dendrite/clientapi/routing/directory_public.go

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// 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 routing
import (
"context"
"math/rand"
"net/http"
"sort"
"strconv"
"strings"
"sync"
"github.com/matrix-org/dendrite/clientapi/api"
"github.com/matrix-org/dendrite/clientapi/httputil"
"github.com/matrix-org/dendrite/clientapi/jsonerror"
currentstateAPI "github.com/matrix-org/dendrite/currentstateserver/api"
roomserverAPI "github.com/matrix-org/dendrite/roomserver/api"
"github.com/matrix-org/gomatrixserverlib"
"github.com/matrix-org/util"
)
var (
cacheMu sync.Mutex
publicRoomsCache []gomatrixserverlib.PublicRoom
)
type PublicRoomReq struct {
Since string `json:"since,omitempty"`
Limit int16 `json:"limit,omitempty"`
Filter filter `json:"filter,omitempty"`
}
type filter struct {
SearchTerms string `json:"generic_search_term,omitempty"`
}
// GetPostPublicRooms implements GET and POST /publicRooms
func GetPostPublicRooms(
req *http.Request, rsAPI roomserverAPI.RoomserverInternalAPI, stateAPI currentstateAPI.CurrentStateInternalAPI,
extRoomsProvider api.ExtraPublicRoomsProvider,
) util.JSONResponse {
var request PublicRoomReq
if fillErr := fillPublicRoomsReq(req, &request); fillErr != nil {
return *fillErr
}
response, err := publicRooms(req.Context(), request, rsAPI, stateAPI, extRoomsProvider)
if err != nil {
util.GetLogger(req.Context()).WithError(err).Errorf("failed to work out public rooms")
return jsonerror.InternalServerError()
}
return util.JSONResponse{
Code: http.StatusOK,
JSON: response,
}
}
func publicRooms(ctx context.Context, request PublicRoomReq, rsAPI roomserverAPI.RoomserverInternalAPI,
stateAPI currentstateAPI.CurrentStateInternalAPI, extRoomsProvider api.ExtraPublicRoomsProvider,
) (*gomatrixserverlib.RespPublicRooms, error) {
response := gomatrixserverlib.RespPublicRooms{
Chunk: []gomatrixserverlib.PublicRoom{},
}
var limit int16
var offset int64
limit = request.Limit
if limit == 0 {
limit = 50
}
offset, err := strconv.ParseInt(request.Since, 10, 64)
// ParseInt returns 0 and an error when trying to parse an empty string
// In that case, we want to assign 0 so we ignore the error
if err != nil && len(request.Since) > 0 {
util.GetLogger(ctx).WithError(err).Error("strconv.ParseInt failed")
return nil, err
}
err = nil
var rooms []gomatrixserverlib.PublicRoom
if request.Since == "" {
rooms = refreshPublicRoomCache(ctx, rsAPI, extRoomsProvider, stateAPI)
} else {
rooms = getPublicRoomsFromCache()
}
response.TotalRoomCountEstimate = len(rooms)
chunk, prev, next := sliceInto(rooms, offset, limit)
if prev >= 0 {
response.PrevBatch = "T" + strconv.Itoa(prev)
}
if next >= 0 {
response.NextBatch = "T" + strconv.Itoa(next)
}
if chunk != nil {
response.Chunk = chunk
}
return &response, err
}
// fillPublicRoomsReq fills the Limit, Since and Filter attributes of a GET or POST request
// on /publicRooms by parsing the incoming HTTP request
// Filter is only filled for POST requests
func fillPublicRoomsReq(httpReq *http.Request, request *PublicRoomReq) *util.JSONResponse {
if httpReq.Method != "GET" && httpReq.Method != "POST" {
return &util.JSONResponse{
Code: http.StatusMethodNotAllowed,
JSON: jsonerror.NotFound("Bad method"),
}
}
if httpReq.Method == "GET" {
limit, err := strconv.Atoi(httpReq.FormValue("limit"))
// Atoi returns 0 and an error when trying to parse an empty string
// In that case, we want to assign 0 so we ignore the error
if err != nil && len(httpReq.FormValue("limit")) > 0 {
util.GetLogger(httpReq.Context()).WithError(err).Error("strconv.Atoi failed")
return &util.JSONResponse{
Code: 400,
JSON: jsonerror.BadJSON("limit param is not a number"),
}
}
request.Limit = int16(limit)
request.Since = httpReq.FormValue("since")
} else {
resErr := httputil.UnmarshalJSONRequest(httpReq, request)
if resErr != nil {
return resErr
}
}
// strip the 'T' which is only required because when sytest does pagination tests it stops
// iterating when !prev_batch which then fails if prev_batch==0, so add arbitrary text to
// make it truthy not falsey.
request.Since = strings.TrimPrefix(request.Since, "T")
return nil
}
// sliceInto returns a subslice of `slice` which honours the since/limit values given.
//
// 0 1 2 3 4 5 6 index
// [A, B, C, D, E, F, G] slice
//
// limit=3 => A,B,C (prev='', next='3')
// limit=3&since=3 => D,E,F (prev='0', next='6')
// limit=3&since=6 => G (prev='3', next='')
//
// A value of '-1' for prev/next indicates no position.
func sliceInto(slice []gomatrixserverlib.PublicRoom, since int64, limit int16) (subset []gomatrixserverlib.PublicRoom, prev, next int) {
prev = -1
next = -1
if since > 0 {
prev = int(since) - int(limit)
}
nextIndex := int(since) + int(limit)
if len(slice) > nextIndex { // there are more rooms ahead of us
next = nextIndex
}
// apply sanity caps
if since < 0 {
since = 0
}
if nextIndex > len(slice) {
nextIndex = len(slice)
}
subset = slice[since:nextIndex]
return
}
func refreshPublicRoomCache(
ctx context.Context, rsAPI roomserverAPI.RoomserverInternalAPI, extRoomsProvider api.ExtraPublicRoomsProvider,
stateAPI currentstateAPI.CurrentStateInternalAPI,
) []gomatrixserverlib.PublicRoom {
cacheMu.Lock()
defer cacheMu.Unlock()
var extraRooms []gomatrixserverlib.PublicRoom
if extRoomsProvider != nil {
extraRooms = extRoomsProvider.Rooms()
}
var queryRes roomserverAPI.QueryPublishedRoomsResponse
err := rsAPI.QueryPublishedRooms(ctx, &roomserverAPI.QueryPublishedRoomsRequest{}, &queryRes)
if err != nil {
util.GetLogger(ctx).WithError(err).Error("QueryPublishedRooms failed")
return publicRoomsCache
}
pubRooms, err := currentstateAPI.PopulatePublicRooms(ctx, queryRes.RoomIDs, stateAPI)
if err != nil {
util.GetLogger(ctx).WithError(err).Error("PopulatePublicRooms failed")
return publicRoomsCache
}
publicRoomsCache = []gomatrixserverlib.PublicRoom{}
publicRoomsCache = append(publicRoomsCache, pubRooms...)
publicRoomsCache = append(publicRoomsCache, extraRooms...)
publicRoomsCache = dedupeAndShuffle(publicRoomsCache)
// sort by total joined member count (big to small)
sort.SliceStable(publicRoomsCache, func(i, j int) bool {
return publicRoomsCache[i].JoinedMembersCount > publicRoomsCache[j].JoinedMembersCount
})
return publicRoomsCache
}
func getPublicRoomsFromCache() []gomatrixserverlib.PublicRoom {
cacheMu.Lock()
defer cacheMu.Unlock()
return publicRoomsCache
}
func dedupeAndShuffle(in []gomatrixserverlib.PublicRoom) []gomatrixserverlib.PublicRoom {
// de-duplicate rooms with the same room ID. We can join the room via any of these aliases as we know these servers
// are alive and well, so we arbitrarily pick one (purposefully shuffling them to spread the load a bit)
var publicRooms []gomatrixserverlib.PublicRoom
haveRoomIDs := make(map[string]bool)
rand.Shuffle(len(in), func(i, j int) {
in[i], in[j] = in[j], in[i]
})
for _, r := range in {
if haveRoomIDs[r.RoomID] {
continue
}
haveRoomIDs[r.RoomID] = true
publicRooms = append(publicRooms, r)
}
return publicRooms
}