*************************
Network Gateway Interface
*************************

Network programs are typically difficult to test because they require
setting up network connections, clients, and servers.  In addition,
application code gets mixed up with networking code.

The Network Gateway Interface (NGI) seeks to improve this situation by
separating application code from network code.  This allows
application and network code to be tested independently and provides
greater separation of concerns.

.. contents::

Changes
*******

==================
1.1.5 (2010-01-19)
==================

Bug fixed:

- Fixed a fatal win32 problem (socket.AF_UNIX usage).

- Removed impropper use of the SO_REUSEADDR socket option on windows.

- The sized adapter performed poorly (because it triggered Nagle's
  algorithm).


==================
1.1.4 (2009-10-28)
==================

Bug fixed:

- Spurious warnings sometimes occurred due to a race condition in
  setting up servers.
- Added missing "writelines" method to zc.ngi.adapters.Lines.

==================
1.1.3 (2009-07-30)
==================

Bug fixed:

- zc.ngi.async bind failures weren't handled properly, causing lots of
  annoying log messages to get spewed, which tesnded to fill up log
  files.

==================
1.1.2 (2009-07-02)
==================

Bugs fixed:

- The zc.ngi.async thread wasn't named. All threads should be named.

==================
1.1.1 (2009-06-29)
==================

Bugs fixed:

- zc.ngi.blocking didn't properly handle connection failures.

==================
1.1.0 (2009-05-26)
==================

Bugs fixed:

- Blocking input and output files didn't properly synchronize closing.

- The testing implementation made muiltiple simultaneous calls to
  handler methods in violation of the promise made in interfaces.py.

- Async TCP servers used too low a listen depth, causing performance
  issues and spurious test failures.

New features:

- Added UDP support.

- Implementation responsibilities were clarified through an
  IImplementation interface.  The "connector" attribute of the testing
  and async implementations was renamed to "connect". The old name
  still works.

- Implementations are now required to log handler errors and to close
  connections in response to connection-handler errors. (Otherwise,
  handlers, and especially handler adapters, would have to do this.)

==================
1.0.1 (2007-05-30)
==================

Bugs fixed:

- Server startups sometimes failed with an error like::

    warning: unhandled read event
    warning: unhandled write event
    warning: unhandled read event
    warning: unhandled write event
    ------
    2007-05-30T22:22:43 ERROR zc.ngi.async.server listener error
    Traceback (most recent call last):
      File "asyncore.py", line 69, in read
        obj.handle_read_event()
      File "asyncore.py", line 385, in handle_read_event
        self.handle_accept()
      File "/zc/ngi/async.py", line 325, in handle_accept
        sock, addr = self.accept()
    TypeError: unpack non-sequence