A class deriving from ASTModel will use a custom __init__ method. The
properties of the custom __init__ are as follows:
- Signals are sent only when needed.
- If there is exactly as much args to __init__ as it has fields
a fast path is taken. The fast path is a rewrite of:
for attname, val in izip(attnames, args):
setattr(self, attname, val)
into this:
self.att1, self.att2, self.att3, ... = args
- Otherwise the init method should work normally. Although this is
_very_ experimental.
AST is used to dynamically alter the original Model.__init__ into a new
__init__ method which has the abovementioned optimizations done. The AST
generation has a lot of comments, so it should be possible to follow what
is done.
Requirements: Python 2.6 or Python 2.7.
Usage:
from astmodel import ASTModel
class SomeModel(ASTModel):
# If you want to force init signal sending, then set
# send_init_signals = True
# otherwise, init_signals are sent only if the Model
# contains ImageFields or GenericForeignKeys.
normal class definition otherwise
Known bugs and limitations:
- Eats your data. In other words, use at your own risk.
I have tested this on Django trunk as of 2011-12-04, all tests passed.
The speed difference (using the included tester) is as follows:
raw init speed, 10000 objects, 11 fields:
astmodel: 0.18s (signals to other models or not)
normal model: 0.37s
with signals: 0.55s (to _other_ model that the tested model!)