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(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'. Where no conflict 200 occurs, return the updated free/busy details; otherwise return None. 201 """ 202 203 conflict = False 204 freebusy = store.get_freebusy(attendee) or [] 205 206 if freebusy: 207 remove_period(freebusy, uid) 208 conflict = have_conflict(freebusy, periods) 209 210 # If the event can be scheduled, it is registered in the free/busy list. 211 212 if not conflict: 213 214 for start, end in periods: 215 insert_period(freebusy, (start, end, uid)) 216 217 if transp in (None, "OPAQUE"): 218 store.set_freebusy(attendee, freebusy) 219 220 return freebusy 221 222 return None 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. 279 280 Return None if the content was not readable or suitable. 281 """ 282 283 try: 284 try: 285 doctype, attrs, elements = obj = parse(f, encoding=encoding) 286 if objtype and doctype == objtype: 287 return to_dict(obj)[objtype][0] 288 elif not objtype: 289 return to_dict(obj)[doctype][0] 290 finally: 291 f.close() 292 except (ParseError, ValueError): 293 pass 294 295 return None 296 297 def to_part(method, calendar): 298 299 """ 300 Write using the given 'method', the 'calendar' details to a MIME 301 text/calendar part. 302 """ 303 304 encoding = "utf-8" 305 out = StringIO() 306 try: 307 imip_store.to_stream(out, imip_store.make_calendar(calendar, method), encoding) 308 part = MIMEText(out.getvalue(), "calendar", encoding) 309 part.set_param("method", method) 310 return part 311 312 finally: 313 out.close() 314 315 class Handler: 316 317 "General handler support." 318 319 def __init__(self, details, recipients): 320 321 """ 322 Initialise the handler with the 'details' of a calendar object and the 323 'recipients' of the object. 324 """ 325 326 self.details = details 327 self.recipients = set(recipients) 328 329 self.uid = get_value(details, "UID") 330 self.sequence = get_value(details, "SEQUENCE") 331 self.dtstamp = get_value(details, "DTSTAMP") 332 333 self.store = imip_store.FileStore() 334 335 try: 336 self.publisher = imip_store.FilePublisher() 337 except OSError: 338 self.publisher = None 339 340 # Access to calendar structures and other data. 341 342 def get_items(self, name, all=True): 343 return get_items(self.details, name, all) 344 345 def get_item(self, name): 346 return get_item(self.details, name) 347 348 def get_value_map(self, name): 349 return get_value_map(self.details, name) 350 351 def get_values(self, name, all=True): 352 return get_values(self.details, name, all) 353 354 def get_value(self, name): 355 return get_value(self.details, name) 356 357 def get_utc_datetime(self, name): 358 return get_utc_datetime(self.details, name) 359 360 def get_periods(self): 361 return get_periods(self.details) 362 363 def update_freebusy(self, attendee, periods): 364 return update_freebusy(attendee, periods, self.get_value("TRANSP"), self.uid, self.store) 365 366 def filter_by_recipients(self, values): 367 return self.recipients.intersection(map(get_address, values)) 368 369 def require_organiser_and_attendees(self): 370 371 """ 372 Return the organiser and attendees for the current object, filtered by 373 the recipients of interest. Return None if no identities are eligible. 374 """ 375 376 attendee_map = self.get_value_map("ATTENDEE") 377 organiser = self.get_item("ORGANIZER") 378 379 # Only provide details for recipients who are also attendees. 380 381 attendees = {} 382 for attendee in map(get_uri, self.filter_by_recipients(attendee_map)): 383 attendees[attendee] = attendee_map[attendee] 384 385 if not attendees and not organiser: 386 return None 387 388 return organiser, attendees 389 390 def have_new_object(self, attendee, objtype): 391 392 """ 393 Return whether the current object is new to the 'attendee' for the 394 given 'objtype'. 395 """ 396 397 f = self.store.get_event(attendee, self.uid) 398 event = f and parse_object(f, "utf-8", objtype) 399 400 # If found, compare SEQUENCE and potentially DTSTAMP. 401 402 if event: 403 sequence = get_value(event, "SEQUENCE") 404 dtstamp = get_value(event, "DTSTAMP") 405 406 # If the request refers to an older version of the event, ignore 407 # it. 408 409 old_dtstamp = self.dtstamp < dtstamp 410 411 if sequence is not None and ( 412 int(self.sequence) < int(sequence) or 413 int(self.sequence) == int(sequence) and old_dtstamp 414 ) or old_dtstamp: 415 416 return False 417 418 return True 419 420 # Handler registry. 421 422 methods = { 423 "ADD" : lambda handler: handler.add, 424 "CANCEL" : lambda handler: handler.cancel, 425 "COUNTER" : lambda handler: handler.counter, 426 "DECLINECOUNTER" : lambda handler: handler.declinecounter, 427 "PUBLISH" : lambda handler: handler.publish, 428 "REFRESH" : lambda handler: handler.refresh, 429 "REPLY" : lambda handler: handler.reply, 430 "REQUEST" : lambda handler: handler.request, 431 } 432 433 # vim: tabstop=4 expandtab shiftwidth=4