markovbot.py

                    self._tweetingjitter)
                interval = self._tweetinginterval + jitter

                # Sleep for the interval (in seconds, hence * 60)
                self._message(u'_autotweet', \
                    u'Next tweet in %d minutes.' % (interval))
                time.sleep(interval*60)


    def _check_file(self, filename, allowedext=None):

        """Checks whether a file exists, and has a certain extension.

        Arguments

        filename        -   String that indicates the path to a .txt file
                        that should be read by the bot.

        Keyword Arguments

        allowedext  -   List of allowed extensions, or None to allow all
                        extensions. Default value is None.

        Returns

        ok          -   Boolean that indicates whether the file exists,
                        andhas an allowed extension (True), or does not
                        (False)
        """

        # Check whether the file exists
        ok = os.path.isfile(filename)

        # Check whether the extension is allowed
        if allowedext != None:
            name, ext = os.path.splitext(filename)
            if ext not in allowedext:
                ok = False

        return ok


    def _construct_tweet(self, database=u'default', seedword=None, \
        prefix=None, suffix=None):

        """Constructs a text for a tweet, based on the current Markov chain.
        The text will be of a length of 140 characters or less, and will
        contain a maximum of 20 words (excluding the prefix and suffix)

        Keyword Arguments

        seedword        -   A string that indicates what word should be in
                        the sentence. If None is passed, or if the word
                        is not in the database, a random word will be
                        chosen. This value can also be a list of words,
                        in which case the list will be processed
                        one-by-one until a word is found that is in the
                        database. Default value is None.

        database        -   A string that indicates the name of the
                        specific database that you want to use to
                        generate the text, or u'default' to use the
                        default database. (default = 'default')

        prefix      -   A string that will be added at the start of each
                        tweet (no ending space required). Pass None if
                        you don't want a prefix. Default value is None.

        suffix      -   A string that will be added at the end of each
                        tweet (no starting space required). Pass None if
                        you don't want a suffix. Default value is None.

        Returns

        tweet       -   A string with a maximum length of 140 characters.
        """

        sl = 10
        response = u''
        while response == u'' or len(response) > 160:
            # Generate some random text
            response = self.generate_text(sl, seedword=seedword, \
                database=database, verbose=False, maxtries=100)
            # Add the prefix
            if prefix != None:
                response = u'%s %s' % (prefix, response)
            # Add the suffix
            if suffix != None:
                response = u'%s %s' % (response, suffix)
            # Reduce the amount of words if the response is too long
            if len(response) > 160:
                sl -= 1

        return response


    def _error(self, methodname, msg):

        """Raises an Exception on behalf of the method involved.

        Arguments

        methodname  -   String indicating the name of the method that is
                        throwing the error.

        message     -   String with the error message.
        """

        raise Exception(u"ERROR in Markovbot.%s: %s" % (methodname, msg))


    def _isalphapunct(self, string):

        """Returns True if all characters in the passed string are
        alphabetic or interpunction, and there is at least one character in
        the string.

        Allowed interpunction is . , ; : ' " ! ?

        Arguments

        string  -       String that needs to be checked.

        Returns

        ok          -   Boolean that indicates whether the string
                        contains only letters and allowed interpunction
                        (True) or not (False).
        """

        if string.replace(u'.',u'').replace(u',',u'').replace(u';',u''). \
            replace(u':',u'').replace(u'!',u'').replace(u'?',u''). \
            replace(u"'",u'').isalpha():
            return True
        else:
            return False


    def _message(self, methodname, msg):

        """Prints a message on behalf of the method involved. Friendly
        verion of self._error

        Arguments

        methodname  -   String indicating the name of the method that is
                        throwing the error.

        message     -   String with the error message.
        """

        print(u"MSG from Markovbot.%s: %s" % (methodname, msg))


    def _triples(self, words):

        """Generate triplets from the word list
        This is inspired by Shabda Raaj's blog on Markov text generation:
        http://agiliq.com/blog/2009/06/generating-pseudo-random-text-with-markov-chains-u/

        Moves over the words, and returns three consecutive words at a time.
        On each call, the function moves one word to the right. For example,
        "What a lovely day" would result in (What, a, lovely) on the first
        call, and in (a, lovely, day) on the next call.

        Arguments

        words       -   List of strings.

        Yields

        (w1, w2, w3)    -   Tuple of three consecutive words
        """

        # We can only do this trick if there are more than three words left
        if len(words) < 3:
            return

        for i in range(len(words) - 2):
            yield (words[i], words[i+1], words[i+2])


    def _twitter_reconnect(self):

        """Logs in to Twitter, using the stored OAuth. This function is
        intended for internal use, and should ONLY be called after
        twitter_login has been called.
        """

        # Report the reconnection attempt.
        self._message(u'_twitter_reconnect', \
            u"Attempting to reconnect to Twitter.")

        # Raise an Exception if the twitter library wasn't imported
        if not IMPTWITTER:
            self._error(u'_twitter_reconnect', u"The 'twitter' library could not be imported. Check whether it is installed correctly.")

        # Log in to a Twitter account
        self._t = twitter.Twitter(auth=self._oauth)
        self._ts = twitter.TwitterStream(auth=self._oauth)
        self._loggedin = True

        # Get the bot's own user credentials
        self._credentials = self._t.account.verify_credentials()

        # Report the reconnection success.
        self._message(u'_twitter_reconnect', \
            u"Successfully reconnected to Twitter!")


os.path.realpath('./')