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dendrite/roomserver/api/output.go
Neil Alexander 965f068d1a
Handle state with input event as new events (#1415)
* SendEventWithState events as new

* Use cumulative state IDs for final event

* Error wrapping in calculateAndSetState

* Handle overwriting same event type and state key

* Hacky way to spot historical events

* Don't exclude from sync

* Don't generate output events when rewriting forward extremities

* Update output event check

* Historical output events

* Define output room event type

* Notify key changes on state

* Don't send our membership event twice

* Deduplicate state entries

* Tweaks

* Remove unnecessary nolint

* Fix current state upsert in sync API

* Send auth events as outliers, state events as rewrite

* Sync API don't consume state events

* Process events actually

* Improve outlier check

* Fix local room check

* Remove extra room check, it seems to break the whole damn world

* Fix federated join check

* Fix nil pointer exception

* Better comments on DeduplicateStateEntries

* Reflow forced federated joins

* Don't force federated join for possibly even local invites

* Comment SendEventWithState better

* Rewrite room state in sync API storage

* Add TODO

* Clean up all room data when receiving create event

* Don't generate output events for rewrites, but instead notify that state is rewritten on the final new event

* Rename to PurgeRoom

* Exclude backfilled messages from /sync

* Split out rewriting state from updating state from state res

Co-authored-by: Kegan Dougal <kegan@matrix.org>
2020-09-15 11:17:46 +01:00

224 lines
11 KiB
Go

// 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.
package api
import (
"github.com/matrix-org/gomatrixserverlib"
)
// An OutputType is a type of roomserver output.
type OutputType string
const (
// OutputTypeNewRoomEvent indicates that the event is an OutputNewRoomEvent
OutputTypeNewRoomEvent OutputType = "new_room_event"
// OutputTypeNewInviteEvent indicates that the event is an OutputNewInviteEvent
OutputTypeNewInviteEvent OutputType = "new_invite_event"
// OutputTypeRetireInviteEvent indicates that the event is an OutputRetireInviteEvent
OutputTypeRetireInviteEvent OutputType = "retire_invite_event"
// OutputTypeRedactedEvent indicates that the event is an OutputRedactedEvent
//
// This event is emitted when a redaction has been 'validated' (meaning both the redaction and the event to redact are known).
// Redaction validation happens when the roomserver receives either:
// - A redaction for which we have the event to redact.
// - Any event for which we have a redaction.
// When the roomserver receives an event, it will check against the redactions table to see if there is a matching redaction
// for the event. If there is, it will mark the redaction as validated and emit this event. In the common case of a redaction
// happening after receiving the event to redact, the roomserver will emit a OutputTypeNewRoomEvent of m.room.redaction
// immediately followed by a OutputTypeRedactedEvent. In the uncommon case of receiving the redaction BEFORE the event to redact,
// the roomserver will emit a OutputTypeNewRoomEvent of the event to redact immediately followed by a OutputTypeRedactedEvent.
//
// In order to honour redactions correctly, downstream components must ignore m.room.redaction events emitted via OutputTypeNewRoomEvent.
// When downstream components receive an OutputTypeRedactedEvent they must:
// - Pull out the event to redact from the database. They should have this because the redaction is validated.
// - Redact the event and set the corresponding `unsigned` fields to indicate it as redacted.
// - Replace the event in the database.
OutputTypeRedactedEvent OutputType = "redacted_event"
// OutputTypeNewPeek indicates that the kafka event is an OutputNewPeek
OutputTypeNewPeek OutputType = "new_peek"
)
// An OutputEvent is an entry in the roomserver output kafka log.
// Consumers should check the type field when consuming this event.
type OutputEvent struct {
// What sort of event this is.
Type OutputType `json:"type"`
// The content of event with type OutputTypeNewRoomEvent
NewRoomEvent *OutputNewRoomEvent `json:"new_room_event,omitempty"`
// The content of event with type OutputTypeNewInviteEvent
NewInviteEvent *OutputNewInviteEvent `json:"new_invite_event,omitempty"`
// The content of event with type OutputTypeRetireInviteEvent
RetireInviteEvent *OutputRetireInviteEvent `json:"retire_invite_event,omitempty"`
// The content of event with type OutputTypeRedactedEvent
RedactedEvent *OutputRedactedEvent `json:"redacted_event,omitempty"`
// The content of event with type OutputTypeNewPeek
NewPeek *OutputNewPeek `json:"new_peek,omitempty"`
}
// Type of the OutputNewRoomEvent.
type OutputRoomEventType int
const (
// The event is a timeline event and likely just happened.
OutputRoomTimeline OutputRoomEventType = iota
// The event is a state event and quite possibly happened in the past.
OutputRoomState
)
// An OutputNewRoomEvent is written when the roomserver receives a new event.
// It contains the full matrix room event and enough information for a
// consumer to construct the current state of the room and the state before the
// event.
//
// When we talk about state in a matrix room we are talking about the state
// after a list of events. The current state is the state after the latest
// event IDs in the room. The state before an event is the state after its
// prev_events.
type OutputNewRoomEvent struct {
// The Event.
Event gomatrixserverlib.HeaderedEvent `json:"event"`
// Does the event completely rewrite the room state? If so, then AddsStateEventIDs
// will contain the entire room state.
RewritesState bool `json:"rewrites_state"`
// The latest events in the room after this event.
// This can be used to set the prev events for new events in the room.
// This also can be used to get the full current state after this event.
LatestEventIDs []string `json:"latest_event_ids"`
// The state event IDs that were added to the state of the room by this event.
// Together with RemovesStateEventIDs this allows the receiver to keep an up to date
// view of the current state of the room.
AddsStateEventIDs []string `json:"adds_state_event_ids"`
// All extra newly added state events. This is only set if there are *extra* events
// other than `Event`. This can happen when forks get merged because state resolution
// may decide a bunch of state events on one branch are now valid, so they will be
// present in this list. This is useful when trying to maintain the current state of a room
// as to do so you need to include both these events and `Event`.
AddStateEvents []gomatrixserverlib.HeaderedEvent `json:"adds_state_events"`
// The state event IDs that were removed from the state of the room by this event.
RemovesStateEventIDs []string `json:"removes_state_event_ids"`
// The ID of the event that was output before this event.
// Or the empty string if this is the first event output for this room.
// This is used by consumers to check if they can safely update their
// current state using the delta supplied in AddsStateEventIDs and
// RemovesStateEventIDs.
//
// If the LastSentEventID doesn't match what they were expecting it to be
// they can use the LatestEventIDs to request the full current state.
LastSentEventID string `json:"last_sent_event_id"`
// The state event IDs that are part of the state at the event, but not
// part of the current state. Together with the StateBeforeRemovesEventIDs
// this can be used to construct the state before the event from the
// current state. The StateBeforeAddsEventIDs and StateBeforeRemovesEventIDs
// delta is applied after the AddsStateEventIDs and RemovesStateEventIDs.
//
// Consumers need to know the state at each event in order to determine
// which users and servers are allowed to see the event. This information
// is needed to apply the history visibility rules and to tell which
// servers we need to push events to over federation.
//
// The state is given as a delta against the current state because they are
// usually either the same state, or differ by just a couple of events.
StateBeforeAddsEventIDs []string `json:"state_before_adds_event_ids"`
// The state event IDs that are part of the current state, but not part
// of the state at the event.
StateBeforeRemovesEventIDs []string `json:"state_before_removes_event_ids"`
// The server name to use to push this event to other servers.
// Or empty if this event shouldn't be pushed to other servers.
//
// This is used by the federation sender component. We need to tell it what
// event it needs to send because it can't tell on its own. Normally if an
// event was created on this server then we are responsible for sending it.
// However there are a couple of exceptions. The first is that when the
// server joins a remote room through another matrix server, it is the job
// of the other matrix server to send the event over federation. The second
// is the reverse of the first, that is when a remote server joins a room
// that we are in over federation using our server it is our responsibility
// to send the join event to other matrix servers.
//
// We encode the server name that the event should be sent using here to
// future proof the API for virtual hosting.
SendAsServer string `json:"send_as_server"`
// The transaction ID of the send request if sent by a local user and one
// was specified
TransactionID *TransactionID `json:"transaction_id"`
}
// AddsState returns all added state events from this event.
//
// This function is needed because `AddStateEvents` will not include a copy of
// the original event to save space, so you cannot use that slice alone.
// Instead, use this function which will add the original event if it is present
// in `AddsStateEventIDs`.
func (ore *OutputNewRoomEvent) AddsState() []gomatrixserverlib.HeaderedEvent {
includeOutputEvent := false
for _, id := range ore.AddsStateEventIDs {
if id == ore.Event.EventID() {
includeOutputEvent = true
break
}
}
if !includeOutputEvent {
return ore.AddStateEvents
}
return append(ore.AddStateEvents, ore.Event)
}
// An OutputNewInviteEvent is written whenever an invite becomes active.
// Invite events can be received outside of an existing room so have to be
// tracked separately from the room events themselves.
type OutputNewInviteEvent struct {
// The room version of the invited room.
RoomVersion gomatrixserverlib.RoomVersion `json:"room_version"`
// The "m.room.member" invite event.
Event gomatrixserverlib.HeaderedEvent `json:"event"`
}
// An OutputRetireInviteEvent is written whenever an existing invite is no longer
// active. An invite stops being active if the user joins the room or if the
// invite is rejected by the user.
type OutputRetireInviteEvent struct {
// The ID of the "m.room.member" invite event.
EventID string
// The target user ID of the "m.room.member" invite event that was retired.
TargetUserID string
// Optional event ID of the event that replaced the invite.
// This can be empty if the invite was rejected locally and we were unable
// to reach the server that originally sent the invite.
RetiredByEventID string
// The "membership" of the user after retiring the invite. One of "join"
// "leave" or "ban".
Membership string
}
// An OutputRedactedEvent is written whenever a redaction has been /validated/.
// Downstream components MUST redact the given event ID if they have stored the
// event JSON. It is guaranteed that this event ID has been seen before.
type OutputRedactedEvent struct {
// The event ID that was redacted
RedactedEventID string
// The value of `unsigned.redacted_because` - the redaction event itself
RedactedBecause gomatrixserverlib.HeaderedEvent
}
// An OutputNewPeek is written whenever a user starts peeking into a room
// using a given device.
type OutputNewPeek struct {
RoomID string
UserID string
DeviceID string
}