On 10/11/10 09:52, Peter Otten wrote:
r0g wrote:
I have a subclass of BaseHHTPRequestHandler which uses a dictonary
"paths" and a function "api_call" which are defined in the main
namespace of the module. I'd rather I was able to pass these object to
the constructor and store them as data attributes "self.paths" and
"self.api_call" but I'm not sure how to do that properly. My
understanding is that one may extend a constructor by defining it's
__init__ method, calling the parents constructor and then adding ones
own attributes to taste. What I don't understand is where or how I am
supposed to get these extra constructor arguments into the class given
that I don't instantiate it myself, it is seemingly instantiated by
HTTPServer class that I pass it to e.g.
httpd = HTTPServer(server_address, PlainAJAXRequestHandler)
I wondered if I ought to instantiate an instance of
PlainAJAXRequestHandler, set the attributes (either manually or by
extending it's constructor) and pass that to HTTPServer but I figured it
expects a class not an instance as it probably wants to spawn one
instance for each request so that would be a non starter. Might I need
to subclass HTTPServer, find the bit that instantiates the request
handler and override that so it passes it's constructor more parameters?
Right now I'm pretty confused, can somebody please tell me how I might
accomplish this, what I'm failing to grasp or point me to the docs that
explain it - I've spent the last hour or two plowing through docs to no
avail, I guess it's a case of keyword ignorance on my part! Code
follows...
Try passing a factory function instead of a class. Untested:
from functools import partial
class PlainAJAXRequestHandler(BaseHTTPRequestHandler):
def __init__(self, api_call, paths, *args, **kw):
BaseHTTPRequestHandler.__init__(self, *args, **kw)
self.api_call = api_call
self.paths = paths
paths = ...
api_call = ...
httpd = HTTPServer(
server_address,
partial(PlainAJAXRequestHandler, paths, api_call))
Great, that looks ideal Peter, thanks very much :)
One more question quick question if you have time... I actually subclass
the class in question later on to provide an SSL secured connection, is
it possible (or even advisable) to do the following to spare me having
to modify the derived classes init (and any subsequent classes' inits)
too?...
PlainAJAXRequestHandler = partial(PlainAJAXRequestHandler, paths, api_call))
^??? Remap name to new extended class
class SecureAJAXRequestHandler(PlainAJAXRequestHandler):
def setup(self):
self.connection = self.request
self.rfile = socket._fileobject(self.request, "rb", self.rbufsize)
self.wfile = socket._fileobject(self.request, "wb", self.wbufsize)
^??? therefore no init needed?
Cheers,
Roger
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