imip-agent

Annotated imiptools/data.py

256:ac813723ed71
2015-02-04 Paul Boddie Made get_periods a method on the Object class, moving the supporting function to the data module.
paul@213 1
#!/usr/bin/env python
paul@213 2
paul@213 3
"""
paul@213 4
Interpretation of vCalendar content.
paul@213 5
paul@213 6
Copyright (C) 2014, 2015 Paul Boddie <paul@boddie.org.uk>
paul@213 7
paul@213 8
This program is free software; you can redistribute it and/or modify it under
paul@213 9
the terms of the GNU General Public License as published by the Free Software
paul@213 10
Foundation; either version 3 of the License, or (at your option) any later
paul@213 11
version.
paul@213 12
paul@213 13
This program is distributed in the hope that it will be useful, but WITHOUT
paul@213 14
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
paul@213 15
FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
paul@213 16
details.
paul@213 17
paul@213 18
You should have received a copy of the GNU General Public License along with
paul@213 19
this program.  If not, see <http://www.gnu.org/licenses/>.
paul@213 20
"""
paul@213 21
paul@256 22
from datetime import datetime, timedelta
paul@213 23
from email.mime.text import MIMEText
paul@256 24
from imiptools.dates import format_datetime, get_datetime, to_utc_datetime
paul@213 25
from vCalendar import iterwrite, parse, ParseError, to_dict, to_node
paul@256 26
from vRecurrence import get_parameters, get_rule
paul@213 27
import email.utils
paul@213 28
paul@213 29
try:
paul@213 30
    from cStringIO import StringIO
paul@213 31
except ImportError:
paul@213 32
    from StringIO import StringIO
paul@213 33
paul@213 34
class Object:
paul@213 35
paul@213 36
    "Access to calendar structures."
paul@213 37
paul@213 38
    def __init__(self, fragment):
paul@213 39
        self.objtype, (self.details, self.attr) = fragment.items()[0]
paul@213 40
paul@213 41
    def get_items(self, name, all=True):
paul@213 42
        return get_items(self.details, name, all)
paul@213 43
paul@213 44
    def get_item(self, name):
paul@213 45
        return get_item(self.details, name)
paul@213 46
paul@213 47
    def get_value_map(self, name):
paul@213 48
        return get_value_map(self.details, name)
paul@213 49
paul@213 50
    def get_values(self, name, all=True):
paul@213 51
        return get_values(self.details, name, all)
paul@213 52
paul@213 53
    def get_value(self, name):
paul@213 54
        return get_value(self.details, name)
paul@213 55
paul@213 56
    def get_utc_datetime(self, name):
paul@213 57
        return get_utc_datetime(self.details, name)
paul@213 58
paul@213 59
    def to_node(self):
paul@213 60
        return to_node({self.objtype : [(self.details, self.attr)]})
paul@213 61
paul@213 62
    def to_part(self, method):
paul@213 63
        return to_part(method, [self.to_node()])
paul@213 64
paul@213 65
    # Direct access to the structure.
paul@213 66
paul@213 67
    def __getitem__(self, name):
paul@213 68
        return self.details[name]
paul@213 69
paul@213 70
    def __setitem__(self, name, value):
paul@213 71
        self.details[name] = value
paul@213 72
paul@213 73
    def __delitem__(self, name):
paul@213 74
        del self.details[name]
paul@213 75
paul@256 76
    # Computed results.
paul@256 77
paul@256 78
    def get_periods(self, window_size=100):
paul@256 79
        return get_periods(self, window_size)
paul@256 80
paul@213 81
# Construction and serialisation.
paul@213 82
paul@213 83
def make_calendar(nodes, method=None):
paul@213 84
paul@213 85
    """
paul@213 86
    Return a complete calendar node wrapping the given 'nodes' and employing the
paul@213 87
    given 'method', if indicated.
paul@213 88
    """
paul@213 89
paul@213 90
    return ("VCALENDAR", {},
paul@213 91
            (method and [("METHOD", {}, method)] or []) +
paul@213 92
            [("VERSION", {}, "2.0")] +
paul@213 93
            nodes
paul@213 94
           )
paul@213 95
paul@222 96
def make_freebusy(freebusy, uid, organiser, attendee=None):
paul@222 97
    
paul@222 98
    """
paul@222 99
    Return a calendar node defining the free/busy details described in the given
paul@222 100
    'freebusy' list, employing the given 'uid', for the given 'organiser', with
paul@222 101
    the optional 'attendee' providing recipient details.
paul@222 102
    """
paul@222 103
    
paul@222 104
    record = []
paul@222 105
    rwrite = record.append
paul@222 106
    
paul@222 107
    rwrite(("ORGANIZER", {}, organiser))
paul@222 108
paul@222 109
    if attendee:
paul@222 110
        rwrite(("ATTENDEE", {}, attendee)) 
paul@222 111
paul@222 112
    rwrite(("UID", {}, uid))
paul@222 113
paul@222 114
    if freebusy:
paul@222 115
        for start, end, uid, transp in freebusy:
paul@222 116
            if transp == "OPAQUE":
paul@222 117
                rwrite(("FREEBUSY", {"FBTYPE" : "BUSY"}, "/".join([start, end])))
paul@222 118
paul@222 119
    return ("VFREEBUSY", {}, record)
paul@222 120
paul@213 121
def parse_object(f, encoding, objtype=None):
paul@213 122
paul@213 123
    """
paul@213 124
    Parse the iTIP content from 'f' having the given 'encoding'. If 'objtype' is
paul@213 125
    given, only objects of that type will be returned. Otherwise, the root of
paul@213 126
    the content will be returned as a dictionary with a single key indicating
paul@213 127
    the object type.
paul@213 128
paul@213 129
    Return None if the content was not readable or suitable.
paul@213 130
    """
paul@213 131
paul@213 132
    try:
paul@213 133
        try:
paul@213 134
            doctype, attrs, elements = obj = parse(f, encoding=encoding)
paul@213 135
            if objtype and doctype == objtype:
paul@213 136
                return to_dict(obj)[objtype][0]
paul@213 137
            elif not objtype:
paul@213 138
                return to_dict(obj)
paul@213 139
        finally:
paul@213 140
            f.close()
paul@213 141
paul@213 142
    # NOTE: Handle parse errors properly.
paul@213 143
paul@213 144
    except (ParseError, ValueError):
paul@213 145
        pass
paul@213 146
paul@213 147
    return None
paul@213 148
paul@213 149
def to_part(method, calendar):
paul@213 150
paul@213 151
    """
paul@213 152
    Write using the given 'method', the 'calendar' details to a MIME
paul@213 153
    text/calendar part.
paul@213 154
    """
paul@213 155
paul@213 156
    encoding = "utf-8"
paul@213 157
    out = StringIO()
paul@213 158
    try:
paul@213 159
        to_stream(out, make_calendar(calendar, method), encoding)
paul@213 160
        part = MIMEText(out.getvalue(), "calendar", encoding)
paul@213 161
        part.set_param("method", method)
paul@213 162
        return part
paul@213 163
paul@213 164
    finally:
paul@213 165
        out.close()
paul@213 166
paul@213 167
def to_stream(out, fragment, encoding="utf-8"):
paul@213 168
    iterwrite(out, encoding=encoding).append(fragment)
paul@213 169
paul@213 170
# Structure access functions.
paul@213 171
paul@213 172
def get_items(d, name, all=True):
paul@213 173
paul@213 174
    """
paul@213 175
    Get all items from 'd' for the given 'name', returning single items if
paul@213 176
    'all' is specified and set to a false value and if only one value is
paul@213 177
    present for the name. Return None if no items are found for the name or if
paul@213 178
    many items are found but 'all' is set to a false value.
paul@213 179
    """
paul@213 180
paul@213 181
    if d.has_key(name):
paul@213 182
        values = d[name]
paul@213 183
        if all:
paul@213 184
            return values
paul@213 185
        elif len(values) == 1:
paul@213 186
            return values[0]
paul@213 187
        else:
paul@213 188
            return None
paul@213 189
    else:
paul@213 190
        return None
paul@213 191
paul@213 192
def get_item(d, name):
paul@213 193
    return get_items(d, name, False)
paul@213 194
paul@213 195
def get_value_map(d, name):
paul@213 196
paul@213 197
    """
paul@213 198
    Return a dictionary for all items in 'd' having the given 'name'. The
paul@213 199
    dictionary will map values for the name to any attributes or qualifiers
paul@213 200
    that may have been present.
paul@213 201
    """
paul@213 202
paul@213 203
    items = get_items(d, name)
paul@213 204
    if items:
paul@213 205
        return dict(items)
paul@213 206
    else:
paul@213 207
        return {}
paul@213 208
paul@213 209
def get_values(d, name, all=True):
paul@213 210
    if d.has_key(name):
paul@213 211
        values = d[name]
paul@213 212
        if not all and len(values) == 1:
paul@213 213
            return values[0][0]
paul@213 214
        else:
paul@213 215
            return map(lambda x: x[0], values)
paul@213 216
    else:
paul@213 217
        return None
paul@213 218
paul@213 219
def get_value(d, name):
paul@213 220
    return get_values(d, name, False)
paul@213 221
paul@213 222
def get_utc_datetime(d, name):
paul@213 223
    value, attr = get_item(d, name)
paul@213 224
    dt = get_datetime(value, attr)
paul@213 225
    return to_utc_datetime(dt)
paul@213 226
paul@213 227
def get_addresses(values):
paul@213 228
    return [address for name, address in email.utils.getaddresses(values)]
paul@213 229
paul@213 230
def get_address(value):
paul@213 231
    return value.lower().startswith("mailto:") and value.lower()[7:] or value
paul@213 232
paul@213 233
def get_uri(value):
paul@213 234
    return value.lower().startswith("mailto:") and value.lower() or ":" in value and value or "mailto:%s" % value.lower()
paul@213 235
paul@213 236
def uri_dict(d):
paul@213 237
    return dict([(get_uri(key), value) for key, value in d.items()])
paul@213 238
paul@213 239
def uri_item(item):
paul@213 240
    return get_uri(item[0]), item[1]
paul@213 241
paul@213 242
def uri_items(items):
paul@213 243
    return [(get_uri(value), attr) for value, attr in items]
paul@213 244
paul@220 245
# Operations on structure data.
paul@220 246
paul@220 247
def is_new_object(old_sequence, new_sequence, old_dtstamp, new_dtstamp, partstat_set):
paul@220 248
paul@220 249
    """
paul@220 250
    Return for the given 'old_sequence' and 'new_sequence', 'old_dtstamp' and
paul@220 251
    'new_dtstamp', and the 'partstat_set' indication, whether the object
paul@220 252
    providing the new information is really newer than the object providing the
paul@220 253
    old information.
paul@220 254
    """
paul@220 255
paul@220 256
    have_sequence = old_sequence is not None and new_sequence is not None
paul@220 257
    is_same_sequence = have_sequence and int(new_sequence) == int(old_sequence)
paul@220 258
paul@220 259
    have_dtstamp = old_dtstamp and new_dtstamp
paul@220 260
    is_old_dtstamp = have_dtstamp and new_dtstamp < old_dtstamp or old_dtstamp and not new_dtstamp
paul@220 261
paul@220 262
    is_old_sequence = have_sequence and (
paul@220 263
        int(new_sequence) < int(old_sequence) or
paul@220 264
        is_same_sequence and is_old_dtstamp
paul@220 265
        )
paul@220 266
paul@220 267
    return is_same_sequence and partstat_set or not is_old_sequence
paul@220 268
paul@256 269
# NOTE: Need to expose the 100 day window for recurring events in the
paul@256 270
# NOTE: configuration.
paul@256 271
paul@256 272
def get_periods(obj, window_size=100):
paul@256 273
paul@256 274
    """
paul@256 275
    Return periods for the given object 'obj', confining materialised periods
paul@256 276
    to the given 'window_size' in days starting from the present moment.
paul@256 277
    """
paul@256 278
paul@256 279
    dtstart = obj.get_utc_datetime("DTSTART")
paul@256 280
    dtend = obj.get_utc_datetime("DTEND")
paul@256 281
paul@256 282
    # NOTE: Need also DURATION support.
paul@256 283
paul@256 284
    duration = dtend - dtstart
paul@256 285
paul@256 286
    # Recurrence rules create multiple instances to be checked.
paul@256 287
    # Conflicts may only be assessed within a period defined by policy
paul@256 288
    # for the agent, with instances outside that period being considered
paul@256 289
    # unchecked.
paul@256 290
paul@256 291
    window_end = datetime.now() + timedelta(window_size)
paul@256 292
paul@256 293
    # NOTE: Need also RDATE and EXDATE support.
paul@256 294
paul@256 295
    rrule = obj.get_value("RRULE")
paul@256 296
paul@256 297
    if rrule:
paul@256 298
        selector = get_rule(dtstart, rrule)
paul@256 299
        parameters = get_parameters(rrule)
paul@256 300
        periods = []
paul@256 301
        for start in selector.materialise(dtstart, window_end, parameters.get("COUNT"), parameters.get("BYSETPOS")):
paul@256 302
            start = datetime(*start, tzinfo=timezone("UTC"))
paul@256 303
            end = start + duration
paul@256 304
            periods.append((format_datetime(start), format_datetime(end)))
paul@256 305
    else:
paul@256 306
        periods = [(format_datetime(dtstart), format_datetime(dtend))]
paul@256 307
paul@256 308
    return periods
paul@256 309
paul@213 310
# vim: tabstop=4 expandtab shiftwidth=4