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pyst: A Python Interface to Asterisk
====================================

Pyst consists of a set of interfaces and libraries to allow programming of
Asterisk from python. The library currently supports AGI, AMI, and the parsing
of Asterisk configuration files. The library also includes debugging facilities
for AGI.

Installation is the standard python install::

 tar xvf pyst.tar.gz
 cd pyst
 python setup.py install --prefix=/usr/local

Documentation is currently only in python docstrings, you can use
pythons built-in help facility::

 import asterisk
 help (asterisk)
 import asterisk.agi
 help (asterisk.agi)
 import asterisk.manager
 help (asterisk.manager)
 import asterisk.config
 help (asterisk.config)

Some notes on platforms: We now specify "platforms = 'Any'" in
``setup.py``. This means, the manager part of the package will probably
run on any platform. The agi scripts on the other hand are called
directly on the host where Asterisk is running. Since Asterisk doesn't
run on windows platforms (and probably never will) the agi part of the
package can only be run on Asterisk platforms.

Credits
-------

Thanks to Karl Putland for writing the original package. 
Thanks to Matthew Nicholson for maintaining the package for some years
and for handing over maintenance when he was no longer interested.

Things to do for pyst
---------------------

This is the original changelog merged into the readme file. I'm not so
sure I really want to change all these things (in particular the
threaded implementation looks good to me). I will maintain a section
summarizing the changes in this README, the ChangeLog won't be
maintained any longer. Detailed changes will be available in the version
control tool (currently svn).

* ChangeLog:
  The ChangeLog needs to be updated from the monotone logs.

* Documentation:
  All of pyst's inline documentation needs to be updated.

* manager.py:
  This should be convereted to be single threaded.  Also there is a race
  condition when a user calls manager.logoff() followed by
  manager.close().  The close() function may still call logoff again if
  the socket thread has not yet cleared the _connected flag.

  A class should be made for each manager action rather than having a
  function in a manager class.  The manager class should be adapted to
  have a send method that know the general format of the classes.

Matthew Nicholson writes on the mailinglist (note that I'm not sure I'll do
this, I'm currently satisfied with the threaded implementation):

    For pyst 0.3 I am planning to clean up the manager.py.  There are
    several know issues with the code.  No one has actually reported these
    as problems, but I have personally had trouble with these.  Currently
    manager.py runs in several threads, the main program thread, a thread to
    read from the network, and an event distribution thread.  This causes
    problems with non thread safe code such as the MySQLdb libraries.  This
    design also causes problems when an event handler throws an exception
    that causes the event processing thread to terminate.

    The second problem is with the way actions are sent.  Each action has a
    specific function associated with it in the manager object that takes
    all possible arguments that may ever be passed to that action.  This
    makes the api somewhat rigid and the Manager object cluttered.

    To solve these problems I am basically going to copy the design of my
    Astxx manager library (written in c++) and make it more python like.
    Each action will be a different object with certain methods to handle
    various tasks, with one function in the actual Manager class to send the
    action.  This will make the Manager class much smaller and much more
    flexible.  The current code will be consolidated into a single threaded
    design with hooks to have the library process events and such.  These
    hooks will be called from the host application's main loop.


Upgrading from older versions
-----------------------------

If upgrading from...

* 0.2:

   - ``get_header()`` methods in ``manager.py`` now work like
     ``dict.get()`` instead of ``dict[key]``


* 0.1.0:

   - ``agi.get_variable`` no longer throws an exception, instead it
     returns an empty string when a channel variable is not set.
   - ``manager.quit()`` has be renamed to ``manager.close()``

Changes
-------

Version 0.3: Minor feature enhancements

New maintainer Ralf Schlatterbeck, this is my first release, please
report any problems via the Sourceforge Bug-Tracker or email me
directly. Thanks to Karl Putland for writing the original package. 
Thanks to Matthew Nicholson for maintaining the package for some years
and for handing over maintenance when he was no longer interested.
The parsing of answers from asterisk was completely rewritten. This
should fix problems people were having with commands returning embedded
'/' or empty lines. Some new manager commands added.

 - Add playdtmf manager command
 - add sippeers and sipshowpeer manager commands
 - rewritten manager communication
 - should no longer choke on '/' in answers returned from a manager
   command (fixes SF Bug 2947866)
 - should now correctly parse multi-line output with embedded empty
   lines, e.g. ``mgr.command('dialplan show')``
 - Bug-fix for list manipulation in ``event_dispatch``, thanks to Jan
   Mueller, see mailinglist comment from 2008-04-18
 - Merge unreleased changes from repository of Matthew Nicholson
   in particular a typo in ``agi.py`` for ``set_autohangup``, and change
   of ``get_header`` methods (see Upgrading instructions). The fixed
   ``manager.command`` support is already in (with a different
   solution). The unreleased changes are also on the 0.2 branch in the
   subversion repository in case somebody is interested.

See the ChangeLog for older changes.