1 #!/usr/bin/env python 2 3 """ 4 Interpretation of vCalendar content. 5 6 Copyright (C) 2014, 2015 Paul Boddie <paul@boddie.org.uk> 7 8 This program is free software; you can redistribute it and/or modify it under 9 the terms of the GNU General Public License as published by the Free Software 10 Foundation; either version 3 of the License, or (at your option) any later 11 version. 12 13 This program is distributed in the hope that it will be useful, but WITHOUT 14 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS 15 FOR A PARTICULAR PURPOSE. See the GNU General Public License for more 16 details. 17 18 You should have received a copy of the GNU General Public License along with 19 this program. If not, see <http://www.gnu.org/licenses/>. 20 """ 21 22 from bisect import bisect_left 23 from datetime import date, datetime, timedelta 24 from email.mime.text import MIMEText 25 from imiptools.dates import format_datetime, get_datetime, get_duration, \ 26 get_freebusy_period, get_period, get_tzid, \ 27 to_timezone, to_utc_datetime 28 from imiptools.period import Period, RecurringPeriod, period_overlaps 29 from vCalendar import iterwrite, parse, ParseError, to_dict, to_node 30 from vRecurrence import get_parameters, get_rule 31 import email.utils 32 33 try: 34 from cStringIO import StringIO 35 except ImportError: 36 from StringIO import StringIO 37 38 class Object: 39 40 "Access to calendar structures." 41 42 def __init__(self, fragment): 43 self.objtype, (self.details, self.attr) = fragment.items()[0] 44 45 def get_uid(self): 46 return self.get_value("UID") 47 48 def get_recurrenceid(self): 49 50 """ 51 Return the recurrence identifier, normalised to a UTC datetime if 52 specified as a datetime, converted to a date object otherwise. If no 53 recurrence identifier is present, None is returned. 54 """ 55 56 recurrenceid = self.get_utc_datetime("RECURRENCE-ID") 57 return recurrenceid and format_datetime(recurrenceid) 58 59 # Structure access. 60 61 def copy(self): 62 return Object(to_dict(self.to_node())) 63 64 def get_items(self, name, all=True): 65 return get_items(self.details, name, all) 66 67 def get_item(self, name): 68 return get_item(self.details, name) 69 70 def get_value_map(self, name): 71 return get_value_map(self.details, name) 72 73 def get_values(self, name, all=True): 74 return get_values(self.details, name, all) 75 76 def get_value(self, name): 77 return get_value(self.details, name) 78 79 def get_utc_datetime(self, name, date_tzid=None): 80 return get_utc_datetime(self.details, name, date_tzid) 81 82 def get_date_values(self, name, tzid=None): 83 items = get_date_value_items(self.details, name, tzid) 84 return items and [value for value, attr in items] 85 86 def get_date_value_items(self, name, tzid=None): 87 return get_date_value_items(self.details, name, tzid) 88 89 def get_datetime(self, name): 90 t = get_datetime_item(self.details, name) 91 if not t: return None 92 dt, attr = t 93 return dt 94 95 def get_datetime_item(self, name): 96 return get_datetime_item(self.details, name) 97 98 def get_duration(self, name): 99 return get_duration(self.get_value(name)) 100 101 def to_node(self): 102 return to_node({self.objtype : [(self.details, self.attr)]}) 103 104 def to_part(self, method): 105 return to_part(method, [self.to_node()]) 106 107 # Direct access to the structure. 108 109 def has_key(self, name): 110 return self.details.has_key(name) 111 112 def get(self, name): 113 return self.details.get(name) 114 115 def __getitem__(self, name): 116 return self.details[name] 117 118 def __setitem__(self, name, value): 119 self.details[name] = value 120 121 def __delitem__(self, name): 122 del self.details[name] 123 124 def remove(self, name): 125 try: 126 del self[name] 127 except KeyError: 128 pass 129 130 def remove_all(self, names): 131 for name in names: 132 self.remove(name) 133 134 # Computed results. 135 136 def get_periods(self, tzid, end): 137 return get_periods(self, tzid, end) 138 139 def get_tzid(self): 140 141 """ 142 Return a time zone identifier used by the start or end datetimes, 143 potentially suitable for converting dates to datetimes. 144 """ 145 146 if not self.has_key("DTSTART"): 147 return None 148 dtstart, dtstart_attr = self.get_datetime_item("DTSTART") 149 dtend, dtend_attr = self.get_datetime_item("DTEND") 150 return get_tzid(dtstart_attr, dtend_attr) 151 152 # Construction and serialisation. 153 154 def make_calendar(nodes, method=None): 155 156 """ 157 Return a complete calendar node wrapping the given 'nodes' and employing the 158 given 'method', if indicated. 159 """ 160 161 return ("VCALENDAR", {}, 162 (method and [("METHOD", {}, method)] or []) + 163 [("VERSION", {}, "2.0")] + 164 nodes 165 ) 166 167 def make_freebusy(freebusy, uid, organiser, organiser_attr=None, attendee=None, 168 attendee_attr=None, period=None): 169 170 """ 171 Return a calendar node defining the free/busy details described in the given 172 'freebusy' list, employing the given 'uid', for the given 'organiser' and 173 optional 'organiser_attr', with the optional 'attendee' providing recipient 174 details together with the optional 'attendee_attr'. 175 176 The result will be constrained to the 'period' if specified. 177 """ 178 179 record = [] 180 rwrite = record.append 181 182 rwrite(("ORGANIZER", organiser_attr or {}, organiser)) 183 184 if attendee: 185 rwrite(("ATTENDEE", attendee_attr or {}, attendee)) 186 187 rwrite(("UID", {}, uid)) 188 189 if freebusy: 190 191 # Get a constrained view if start and end limits are specified. 192 193 if period: 194 periods = period_overlaps(freebusy, period, True) 195 else: 196 periods = freebusy 197 198 # Write the limits of the resource. 199 200 if periods: 201 rwrite(("DTSTART", {"VALUE" : "DATE-TIME"}, format_datetime(periods[0].get_start_point()))) 202 rwrite(("DTEND", {"VALUE" : "DATE-TIME"}, format_datetime(periods[-1].get_end_point()))) 203 else: 204 rwrite(("DTSTART", {"VALUE" : "DATE-TIME"}, format_datetime(period.get_start_point()))) 205 rwrite(("DTEND", {"VALUE" : "DATE-TIME"}, format_datetime(period.get_end_point()))) 206 207 for p in periods: 208 if p.transp == "OPAQUE": 209 rwrite(("FREEBUSY", {"FBTYPE" : "BUSY"}, "/".join( 210 map(format_datetime, [p.get_start_point(), p.get_end_point()]) 211 ))) 212 213 return ("VFREEBUSY", {}, record) 214 215 def parse_object(f, encoding, objtype=None): 216 217 """ 218 Parse the iTIP content from 'f' having the given 'encoding'. If 'objtype' is 219 given, only objects of that type will be returned. Otherwise, the root of 220 the content will be returned as a dictionary with a single key indicating 221 the object type. 222 223 Return None if the content was not readable or suitable. 224 """ 225 226 try: 227 try: 228 doctype, attrs, elements = obj = parse(f, encoding=encoding) 229 if objtype and doctype == objtype: 230 return to_dict(obj)[objtype][0] 231 elif not objtype: 232 return to_dict(obj) 233 finally: 234 f.close() 235 236 # NOTE: Handle parse errors properly. 237 238 except (ParseError, ValueError): 239 pass 240 241 return None 242 243 def to_part(method, calendar): 244 245 """ 246 Write using the given 'method', the 'calendar' details to a MIME 247 text/calendar part. 248 """ 249 250 encoding = "utf-8" 251 out = StringIO() 252 try: 253 to_stream(out, make_calendar(calendar, method), encoding) 254 part = MIMEText(out.getvalue(), "calendar", encoding) 255 part.set_param("method", method) 256 return part 257 258 finally: 259 out.close() 260 261 def to_stream(out, fragment, encoding="utf-8"): 262 iterwrite(out, encoding=encoding).append(fragment) 263 264 # Structure access functions. 265 266 def get_items(d, name, all=True): 267 268 """ 269 Get all items from 'd' for the given 'name', returning single items if 270 'all' is specified and set to a false value and if only one value is 271 present for the name. Return None if no items are found for the name or if 272 many items are found but 'all' is set to a false value. 273 """ 274 275 if d.has_key(name): 276 items = d[name] 277 if all: 278 return items 279 elif len(items) == 1: 280 return items[0] 281 else: 282 return None 283 else: 284 return None 285 286 def get_item(d, name): 287 return get_items(d, name, False) 288 289 def get_value_map(d, name): 290 291 """ 292 Return a dictionary for all items in 'd' having the given 'name'. The 293 dictionary will map values for the name to any attributes or qualifiers 294 that may have been present. 295 """ 296 297 items = get_items(d, name) 298 if items: 299 return dict(items) 300 else: 301 return {} 302 303 def values_from_items(items): 304 return map(lambda x: x[0], items) 305 306 def get_values(d, name, all=True): 307 if d.has_key(name): 308 items = d[name] 309 if not all and len(items) == 1: 310 return items[0][0] 311 else: 312 return values_from_items(items) 313 else: 314 return None 315 316 def get_value(d, name): 317 return get_values(d, name, False) 318 319 def get_date_value_items(d, name, tzid=None): 320 321 """ 322 Obtain items from 'd' having the given 'name', where a single item yields 323 potentially many values. Return a list of tuples of the form (value, 324 attributes) where the attributes have been given for the property in 'd'. 325 """ 326 327 items = get_items(d, name) 328 if items: 329 all_items = [] 330 for item in items: 331 values, attr = item 332 if not attr.has_key("TZID") and tzid: 333 attr["TZID"] = tzid 334 if not isinstance(values, list): 335 values = [values] 336 for value in values: 337 all_items.append((get_datetime(value, attr) or get_period(value, attr), attr)) 338 return all_items 339 else: 340 return None 341 342 def get_utc_datetime(d, name, date_tzid=None): 343 344 """ 345 Return the value provided by 'd' for 'name' as a datetime in the UTC zone 346 or as a date, converting any date to a datetime if 'date_tzid' is specified. 347 """ 348 349 t = get_datetime_item(d, name) 350 if not t: 351 return None 352 else: 353 dt, attr = t 354 return to_utc_datetime(dt, date_tzid) 355 356 def get_datetime_item(d, name): 357 358 """ 359 Return the value provided by 'd' for 'name' as a datetime or as a date, 360 together with the attributes describing it. Return None if no value exists 361 for 'name' in 'd'. 362 """ 363 364 t = get_item(d, name) 365 if not t: 366 return None 367 else: 368 value, attr = t 369 return get_datetime(value, attr), attr 370 371 # Conversion functions. 372 373 def get_addresses(values): 374 return [address for name, address in email.utils.getaddresses(values)] 375 376 def get_address(value): 377 value = value.lower() 378 return value.startswith("mailto:") and value[7:] or value 379 380 def get_uri(value): 381 return value.lower().startswith("mailto:") and value.lower() or ":" in value and value or "mailto:%s" % value.lower() 382 383 uri_value = get_uri 384 385 def uri_values(values): 386 return map(get_uri, values) 387 388 def uri_dict(d): 389 return dict([(get_uri(key), value) for key, value in d.items()]) 390 391 def uri_item(item): 392 return get_uri(item[0]), item[1] 393 394 def uri_items(items): 395 return [(get_uri(value), attr) for value, attr in items] 396 397 # Operations on structure data. 398 399 def is_new_object(old_sequence, new_sequence, old_dtstamp, new_dtstamp, partstat_set): 400 401 """ 402 Return for the given 'old_sequence' and 'new_sequence', 'old_dtstamp' and 403 'new_dtstamp', and the 'partstat_set' indication, whether the object 404 providing the new information is really newer than the object providing the 405 old information. 406 """ 407 408 have_sequence = old_sequence is not None and new_sequence is not None 409 is_same_sequence = have_sequence and int(new_sequence) == int(old_sequence) 410 411 have_dtstamp = old_dtstamp and new_dtstamp 412 is_old_dtstamp = have_dtstamp and new_dtstamp < old_dtstamp or old_dtstamp and not new_dtstamp 413 414 is_old_sequence = have_sequence and ( 415 int(new_sequence) < int(old_sequence) or 416 is_same_sequence and is_old_dtstamp 417 ) 418 419 return is_same_sequence and partstat_set or not is_old_sequence 420 421 def get_periods(obj, tzid, window_end, inclusive=False): 422 423 """ 424 Return periods for the given object 'obj', confining materialised periods 425 to before the given 'window_end' datetime. If 'inclusive' is set to a true 426 value, any period occurring at the 'window_end' will be included. 427 """ 428 429 rrule = obj.get_value("RRULE") 430 431 # Use localised datetimes. 432 433 dtstart, dtstart_attr = obj.get_datetime_item("DTSTART") 434 435 if obj.has_key("DTEND"): 436 dtend, dtend_attr = obj.get_datetime_item("DTEND") 437 duration = dtend - dtstart 438 elif obj.has_key("DURATION"): 439 duration = obj.get_duration("DURATION") 440 dtend = dtstart + duration 441 dtend_attr = dtstart_attr 442 else: 443 dtend, dtend_attr = dtstart, dtstart_attr 444 445 tzid = obj.get_tzid() or tzid 446 447 if not rrule: 448 periods = [RecurringPeriod(dtstart, dtend, tzid, "DTSTART", dtstart_attr, dtend_attr)] 449 else: 450 # Recurrence rules create multiple instances to be checked. 451 # Conflicts may only be assessed within a period defined by policy 452 # for the agent, with instances outside that period being considered 453 # unchecked. 454 455 selector = get_rule(dtstart, rrule) 456 parameters = get_parameters(rrule) 457 periods = [] 458 459 until = parameters.get("UNTIL") 460 if until: 461 window_end = min(to_timezone(get_datetime(until, dtstart_attr), tzid), window_end) 462 inclusive = True 463 464 for start in selector.materialise(dtstart, window_end, parameters.get("COUNT"), parameters.get("BYSETPOS"), inclusive): 465 create = len(start) == 3 and date or datetime 466 start = to_timezone(create(*start), tzid) 467 end = start + duration 468 periods.append(RecurringPeriod(start, end, tzid, "RRULE")) 469 470 # Add recurrence dates. 471 472 rdates = obj.get_date_value_items("RDATE", tzid) 473 474 if rdates: 475 for rdate, rdate_attr in rdates: 476 if isinstance(rdate, tuple): 477 periods.append(RecurringPeriod(rdate[0], rdate[1], tzid, "RDATE", rdate_attr)) 478 else: 479 periods.append(RecurringPeriod(rdate, rdate + duration, tzid, "RDATE", rdate_attr)) 480 481 # Return a sorted list of the periods. 482 483 periods.sort() 484 485 # Exclude exception dates. 486 487 exdates = obj.get_date_values("EXDATE", tzid) 488 489 if exdates: 490 for exdate in exdates: 491 if isinstance(exdate, tuple): 492 period = Period(exdate[0], exdate[1], tzid) 493 else: 494 period = Period(exdate, exdate + duration, tzid) 495 i = bisect_left(periods, period) 496 while i < len(periods) and periods[i] == period: 497 del periods[i] 498 499 return periods 500 501 def get_sender_identities(mapping): 502 503 """ 504 Return a mapping from actual senders to the identities for which they 505 have provided data, extracting this information from the given 506 'mapping'. 507 """ 508 509 senders = {} 510 511 for value, attr in mapping.items(): 512 sent_by = attr.get("SENT-BY") 513 if sent_by: 514 sender = get_uri(sent_by) 515 else: 516 sender = value 517 518 if not senders.has_key(sender): 519 senders[sender] = [] 520 521 senders[sender].append(value) 522 523 return senders 524 525 # NOTE: Need to expose the 100 day window for recurring events in the 526 # NOTE: configuration. 527 528 def get_window_end(tzid, window_size=100): 529 return to_timezone(datetime.now(), tzid) + timedelta(window_size) 530 531 # vim: tabstop=4 expandtab shiftwidth=4