dendrite/setup/mscs/msc2836/msc2836.go

531 lines
17 KiB
Go

// 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 msc2836 'Threading' implements https://github.com/matrix-org/matrix-doc/pull/2836
package msc2836
import (
"bytes"
"context"
"encoding/json"
"fmt"
"io"
"net/http"
"time"
"github.com/matrix-org/dendrite/clientapi/jsonerror"
fs "github.com/matrix-org/dendrite/federationsender/api"
"github.com/matrix-org/dendrite/internal/hooks"
"github.com/matrix-org/dendrite/internal/httputil"
roomserver "github.com/matrix-org/dendrite/roomserver/api"
"github.com/matrix-org/dendrite/setup"
userapi "github.com/matrix-org/dendrite/userapi/api"
"github.com/matrix-org/gomatrixserverlib"
"github.com/matrix-org/util"
)
const (
constRelType = "m.reference"
constRoomIDKey = "relationship_room_id"
constRoomServers = "relationship_servers"
)
type EventRelationshipRequest struct {
EventID string `json:"event_id"`
MaxDepth int `json:"max_depth"`
MaxBreadth int `json:"max_breadth"`
Limit int `json:"limit"`
DepthFirst bool `json:"depth_first"`
RecentFirst bool `json:"recent_first"`
IncludeParent bool `json:"include_parent"`
IncludeChildren bool `json:"include_children"`
Direction string `json:"direction"`
Batch string `json:"batch"`
AutoJoin bool `json:"auto_join"`
}
func NewEventRelationshipRequest(body io.Reader) (*EventRelationshipRequest, error) {
var relation EventRelationshipRequest
relation.Defaults()
if err := json.NewDecoder(body).Decode(&relation); err != nil {
return nil, err
}
return &relation, nil
}
func (r *EventRelationshipRequest) Defaults() {
r.Limit = 100
r.MaxBreadth = 10
r.MaxDepth = 3
r.DepthFirst = false
r.RecentFirst = true
r.IncludeParent = false
r.IncludeChildren = false
r.Direction = "down"
}
type EventRelationshipResponse struct {
Events []gomatrixserverlib.ClientEvent `json:"events"`
NextBatch string `json:"next_batch"`
Limited bool `json:"limited"`
}
// Enable this MSC
// nolint:gocyclo
func Enable(
base *setup.BaseDendrite, rsAPI roomserver.RoomserverInternalAPI, fsAPI fs.FederationSenderInternalAPI,
userAPI userapi.UserInternalAPI, keyRing gomatrixserverlib.JSONVerifier,
) error {
db, err := NewDatabase(&base.Cfg.MSCs.Database)
if err != nil {
return fmt.Errorf("Cannot enable MSC2836: %w", err)
}
hooks.Enable()
hooks.Attach(hooks.KindNewEventPersisted, func(headeredEvent interface{}) {
he := headeredEvent.(*gomatrixserverlib.HeaderedEvent)
hookErr := db.StoreRelation(context.Background(), he)
if hookErr != nil {
util.GetLogger(context.Background()).WithError(hookErr).Error(
"failed to StoreRelation",
)
}
})
hooks.Attach(hooks.KindNewEventReceived, func(headeredEvent interface{}) {
he := headeredEvent.(*gomatrixserverlib.HeaderedEvent)
ctx := context.Background()
// we only inject metadata for events our server sends
userID := he.Sender()
_, domain, err := gomatrixserverlib.SplitID('@', userID)
if err != nil {
return
}
if domain != base.Cfg.Global.ServerName {
return
}
// if this event has an m.relationship, add on the room_id and servers to unsigned
parent, child, relType := parentChildEventIDs(he)
if parent == "" || child == "" || relType == "" {
return
}
event, joinedToRoom := getEventIfVisible(ctx, rsAPI, parent, userID)
if !joinedToRoom {
return
}
err = he.SetUnsignedField(constRoomIDKey, event.RoomID())
if err != nil {
util.GetLogger(context.Background()).WithError(err).Warn("Failed to SetUnsignedField")
return
}
var servers []gomatrixserverlib.ServerName
if fsAPI != nil {
var res fs.QueryJoinedHostServerNamesInRoomResponse
err = fsAPI.QueryJoinedHostServerNamesInRoom(ctx, &fs.QueryJoinedHostServerNamesInRoomRequest{
RoomID: event.RoomID(),
}, &res)
if err != nil {
util.GetLogger(context.Background()).WithError(err).Warn("Failed to QueryJoinedHostServerNamesInRoom")
return
}
servers = res.ServerNames
} else {
servers = []gomatrixserverlib.ServerName{
base.Cfg.Global.ServerName,
}
}
err = he.SetUnsignedField(constRoomServers, servers)
if err != nil {
util.GetLogger(context.Background()).WithError(err).Warn("Failed to SetUnsignedField")
return
}
})
base.PublicClientAPIMux.Handle("/unstable/event_relationships",
httputil.MakeAuthAPI("eventRelationships", userAPI, eventRelationshipHandler(db, rsAPI)),
).Methods(http.MethodPost, http.MethodOptions)
base.PublicFederationAPIMux.Handle("/unstable/event_relationships", httputil.MakeExternalAPI(
"msc2836_event_relationships", func(req *http.Request) util.JSONResponse {
fedReq, errResp := gomatrixserverlib.VerifyHTTPRequest(
req, time.Now(), base.Cfg.Global.ServerName, keyRing,
)
if fedReq == nil {
return errResp
}
return federatedEventRelationship(req.Context(), fedReq, db, rsAPI)
},
)).Methods(http.MethodPost, http.MethodOptions)
return nil
}
type reqCtx struct {
ctx context.Context
rsAPI roomserver.RoomserverInternalAPI
db Database
req *EventRelationshipRequest
userID string
isFederatedRequest bool
}
func eventRelationshipHandler(db Database, rsAPI roomserver.RoomserverInternalAPI) func(*http.Request, *userapi.Device) util.JSONResponse {
return func(req *http.Request, device *userapi.Device) util.JSONResponse {
relation, err := NewEventRelationshipRequest(req.Body)
if err != nil {
util.GetLogger(req.Context()).WithError(err).Error("failed to decode HTTP request as JSON")
return util.JSONResponse{
Code: 400,
JSON: jsonerror.BadJSON(fmt.Sprintf("invalid json: %s", err)),
}
}
rc := reqCtx{
ctx: req.Context(),
req: relation,
userID: device.UserID,
rsAPI: rsAPI,
isFederatedRequest: false,
db: db,
}
res, resErr := rc.process()
if resErr != nil {
return *resErr
}
return util.JSONResponse{
Code: 200,
JSON: res,
}
}
}
func federatedEventRelationship(ctx context.Context, fedReq *gomatrixserverlib.FederationRequest, db Database, rsAPI roomserver.RoomserverInternalAPI) util.JSONResponse {
relation, err := NewEventRelationshipRequest(bytes.NewBuffer(fedReq.Content()))
if err != nil {
util.GetLogger(ctx).WithError(err).Error("failed to decode HTTP request as JSON")
return util.JSONResponse{
Code: 400,
JSON: jsonerror.BadJSON(fmt.Sprintf("invalid json: %s", err)),
}
}
rc := reqCtx{
ctx: ctx,
req: relation,
userID: "",
rsAPI: rsAPI,
isFederatedRequest: true,
db: db,
}
res, resErr := rc.process()
if resErr != nil {
return *resErr
}
return util.JSONResponse{
Code: 200,
JSON: res,
}
}
func (rc *reqCtx) process() (*EventRelationshipResponse, *util.JSONResponse) {
var res EventRelationshipResponse
var returnEvents []*gomatrixserverlib.HeaderedEvent
// Can the user see (according to history visibility) event_id? If no, reject the request, else continue.
// We should have the event being referenced so don't give any claimed room ID / servers
event := rc.getEventIfVisible(rc.req.EventID, "", nil)
if event == nil {
return nil, &util.JSONResponse{
Code: 403,
JSON: jsonerror.Forbidden("Event does not exist or you are not authorised to see it"),
}
}
// Retrieve the event. Add it to response array.
returnEvents = append(returnEvents, event)
if rc.req.IncludeParent {
if parentEvent := rc.includeParent(event); parentEvent != nil {
returnEvents = append(returnEvents, parentEvent)
}
}
if rc.req.IncludeChildren {
remaining := rc.req.Limit - len(returnEvents)
if remaining > 0 {
children, resErr := rc.includeChildren(rc.db, event.EventID(), remaining, rc.req.RecentFirst)
if resErr != nil {
return nil, resErr
}
returnEvents = append(returnEvents, children...)
}
}
remaining := rc.req.Limit - len(returnEvents)
var walkLimited bool
if remaining > 0 {
included := make(map[string]bool, len(returnEvents))
for _, ev := range returnEvents {
included[ev.EventID()] = true
}
var events []*gomatrixserverlib.HeaderedEvent
events, walkLimited = walkThread(
rc.ctx, rc.db, rc, included, remaining,
)
returnEvents = append(returnEvents, events...)
}
res.Events = make([]gomatrixserverlib.ClientEvent, len(returnEvents))
for i, ev := range returnEvents {
res.Events[i] = gomatrixserverlib.HeaderedToClientEvent(ev, gomatrixserverlib.FormatAll)
}
res.Limited = remaining == 0 || walkLimited
return &res, nil
}
// If include_parent: true and there is a valid m.relationship field in the event,
// retrieve the referenced event. Apply history visibility check to that event and if it passes, add it to the response array.
func (rc *reqCtx) includeParent(event *gomatrixserverlib.HeaderedEvent) (parent *gomatrixserverlib.HeaderedEvent) {
parentID, _, _ := parentChildEventIDs(event)
if parentID == "" {
return nil
}
claimedRoomID, claimedServers := roomIDAndServers(event)
return rc.getEventIfVisible(parentID, claimedRoomID, claimedServers)
}
// If include_children: true, lookup all events which have event_id as an m.relationship
// Apply history visibility checks to all these events and add the ones which pass into the response array,
// honouring the recent_first flag and the limit.
func (rc *reqCtx) includeChildren(db Database, parentID string, limit int, recentFirst bool) ([]*gomatrixserverlib.HeaderedEvent, *util.JSONResponse) {
children, err := db.ChildrenForParent(rc.ctx, parentID, constRelType, recentFirst)
if err != nil {
util.GetLogger(rc.ctx).WithError(err).Error("failed to get ChildrenForParent")
resErr := jsonerror.InternalServerError()
return nil, &resErr
}
var childEvents []*gomatrixserverlib.HeaderedEvent
for _, child := range children {
// in order for us to even know about the children the server must be joined to those rooms, hence pass no claimed room ID or servers.
childEvent := rc.getEventIfVisible(child.EventID, "", nil)
if childEvent != nil {
childEvents = append(childEvents, childEvent)
}
}
if len(childEvents) > limit {
return childEvents[:limit], nil
}
return childEvents, nil
}
// Begin to walk the thread DAG in the direction specified, either depth or breadth first according to the depth_first flag,
// honouring the limit, max_depth and max_breadth values according to the following rules
// nolint: unparam
func walkThread(
ctx context.Context, db Database, rc *reqCtx, included map[string]bool, limit int,
) ([]*gomatrixserverlib.HeaderedEvent, bool) {
if rc.req.Direction != "down" {
util.GetLogger(ctx).Error("not implemented: direction=up")
return nil, false
}
var result []*gomatrixserverlib.HeaderedEvent
eventWalker := walker{
ctx: ctx,
req: rc.req,
db: db,
fn: func(wi *walkInfo) bool {
// If already processed event, skip.
if included[wi.EventID] {
return false
}
// If the response array is >= limit, stop.
if len(result) >= limit {
return true
}
// Process the event.
// TODO: Include edge information: room ID and servers
event := rc.getEventIfVisible(wi.EventID, "", nil)
if event != nil {
result = append(result, event)
}
included[wi.EventID] = true
return false
},
}
limited, err := eventWalker.WalkFrom(rc.req.EventID)
if err != nil {
util.GetLogger(ctx).WithError(err).Errorf("Failed to WalkFrom %s", rc.req.EventID)
}
return result, limited
}
func (rc *reqCtx) getEventIfVisible(eventID string, claimedRoomID string, claimedServers []string) *gomatrixserverlib.HeaderedEvent {
event, joinedToRoom := getEventIfVisible(rc.ctx, rc.rsAPI, eventID, rc.userID)
if event != nil && joinedToRoom {
return event
}
// either we don't have the event or we aren't joined to the room, regardless we should try joining if auto join is enabled
if !rc.req.AutoJoin {
return nil
}
// if we're doing this on behalf of a random server don't auto-join rooms regardless of what the request says
if rc.isFederatedRequest {
return nil
}
roomID := claimedRoomID
var servers []gomatrixserverlib.ServerName
if event != nil {
roomID = event.RoomID()
}
for _, s := range claimedServers {
servers = append(servers, gomatrixserverlib.ServerName(s))
}
var joinRes roomserver.PerformJoinResponse
rc.rsAPI.PerformJoin(rc.ctx, &roomserver.PerformJoinRequest{
UserID: rc.userID,
Content: map[string]interface{}{},
RoomIDOrAlias: roomID,
ServerNames: servers,
}, &joinRes)
if joinRes.Error != nil {
util.GetLogger(rc.ctx).WithError(joinRes.Error).WithField("room_id", roomID).Error("Failed to auto-join room")
return nil
}
if event != nil {
return event
}
// TODO: hit /event_relationships on the server we joined via
util.GetLogger(rc.ctx).Infof("joined room but need to fetch event TODO")
return nil
}
func getEventIfVisible(ctx context.Context, rsAPI roomserver.RoomserverInternalAPI, eventID, userID string) (*gomatrixserverlib.HeaderedEvent, bool) {
var queryEventsRes roomserver.QueryEventsByIDResponse
err := rsAPI.QueryEventsByID(ctx, &roomserver.QueryEventsByIDRequest{
EventIDs: []string{eventID},
}, &queryEventsRes)
if err != nil {
util.GetLogger(ctx).WithError(err).Error("getEventIfVisible: failed to QueryEventsByID")
return nil, false
}
if len(queryEventsRes.Events) == 0 {
util.GetLogger(ctx).Infof("event does not exist")
return nil, false // event does not exist
}
event := queryEventsRes.Events[0]
// Allow events if the member is in the room
// TODO: This does not honour history_visibility
// TODO: This does not honour m.room.create content
var queryMembershipRes roomserver.QueryMembershipForUserResponse
err = rsAPI.QueryMembershipForUser(ctx, &roomserver.QueryMembershipForUserRequest{
RoomID: event.RoomID(),
UserID: userID,
}, &queryMembershipRes)
if err != nil {
util.GetLogger(ctx).WithError(err).Error("getEventIfVisible: failed to QueryMembershipForUser")
return nil, false
}
return event, queryMembershipRes.IsInRoom
}
type walkInfo struct {
eventInfo
SiblingNumber int
Depth int
}
type walker struct {
ctx context.Context
req *EventRelationshipRequest
db Database
fn func(wi *walkInfo) bool // callback invoked for each event walked, return true to terminate the walk
}
// WalkFrom the event ID given
func (w *walker) WalkFrom(eventID string) (limited bool, err error) {
children, err := w.db.ChildrenForParent(w.ctx, eventID, constRelType, w.req.RecentFirst)
if err != nil {
util.GetLogger(w.ctx).WithError(err).Error("WalkFrom() ChildrenForParent failed, cannot walk")
return false, err
}
var next *walkInfo
toWalk := w.addChildren(nil, children, 1)
next, toWalk = w.nextChild(toWalk)
for next != nil {
stop := w.fn(next)
if stop {
return true, nil
}
// find the children's children
children, err = w.db.ChildrenForParent(w.ctx, next.EventID, constRelType, w.req.RecentFirst)
if err != nil {
util.GetLogger(w.ctx).WithError(err).Error("WalkFrom() ChildrenForParent failed, cannot walk")
return false, err
}
toWalk = w.addChildren(toWalk, children, next.Depth+1)
next, toWalk = w.nextChild(toWalk)
}
return false, nil
}
// addChildren adds an event's children to the to walk data structure
func (w *walker) addChildren(toWalk []walkInfo, children []eventInfo, depthOfChildren int) []walkInfo {
// Check what number child this event is (ordered by recent_first) compared to its parent, does it exceed (greater than) max_breadth? If yes, skip.
if len(children) > w.req.MaxBreadth {
children = children[:w.req.MaxBreadth]
}
// Check how deep the event is compared to event_id, does it exceed (greater than) max_depth? If yes, skip.
if depthOfChildren > w.req.MaxDepth {
return toWalk
}
if w.req.DepthFirst {
// the slice is a stack so push them in reverse order so we pop them in the correct order
// e.g [3,2,1] => [3,2] , 1 => [3] , 2 => [] , 3
for i := len(children) - 1; i >= 0; i-- {
toWalk = append(toWalk, walkInfo{
eventInfo: children[i],
SiblingNumber: i + 1, // index from 1
Depth: depthOfChildren,
})
}
} else {
// the slice is a queue so push them in normal order to we dequeue them in the correct order
// e.g [1,2,3] => 1, [2, 3] => 2 , [3] => 3, []
for i := range children {
toWalk = append(toWalk, walkInfo{
eventInfo: children[i],
SiblingNumber: i + 1, // index from 1
Depth: depthOfChildren,
})
}
}
return toWalk
}
func (w *walker) nextChild(toWalk []walkInfo) (*walkInfo, []walkInfo) {
if len(toWalk) == 0 {
return nil, nil
}
var child walkInfo
if w.req.DepthFirst {
// toWalk is a stack so pop the child off
child, toWalk = toWalk[len(toWalk)-1], toWalk[:len(toWalk)-1]
return &child, toWalk
}
// toWalk is a queue so shift the child off
child, toWalk = toWalk[0], toWalk[1:]
return &child, toWalk
}