summary refs log tree commit diff
path: root/synapse/storage/user_directory.py
blob: dfdcbb31810ab01f765740fe5343a90dd2c4af1c (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
# -*- coding: utf-8 -*-
# Copyright 2017 Vector Creations Ltd
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

from twisted.internet import defer

from ._base import SQLBaseStore

from synapse.util.caches.descriptors import cached, cachedInlineCallbacks
from synapse.api.constants import EventTypes, JoinRules
from synapse.storage.engines import PostgresEngine, Sqlite3Engine
from synapse.types import get_domain_from_id, get_localpart_from_id

import re
import logging

logger = logging.getLogger(__name__)


class UserDirectoryStore(SQLBaseStore):
    @cachedInlineCallbacks(cache_context=True)
    def is_room_world_readable_or_publicly_joinable(self, room_id, cache_context):
        """Check if the room is either world_readable or publically joinable
        """
        current_state_ids = yield self.get_current_state_ids(
            room_id, on_invalidate=cache_context.invalidate
        )

        join_rules_id = current_state_ids.get((EventTypes.JoinRules, ""))
        if join_rules_id:
            join_rule_ev = yield self.get_event(join_rules_id, allow_none=True)
            if join_rule_ev:
                if join_rule_ev.content.get("join_rule") == JoinRules.PUBLIC:
                    defer.returnValue(True)

        hist_vis_id = current_state_ids.get((EventTypes.RoomHistoryVisibility, ""))
        if hist_vis_id:
            hist_vis_ev = yield self.get_event(hist_vis_id, allow_none=True)
            if hist_vis_ev:
                if hist_vis_ev.content.get("history_visibility") == "world_readable":
                    defer.returnValue(True)

        defer.returnValue(False)

    @defer.inlineCallbacks
    def add_users_to_public_room(self, room_id, user_ids):
        """Add user to the list of users in public rooms

        Args:
            room_id (str): A room_id that all users are in that is world_readable
                or publically joinable
            user_ids (list(str)): Users to add
        """
        yield self._simple_insert_many(
            table="users_in_public_rooms",
            values=[
                {
                    "user_id": user_id,
                    "room_id": room_id,
                }
                for user_id in user_ids
            ],
            desc="add_users_to_public_room"
        )
        for user_id in user_ids:
            self.get_user_in_public_room.invalidate((user_id,))

    def add_profiles_to_user_dir(self, room_id, users_with_profile):
        """Add profiles to the user directory

        Args:
            room_id (str): A room_id that all users are joined to
            users_with_profile (dict): Users to add to directory in the form of
                mapping of user_id -> ProfileInfo
        """
        if isinstance(self.database_engine, PostgresEngine):
            # We weight the loclpart most highly, then display name and finally
            # server name
            sql = """
                INSERT INTO user_directory_search(user_id, vector)
                VALUES (?,
                    setweight(to_tsvector('english', ?), 'A')
                    || setweight(to_tsvector('english', ?), 'D')
                    || setweight(to_tsvector('english', COALESCE(?, '')), 'B')
                )
            """
            args = (
                (
                    user_id, get_localpart_from_id(user_id), get_domain_from_id(user_id),
                    profile.display_name,
                )
                for user_id, profile in users_with_profile.iteritems()
            )
        elif isinstance(self.database_engine, Sqlite3Engine):
            sql = """
                INSERT INTO user_directory_search(user_id, value)
                VALUES (?,?)
            """
            args = (
                (
                    user_id,
                    "%s %s" % (user_id, p.display_name,) if p.display_name else user_id
                )
                for user_id, p in users_with_profile.iteritems()
            )
        else:
            # This should be unreachable.
            raise Exception("Unrecognized database engine")

        def _add_profiles_to_user_dir_txn(txn):
            txn.executemany(sql, args)
            self._simple_insert_many_txn(
                txn,
                table="user_directory",
                values=[
                    {
                        "user_id": user_id,
                        "room_id": room_id,
                        "display_name": profile.display_name,
                        "avatar_url": profile.avatar_url,
                    }
                    for user_id, profile in users_with_profile.iteritems()
                ]
            )
            for user_id in users_with_profile:
                txn.call_after(
                    self.get_user_in_directory.invalidate, (user_id,)
                )

        return self.runInteraction(
            "add_profiles_to_user_dir", _add_profiles_to_user_dir_txn
        )

    @defer.inlineCallbacks
    def update_user_in_user_dir(self, user_id, room_id):
        yield self._simple_update_one(
            table="user_directory",
            keyvalues={"user_id": user_id},
            updatevalues={"room_id": room_id},
            desc="update_user_in_user_dir",
        )
        self.get_user_in_directory.invalidate((user_id,))

    def update_profile_in_user_dir(self, user_id, display_name, avatar_url, room_id):
        def _update_profile_in_user_dir_txn(txn):
            new_entry = self._simple_upsert_txn(
                txn,
                table="user_directory",
                keyvalues={"user_id": user_id},
                insertion_values={"room_id": room_id},
                values={"display_name": display_name, "avatar_url": avatar_url},
                lock=False,  # We're only inserter
            )

            if isinstance(self.database_engine, PostgresEngine):
                # We weight the localpart most highly, then display name and finally
                # server name
                if new_entry:
                    sql = """
                        INSERT INTO user_directory_search(user_id, vector)
                        VALUES (?,
                            setweight(to_tsvector('english', ?), 'A')
                            || setweight(to_tsvector('english', ?), 'D')
                            || setweight(to_tsvector('english', COALESCE(?, '')), 'B')
                        )
                    """
                    txn.execute(
                        sql,
                        (
                            user_id, get_localpart_from_id(user_id),
                            get_domain_from_id(user_id), display_name,
                        )
                    )
                else:
                    sql = """
                        UPDATE user_directory_search
                        SET vector = setweight(to_tsvector('english', ?), 'A')
                            || setweight(to_tsvector('english', ?), 'D')
                            || setweight(to_tsvector('english', COALESCE(?, '')), 'B')
                        WHERE user_id = ?
                    """
                    txn.execute(
                        sql,
                        (
                            get_localpart_from_id(user_id), get_domain_from_id(user_id),
                            display_name, user_id,
                        )
                    )
            elif isinstance(self.database_engine, Sqlite3Engine):
                value = "%s %s" % (user_id, display_name,) if display_name else user_id
                self._simple_upsert_txn(
                    txn,
                    table="user_directory_search",
                    keyvalues={"user_id": user_id},
                    values={"value": value},
                    lock=False,  # We're only inserter
                )
            else:
                # This should be unreachable.
                raise Exception("Unrecognized database engine")

            txn.call_after(self.get_user_in_directory.invalidate, (user_id,))

        return self.runInteraction(
            "update_profile_in_user_dir", _update_profile_in_user_dir_txn
        )

    @defer.inlineCallbacks
    def update_user_in_public_user_list(self, user_id, room_id):
        yield self._simple_update_one(
            table="users_in_public_rooms",
            keyvalues={"user_id": user_id},
            updatevalues={"room_id": room_id},
            desc="update_user_in_public_user_list",
        )
        self.get_user_in_public_room.invalidate((user_id,))

    def remove_from_user_dir(self, user_id):
        def _remove_from_user_dir_txn(txn):
            self._simple_delete_txn(
                txn,
                table="user_directory",
                keyvalues={"user_id": user_id},
            )
            self._simple_delete_txn(
                txn,
                table="user_directory_search",
                keyvalues={"user_id": user_id},
            )
            self._simple_delete_txn(
                txn,
                table="users_in_public_rooms",
                keyvalues={"user_id": user_id},
            )
            txn.call_after(
                self.get_user_in_directory.invalidate, (user_id,)
            )
            txn.call_after(
                self.get_user_in_public_room.invalidate, (user_id,)
            )
        return self.runInteraction(
            "remove_from_user_dir", _remove_from_user_dir_txn,
        )

    @defer.inlineCallbacks
    def remove_from_user_in_public_room(self, user_id):
        yield self._simple_delete(
            table="users_in_public_rooms",
            keyvalues={"user_id": user_id},
            desc="remove_from_user_in_public_room",
        )
        self.get_user_in_public_room.invalidate((user_id,))

    def get_users_in_public_due_to_room(self, room_id):
        """Get all user_ids that are in the room directory becuase they're
        in the given room_id
        """
        return self._simple_select_onecol(
            table="users_in_public_rooms",
            keyvalues={"room_id": room_id},
            retcol="user_id",
            desc="get_users_in_public_due_to_room",
        )

    @defer.inlineCallbacks
    def get_users_in_dir_due_to_room(self, room_id):
        """Get all user_ids that are in the room directory becuase they're
        in the given room_id
        """
        user_ids_dir = yield self._simple_select_onecol(
            table="user_directory",
            keyvalues={"room_id": room_id},
            retcol="user_id",
            desc="get_users_in_dir_due_to_room",
        )

        user_ids_pub = yield self._simple_select_onecol(
            table="users_in_public_rooms",
            keyvalues={"room_id": room_id},
            retcol="user_id",
            desc="get_users_in_dir_due_to_room",
        )

        user_ids_share = yield self._simple_select_onecol(
            table="users_who_share_rooms",
            keyvalues={"room_id": room_id},
            retcol="user_id",
            desc="get_users_in_dir_due_to_room",
        )

        user_ids = set(user_ids_dir)
        user_ids.update(user_ids_pub)
        user_ids.update(user_ids_share)

        defer.returnValue(user_ids)

    @defer.inlineCallbacks
    def get_all_rooms(self):
        """Get all room_ids we've ever known about, in ascending order of "size"
        """
        sql = """
            SELECT room_id FROM current_state_events
            GROUP BY room_id
            ORDER BY count(*) ASC
        """
        rows = yield self._execute("get_all_rooms", None, sql)
        defer.returnValue([room_id for room_id, in rows])

    @defer.inlineCallbacks
    def get_all_local_users(self):
        """Get all local users
        """
        sql = """
            SELECT name FROM users
        """
        rows = yield self._execute("get_all_local_users", None, sql)
        defer.returnValue([name for name, in rows])

    def add_users_who_share_room(self, room_id, share_private, user_id_tuples):
        """Insert entries into the users_who_share_rooms table. The first
        user should be a local user.

        Args:
            room_id (str)
            share_private (bool): Is the room private
            user_id_tuples([(str, str)]): iterable of 2-tuple of user IDs.
        """
        def _add_users_who_share_room_txn(txn):
            self._simple_insert_many_txn(
                txn,
                table="users_who_share_rooms",
                values=[
                    {
                        "user_id": user_id,
                        "other_user_id": other_user_id,
                        "room_id": room_id,
                        "share_private": share_private,
                    }
                    for user_id, other_user_id in user_id_tuples
                ],
            )
            for user_id, other_user_id in user_id_tuples:
                txn.call_after(
                    self.get_users_who_share_room_from_dir.invalidate,
                    (user_id,),
                )
                txn.call_after(
                    self.get_if_users_share_a_room.invalidate,
                    (user_id, other_user_id),
                )
        return self.runInteraction(
            "add_users_who_share_room", _add_users_who_share_room_txn
        )

    def update_users_who_share_room(self, room_id, share_private, user_id_sets):
        """Updates entries in the users_who_share_rooms table. The first
        user should be a local user.

        Args:
            room_id (str)
            share_private (bool): Is the room private
            user_id_tuples([(str, str)]): iterable of 2-tuple of user IDs.
        """
        def _update_users_who_share_room_txn(txn):
            sql = """
                UPDATE users_who_share_rooms
                SET room_id = ?, share_private = ?
                WHERE user_id = ? AND other_user_id = ?
            """
            txn.executemany(
                sql,
                (
                    (room_id, share_private, uid, oid)
                    for uid, oid in user_id_sets
                )
            )
            for user_id, other_user_id in user_id_sets:
                txn.call_after(
                    self.get_users_who_share_room_from_dir.invalidate,
                    (user_id,),
                )
                txn.call_after(
                    self.get_if_users_share_a_room.invalidate,
                    (user_id, other_user_id),
                )
        return self.runInteraction(
            "update_users_who_share_room", _update_users_who_share_room_txn
        )

    def remove_user_who_share_room(self, user_id, other_user_id):
        """Deletes entries in the users_who_share_rooms table. The first
        user should be a local user.

        Args:
            room_id (str)
            share_private (bool): Is the room private
            user_id_tuples([(str, str)]): iterable of 2-tuple of user IDs.
        """
        def _remove_user_who_share_room_txn(txn):
            self._simple_delete_txn(
                txn,
                table="users_who_share_rooms",
                keyvalues={
                    "user_id": user_id,
                    "other_user_id": other_user_id,
                },
            )
            txn.call_after(
                self.get_users_who_share_room_from_dir.invalidate,
                (user_id,),
            )
            txn.call_after(
                self.get_if_users_share_a_room.invalidate,
                (user_id, other_user_id),
            )

        return self.runInteraction(
            "remove_user_who_share_room", _remove_user_who_share_room_txn
        )

    @cached(max_entries=500000)
    def get_if_users_share_a_room(self, user_id, other_user_id):
        """Gets if users share a room.

        Args:
            user_id (str): Must be a local user_id
            other_user_id (str)

        Returns:
            bool|None: None if they don't share a room, otherwise whether they
            share a private room or not.
        """
        return self._simple_select_one_onecol(
            table="users_who_share_rooms",
            keyvalues={
                "user_id": user_id,
                "other_user_id": other_user_id,
            },
            retcol="share_private",
            allow_none=True,
            desc="get_if_users_share_a_room",
        )

    @cachedInlineCallbacks(max_entries=500000, iterable=True)
    def get_users_who_share_room_from_dir(self, user_id):
        """Returns the set of users who share a room with `user_id`

        Args:
            user_id(str): Must be a local user

        Returns:
            dict: user_id -> share_private mapping
        """
        rows = yield self._simple_select_list(
            table="users_who_share_rooms",
            keyvalues={
                "user_id": user_id,
            },
            retcols=("other_user_id", "share_private",),
            desc="get_users_who_share_room_with_user",
        )

        defer.returnValue({
            row["other_user_id"]: row["share_private"]
            for row in rows
        })

    def get_users_in_share_dir_with_room_id(self, user_id, room_id):
        """Get all user tuples that are in the users_who_share_rooms due to the
        given room_id.

        Returns:
            [(user_id, other_user_id)]: where one of the two will match the given
            user_id.
        """
        sql = """
            SELECT user_id, other_user_id FROM users_who_share_rooms
            WHERE room_id = ? AND (user_id = ? OR other_user_id = ?)
        """
        return self._execute(
            "get_users_in_share_dir_with_room_id", None, sql, room_id, user_id, user_id
        )

    @defer.inlineCallbacks
    def get_rooms_in_common_for_users(self, user_id, other_user_id):
        """Given two user_ids find out the list of rooms they share.
        """
        sql = """
            SELECT room_id FROM (
                SELECT c.room_id FROM current_state_events AS c
                INNER JOIN room_memberships USING (event_id)
                WHERE type = 'm.room.member'
                    AND membership = 'join'
                    AND state_key = ?
            ) AS f1 INNER JOIN (
                SELECT c.room_id FROM current_state_events AS c
                INNER JOIN room_memberships USING (event_id)
                WHERE type = 'm.room.member'
                    AND membership = 'join'
                    AND state_key = ?
            ) f2 USING (room_id)
        """

        rows = yield self._execute(
            "get_rooms_in_common_for_users", None, sql, user_id, other_user_id
        )

        defer.returnValue([room_id for room_id, in rows])

    def delete_all_from_user_dir(self):
        """Delete the entire user directory
        """
        def _delete_all_from_user_dir_txn(txn):
            txn.execute("DELETE FROM user_directory")
            txn.execute("DELETE FROM user_directory_search")
            txn.execute("DELETE FROM users_in_public_rooms")
            txn.execute("DELETE FROM users_who_share_rooms")
            txn.call_after(self.get_user_in_directory.invalidate_all)
            txn.call_after(self.get_user_in_public_room.invalidate_all)
            txn.call_after(self.get_users_who_share_room_from_dir.invalidate_all)
            txn.call_after(self.get_if_users_share_a_room.invalidate_all)
        return self.runInteraction(
            "delete_all_from_user_dir", _delete_all_from_user_dir_txn
        )

    @cached()
    def get_user_in_directory(self, user_id):
        return self._simple_select_one(
            table="user_directory",
            keyvalues={"user_id": user_id},
            retcols=("room_id", "display_name", "avatar_url",),
            allow_none=True,
            desc="get_user_in_directory",
        )

    @cached()
    def get_user_in_public_room(self, user_id):
        return self._simple_select_one(
            table="users_in_public_rooms",
            keyvalues={"user_id": user_id},
            retcols=("room_id",),
            allow_none=True,
            desc="get_user_in_public_room",
        )

    def get_user_directory_stream_pos(self):
        return self._simple_select_one_onecol(
            table="user_directory_stream_pos",
            keyvalues={},
            retcol="stream_id",
            desc="get_user_directory_stream_pos",
        )

    def update_user_directory_stream_pos(self, stream_id):
        return self._simple_update_one(
            table="user_directory_stream_pos",
            keyvalues={},
            updatevalues={"stream_id": stream_id},
            desc="update_user_directory_stream_pos",
        )

    def get_current_state_deltas(self, prev_stream_id):
        prev_stream_id = int(prev_stream_id)
        if not self._curr_state_delta_stream_cache.has_any_entity_changed(prev_stream_id):
            return []

        def get_current_state_deltas_txn(txn):
            # First we calculate the max stream id that will give us less than
            # N results.
            # We arbitarily limit to 100 stream_id entries to ensure we don't
            # select toooo many.
            sql = """
                SELECT stream_id, count(*)
                FROM current_state_delta_stream
                WHERE stream_id > ?
                GROUP BY stream_id
                ORDER BY stream_id ASC
                LIMIT 100
            """
            txn.execute(sql, (prev_stream_id,))

            total = 0
            max_stream_id = prev_stream_id
            for max_stream_id, count in txn:
                total += count
                if total > 100:
                    # We arbitarily limit to 100 entries to ensure we don't
                    # select toooo many.
                    break

            # Now actually get the deltas
            sql = """
                SELECT stream_id, room_id, type, state_key, event_id, prev_event_id
                FROM current_state_delta_stream
                WHERE ? < stream_id AND stream_id <= ?
                ORDER BY stream_id ASC
            """
            txn.execute(sql, (prev_stream_id, max_stream_id,))
            return self.cursor_to_dict(txn)

        return self.runInteraction(
            "get_current_state_deltas", get_current_state_deltas_txn
        )

    def get_max_stream_id_in_current_state_deltas(self):
        return self._simple_select_one_onecol(
            table="current_state_delta_stream",
            keyvalues={},
            retcol="COALESCE(MAX(stream_id), -1)",
            desc="get_max_stream_id_in_current_state_deltas",
        )

    @defer.inlineCallbacks
    def search_user_dir(self, user_id, search_term, limit):
        """Searches for users in directory

        Returns:
            dict of the form::

                {
                    "limited": <bool>,  # whether there were more results or not
                    "results": [  # Ordered by best match first
                        {
                            "user_id": <user_id>,
                            "display_name": <display_name>,
                            "avatar_url": <avatar_url>
                        }
                    ]
                }
        """

        if self.hs.config.user_directory_search_all_users:
            # make s.user_id null to keep the ordering algorithm happy
            join_clause = """
                CROSS JOIN (SELECT NULL as user_id) AS s
            """
            join_args = ()
            where_clause = "1=1"
        else:
            join_clause = """
                LEFT JOIN users_in_public_rooms AS p USING (user_id)
                LEFT JOIN (
                    SELECT other_user_id AS user_id FROM users_who_share_rooms
                    WHERE user_id = ? AND share_private
                ) AS s USING (user_id)
            """
            join_args = (user_id,)
            where_clause = "(s.user_id IS NOT NULL OR p.user_id IS NOT NULL)"

        if isinstance(self.database_engine, PostgresEngine):
            full_query, exact_query, prefix_query = _parse_query_postgres(search_term)

            # We order by rank and then if they have profile info
            # The ranking algorithm is hand tweaked for "best" results. Broadly
            # the idea is we give a higher weight to exact matches.
            # The array of numbers are the weights for the various part of the
            # search: (domain, _, display name, localpart)
            sql = """
                SELECT d.user_id, display_name, avatar_url
                FROM user_directory_search
                INNER JOIN user_directory AS d USING (user_id)
                %s
                WHERE
                    %s
                    AND vector @@ to_tsquery('english', ?)
                ORDER BY
                    (CASE WHEN s.user_id IS NOT NULL THEN 4.0 ELSE 1.0 END)
                    * (CASE WHEN display_name IS NOT NULL THEN 1.2 ELSE 1.0 END)
                    * (CASE WHEN avatar_url IS NOT NULL THEN 1.2 ELSE 1.0 END)
                    * (
                        3 * ts_rank_cd(
                            '{0.1, 0.1, 0.9, 1.0}',
                            vector,
                            to_tsquery('english', ?),
                            8
                        )
                        + ts_rank_cd(
                            '{0.1, 0.1, 0.9, 1.0}',
                            vector,
                            to_tsquery('english', ?),
                            8
                        )
                    )
                    DESC,
                    display_name IS NULL,
                    avatar_url IS NULL
                LIMIT ?
            """ % (join_clause, where_clause)
            args = join_args + (full_query, exact_query, prefix_query, limit + 1,)
        elif isinstance(self.database_engine, Sqlite3Engine):
            search_query = _parse_query_sqlite(search_term)

            sql = """
                SELECT d.user_id, display_name, avatar_url
                FROM user_directory_search
                INNER JOIN user_directory AS d USING (user_id)
                %s
                WHERE
                    %s
                    AND value MATCH ?
                ORDER BY
                    rank(matchinfo(user_directory_search)) DESC,
                    display_name IS NULL,
                    avatar_url IS NULL
                LIMIT ?
            """ % (join_clause, where_clause)
            args = join_args + (search_query, limit + 1)
        else:
            # This should be unreachable.
            raise Exception("Unrecognized database engine")

        results = yield self._execute(
            "search_user_dir", self.cursor_to_dict, sql, *args
        )

        limited = len(results) > limit

        defer.returnValue({
            "limited": limited,
            "results": results,
        })


def _parse_query_sqlite(search_term):
    """Takes a plain unicode string from the user and converts it into a form
    that can be passed to database.
    We use this so that we can add prefix matching, which isn't something
    that is supported by default.

    We specifically add both a prefix and non prefix matching term so that
    exact matches get ranked higher.
    """

    # Pull out the individual words, discarding any non-word characters.
    results = re.findall(r"([\w\-]+)", search_term, re.UNICODE)
    return " & ".join("(%s* OR %s)" % (result, result,) for result in results)


def _parse_query_postgres(search_term):
    """Takes a plain unicode string from the user and converts it into a form
    that can be passed to database.
    We use this so that we can add prefix matching, which isn't something
    that is supported by default.
    """

    # Pull out the individual words, discarding any non-word characters.
    results = re.findall(r"([\w\-]+)", search_term, re.UNICODE)

    both = " & ".join("(%s:* | %s)" % (result, result,) for result in results)
    exact = " & ".join("%s" % (result,) for result in results)
    prefix = " & ".join("%s:*" % (result,) for result in results)

    return both, exact, prefix