PyAMF 0.5 released

PyAMF is a lightweight library that allows Flash Player and Python applications to communicate via Adobe's ActionScript Message Format.

PyAMF 0.5 is a cleanup of the internals of 0.4 and it provides some performance optimisations. In accomplishing this, a number of features were added.

  • A new way to handle attribute en/decoding. New features include excluding attributes, read-only attributes, and proxied attributes. If you use external classes, this one is also for you. Check the wiki for more details.
  • The lazy loading module (pyamf.util.imports) that powers the adapter modules has been completely revamped. There were too many edge cases that would cause problems in the import mechanism. We now supply a module finder/loader in sys.meta_path so we can intercept the import calls. This has completely cleared up the problems we were seeing and it has the added benefit of halving the time it took to run the 650+ unit tests in the suite!
  • The cPyAMF extension has been completely revamped and no longer uses cStringIO to handle the byte packing. The extension has also been extended to cover more of the library. This has given a nice speed-up but we are by no means finished.
  • Support for non-UTC timezones has been added. If you supply timezone_offset to the pyamf.remoting.gateway.*.*Gateway classes then any datetimes will be offset against that figure (in seconds). This is only useful for legacy systems so you don't need to change anything if you are already using UTC (in fact using UTC is the recommended practice).
  • Support has been provided for decoding and encoding ISmallMessage objects. This means better integration with BlazeDS and sets the foundations for better Flex Messaging support.
  • A new way to bulk register classes has been introduced - register_package. You can register a module:

import pyamf from myproj.myapp import models pyamf.register_package(models, '')

Backward incompatible API Changes

  • The pyamf.logging module has been removed because it didn't do very much.
  • A number of utility functions that weren't being used, or were implemented in the Python standard library, have been removed. These include:
    • pyamf.util.getmro
    • pyamf.util.make_classic_instance
    • pyamf.util.IndexedCollection.remove
  • The dependancy on fpconst has been removed. This means that PyAMF will make no attempt to correct what the Python interpreter spits out for exceptional floats (see our blog post about the issue).
  • Most of the arguments for pyamf.register_class were removed, due to the new attribute control (see above).

Gateway updates

  • The logger attribute is now set to None by default. Supply a logger instance to reactivate the old functionality.
  • If debug is False then any stacktraces will not be sent to the client.

Python 2.6 integration

Besides greater stability for the Windows platform, more types from the Python 2.6 standard library are now supported, including:

Module Encode Decode
collections.deque list list
collections.defaultdict untyped object dict
collections.namedtuple list list
array.array list list


Flash Player

Python exceptions are now mapped to Flash exceptions (where possible), including the name and message attributes. You can now map error classes:

import pyamf pyamf.register_class(ValueError, '')


  • Django models can now have dynamic properties assigned to them and they will be encoded correctly.
  • Support for model inheritance:

from django.db import models class CommonInfo(models.Model): name = models.CharField(max_length=100) age = models.PositiveIntegerField() class Meta: abstract = True class Student(CommonInfo): home_group = models.CharField(max_length=5)

  • Support for FileField/ImageField (thanks @jhooks!).
  • parent->child relationships will be referenced correctly, such that
    parent.child.parent is parent. In this situation, PyAMF 0.4 would encode 3 separate objects, but PyAMF 0.5 will correctly encode 2 (parent being encoded as a reference).

Google App Engine

  • Better support for the standard property types has been included (specifically db.FloatProperty).
  • Support for db.polymodel.PolyModel has been included.

from google.appengine.ext.db import polymodel class Poly(polymodel.PolyModel): s = db.StringProperty() class DeepPoly(Poly): d = db.IntegerProperty()


Check out the download page, installation instructions.

Got questions? First stop is the mailing list or IRC.


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