mirror of
https://github.com/matrix-org/dendrite
synced 2024-11-18 07:40:53 +01:00
851 lines
29 KiB
Go
851 lines
29 KiB
Go
// Copyright 2020 The Matrix.org Foundation C.I.C.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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// Package msc2836 'Threading' implements https://github.com/matrix-org/matrix-doc/pull/2836
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package msc2836
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import (
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"bytes"
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"context"
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"crypto/sha256"
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"encoding/json"
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"fmt"
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"io"
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"net/http"
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"sort"
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"strings"
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"time"
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"github.com/matrix-org/dendrite/clientapi/jsonerror"
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fs "github.com/matrix-org/dendrite/federationsender/api"
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"github.com/matrix-org/dendrite/internal/hooks"
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"github.com/matrix-org/dendrite/internal/httputil"
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roomserver "github.com/matrix-org/dendrite/roomserver/api"
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"github.com/matrix-org/dendrite/setup"
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userapi "github.com/matrix-org/dendrite/userapi/api"
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"github.com/matrix-org/gomatrixserverlib"
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"github.com/matrix-org/util"
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)
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const (
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constRelType = "m.reference"
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)
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type EventRelationshipRequest struct {
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EventID string `json:"event_id"`
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RoomID string `json:"room_id"`
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MaxDepth int `json:"max_depth"`
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MaxBreadth int `json:"max_breadth"`
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Limit int `json:"limit"`
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DepthFirst bool `json:"depth_first"`
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RecentFirst bool `json:"recent_first"`
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IncludeParent bool `json:"include_parent"`
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IncludeChildren bool `json:"include_children"`
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Direction string `json:"direction"`
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Batch string `json:"batch"`
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}
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func NewEventRelationshipRequest(body io.Reader) (*EventRelationshipRequest, error) {
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var relation EventRelationshipRequest
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relation.Defaults()
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if err := json.NewDecoder(body).Decode(&relation); err != nil {
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return nil, err
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}
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return &relation, nil
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}
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func (r *EventRelationshipRequest) Defaults() {
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r.Limit = 100
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r.MaxBreadth = 10
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r.MaxDepth = 3
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r.DepthFirst = false
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r.RecentFirst = true
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r.IncludeParent = false
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r.IncludeChildren = false
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r.Direction = "down"
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}
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type EventRelationshipResponse struct {
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Events []gomatrixserverlib.ClientEvent `json:"events"`
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NextBatch string `json:"next_batch"`
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Limited bool `json:"limited"`
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}
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func toClientResponse(res *gomatrixserverlib.MSC2836EventRelationshipsResponse) *EventRelationshipResponse {
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out := &EventRelationshipResponse{
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Events: gomatrixserverlib.ToClientEvents(res.Events, gomatrixserverlib.FormatAll),
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Limited: res.Limited,
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NextBatch: res.NextBatch,
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}
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return out
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}
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// Enable this MSC
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func Enable(
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base *setup.BaseDendrite, rsAPI roomserver.RoomserverInternalAPI, fsAPI fs.FederationSenderInternalAPI,
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userAPI userapi.UserInternalAPI, keyRing gomatrixserverlib.JSONVerifier,
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) error {
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db, err := NewDatabase(&base.Cfg.MSCs.Database)
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if err != nil {
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return fmt.Errorf("Cannot enable MSC2836: %w", err)
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}
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hooks.Enable()
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hooks.Attach(hooks.KindNewEventPersisted, func(headeredEvent interface{}) {
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he := headeredEvent.(*gomatrixserverlib.HeaderedEvent)
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hookErr := db.StoreRelation(context.Background(), he)
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if hookErr != nil {
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util.GetLogger(context.Background()).WithError(hookErr).WithField("event_id", he.EventID()).Error(
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"failed to StoreRelation",
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)
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}
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// we need to update child metadata here as well as after doing remote /event_relationships requests
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// so we catch child metadata originating from /send transactions
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hookErr = db.UpdateChildMetadata(context.Background(), he)
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if hookErr != nil {
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util.GetLogger(context.Background()).WithError(err).WithField("event_id", he.EventID()).Warn(
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"failed to update child metadata for event",
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)
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}
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})
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base.PublicClientAPIMux.Handle("/unstable/event_relationships",
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httputil.MakeAuthAPI("eventRelationships", userAPI, eventRelationshipHandler(db, rsAPI, fsAPI)),
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).Methods(http.MethodPost, http.MethodOptions)
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base.PublicFederationAPIMux.Handle("/unstable/event_relationships", httputil.MakeExternalAPI(
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"msc2836_event_relationships", func(req *http.Request) util.JSONResponse {
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fedReq, errResp := gomatrixserverlib.VerifyHTTPRequest(
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req, time.Now(), base.Cfg.Global.ServerName, keyRing,
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)
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if fedReq == nil {
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return errResp
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}
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return federatedEventRelationship(req.Context(), fedReq, db, rsAPI, fsAPI)
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},
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)).Methods(http.MethodPost, http.MethodOptions)
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return nil
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}
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type reqCtx struct {
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ctx context.Context
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rsAPI roomserver.RoomserverInternalAPI
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db Database
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req *EventRelationshipRequest
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userID string
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roomVersion gomatrixserverlib.RoomVersion
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// federated request args
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isFederatedRequest bool
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serverName gomatrixserverlib.ServerName
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fsAPI fs.FederationSenderInternalAPI
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}
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func eventRelationshipHandler(db Database, rsAPI roomserver.RoomserverInternalAPI, fsAPI fs.FederationSenderInternalAPI) func(*http.Request, *userapi.Device) util.JSONResponse {
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return func(req *http.Request, device *userapi.Device) util.JSONResponse {
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relation, err := NewEventRelationshipRequest(req.Body)
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if err != nil {
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util.GetLogger(req.Context()).WithError(err).Error("failed to decode HTTP request as JSON")
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return util.JSONResponse{
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Code: 400,
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JSON: jsonerror.BadJSON(fmt.Sprintf("invalid json: %s", err)),
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}
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}
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rc := reqCtx{
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ctx: req.Context(),
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req: relation,
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userID: device.UserID,
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rsAPI: rsAPI,
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fsAPI: fsAPI,
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isFederatedRequest: false,
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db: db,
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}
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res, resErr := rc.process()
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if resErr != nil {
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return *resErr
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}
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return util.JSONResponse{
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Code: 200,
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JSON: toClientResponse(res),
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}
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}
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}
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func federatedEventRelationship(
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ctx context.Context, fedReq *gomatrixserverlib.FederationRequest, db Database, rsAPI roomserver.RoomserverInternalAPI, fsAPI fs.FederationSenderInternalAPI,
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) util.JSONResponse {
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relation, err := NewEventRelationshipRequest(bytes.NewBuffer(fedReq.Content()))
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if err != nil {
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util.GetLogger(ctx).WithError(err).Error("failed to decode HTTP request as JSON")
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return util.JSONResponse{
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Code: 400,
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JSON: jsonerror.BadJSON(fmt.Sprintf("invalid json: %s", err)),
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}
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}
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rc := reqCtx{
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ctx: ctx,
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req: relation,
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rsAPI: rsAPI,
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db: db,
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// federation args
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isFederatedRequest: true,
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fsAPI: fsAPI,
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serverName: fedReq.Origin(),
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}
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res, resErr := rc.process()
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if resErr != nil {
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return *resErr
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}
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// add auth chain information
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requiredAuthEventsSet := make(map[string]bool)
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var requiredAuthEvents []string
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for _, ev := range res.Events {
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for _, a := range ev.AuthEventIDs() {
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if requiredAuthEventsSet[a] {
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continue
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}
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requiredAuthEvents = append(requiredAuthEvents, a)
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requiredAuthEventsSet[a] = true
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}
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}
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var queryRes roomserver.QueryAuthChainResponse
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err = rsAPI.QueryAuthChain(ctx, &roomserver.QueryAuthChainRequest{
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EventIDs: requiredAuthEvents,
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}, &queryRes)
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if err != nil {
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// they may already have the auth events so don't fail this request
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util.GetLogger(ctx).WithError(err).Error("Failed to QueryAuthChain")
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}
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res.AuthChain = make([]*gomatrixserverlib.Event, len(queryRes.AuthChain))
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for i := range queryRes.AuthChain {
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res.AuthChain[i] = queryRes.AuthChain[i].Unwrap()
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}
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return util.JSONResponse{
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Code: 200,
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JSON: res,
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}
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}
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func (rc *reqCtx) process() (*gomatrixserverlib.MSC2836EventRelationshipsResponse, *util.JSONResponse) {
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var res gomatrixserverlib.MSC2836EventRelationshipsResponse
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var returnEvents []*gomatrixserverlib.HeaderedEvent
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// Can the user see (according to history visibility) event_id? If no, reject the request, else continue.
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event := rc.getLocalEvent(rc.req.EventID)
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if event == nil {
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event = rc.fetchUnknownEvent(rc.req.EventID, rc.req.RoomID)
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}
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if rc.req.RoomID == "" && event != nil {
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rc.req.RoomID = event.RoomID()
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}
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if event == nil || !rc.authorisedToSeeEvent(event) {
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return nil, &util.JSONResponse{
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Code: 403,
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JSON: jsonerror.Forbidden("Event does not exist or you are not authorised to see it"),
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}
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}
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rc.roomVersion = event.Version()
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// Retrieve the event. Add it to response array.
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returnEvents = append(returnEvents, event)
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if rc.req.IncludeParent {
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if parentEvent := rc.includeParent(event); parentEvent != nil {
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returnEvents = append(returnEvents, parentEvent)
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}
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}
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if rc.req.IncludeChildren {
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remaining := rc.req.Limit - len(returnEvents)
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if remaining > 0 {
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children, resErr := rc.includeChildren(rc.db, event.EventID(), remaining, rc.req.RecentFirst)
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if resErr != nil {
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return nil, resErr
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}
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returnEvents = append(returnEvents, children...)
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}
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}
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remaining := rc.req.Limit - len(returnEvents)
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var walkLimited bool
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if remaining > 0 {
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included := make(map[string]bool, len(returnEvents))
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for _, ev := range returnEvents {
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included[ev.EventID()] = true
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}
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var events []*gomatrixserverlib.HeaderedEvent
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events, walkLimited = walkThread(
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rc.ctx, rc.db, rc, included, remaining,
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)
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returnEvents = append(returnEvents, events...)
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}
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res.Events = make([]*gomatrixserverlib.Event, len(returnEvents))
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for i, ev := range returnEvents {
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// for each event, extract the children_count | hash and add it as unsigned data.
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rc.addChildMetadata(ev)
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res.Events[i] = ev.Unwrap()
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}
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res.Limited = remaining == 0 || walkLimited
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return &res, nil
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}
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// fetchUnknownEvent retrieves an unknown event from the room specified. This server must
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// be joined to the room in question. This has the side effect of injecting surround threaded
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// events into the roomserver.
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func (rc *reqCtx) fetchUnknownEvent(eventID, roomID string) *gomatrixserverlib.HeaderedEvent {
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if rc.isFederatedRequest || roomID == "" {
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// we don't do fed hits for fed requests, and we can't ask servers without a room ID!
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return nil
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}
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logger := util.GetLogger(rc.ctx).WithField("room_id", roomID)
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// if they supplied a room_id, check the room exists.
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var queryVerRes roomserver.QueryRoomVersionForRoomResponse
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err := rc.rsAPI.QueryRoomVersionForRoom(rc.ctx, &roomserver.QueryRoomVersionForRoomRequest{
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RoomID: roomID,
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}, &queryVerRes)
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if err != nil {
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logger.WithError(err).Warn("failed to query room version for room, does this room exist?")
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return nil
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}
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// check the user is joined to that room
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var queryMemRes roomserver.QueryMembershipForUserResponse
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err = rc.rsAPI.QueryMembershipForUser(rc.ctx, &roomserver.QueryMembershipForUserRequest{
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RoomID: roomID,
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UserID: rc.userID,
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}, &queryMemRes)
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if err != nil {
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logger.WithError(err).Warn("failed to query membership for user in room")
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return nil
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}
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if !queryMemRes.IsInRoom {
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return nil
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}
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// ask one of the servers in the room for the event
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var queryRes fs.QueryJoinedHostServerNamesInRoomResponse
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err = rc.fsAPI.QueryJoinedHostServerNamesInRoom(rc.ctx, &fs.QueryJoinedHostServerNamesInRoomRequest{
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RoomID: roomID,
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}, &queryRes)
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if err != nil {
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logger.WithError(err).Error("failed to QueryJoinedHostServerNamesInRoom")
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return nil
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}
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// query up to 5 servers
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serversToQuery := queryRes.ServerNames
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if len(serversToQuery) > 5 {
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serversToQuery = serversToQuery[:5]
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}
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// fetch the event, along with some of the surrounding thread (if it's threaded) and the auth chain.
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// Inject the response into the roomserver to remember the event across multiple calls and to set
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// unexplored flags correctly.
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for _, srv := range serversToQuery {
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res, err := rc.MSC2836EventRelationships(eventID, srv, queryVerRes.RoomVersion)
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if err != nil {
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continue
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}
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rc.injectResponseToRoomserver(res)
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for _, ev := range res.Events {
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if ev.EventID() == eventID {
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return ev.Headered(ev.Version())
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}
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}
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}
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logger.WithField("servers", serversToQuery).Warn("failed to query event relationships")
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return nil
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}
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// If include_parent: true and there is a valid m.relationship field in the event,
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// retrieve the referenced event. Apply history visibility check to that event and if it passes, add it to the response array.
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func (rc *reqCtx) includeParent(childEvent *gomatrixserverlib.HeaderedEvent) (parent *gomatrixserverlib.HeaderedEvent) {
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parentID, _, _ := parentChildEventIDs(childEvent)
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if parentID == "" {
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return nil
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}
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return rc.lookForEvent(parentID)
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}
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// If include_children: true, lookup all events which have event_id as an m.relationship
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// Apply history visibility checks to all these events and add the ones which pass into the response array,
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// honouring the recent_first flag and the limit.
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func (rc *reqCtx) includeChildren(db Database, parentID string, limit int, recentFirst bool) ([]*gomatrixserverlib.HeaderedEvent, *util.JSONResponse) {
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if rc.hasUnexploredChildren(parentID) {
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// we need to do a remote request to pull in the children as we are missing them locally.
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serversToQuery := rc.getServersForEventID(parentID)
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var result *gomatrixserverlib.MSC2836EventRelationshipsResponse
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for _, srv := range serversToQuery {
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res, err := rc.fsAPI.MSC2836EventRelationships(rc.ctx, srv, gomatrixserverlib.MSC2836EventRelationshipsRequest{
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EventID: parentID,
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Direction: "down",
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Limit: 100,
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MaxBreadth: -1,
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MaxDepth: 1, // we just want the children from this parent
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RecentFirst: true,
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}, rc.roomVersion)
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if err != nil {
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util.GetLogger(rc.ctx).WithError(err).WithField("server", srv).Error("includeChildren: failed to call MSC2836EventRelationships")
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} else {
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result = &res
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break
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}
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}
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if result != nil {
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rc.injectResponseToRoomserver(result)
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}
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// fallthrough to pull these new events from the DB
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}
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children, err := db.ChildrenForParent(rc.ctx, parentID, constRelType, recentFirst)
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if err != nil {
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util.GetLogger(rc.ctx).WithError(err).Error("failed to get ChildrenForParent")
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resErr := jsonerror.InternalServerError()
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return nil, &resErr
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}
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var childEvents []*gomatrixserverlib.HeaderedEvent
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for _, child := range children {
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childEvent := rc.lookForEvent(child.EventID)
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if childEvent != nil {
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childEvents = append(childEvents, childEvent)
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}
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}
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if len(childEvents) > limit {
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return childEvents[:limit], nil
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}
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return childEvents, nil
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}
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// Begin to walk the thread DAG in the direction specified, either depth or breadth first according to the depth_first flag,
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// honouring the limit, max_depth and max_breadth values according to the following rules
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func walkThread(
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ctx context.Context, db Database, rc *reqCtx, included map[string]bool, limit int,
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) ([]*gomatrixserverlib.HeaderedEvent, bool) {
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var result []*gomatrixserverlib.HeaderedEvent
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eventWalker := walker{
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ctx: ctx,
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req: rc.req,
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db: db,
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fn: func(wi *walkInfo) bool {
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// If already processed event, skip.
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if included[wi.EventID] {
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return false
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}
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// If the response array is >= limit, stop.
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if len(result) >= limit {
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return true
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}
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// Process the event.
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// if event is not found, use remoteEventRelationships to explore that part of the thread remotely.
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// This will probably be easiest if the event relationships response is directly pumped into the database
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// so the next walk will do the right thing. This requires those events to be authed and likely injected as
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// outliers into the roomserver DB, which will de-dupe appropriately.
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event := rc.lookForEvent(wi.EventID)
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if event != nil {
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result = append(result, event)
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}
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included[wi.EventID] = true
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return false
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},
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}
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limited, err := eventWalker.WalkFrom(rc.req.EventID)
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if err != nil {
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util.GetLogger(ctx).WithError(err).Errorf("Failed to WalkFrom %s", rc.req.EventID)
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}
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return result, limited
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}
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// MSC2836EventRelationships performs an /event_relationships request to a remote server
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func (rc *reqCtx) MSC2836EventRelationships(eventID string, srv gomatrixserverlib.ServerName, ver gomatrixserverlib.RoomVersion) (*gomatrixserverlib.MSC2836EventRelationshipsResponse, error) {
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res, err := rc.fsAPI.MSC2836EventRelationships(rc.ctx, srv, gomatrixserverlib.MSC2836EventRelationshipsRequest{
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EventID: eventID,
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DepthFirst: rc.req.DepthFirst,
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Direction: rc.req.Direction,
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Limit: rc.req.Limit,
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MaxBreadth: rc.req.MaxBreadth,
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MaxDepth: rc.req.MaxDepth,
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RecentFirst: rc.req.RecentFirst,
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}, ver)
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if err != nil {
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util.GetLogger(rc.ctx).WithError(err).Error("Failed to call MSC2836EventRelationships")
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return nil, err
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}
|
|
return &res, nil
|
|
|
|
}
|
|
|
|
// authorisedToSeeEvent checks that the user or server is allowed to see this event. Returns true if allowed to
|
|
// see this request. This only needs to be done once per room at present as we just check for joined status.
|
|
func (rc *reqCtx) authorisedToSeeEvent(event *gomatrixserverlib.HeaderedEvent) bool {
|
|
if rc.isFederatedRequest {
|
|
// make sure the server is in this room
|
|
var res fs.QueryJoinedHostServerNamesInRoomResponse
|
|
err := rc.fsAPI.QueryJoinedHostServerNamesInRoom(rc.ctx, &fs.QueryJoinedHostServerNamesInRoomRequest{
|
|
RoomID: event.RoomID(),
|
|
}, &res)
|
|
if err != nil {
|
|
util.GetLogger(rc.ctx).WithError(err).Error("authorisedToSeeEvent: failed to QueryJoinedHostServerNamesInRoom")
|
|
return false
|
|
}
|
|
for _, srv := range res.ServerNames {
|
|
if srv == rc.serverName {
|
|
return true
|
|
}
|
|
}
|
|
return false
|
|
}
|
|
// make sure the user is in this room
|
|
// 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 := rc.rsAPI.QueryMembershipForUser(rc.ctx, &roomserver.QueryMembershipForUserRequest{
|
|
RoomID: event.RoomID(),
|
|
UserID: rc.userID,
|
|
}, &queryMembershipRes)
|
|
if err != nil {
|
|
util.GetLogger(rc.ctx).WithError(err).Error("authorisedToSeeEvent: failed to QueryMembershipForUser")
|
|
return false
|
|
}
|
|
return queryMembershipRes.IsInRoom
|
|
}
|
|
|
|
func (rc *reqCtx) getServersForEventID(eventID string) []gomatrixserverlib.ServerName {
|
|
if rc.req.RoomID == "" {
|
|
util.GetLogger(rc.ctx).WithField("event_id", eventID).Error(
|
|
"getServersForEventID: event exists in unknown room",
|
|
)
|
|
return nil
|
|
}
|
|
if rc.roomVersion == "" {
|
|
util.GetLogger(rc.ctx).WithField("event_id", eventID).Errorf(
|
|
"getServersForEventID: event exists in %s with unknown room version", rc.req.RoomID,
|
|
)
|
|
return nil
|
|
}
|
|
var queryRes fs.QueryJoinedHostServerNamesInRoomResponse
|
|
err := rc.fsAPI.QueryJoinedHostServerNamesInRoom(rc.ctx, &fs.QueryJoinedHostServerNamesInRoomRequest{
|
|
RoomID: rc.req.RoomID,
|
|
}, &queryRes)
|
|
if err != nil {
|
|
util.GetLogger(rc.ctx).WithError(err).Error("getServersForEventID: failed to QueryJoinedHostServerNamesInRoom")
|
|
return nil
|
|
}
|
|
// query up to 5 servers
|
|
serversToQuery := queryRes.ServerNames
|
|
if len(serversToQuery) > 5 {
|
|
serversToQuery = serversToQuery[:5]
|
|
}
|
|
return serversToQuery
|
|
}
|
|
|
|
func (rc *reqCtx) remoteEventRelationships(eventID string) *gomatrixserverlib.MSC2836EventRelationshipsResponse {
|
|
if rc.isFederatedRequest {
|
|
return nil // we don't query remote servers for remote requests
|
|
}
|
|
serversToQuery := rc.getServersForEventID(eventID)
|
|
var res *gomatrixserverlib.MSC2836EventRelationshipsResponse
|
|
var err error
|
|
for _, srv := range serversToQuery {
|
|
res, err = rc.MSC2836EventRelationships(eventID, srv, rc.roomVersion)
|
|
if err != nil {
|
|
util.GetLogger(rc.ctx).WithError(err).WithField("server", srv).Error("remoteEventRelationships: failed to call MSC2836EventRelationships")
|
|
} else {
|
|
break
|
|
}
|
|
}
|
|
return res
|
|
}
|
|
|
|
// lookForEvent returns the event for the event ID given, by trying to query remote servers
|
|
// if the event ID is unknown via /event_relationships.
|
|
func (rc *reqCtx) lookForEvent(eventID string) *gomatrixserverlib.HeaderedEvent {
|
|
event := rc.getLocalEvent(eventID)
|
|
if event == nil {
|
|
queryRes := rc.remoteEventRelationships(eventID)
|
|
if queryRes != nil {
|
|
// inject all the events into the roomserver then return the event in question
|
|
rc.injectResponseToRoomserver(queryRes)
|
|
for _, ev := range queryRes.Events {
|
|
if ev.EventID() == eventID && rc.req.RoomID == ev.RoomID() {
|
|
return ev.Headered(ev.Version())
|
|
}
|
|
}
|
|
}
|
|
} else if rc.hasUnexploredChildren(eventID) {
|
|
// we have the local event but we may need to do a remote hit anyway if we are exploring the thread and have unknown children.
|
|
// If we don't do this then we risk never fetching the children.
|
|
queryRes := rc.remoteEventRelationships(eventID)
|
|
if queryRes != nil {
|
|
rc.injectResponseToRoomserver(queryRes)
|
|
err := rc.db.MarkChildrenExplored(context.Background(), eventID)
|
|
if err != nil {
|
|
util.GetLogger(rc.ctx).WithError(err).Warnf("failed to mark children of %s as explored", eventID)
|
|
}
|
|
}
|
|
}
|
|
if rc.req.RoomID == event.RoomID() {
|
|
return event
|
|
}
|
|
return nil
|
|
}
|
|
|
|
func (rc *reqCtx) getLocalEvent(eventID string) *gomatrixserverlib.HeaderedEvent {
|
|
var queryEventsRes roomserver.QueryEventsByIDResponse
|
|
err := rc.rsAPI.QueryEventsByID(rc.ctx, &roomserver.QueryEventsByIDRequest{
|
|
EventIDs: []string{eventID},
|
|
}, &queryEventsRes)
|
|
if err != nil {
|
|
util.GetLogger(rc.ctx).WithError(err).Error("getLocalEvent: failed to QueryEventsByID")
|
|
return nil
|
|
}
|
|
if len(queryEventsRes.Events) == 0 {
|
|
util.GetLogger(rc.ctx).WithField("event_id", eventID).Infof("getLocalEvent: event does not exist")
|
|
return nil // event does not exist
|
|
}
|
|
return queryEventsRes.Events[0]
|
|
}
|
|
|
|
// injectResponseToRoomserver injects the events
|
|
// into the roomserver as KindOutlier, with auth chains.
|
|
func (rc *reqCtx) injectResponseToRoomserver(res *gomatrixserverlib.MSC2836EventRelationshipsResponse) {
|
|
var stateEvents []*gomatrixserverlib.Event
|
|
var messageEvents []*gomatrixserverlib.Event
|
|
for _, ev := range res.Events {
|
|
if ev.StateKey() != nil {
|
|
stateEvents = append(stateEvents, ev)
|
|
} else {
|
|
messageEvents = append(messageEvents, ev)
|
|
}
|
|
}
|
|
respState := gomatrixserverlib.RespState{
|
|
AuthEvents: res.AuthChain,
|
|
StateEvents: stateEvents,
|
|
}
|
|
eventsInOrder, err := respState.Events()
|
|
if err != nil {
|
|
util.GetLogger(rc.ctx).WithError(err).Error("failed to calculate order to send events in MSC2836EventRelationshipsResponse")
|
|
return
|
|
}
|
|
// everything gets sent as an outlier because auth chain events may be disjoint from the DAG
|
|
// as may the threaded events.
|
|
var ires []roomserver.InputRoomEvent
|
|
for _, outlier := range append(eventsInOrder, messageEvents...) {
|
|
ires = append(ires, roomserver.InputRoomEvent{
|
|
Kind: roomserver.KindOutlier,
|
|
Event: outlier.Headered(outlier.Version()),
|
|
AuthEventIDs: outlier.AuthEventIDs(),
|
|
})
|
|
}
|
|
// we've got the data by this point so use a background context
|
|
err = roomserver.SendInputRoomEvents(context.Background(), rc.rsAPI, ires)
|
|
if err != nil {
|
|
util.GetLogger(rc.ctx).WithError(err).Error("failed to inject MSC2836EventRelationshipsResponse into the roomserver")
|
|
}
|
|
// update the child count / hash columns for these nodes. We need to do this here because not all events will make it
|
|
// through to the KindNewEventPersisted hook because the roomserver will ignore duplicates. Duplicates have meaning though
|
|
// as the `unsigned` field may differ (if the number of children changes).
|
|
for _, ev := range ires {
|
|
err = rc.db.UpdateChildMetadata(context.Background(), ev.Event)
|
|
if err != nil {
|
|
util.GetLogger(rc.ctx).WithError(err).WithField("event_id", ev.Event.EventID()).Warn("failed to update child metadata for event")
|
|
}
|
|
}
|
|
}
|
|
|
|
func (rc *reqCtx) addChildMetadata(ev *gomatrixserverlib.HeaderedEvent) {
|
|
count, hash := rc.getChildMetadata(ev.EventID())
|
|
if count == 0 {
|
|
return
|
|
}
|
|
err := ev.SetUnsignedField("children_hash", gomatrixserverlib.Base64Bytes(hash))
|
|
if err != nil {
|
|
util.GetLogger(rc.ctx).WithError(err).Warn("Failed to set children_hash")
|
|
}
|
|
err = ev.SetUnsignedField("children", map[string]int{
|
|
constRelType: count,
|
|
})
|
|
if err != nil {
|
|
util.GetLogger(rc.ctx).WithError(err).Warn("Failed to set children count")
|
|
}
|
|
}
|
|
|
|
func (rc *reqCtx) getChildMetadata(eventID string) (count int, hash []byte) {
|
|
children, err := rc.db.ChildrenForParent(rc.ctx, eventID, constRelType, false)
|
|
if err != nil {
|
|
util.GetLogger(rc.ctx).WithError(err).Warn("Failed to get ChildrenForParent for getting child metadata")
|
|
return
|
|
}
|
|
if len(children) == 0 {
|
|
return
|
|
}
|
|
// sort it lexiographically
|
|
sort.Slice(children, func(i, j int) bool {
|
|
return children[i].EventID < children[j].EventID
|
|
})
|
|
// hash it
|
|
var eventIDs strings.Builder
|
|
for _, c := range children {
|
|
_, _ = eventIDs.WriteString(c.EventID)
|
|
}
|
|
hashValBytes := sha256.Sum256([]byte(eventIDs.String()))
|
|
|
|
count = len(children)
|
|
hash = hashValBytes[:]
|
|
return
|
|
}
|
|
|
|
// hasUnexploredChildren returns true if this event has unexplored children.
|
|
// "An event has unexplored children if the `unsigned` child count on the parent does not match
|
|
// how many children the server believes the parent to have. In addition, if the counts match but
|
|
// the hashes do not match, then the event is unexplored."
|
|
func (rc *reqCtx) hasUnexploredChildren(eventID string) bool {
|
|
if rc.isFederatedRequest {
|
|
return false // we only explore children for clients, not servers.
|
|
}
|
|
// extract largest child count from event
|
|
eventCount, eventHash, explored, err := rc.db.ChildMetadata(rc.ctx, eventID)
|
|
if err != nil {
|
|
util.GetLogger(rc.ctx).WithError(err).WithField("event_id", eventID).Warn(
|
|
"failed to get ChildMetadata from db",
|
|
)
|
|
return false
|
|
}
|
|
// if there are no recorded children then we know we have >= children.
|
|
// if the event has already been explored (read: we hit /event_relationships successfully)
|
|
// then don't do it again. We'll only re-do this if we get an even bigger children count,
|
|
// see Database.UpdateChildMetadata
|
|
if eventCount == 0 || explored {
|
|
return false // short-circuit
|
|
}
|
|
|
|
// calculate child count for event
|
|
calcCount, calcHash := rc.getChildMetadata(eventID)
|
|
|
|
if eventCount < calcCount {
|
|
return false // we have more children
|
|
} else if eventCount > calcCount {
|
|
return true // the event has more children than we know about
|
|
}
|
|
// we have the same count, so a mismatched hash means some children are different
|
|
return !bytes.Equal(eventHash, calcHash)
|
|
}
|
|
|
|
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.childrenForParent(eventID)
|
|
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.childrenForParent(next.EventID)
|
|
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
|
|
}
|
|
|
|
// childrenForParent returns the children events for this event ID, honouring the direction: up|down flags
|
|
// meaning this can actually be returning the parent for the event instead of the children.
|
|
func (w *walker) childrenForParent(eventID string) ([]eventInfo, error) {
|
|
if w.req.Direction == "down" {
|
|
return w.db.ChildrenForParent(w.ctx, eventID, constRelType, w.req.RecentFirst)
|
|
}
|
|
// find the event to pull out the parent
|
|
ei, err := w.db.ParentForChild(w.ctx, eventID, constRelType)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
if ei != nil {
|
|
return []eventInfo{*ei}, nil
|
|
}
|
|
return nil, nil
|
|
}
|