From 4eb7f5d75f45fbfdf51095bf13a924ca59fb777c Mon Sep 17 00:00:00 2001
From: Neil Alexander <neilalexander@users.noreply.github.com>
Date: Wed, 5 Feb 2020 13:39:04 +0000
Subject: [PATCH] Add wiring for querying the roomserver for the default room
 version

---
 roomserver/api/query.go   | 31 +++++++++++++++++++++++++++++++
 roomserver/query/query.go | 11 +++++++++++
 2 files changed, 42 insertions(+)

diff --git a/roomserver/api/query.go b/roomserver/api/query.go
index b3fa01840..edf4de983 100644
--- a/roomserver/api/query.go
+++ b/roomserver/api/query.go
@@ -244,6 +244,14 @@ type QueryServersInRoomAtEventResponse struct {
 	Servers []gomatrixserverlib.ServerName `json:"servers"`
 }
 
+// QueryDefaultRoomVersion asks for the default room version
+type QueryDefaultRoomVersionRequest struct{}
+
+// QueryDefaultRoomVersionResponse is a response to QueryServersInRoomAtEventResponse
+type QueryDefaultRoomVersionResponse struct {
+	RoomVersion int64
+}
+
 // RoomserverQueryAPI is used to query information from the room server.
 type RoomserverQueryAPI interface {
 	// Query the latest events and state for a room from the room server.
@@ -323,6 +331,13 @@ type RoomserverQueryAPI interface {
 		request *QueryServersInRoomAtEventRequest,
 		response *QueryServersInRoomAtEventResponse,
 	) error
+
+	// Asks for the default room version as preferred by the server.
+	QueryDefaultRoomVersion(
+		ctx context.Context,
+		request *QueryDefaultRoomVersionRequest,
+		response *QueryDefaultRoomVersionResponse,
+	) error
 }
 
 // RoomserverQueryLatestEventsAndStatePath is the HTTP path for the QueryLatestEventsAndState API.
@@ -358,6 +373,9 @@ const RoomserverQueryBackfillPath = "/api/roomserver/queryBackfill"
 // RoomserverQueryServersInRoomAtEventPath is the HTTP path for the QueryServersInRoomAtEvent API
 const RoomserverQueryServersInRoomAtEventPath = "/api/roomserver/queryServersInRoomAtEvents"
 
+// RoomserverQueryDefaultRoomVersionPath is the HTTP path for the QueryDefaultRoomVersion API
+const RoomserverQueryDefaultRoomVersionPath = "/api/roomserver/queryDefaultRoomVersion"
+
 // NewRoomserverQueryAPIHTTP creates a RoomserverQueryAPI implemented by talking to a HTTP POST API.
 // If httpClient is nil then it uses the http.DefaultClient
 func NewRoomserverQueryAPIHTTP(roomserverURL string, httpClient *http.Client) RoomserverQueryAPI {
@@ -514,3 +532,16 @@ func (h *httpRoomserverQueryAPI) QueryServersInRoomAtEvent(
 	apiURL := h.roomserverURL + RoomserverQueryServersInRoomAtEventPath
 	return commonHTTP.PostJSON(ctx, span, h.httpClient, apiURL, request, response)
 }
+
+// QueryServersInRoomAtEvent implements RoomServerQueryAPI
+func (h *httpRoomserverQueryAPI) QueryDefaultRoomVersion(
+	ctx context.Context,
+	request *QueryDefaultRoomVersionRequest,
+	response *QueryDefaultRoomVersionResponse,
+) error {
+	span, ctx := opentracing.StartSpanFromContext(ctx, "QueryDefaultRoomVersion")
+	defer span.Finish()
+
+	apiURL := h.roomserverURL + RoomserverQueryDefaultRoomVersionPath
+	return commonHTTP.PostJSON(ctx, span, h.httpClient, apiURL, request, response)
+}
diff --git a/roomserver/query/query.go b/roomserver/query/query.go
index d318fc001..907e45bb7 100644
--- a/roomserver/query/query.go
+++ b/roomserver/query/query.go
@@ -25,6 +25,7 @@ import (
 	"github.com/matrix-org/dendrite/roomserver/state"
 	"github.com/matrix-org/dendrite/roomserver/state/database"
 	"github.com/matrix-org/dendrite/roomserver/types"
+	"github.com/matrix-org/dendrite/roomserver/version"
 	"github.com/matrix-org/gomatrixserverlib"
 	"github.com/matrix-org/util"
 )
@@ -723,6 +724,16 @@ func (r *RoomserverQueryAPI) QueryServersInRoomAtEvent(
 	return nil
 }
 
+// QueryDefaultRoomVersion implements api.RoomserverQueryAPI
+func (r *RoomserverQueryAPI) QueryDefaultRoomVersion(
+	ctx context.Context,
+	request *api.QueryDefaultRoomVersionRequest,
+	response *api.QueryDefaultRoomVersionResponse,
+) error {
+	response.RoomVersion = int64(version.GetDefaultRoomVersion())
+	return nil
+}
+
 // SetupHTTP adds the RoomserverQueryAPI handlers to the http.ServeMux.
 // nolint: gocyclo
 func (r *RoomserverQueryAPI) SetupHTTP(servMux *http.ServeMux) {