Setting up the TwistedQuotes application

Goal

This document describes how to set up the TwistedQuotes application used in a number of other documents, such as designing Twisted applications.

Setting up the TwistedQuotes project directory

1. Make a TwistedQuotes directory on your system
2. Place the following files in the TwistedQuotes directory:

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     """
     Twisted Quotes
     """
     

     Source listing - listings/TwistedQuotes/__init__.py
     (this file marks it as a package, see this section of the Python tutorial for more on packages)

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     from random import choice
     
     from zope.interface import implements
     
     from TwistedQuotes import quoteproto
     
     
     
     class StaticQuoter:
         """
         Return a static quote.
         """
     
         implements(quoteproto.IQuoter)
     
         def __init__(self, quote):
             self.quote = quote
     
     
         def getQuote(self):
             return self.quote
     
     
     
     class FortuneQuoter:
         """
         Load quotes from a fortune-format file.
         """
         implements(quoteproto.IQuoter)
     
         def __init__(self, filenames):
             self.filenames = filenames
     
     
         def getQuote(self):
             quoteFile = file(choice(self.filenames))
             quotes = quoteFile.read().split('\n%\n')
             quoteFile.close()
             return choice(quotes)
     

     Source listing - listings/TwistedQuotes/quoters.py

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     from zope.interface import Interface
     
     from twisted.internet.protocol import Factory, Protocol
     
     
     
     class IQuoter(Interface):
         """
         An object that returns quotes.
         """
         def getQuote():
             """
             Return a quote.
             """
     
     
     
     class QOTD(Protocol):
         def connectionMade(self):
             self.transport.write(self.factory.quoter.getQuote()+'\r\n')
             self.transport.loseConnection()
     
     
     
     class QOTDFactory(Factory):
         """
         A factory for the Quote of the Day protocol.
     
         @type quoter: L{IQuoter} provider
         @ivar quoter: An object which provides L{IQuoter} which will be used by
             the L{QOTD} protocol to get quotes to emit.
         """
         protocol = QOTD
     
         def __init__(self, quoter):
             self.quoter = quoter
     

     Source listing - listings/TwistedQuotes/quoteproto.py
3. Add the TwistedQuotes directory's parent to your Python path. For example, if the TwistedQuotes directory's path is /mystuff/TwistedQuotes or c:\mystuff\TwistedQuotes add /mystuff to your Python path. On UNIX this would be export PYTHONPATH=/mystuff:$PYTHONPATH, on Microsoft Windows change the PYTHONPATH variable through the Systems Properties dialog by adding ;c:\mystuff at the end.
4. Test your package by trying to import it in the Python interpreter:

   Python 2.1.3 (#1, Apr 20 2002, 22:45:31)
   [GCC 2.95.4 20011002 (Debian prerelease)] on linux2
   Type "copyright", "credits" or "license" for more information.
   >>> import TwistedQuotes
   >>> # No traceback means you're fine.