1 """
2 The live module provides a mechanism of periodically checking which games are
3 being actively played.
4
5 It requires the third party library pytz to be
6 installed, which makes sure game times are compared properly with respect
7 to time zones. pytz can be downloaded from PyPI:
8 http://pypi.python.org/pypi/pytz/
9
10 It works by periodically downloading data from NFL.com for games that started
11 before the current time. Once a game completes, the live module stops asking
12 NFL.com for data for that game.
13
14 If there are no games being actively played (i.e., it's been more than N hours
15 since the last game started), then the live module sleeps for longer periods
16 of time.
17
18 Thus, the live module can switch between two different modes: active and
19 inactive.
20
21 In the active mode, the live module downloads data from NFL.com in
22 short intervals. A transition to an inactive mode occurs when no more games
23 are being played.
24
25 In the inactive mode, the live module only checks if a game is playing (or
26 about to play) every 15 minutes. If a game is playing or about to play, the
27 live module switches to the active mode. Otherwise, it stays in the inactive
28 mode.
29
30 With this strategy, if the live module is working properly, you could
31 theoretically keep it running for the entire season.
32
33 (N.B. Half-time is ignored. Games are either being actively played or not.)
34
35 Alpha status
36 ============
37 This module is emphatically in alpha status. I believe things will work OK for
38 the regular season, but the postseason brings new challenges. Moreover, it
39 will probably affect the API at least a little bit.
40 """
41 import datetime
42 import time
43 import urllib2
44 import xml.dom.minidom as xml
45
46 try:
47 import pytz
48 except ImportError:
49 pass
50
51 import nflgame.game
52 import nflgame.schedule
53
54
55
56
57 _MAX_GAME_TIME = 60 * 60 * 6
58 """
59 The assumed maximum time allowed for a game to complete. This is used to
60 determine whether a particular game that isn't over is currently active.
61 """
62
63 _WEEK_INTERVAL = 60 * 60 * 12
64 """
65 How often to check what the current week is. By default, it is twice a day.
66 """
67
68 _CUR_SCHEDULE_URL = "http://www.nfl.com/liveupdate/scorestrip/ss.xml"
69 """
70 Pinged infrequently to discover the current week number, year and week type.
71 The actual schedule of games is taken from the schedule module.
72 """
73
74
75 _POST_URL = "http://static.nfl.com/liveupdate/scorestrip/postseason/ss.xml"
76 """
77 The URL for the XML schedule of the post season. This is only used
78 during the post season.
79
80 TODO: How do we know if it's the post season?
81 """
82
83 _EASTERN_TZ = pytz.timezone('US/Eastern')
84 """Used to convert game times in EST to UTC."""
85
86 _cur_week = None
87 """The current week. It is updated infrequently automatically."""
88
89 _cur_year = None
90 """The current year. It is updated infrequently automatically."""
91
92 _preseason = False
93 """True when it's the preseason."""
94
95 _regular = False
96 """True when it's the regular season."""
97
98 _completed = []
99 """
100 A list of game eids that have been completed since the live module started
101 checking for updated game stats.
102 """
103
104
106 """
107 Returns a tuple (year, week) where year is the current year of the season
108 and week is the current week number of games being played.
109 i.e., (2012, 3).
110
111 N.B. This always downloads the schedule XML data.
112 """
113 dom = xml.parse(urllib2.urlopen(_CUR_SCHEDULE_URL))
114 gms = dom.getElementsByTagName('gms')[0]
115 year = int(gms.getAttribute('y'))
116 week = int(gms.getAttribute('w'))
117 return (year, week)
118
119
120 -def current_games(year=None, week=None,
121 regular=True, postseason=False, preseason=False):
122 """
123 Returns a list of game.Games of games that are currently playing.
124 This fetches all current information from NFL.com.
125
126 If either year or week is none, then the current year and week are
127 fetched from the schedule on NFL.com. If they are *both* provided, then
128 the schedule from NFL.com won't need to be downloaded, and thus saving
129 time.
130
131 So for example::
132
133 year, week = nflgame.live.current_year_and_week()
134 while True:
135 games = nflgame.live.current_games(year, week)
136 # Do something with games
137 time.sleep(60)
138
139 Finally, if the optional parameter postseason/preseason is True, then the
140 week parameter will refer to the postseason/preseason week rather than the
141 regular season week.
142 """
143 if year is None or week is None:
144 year, week = current_year_and_week()
145
146 games = []
147 now = _now()
148 gen = _games_in_week(year, week, regular=regular, postseason=postseason,
149 preseason=preseason)
150 for info in gen:
151 gametime = _game_datetime(info)
152 if gametime >= now:
153 if (gametime - now).total_seconds() <= 60 * 60 * 36:
154 games.append(info['eid'])
155 elif (now - gametime).total_seconds() <= _MAX_GAME_TIME:
156 games.append(info['eid'])
157 return games
158
159
160 -def run(callback, active_interval=15, inactive_interval=900, stop=None):
161 """
162 Starts checking for games that are currently playing.
163
164 Every time there is an update, callback will be called with two lists:
165 active and completed. The active list is a list of game.Game that are
166 currently being played. The completed list is a list of game.Game that
167 have just finished. A game will appear in the completed list only once,
168 after which that game will not be in either the active or completed lists.
169 No game can ever be in both lists at the same time.
170
171 It is possible that a game in the active list is not yet playing because
172 it hasn't started yet. It ends up in the active list because the "pregame"
173 has started on NFL.com's GameCenter web site, and sometimes game data is
174 partially filled. When this is the case, the 'playing' method on
175 a nflgame.game.Game will return False.
176
177 When in the active mode (see live module description), active_interval
178 specifies the number of seconds to wait between checking for updated game
179 data. Please do not make this number too low to avoid angering NFL.com.
180 If you anger them too much, it is possible that they could ban your IP
181 address.
182
183 Note that NFL.com's GameCenter page is updated every 15 seconds, so
184 setting the active_interval much smaller than that is wasteful.
185
186 When in the inactive mode (see live module description), inactive_interval
187 specifies the number of seconds to wait between checking whether any games
188 have started or are about to start.
189
190 With the default parameters, run will never stop. However, you may set
191 stop to a Python datetime.datetime value. After time passes the stopping
192 point, run will quit. (Technically, it's possible that it won't quit until
193 at most inactive_interval seconds after the stopping point is reached.)
194 The stop value is compared against datetime.datetime.now().
195 """
196 active = False
197 last_week_check = _update_week_number()
198
199
200
201
202 for info in _active_games(inactive_interval):
203 game = nflgame.game.Game(info['eid'])
204
205
206
207 if game is None:
208 continue
209
210
211
212 if game.game_over():
213 _completed.append(info['eid'])
214
215 while True:
216 if stop is not None and datetime.datetime.now() > stop:
217 return
218
219 if time.time() - last_week_check > _WEEK_INTERVAL:
220 last_week_check = _update_week_number()
221
222 games = _active_games(inactive_interval)
223 if active:
224 active = _run_active(callback, games)
225 if not active:
226 continue
227 time.sleep(active_interval)
228 else:
229 active = not _run_inactive(games)
230 if active:
231 continue
232 time.sleep(inactive_interval)
233
234
236 """
237 The active mode traverses each of the active games and fetches info for
238 each from NFL.com.
239
240 Then each game (that has info available on NFL.com---that is, the game
241 has started) is added to one of two lists: active and completed, which
242 are passed as the first and second parameters to callback. A game is
243 put in the active list if it's still being played, and into the completed
244 list if it has finished. In the latter case, it is added to a global store
245 of completed games and will never be passed to callback again.
246 """
247
248
249 if len(games) == 0:
250 return False
251
252 active, completed = [], []
253 for info in games:
254 game = nflgame.game.Game(info['eid'])
255
256
257
258 if game is None:
259 continue
260
261
262 if game.game_over():
263 completed.append(game)
264 _completed.append(info['eid'])
265 else:
266 active.append(game)
267
268 callback(active, completed)
269 return True
270
271
273 """
274 The inactive mode simply checks if there are any active games. If there
275 are, inactive mode needs to stop and transition to active mode---thus
276 we return False. If there aren't any active games, then the inactive
277 mode should continue, where we return True.
278
279 That is, so long as there are no active games, we go back to sleep.
280 """
281 return len(games) == 0
282
283
285 """
286 Returns a list of all active games. In this case, an active game is a game
287 that will start within inactive_interval seconds, or has started within
288 _MAX_GAME_TIME seconds in the past.
289 """
290 gen = _games_in_week(_cur_year, _cur_week,
291 regular=_regular,
292 postseason=False,
293 preseason=_preseason)
294 games = []
295 for info in gen:
296 if not _game_is_active(info, inactive_interval):
297 continue
298 games.append(info)
299 return games
300
301
302 -def _games_in_week(year, week,
303 regular=True, postseason=False, preseason=False):
304 """
305 A generator for the games matching the year/week/preseason parameters.
306 """
307 for (y, t, w, _, _), info in nflgame.schedule.games:
308 if y != year:
309 continue
310 if w != week:
311 continue
312 if t == 'PRE' and not preseason:
313 continue
314 if t == 'REG' and not regular:
315 continue
316 yield info
317
318
320 """
321 Returns true if the game is active. A game is considered active if the
322 game start time is in the past and not in the completed list (which is
323 a private module level variable that is populated automatically) or if the
324 game start time is within inactive_interval seconds from starting.
325 """
326 gametime = _game_datetime(gameinfo)
327 now = _now()
328 if gametime >= now:
329 return (gametime - now).total_seconds() <= inactive_interval
330 return gameinfo['eid'] not in _completed
331
332
334 hour, minute = gameinfo['time'].strip().split(':')
335 d = datetime.datetime(gameinfo['year'], gameinfo['month'], gameinfo['day'],
336 (int(hour) + 12) % 24, int(minute))
337 return _EASTERN_TZ.localize(d).astimezone(pytz.utc)
338
339
341 return datetime.datetime.now(pytz.utc)
342
343
354