1 files changed, 102 insertions, 0 deletions
diff --git a/federationapi/routing/peek.go b/federationapi/routing/peek.go
new file mode 100644
index 00000000..8f83cb15
--- /dev/null
+++ b/federationapi/routing/peek.go
@@ -0,0 +1,102 @@
+// Copyright 2020 New Vector Ltd
+//
+// 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 (
+	"net/http"
+
+	"github.com/matrix-org/dendrite/clientapi/jsonerror"
+	"github.com/matrix-org/dendrite/roomserver/api"
+	"github.com/matrix-org/dendrite/setup/config"
+	"github.com/matrix-org/gomatrixserverlib"
+	"github.com/matrix-org/util"
+)
+
+// Peek implements the SS /peek API, handling inbound peeks
+func Peek(
+	httpReq *http.Request,
+	request *gomatrixserverlib.FederationRequest,
+	cfg *config.FederationAPI,
+	rsAPI api.RoomserverInternalAPI,
+	roomID, peekID string,
+	remoteVersions []gomatrixserverlib.RoomVersion,
+) util.JSONResponse {
+	// TODO: check if we're just refreshing an existing peek by querying the federationsender
+
+	verReq := api.QueryRoomVersionForRoomRequest{RoomID: roomID}
+	verRes := api.QueryRoomVersionForRoomResponse{}
+	if err := rsAPI.QueryRoomVersionForRoom(httpReq.Context(), &verReq, &verRes); err != nil {
+		return util.JSONResponse{
+			Code: http.StatusInternalServerError,
+			JSON: jsonerror.InternalServerError(),
+		}
+	}
+
+	// Check that the room that the peeking server is trying to peek is actually
+	// one of the room versions that they listed in their supported ?ver= in
+	// the peek URL.
+	remoteSupportsVersion := false
+	for _, v := range remoteVersions {
+		if v == verRes.RoomVersion {
+			remoteSupportsVersion = true
+			break
+		}
+	}
+	// If it isn't, stop trying to peek the room.
+	if !remoteSupportsVersion {
+		return util.JSONResponse{
+			Code: http.StatusBadRequest,
+			JSON: jsonerror.IncompatibleRoomVersion(verRes.RoomVersion),
+		}
+	}
+
+	// TODO: Check history visibility
+
+	// tell the peeking server to renew every hour
+	renewalInterval := int64(60 * 60 * 1000 * 1000)
+
+	var response api.PerformInboundPeekResponse
+	err := rsAPI.PerformInboundPeek(
+		httpReq.Context(),
+		&api.PerformInboundPeekRequest{
+			RoomID:          roomID,
+			PeekID:          peekID,
+			ServerName:      request.Origin(),
+			RenewalInterval: renewalInterval,
+		},
+		&response,
+	)
+	if err != nil {
+		resErr := util.ErrorResponse(err)
+		return resErr
+	}
+
+	if !response.RoomExists {
+		return util.JSONResponse{Code: http.StatusNotFound, JSON: nil}
+	}
+
+	respPeek := gomatrixserverlib.RespPeek{
+		StateEvents:     gomatrixserverlib.UnwrapEventHeaders(response.StateEvents),
+		AuthEvents:      gomatrixserverlib.UnwrapEventHeaders(response.AuthChainEvents),
+		RoomVersion:     response.RoomVersion,
+		LatestEvent:     response.LatestEvent.Unwrap(),
+		RenewalInterval: renewalInterval,
+	}
+
+	return util.JSONResponse{
+		Code: http.StatusOK,
+		JSON: respPeek,
+	}
+}