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