1 #!/usr/bin/env python 2 3 """ 4 Interpretation and preparation of iMIP content, together with a content handling 5 mechanism employed by specific recipients. 6 """ 7 8 from datetime import date, datetime, timedelta 9 from email.mime.text import MIMEText 10 from imiptools.period import have_conflict, insert_period, remove_period 11 from pytz import timezone, UnknownTimeZoneError 12 from vCalendar import parse, ParseError, to_dict 13 from vRecurrence import get_parameters, get_rule 14 import imip_store 15 import re 16 17 try: 18 from cStringIO import StringIO 19 except ImportError: 20 from StringIO import StringIO 21 22 # iCalendar date and datetime parsing (from DateSupport in MoinSupport). 23 24 date_icalendar_regexp_str = ur'(?P<year>[0-9]{4})(?P<month>[0-9]{2})(?P<day>[0-9]{2})' 25 datetime_icalendar_regexp_str = date_icalendar_regexp_str + \ 26 ur'(?:' \ 27 ur'T(?P<hour>[0-2][0-9])(?P<minute>[0-5][0-9])(?P<second>[0-6][0-9])' \ 28 ur'(?P<utc>Z)?' \ 29 ur')?' 30 31 match_date_icalendar = re.compile(date_icalendar_regexp_str, re.UNICODE).match 32 match_datetime_icalendar = re.compile(datetime_icalendar_regexp_str, re.UNICODE).match 33 34 # Content interpretation. 35 36 def get_items(d, name, all=True): 37 38 """ 39 Get all items from 'd' with the given 'name', returning single items if 40 'all' is specified and set to a false value and if only one value is 41 present for the name. Return None if no items are found for the name. 42 """ 43 44 if d.has_key(name): 45 values = d[name] 46 if not all and len(values) == 1: 47 return values[0] 48 else: 49 return values 50 else: 51 return None 52 53 def get_item(d, name): 54 return get_items(d, name, False) 55 56 def get_value_map(d, name): 57 58 """ 59 Return a dictionary for all items in 'd' having the given 'name'. The 60 dictionary will map values for the name to any attributes or qualifiers 61 that may have been present. 62 """ 63 64 items = get_items(d, name) 65 if items: 66 return dict(items) 67 else: 68 return {} 69 70 def get_values(d, name, all=True): 71 if d.has_key(name): 72 values = d[name] 73 if not all and len(values) == 1: 74 return values[0][0] 75 else: 76 return map(lambda x: x[0], values) 77 else: 78 return None 79 80 def get_value(d, name): 81 return get_values(d, name, False) 82 83 def get_utc_datetime(d, name): 84 value, attr = get_item(d, name) 85 dt = get_datetime(value, attr) 86 return to_utc_datetime(dt) 87 88 def to_utc_datetime(dt): 89 if not dt: 90 return None 91 elif isinstance(dt, datetime): 92 return dt.astimezone(timezone("UTC")) 93 else: 94 return dt 95 96 def to_timezone(dt, name): 97 try: 98 tz = name and timezone(name) or None 99 except UnknownTimeZoneError: 100 tz = None 101 if tz is not None: 102 if not dt.tzinfo: 103 return tz.localize(dt) 104 else: 105 return dt.astimezone(tz) 106 else: 107 return dt 108 109 def format_datetime(dt): 110 if not dt: 111 return None 112 elif isinstance(dt, datetime): 113 if dt.tzname() == "UTC": 114 return dt.strftime("%Y%m%dT%H%M%SZ") 115 else: 116 return dt.strftime("%Y%m%dT%H%M%S") 117 else: 118 return dt.strftime("%Y%m%d") 119 120 def get_address(value): 121 return value.startswith("mailto:") and value[7:] or value 122 123 def get_uri(value): 124 return value.startswith("mailto:") and value or "mailto:%s" % value 125 126 def get_datetime(value, attr=None): 127 128 """ 129 Return a datetime object from the given 'value' in iCalendar format, using 130 the 'attr' mapping (if specified) to control the conversion. 131 """ 132 133 if not attr or attr.get("VALUE") in (None, "DATE-TIME"): 134 m = match_datetime_icalendar(value) 135 if m: 136 dt = datetime( 137 int(m.group("year")), int(m.group("month")), int(m.group("day")), 138 int(m.group("hour")), int(m.group("minute")), int(m.group("second")) 139 ) 140 141 # Impose the indicated timezone. 142 # NOTE: This needs an ambiguity policy for DST changes. 143 144 return to_timezone(dt, m.group("utc") and "UTC" or attr and attr.get("TZID") or None) 145 146 if not attr or attr.get("VALUE") == "DATE": 147 m = match_date_icalendar(value) 148 if m: 149 return date( 150 int(m.group("year")), int(m.group("month")), int(m.group("day")) 151 ) 152 return None 153 154 # NOTE: Need to expose the 100 day window for recurring events in the 155 # NOTE: configuration. 156 157 def get_periods(obj, window_size=100): 158 159 """ 160 Return periods for the given object 'obj', confining materialised periods 161 to the given 'window_size' in days starting from the present moment. 162 """ 163 164 dtstart = get_utc_datetime(obj, "DTSTART") 165 dtend = get_utc_datetime(obj, "DTEND") 166 167 # NOTE: Need also DURATION support. 168 169 duration = dtend - dtstart 170 171 # Recurrence rules create multiple instances to be checked. 172 # Conflicts may only be assessed within a period defined by policy 173 # for the agent, with instances outside that period being considered 174 # unchecked. 175 176 window_end = datetime.now() + timedelta(window_size) 177 178 # NOTE: Need also RDATE and EXDATE support. 179 180 rrule = get_value(obj, "RRULE") 181 182 if rrule: 183 selector = get_rule(dtstart, rrule) 184 parameters = get_parameters(rrule) 185 periods = [] 186 for start in selector.materialise(dtstart, window_end, parameters.get("COUNT"), parameters.get("BYSETPOS")): 187 start = datetime(*start, tzinfo=timezone("UTC")) 188 end = start + duration 189 periods.append((format_datetime(start), format_datetime(end))) 190 else: 191 periods = [(format_datetime(dtstart), format_datetime(dtend))] 192 193 return periods 194 195 def update_freebusy(freebusy, attendee, periods, transp, uid, store): 196 197 """ 198 For the given 'attendee', update the free/busy details with the given 199 'periods', 'transp' setting and 'uid' in the 'store'. 200 """ 201 202 remove_period(freebusy, uid) 203 204 for start, end in periods: 205 insert_period(freebusy, (start, end, uid)) 206 207 if transp in (None, "OPAQUE"): 208 store.set_freebusy(attendee, freebusy) 209 210 def can_schedule(freebusy, periods, uid): 211 212 """ 213 Return whether the 'freebusy' list can accommodate the given 'periods' 214 employing the specified 'uid'. 215 """ 216 217 for conflict in have_conflict(freebusy, periods, True): 218 start, end, found_uid = conflict 219 if found_uid != uid: 220 return False 221 222 return True 223 224 # Handler mechanism objects. 225 226 def handle_itip_part(part, recipients, handlers): 227 228 """ 229 Handle the given iTIP 'part' for the given 'recipients' using the given 230 'handlers'. Return a list of responses, each response being a tuple of the 231 form (is-outgoing, message-part). 232 """ 233 234 method = part.get_param("method") 235 236 # Decode the data and parse it. 237 238 f = StringIO(part.get_payload(decode=True)) 239 240 itip = parse_object(f, part.get_content_charset(), "VCALENDAR") 241 242 # Ignore the part if not a calendar object. 243 244 if not itip: 245 return [] 246 247 # Require consistency between declared and employed methods. 248 249 if get_value(itip, "METHOD") == method: 250 251 # Look for different kinds of sections. 252 253 all_results = [] 254 255 for name, cls in handlers: 256 for details in get_values(itip, name) or []: 257 258 # Dispatch to a handler and obtain any response. 259 260 handler = cls(details, recipients) 261 result = methods[method](handler)() 262 263 # Concatenate responses for a single calendar object. 264 265 if result: 266 response_method, part = result 267 outgoing = method != response_method 268 all_results.append((outgoing, part)) 269 270 return all_results 271 272 return [] 273 274 def parse_object(f, encoding, objtype=None): 275 276 """ 277 Parse the iTIP content from 'f' having the given 'encoding'. If 'objtype' is 278 given, only objects of that type will be returned. Otherwise, the root of 279 the content will be returned as a dictionary with a single key indicating 280 the object type. 281 282 Return None if the content was not readable or suitable. 283 """ 284 285 try: 286 try: 287 doctype, attrs, elements = obj = parse(f, encoding=encoding) 288 if objtype and doctype == objtype: 289 return to_dict(obj)[objtype][0] 290 elif not objtype: 291 return to_dict(obj) 292 finally: 293 f.close() 294 except (ParseError, ValueError): 295 pass 296 297 return None 298 299 def to_part(method, calendar): 300 301 """ 302 Write using the given 'method', the 'calendar' details to a MIME 303 text/calendar part. 304 """ 305 306 encoding = "utf-8" 307 out = StringIO() 308 try: 309 imip_store.to_stream(out, imip_store.make_calendar(calendar, method), encoding) 310 part = MIMEText(out.getvalue(), "calendar", encoding) 311 part.set_param("method", method) 312 return part 313 314 finally: 315 out.close() 316 317 class Handler: 318 319 "General handler support." 320 321 def __init__(self, details, recipients): 322 323 """ 324 Initialise the handler with the 'details' of a calendar object and the 325 'recipients' of the object. 326 """ 327 328 self.details = details 329 self.recipients = set(recipients) 330 331 self.uid = get_value(details, "UID") 332 self.sequence = get_value(details, "SEQUENCE") 333 self.dtstamp = get_value(details, "DTSTAMP") 334 335 self.store = imip_store.FileStore() 336 337 try: 338 self.publisher = imip_store.FilePublisher() 339 except OSError: 340 self.publisher = None 341 342 # Access to calendar structures and other data. 343 344 def get_items(self, name, all=True): 345 return get_items(self.details, name, all) 346 347 def get_item(self, name): 348 return get_item(self.details, name) 349 350 def get_value_map(self, name): 351 return get_value_map(self.details, name) 352 353 def get_values(self, name, all=True): 354 return get_values(self.details, name, all) 355 356 def get_value(self, name): 357 return get_value(self.details, name) 358 359 def get_utc_datetime(self, name): 360 return get_utc_datetime(self.details, name) 361 362 def get_periods(self): 363 return get_periods(self.details) 364 365 def update_freebusy(self, freebusy, attendee, periods): 366 return update_freebusy(freebusy, attendee, periods, self.get_value("TRANSP"), self.uid, self.store) 367 368 def can_schedule(self, freebusy, periods): 369 return can_schedule(freebusy, periods, self.uid) 370 371 def filter_by_recipients(self, values): 372 return self.recipients.intersection(map(get_address, values)) 373 374 def require_organiser_and_attendees(self): 375 376 """ 377 Return the organiser and attendees for the current object, filtered by 378 the recipients of interest. Return None if no identities are eligible. 379 """ 380 381 attendee_map = self.get_value_map("ATTENDEE") 382 organiser = self.get_item("ORGANIZER") 383 384 # Only provide details for recipients who are also attendees. 385 386 attendees = {} 387 for attendee in map(get_uri, self.filter_by_recipients(attendee_map)): 388 attendees[attendee] = attendee_map[attendee] 389 390 if not attendees and not organiser: 391 return None 392 393 return organiser, attendees 394 395 def have_new_object(self, attendee, objtype): 396 397 """ 398 Return whether the current object is new to the 'attendee' for the 399 given 'objtype'. 400 """ 401 402 f = self.store.get_event(attendee, self.uid) 403 event = f and parse_object(f, "utf-8", objtype) 404 405 # If found, compare SEQUENCE and potentially DTSTAMP. 406 407 if event: 408 sequence = get_value(event, "SEQUENCE") 409 dtstamp = get_value(event, "DTSTAMP") 410 411 # If the request refers to an older version of the event, ignore 412 # it. 413 414 old_dtstamp = self.dtstamp < dtstamp 415 416 if sequence is not None and ( 417 int(self.sequence) < int(sequence) or 418 int(self.sequence) == int(sequence) and old_dtstamp 419 ) or old_dtstamp: 420 421 return False 422 423 return True 424 425 # Handler registry. 426 427 methods = { 428 "ADD" : lambda handler: handler.add, 429 "CANCEL" : lambda handler: handler.cancel, 430 "COUNTER" : lambda handler: handler.counter, 431 "DECLINECOUNTER" : lambda handler: handler.declinecounter, 432 "PUBLISH" : lambda handler: handler.publish, 433 "REFRESH" : lambda handler: handler.refresh, 434 "REPLY" : lambda handler: handler.reply, 435 "REQUEST" : lambda handler: handler.request, 436 } 437 438 # vim: tabstop=4 expandtab shiftwidth=4