every stream-like connection can be represented by IO::Async::Stream, so separating the transport layer from the protocol layer is required. This wasn't possible by subclassing, whereas object containment makes it much simpler.

Net::Async::FTP, Net::Async::HTTP, and Net::Async::IRC have all been updated to use it, and most other use cases should be simple to change.

The final main change is that $loop->connect and IO::Async::Listener now support direct on_stream or on_socket continuations, which will be provided an instance of Stream or Socket directly, rather than requiring the invoked code to wrap one. This can then be easily configured as a IO::Async::Protocol's transport.

Having made this change, it leads the way to transparent SSL support across all protocols, and possibly other concerns like SOCKS proxies, by extending the arguments to $loop->connect or Listener. But that's for another post...

Finally, I should announce that I've now started a channel on irc.perl.org called #ioasync, as the official IRC home for IO::Async. Feel free to drop by if you have any issues, comments, questions,...

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