Based on [MSC3575](https://github.com/matrix-org/matrix-spec-proposals/pull/3575): Sliding Sync
This iteration only focuses on returning the list of room IDs in the sliding window API (without sorting/filtering).
Rooms appear in the Sliding sync response based on:
- `invite`, `join`, `knock`, `ban` membership events
- Kicks (`leave` membership events where `sender` is different from the `user_id`/`state_key`)
- `newly_left` (rooms that were left during the given token range, > `from_token` and <= `to_token`)
- In order for bans/kicks to not show up, you need to `/forget` those rooms. This doesn't modify the event itself though and only adds the `forgotten` flag to `room_memberships` in Synapse. There isn't a way to tell when a room was forgotten at the moment so we can't factor it into the from/to range.
### Example request
`POST http://localhost:8008/_matrix/client/unstable/org.matrix.msc3575/sync`
```json
{
"lists": {
"foo-list": {
"ranges": [ [0, 99] ],
"sort": [ "by_notification_level", "by_recency", "by_name" ],
"required_state": [
["m.room.join_rules", ""],
["m.room.history_visibility", ""],
["m.space.child", "*"]
],
"timeline_limit": 100
}
}
}
```
Response:
```json
{
"next_pos": "s58_224_0_13_10_1_1_16_0_1",
"lists": {
"foo-list": {
"count": 1,
"ops": [
{
"op": "SYNC",
"range": [0, 99],
"room_ids": [
"!MmgikIyFzsuvtnbvVG:my.synapse.linux.server"
]
}
]
}
},
"rooms": {},
"extensions": {}
}
```
