crowdguru/guru.py

   1 # Copyright 2009 Google Inc.
   2 #
   3 # Licensed under the Apache License, Version 2.0 (the "License");
   4 # you may not use this file except in compliance with the License.
   5 # You may obtain a copy of the License at
   6 #
   7 # http://www.apache.org/licenses/LICENSE-2.0
   8 #
   9 # Unless required by applicable law or agreed to in writing, software
  10 # distributed under the License is distributed on an "AS IS" BASIS,
  11 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  12 # See the License for the specific language governing permissions and
  13 # limitations under the License.
  14
  15 import datetime
  16 import logging
  17 import os
  18 import re
  19 import wsgiref.handlers
  20 from google.appengine.api import xmpp
  21 from google.appengine.api import users
  22 from google.appengine.ext import db
  23 from google.appengine.ext import webapp
  24 from google.appengine.ext.ereporter import report_generator
  25 from google.appengine.ext.webapp import template
  26 from google.appengine.ext.webapp import xmpp_handlers
  27
  28
  29 PONDER_MSG = "Hmm. Let me think on that a bit."
  30 TELLME_MSG = "While I'm thinking, perhaps you can answer me this: %s"
  31 SOMEONE_ANSWERED_MSG = ("We seek those who are wise and fast. One out of two "
  32                         "is not enough. Another has answered my question.")
  33 ANSWER_INTRO_MSG = "You asked me: %s"
  34 ANSWER_MSG = "I have thought long and hard, and concluded: %s"
  35 WAIT_MSG = ("Please! One question at a time! You can ask me another once you "
  36             "have an answer to your current question.")
  37 THANKS_MSG = "Thank you for your wisdom."
  38 TELLME_THANKS_MSG = ("Thank you for your wisdom."
  39                      " I'm still thinking about your question.")
  40 EMPTYQ_MSG = "Sorry, I don't have anything to ask you at the moment."
  41 HELP_MSG = ("I am the amazing Crowd Guru. Ask me a question by typing '/tellme "
  42             "the meaning of life', and I will answer you forthwith! To learn "
  43             "more, go to %s/")
  44 MAX_ANSWER_TIME = 120
  45
  46
  47 class Question(db.Model):
  48   question = db.TextProperty(required=True)
  49   asker = db.IMProperty(required=True)
  50   asked = db.DateTimeProperty(required=True, auto_now_add=True)
  51
  52   assignees = db.ListProperty(db.IM)
  53   last_assigned = db.DateTimeProperty()
  54
  55   answer = db.TextProperty()
  56   answerer = db.IMProperty()
  57   answered = db.DateTimeProperty()
  58
  59   @staticmethod
  60   def _tryAssignTx(key, user, expiry):
  61     """Assigns and returns the question if it's not assigned already.
  62
  63     Args:
  64       key: db.Key: The key of a Question to try and assign.
  65       user: db.IM: The user to assign the question to.
  66     Returns:
  67       The Question object. If it was already assigned, no change is made
  68     """
  69     question = Question.get(key)
  70     if not question.last_assigned or question.last_assigned < expiry:
  71       question.assignees.append(user)
  72       question.last_assigned = datetime.datetime.now()
  73       question.put()
  74     return question
  75
  76   @staticmethod
  77   def assignQuestion(user):
  78     """Gets an unanswered question and assigns it to a user to answer.
  79
  80     Args:
  81       user: db.IM: The identity of the user to assign a question to.
  82     Returns:
  83       The Question entity assigned to the user, or None if there are no
  84         unanswered questions.
  85     """
  86     question = None
  87     while question == None or user not in question.assignees:
  88       # Assignments made before this timestamp have expired.
  89       expiry = (datetime.datetime.now()
  90                 - datetime.timedelta(seconds=MAX_ANSWER_TIME))
  91
  92       # Find a candidate question
  93       q = Question.all()
  94       q.filter("answerer =", None)
  95       q.filter("last_assigned <", expiry).order("last_assigned")
  96       # If a question has never been assigned, order by when it was asked
  97       q.order("asked")
  98       candidates = [x for x in q.fetch(2) if x.asker != user]
  99       if not candidates:
 100         # No valid questions in queue.
 101         break
 102
 103       # Try and assign it
 104       question = db.run_in_transaction(Question._tryAssignTx,
 105                                        candidates[0].key(), user, expiry)
 106
 107     # Expire the assignment after a couple of minutes
 108     return question
 109
 110   def _unassignTx(self, user):
 111     question = Question.get(self.key())
 112     if user in question.assignees:
 113       question.assignees.remove(user)
 114       question.put()
 115
 116   def unassign(self, user):
 117     """Unassigns the given user to this question.
 118
 119     Args:
 120       user: db.IM: The user who will no longer be answering this question.
 121     """
 122     db.run_in_transaction(self._unassignTx, user)
 123
 124
 125 class XmppHandler(xmpp_handlers.CommandHandler):
 126   """Handler class for all XMPP activity."""
 127
 128   def _GetAsked(self, user):
 129     """Returns the user's outstanding asked question, if any."""
 130     q = Question.all()
 131     q.filter("asker =", user)
 132     q.filter("answer =", None)
 133     return q.get()
 134
 135   def _GetAnswering(self, user):
 136     """Returns the question the user is answering, if any."""
 137     q = Question.all()
 138     q.filter("assignees =", user)
 139     q.filter("answer =", None)
 140     return q.get()
 141
 142   def unhandled_command(self, message=None):
 143     # Show help text
 144     message.reply(HELP_MSG % (self.request.host_url,))
 145
 146   def askme_command(self, message=None):
 147     im_from = db.IM("xmpp", message.sender)
 148     currently_answering = self._GetAnswering(im_from)
 149     question = Question.assignQuestion(im_from)
 150     if question:
 151       message.reply(TELLME_MSG % (question.question,))
 152     else:
 153       message.reply(EMPTYQ_MSG)
 154     # Don't unassign their current question until we've picked a new one.
 155     if currently_answering:
 156       currently_answering.unassign(im_from)
 157
 158   def text_message(self, message=None):
 159     im_from = db.IM("xmpp", message.sender)
 160     question = self._GetAnswering(im_from)
 161     if question:
 162       other_assignees = question.assignees
 163       other_assignees.remove(im_from)
 164
 165       # Answering a question
 166       question.answer = message.arg
 167       question.answerer = im_from
 168       question.assignees = []
 169       question.answered = datetime.datetime.now()
 170       question.put()
 171
 172       # Send the answer to the asker
 173       xmpp.send_message([question.asker.address],
 174                         ANSWER_INTRO_MSG % (question.question,))
 175       xmpp.send_message([question.asker.address], ANSWER_MSG % (message.arg,))
 176
 177       # Send acknowledgement to the answerer
 178       asked_question = self._GetAsked(im_from)
 179       if asked_question:
 180         message.reply(TELLME_THANKS_MSG)
 181       else:
 182         message.reply(THANKS_MSG)
 183
 184       # Tell any other assignees their help is no longer required
 185       if other_assignees:
 186         xmpp.send_message([x.address for x in other_assignees],
 187                           SOMEONE_ANSWERED_MSG)
 188     else:
 189       self.unhandled_command(message)
 190
 191   def tellme_command(self, message=None):
 192     im_from = db.IM("xmpp", message.sender)
 193     asked_question = self._GetAsked(im_from)
 194     currently_answering = self._GetAnswering(im_from)
 195
 196     if asked_question:
 197       # Already have a question
 198       message.reply(WAIT_MSG)
 199     else:
 200       # Asking a question
 201       asked_question = Question(question=message.arg, asker=im_from)
 202       asked_question.put()
 203
 204       if not currently_answering:
 205         # Try and find one for them to answer
 206         question = Question.assignQuestion(im_from)
 207         if question:
 208           message.reply(TELLME_MSG % (question.question,))
 209           return
 210       message.reply(PONDER_MSG)
 211
 212
 213 class LatestHandler(webapp.RequestHandler):
 214   """Displays the most recently answered questions."""
 215
 216   def Render(self, template_file, template_values):
 217     path = os.path.join(os.path.dirname(__file__), 'templates', template_file)
 218     self.response.out.write(template.render(path, template_values))
 219
 220   def get(self):
 221     q = Question.all().order('-answered').filter('answered >', None)
 222     template_values = {
 223       'questions': q.fetch(20),
 224     }
 225     self.Render("latest.html", template_values)
 226
 227
 228 def main():
 229   app = webapp.WSGIApplication([
 230       ('/', LatestHandler),
 231       ('/_ah/xmpp/message/chat/', XmppHandler),
 232       ], debug=True)
 233   wsgiref.handlers.CGIHandler().run(app)
 234
 235
 236 if __name__ == '__main__':
 237   main()