matrix-prometheus/vendor/maunium.net/go/mautrix/sync.go

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2023-01-13 21:24:39 +01:00
// Copyright (c) 2020 Tulir Asokan
//
// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this
// file, You can obtain one at http://mozilla.org/MPL/2.0/.
package mautrix
import (
"fmt"
"runtime/debug"
"time"
"maunium.net/go/mautrix/event"
"maunium.net/go/mautrix/id"
)
// EventSource represents the part of the sync response that an event came from.
type EventSource int
const (
EventSourcePresence EventSource = 1 << iota
EventSourceJoin
EventSourceInvite
EventSourceLeave
EventSourceAccountData
EventSourceTimeline
EventSourceState
EventSourceEphemeral
EventSourceToDevice
)
func (es EventSource) String() string {
switch {
case es == EventSourcePresence:
return "presence"
case es == EventSourceAccountData:
return "user account data"
case es == EventSourceToDevice:
return "to-device"
case es&EventSourceJoin != 0:
es -= EventSourceJoin
switch es {
case EventSourceState:
return "joined state"
case EventSourceTimeline:
return "joined timeline"
case EventSourceEphemeral:
return "room ephemeral (joined)"
case EventSourceAccountData:
return "room account data (joined)"
}
case es&EventSourceInvite != 0:
es -= EventSourceInvite
switch es {
case EventSourceState:
return "invited state"
}
case es&EventSourceLeave != 0:
es -= EventSourceLeave
switch es {
case EventSourceState:
return "left state"
case EventSourceTimeline:
return "left timeline"
}
}
return fmt.Sprintf("unknown (%d)", es)
}
// EventHandler handles a single event from a sync response.
type EventHandler func(source EventSource, evt *event.Event)
// SyncHandler handles a whole sync response. If the return value is false, handling will be stopped completely.
type SyncHandler func(resp *RespSync, since string) bool
// Syncer is an interface that must be satisfied in order to do /sync requests on a client.
type Syncer interface {
// Process the /sync response. The since parameter is the since= value that was used to produce the response.
// This is useful for detecting the very first sync (since=""). If an error is return, Syncing will be stopped
// permanently.
ProcessResponse(resp *RespSync, since string) error
// OnFailedSync returns either the time to wait before retrying or an error to stop syncing permanently.
OnFailedSync(res *RespSync, err error) (time.Duration, error)
// GetFilterJSON for the given user ID. NOT the filter ID.
GetFilterJSON(userID id.UserID) *Filter
}
type ExtensibleSyncer interface {
OnSync(callback SyncHandler)
OnEvent(callback EventHandler)
OnEventType(eventType event.Type, callback EventHandler)
}
// DefaultSyncer is the default syncing implementation. You can either write your own syncer, or selectively
// replace parts of this default syncer (e.g. the ProcessResponse method). The default syncer uses the observer
// pattern to notify callers about incoming events. See DefaultSyncer.OnEventType for more information.
type DefaultSyncer struct {
// syncListeners want the whole sync response, e.g. the crypto machine
syncListeners []SyncHandler
// globalListeners want all events
globalListeners []EventHandler
// listeners want a specific event type
listeners map[event.Type][]EventHandler
// ParseEventContent determines whether or not event content should be parsed before passing to handlers.
ParseEventContent bool
// ParseErrorHandler is called when event.Content.ParseRaw returns an error.
// If it returns false, the event will not be forwarded to listeners.
ParseErrorHandler func(evt *event.Event, err error) bool
}
var _ Syncer = (*DefaultSyncer)(nil)
var _ ExtensibleSyncer = (*DefaultSyncer)(nil)
// NewDefaultSyncer returns an instantiated DefaultSyncer
func NewDefaultSyncer() *DefaultSyncer {
return &DefaultSyncer{
listeners: make(map[event.Type][]EventHandler),
syncListeners: []SyncHandler{},
globalListeners: []EventHandler{},
ParseEventContent: true,
ParseErrorHandler: func(evt *event.Event, err error) bool {
return false
},
}
}
// ProcessResponse processes the /sync response in a way suitable for bots. "Suitable for bots" means a stream of
// unrepeating events. Returns a fatal error if a listener panics.
func (s *DefaultSyncer) ProcessResponse(res *RespSync, since string) (err error) {
defer func() {
if r := recover(); r != nil {
err = fmt.Errorf("ProcessResponse panicked! since=%s panic=%s\n%s", since, r, debug.Stack())
}
}()
for _, listener := range s.syncListeners {
if !listener(res, since) {
return
}
}
s.processSyncEvents("", res.Presence.Events, EventSourcePresence)
s.processSyncEvents("", res.AccountData.Events, EventSourceAccountData)
for roomID, roomData := range res.Rooms.Join {
s.processSyncEvents(roomID, roomData.State.Events, EventSourceJoin|EventSourceState)
s.processSyncEvents(roomID, roomData.Timeline.Events, EventSourceJoin|EventSourceTimeline)
s.processSyncEvents(roomID, roomData.Ephemeral.Events, EventSourceJoin|EventSourceEphemeral)
s.processSyncEvents(roomID, roomData.AccountData.Events, EventSourceJoin|EventSourceAccountData)
}
for roomID, roomData := range res.Rooms.Invite {
s.processSyncEvents(roomID, roomData.State.Events, EventSourceInvite|EventSourceState)
}
for roomID, roomData := range res.Rooms.Leave {
s.processSyncEvents(roomID, roomData.State.Events, EventSourceLeave|EventSourceState)
s.processSyncEvents(roomID, roomData.Timeline.Events, EventSourceLeave|EventSourceTimeline)
}
return
}
func (s *DefaultSyncer) processSyncEvents(roomID id.RoomID, events []*event.Event, source EventSource) {
for _, evt := range events {
s.processSyncEvent(roomID, evt, source)
}
}
func (s *DefaultSyncer) processSyncEvent(roomID id.RoomID, evt *event.Event, source EventSource) {
evt.RoomID = roomID
// Ensure the type class is correct. It's safe to mutate the class since the event type is not a pointer.
// Listeners are keyed by type structs, which means only the correct class will pass.
switch {
case evt.StateKey != nil:
evt.Type.Class = event.StateEventType
case source == EventSourcePresence, source&EventSourceEphemeral != 0:
evt.Type.Class = event.EphemeralEventType
case source&EventSourceAccountData != 0:
evt.Type.Class = event.AccountDataEventType
case source == EventSourceToDevice:
evt.Type.Class = event.ToDeviceEventType
default:
evt.Type.Class = event.MessageEventType
}
if s.ParseEventContent {
err := evt.Content.ParseRaw(evt.Type)
if err != nil && !s.ParseErrorHandler(evt, err) {
return
}
}
s.notifyListeners(source, evt)
}
func (s *DefaultSyncer) notifyListeners(source EventSource, evt *event.Event) {
for _, fn := range s.globalListeners {
fn(source, evt)
}
listeners, exists := s.listeners[evt.Type]
if exists {
for _, fn := range listeners {
fn(source, evt)
}
}
}
// OnEventType allows callers to be notified when there are new events for the given event type.
// There are no duplicate checks.
func (s *DefaultSyncer) OnEventType(eventType event.Type, callback EventHandler) {
_, exists := s.listeners[eventType]
if !exists {
s.listeners[eventType] = []EventHandler{}
}
s.listeners[eventType] = append(s.listeners[eventType], callback)
}
func (s *DefaultSyncer) OnSync(callback SyncHandler) {
s.syncListeners = append(s.syncListeners, callback)
}
func (s *DefaultSyncer) OnEvent(callback EventHandler) {
s.globalListeners = append(s.globalListeners, callback)
}
// OnFailedSync always returns a 10 second wait period between failed /syncs, never a fatal error.
func (s *DefaultSyncer) OnFailedSync(res *RespSync, err error) (time.Duration, error) {
return 10 * time.Second, nil
}
// GetFilterJSON returns a filter with a timeline limit of 50.
func (s *DefaultSyncer) GetFilterJSON(userID id.UserID) *Filter {
return &Filter{
Room: RoomFilter{
Timeline: FilterPart{
Limit: 50,
},
},
}
}
// OldEventIgnorer is an utility struct for bots to ignore events from before the bot joined the room.
// Create a struct and call Register with your DefaultSyncer to register the sync handler.
type OldEventIgnorer struct {
UserID id.UserID
}
func (oei *OldEventIgnorer) Register(syncer ExtensibleSyncer) {
syncer.OnSync(oei.DontProcessOldEvents)
}
// DontProcessOldEvents returns true if a sync response should be processed. May modify the response to remove
// stuff that shouldn't be processed.
func (oei *OldEventIgnorer) DontProcessOldEvents(resp *RespSync, since string) bool {
if since == "" {
return false
}
// This is a horrible hack because /sync will return the most recent messages for a room
// as soon as you /join it. We do NOT want to process those events in that particular room
// because they may have already been processed (if you toggle the bot in/out of the room).
//
// Work around this by inspecting each room's timeline and seeing if an m.room.member event for us
// exists and is "join" and then discard processing that room entirely if so.
// TODO: We probably want to process messages from after the last join event in the timeline.
for roomID, roomData := range resp.Rooms.Join {
for i := len(roomData.Timeline.Events) - 1; i >= 0; i-- {
evt := roomData.Timeline.Events[i]
if evt.Type == event.StateMember && evt.GetStateKey() == string(oei.UserID) {
membership, _ := evt.Content.Raw["membership"].(string)
if membership == "join" {
_, ok := resp.Rooms.Join[roomID]
if !ok {
continue
}
delete(resp.Rooms.Join, roomID) // don't re-process messages
delete(resp.Rooms.Invite, roomID) // don't re-process invites
break
}
}
}
}
return true
}