[Twisted-Python] Re: Newbie - guidance required please

Frank Millman frank at chagford.com
Tue Nov 8 10:22:04 EST 2005

Nicola Larosa wrote:

[big snip]

> The winning point, for me, more than the impressive amount of 
> built-in network infrastructure, was its asynchronous, 
> event-driven concurrency model. Once you read this:
> Generalization of Deferred Execution in Python 
> http://www.python.org/pycon/papers/deferex/
> you stop and think: "How could have I been relying on 
> *threads* all this time?!?"
> (The signature is quite on-topic here. :-) )

Interesting paper - thanks for the link.

> After you've finished the above paper, study this:
> Asynchronous Programming with Twisted
> http://twistedmatrix.com/projects/core/documentation/howto/async.html
> and the linked docs at the end. You're not going anywhere 
> with Twisted until Deferreds are firmly under your belt.

I have already read this a few times - I will have to read it a few more,
but it is starting to sink in.

> Other important things are interfaces and adapters:
> Components: Interfaces and Adapters
> http://twistedmatrix.com/projects/core/documentation/howto/com
> ponents.html

This was very important - I had not read this one yet, but it is clearly
crucial, especially for cred.py.

> More details here:
> http://svn.zope.org/*checkout*/Zope3/trunk/src/zope/interface/

If I click on this link, I get the following traceback:

An Exception Has Occurred
Python Traceback

Traceback (most recent call last):
  File "/usr/local/viewcvs-1.0-dev/lib/viewcvs.py", line 3196, in main
  File "/usr/local/viewcvs-1.0-dev/lib/viewcvs.py", line 351, in run_viewcvs
  File "/usr/local/viewcvs-1.0-dev/lib/viewcvs.py", line 1892, in
    fp, revision = request.repos.openfile(request.path_parts, rev)
  File "/usr/local/viewcvs-1.0-dev/lib/vclib/svn/__init__.py", line 358, in
    fp = FileContentsPipe(self.fsroot, path, self.pool)
  File "/usr/local/viewcvs-1.0-dev/lib/vclib/svn/__init__.py", line 264, in
    self._stream = fs.file_contents(root, path, self._pool)
SubversionException: ('Attempted to get textual contents of a *non*-file
node', 160017)

> Of course, Python and Twisted are just layers in the stack. 
> Above them there are Nevow, and Axiom, and Mantissa, and... :-)
> Good luck in your endeavors, you're fiddling with some 
> powerful tools here!
>  ;-)
> --
> Nicola Larosa - nico at tekNico.net

Thanks for the support and the really useful feedback.

I am sure I will be back with some more questions, but I have enough to be
going on with for now.


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