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
|
// Copyright 2020 The Matrix.org Foundation C.I.C.
//
// 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.
package eventutil
import (
"context"
"errors"
"fmt"
"time"
"github.com/matrix-org/dendrite/internal/config"
"github.com/matrix-org/dendrite/roomserver/api"
"github.com/matrix-org/gomatrixserverlib"
)
// ErrRoomNoExists is returned when trying to lookup the state of a room that
// doesn't exist
var ErrRoomNoExists = errors.New("Room does not exist")
// QueryAndBuildEvent builds a Matrix event using the event builder and roomserver query
// API client provided. If also fills roomserver query API response (if provided)
// in case the function calling FillBuilder needs to use it.
// Returns ErrRoomNoExists if the state of the room could not be retrieved because
// the room doesn't exist
// Returns an error if something else went wrong
func QueryAndBuildEvent(
ctx context.Context,
builder *gomatrixserverlib.EventBuilder, cfg *config.Global, evTime time.Time,
rsAPI api.RoomserverInternalAPI, queryRes *api.QueryLatestEventsAndStateResponse,
) (*gomatrixserverlib.HeaderedEvent, error) {
if queryRes == nil {
queryRes = &api.QueryLatestEventsAndStateResponse{}
}
eventsNeeded, err := queryRequiredEventsForBuilder(ctx, builder, rsAPI, queryRes)
if err != nil {
// This can pass through a ErrRoomNoExists to the caller
return nil, err
}
return BuildEvent(ctx, builder, cfg, evTime, eventsNeeded, queryRes)
}
// BuildEvent builds a Matrix event from the builder and QueryLatestEventsAndStateResponse
// provided.
func BuildEvent(
ctx context.Context,
builder *gomatrixserverlib.EventBuilder, cfg *config.Global, evTime time.Time,
eventsNeeded *gomatrixserverlib.StateNeeded, queryRes *api.QueryLatestEventsAndStateResponse,
) (*gomatrixserverlib.HeaderedEvent, error) {
err := addPrevEventsToEvent(builder, eventsNeeded, queryRes)
if err != nil {
return nil, err
}
event, err := builder.Build(
evTime, cfg.ServerName, cfg.KeyID,
cfg.PrivateKey, queryRes.RoomVersion,
)
if err != nil {
return nil, err
}
return event.Headered(queryRes.RoomVersion), nil
}
// queryRequiredEventsForBuilder queries the roomserver for auth/prev events needed for this builder.
func queryRequiredEventsForBuilder(
ctx context.Context,
builder *gomatrixserverlib.EventBuilder,
rsAPI api.RoomserverInternalAPI, queryRes *api.QueryLatestEventsAndStateResponse,
) (*gomatrixserverlib.StateNeeded, error) {
eventsNeeded, err := gomatrixserverlib.StateNeededForEventBuilder(builder)
if err != nil {
return nil, fmt.Errorf("gomatrixserverlib.StateNeededForEventBuilder: %w", err)
}
if len(eventsNeeded.Tuples()) == 0 {
return nil, errors.New("expecting state tuples for event builder, got none")
}
// Ask the roomserver for information about this room
queryReq := api.QueryLatestEventsAndStateRequest{
RoomID: builder.RoomID,
StateToFetch: eventsNeeded.Tuples(),
}
return &eventsNeeded, rsAPI.QueryLatestEventsAndState(ctx, &queryReq, queryRes)
}
// addPrevEventsToEvent fills out the prev_events and auth_events fields in builder
func addPrevEventsToEvent(
builder *gomatrixserverlib.EventBuilder,
eventsNeeded *gomatrixserverlib.StateNeeded,
queryRes *api.QueryLatestEventsAndStateResponse,
) error {
if !queryRes.RoomExists {
return ErrRoomNoExists
}
eventFormat, err := queryRes.RoomVersion.EventFormat()
if err != nil {
return fmt.Errorf("queryRes.RoomVersion.EventFormat: %w", err)
}
builder.Depth = queryRes.Depth
authEvents := gomatrixserverlib.NewAuthEvents(nil)
for i := range queryRes.StateEvents {
err = authEvents.AddEvent(queryRes.StateEvents[i].Event)
if err != nil {
return fmt.Errorf("authEvents.AddEvent: %w", err)
}
}
refs, err := eventsNeeded.AuthEventReferences(&authEvents)
if err != nil {
return fmt.Errorf("eventsNeeded.AuthEventReferences: %w", err)
}
truncAuth, truncPrev := truncateAuthAndPrevEvents(refs, queryRes.LatestEvents)
switch eventFormat {
case gomatrixserverlib.EventFormatV1:
builder.AuthEvents = truncAuth
builder.PrevEvents = truncPrev
case gomatrixserverlib.EventFormatV2:
v2AuthRefs, v2PrevRefs := []string{}, []string{}
for _, ref := range truncAuth {
v2AuthRefs = append(v2AuthRefs, ref.EventID)
}
for _, ref := range truncPrev {
v2PrevRefs = append(v2PrevRefs, ref.EventID)
}
builder.AuthEvents = v2AuthRefs
builder.PrevEvents = v2PrevRefs
}
return nil
}
// truncateAuthAndPrevEvents limits the number of events we add into
// an event as prev_events or auth_events.
// NOTSPEC: The limits here feel a bit arbitrary but they are currently
// here because of https://github.com/matrix-org/matrix-doc/issues/2307
// and because Synapse will just drop events that don't comply.
func truncateAuthAndPrevEvents(auth, prev []gomatrixserverlib.EventReference) (
truncAuth, truncPrev []gomatrixserverlib.EventReference,
) {
truncAuth, truncPrev = auth, prev
if len(truncAuth) > 10 {
truncAuth = truncAuth[:10]
}
if len(truncPrev) > 20 {
truncPrev = truncPrev[:20]
}
return
}
// RedactEvent redacts the given event and sets the unsigned field appropriately. This should be used by
// downstream components to the roomserver when an OutputTypeRedactedEvent occurs.
func RedactEvent(redactionEvent, redactedEvent *gomatrixserverlib.Event) (*gomatrixserverlib.Event, error) {
// sanity check
if redactionEvent.Type() != gomatrixserverlib.MRoomRedaction {
return nil, fmt.Errorf("RedactEvent: redactionEvent isn't a redaction event, is '%s'", redactionEvent.Type())
}
r := redactedEvent.Redact()
err := r.SetUnsignedField("redacted_because", redactionEvent)
if err != nil {
return nil, err
}
// NOTSPEC: sytest relies on this unspecced field existing :(
err = r.SetUnsignedField("redacted_by", redactionEvent.EventID())
if err != nil {
return nil, err
}
return r, nil
}
|
