1 files changed, 271 insertions, 0 deletions
diff --git a/roomserver/internal/alias.go b/roomserver/internal/alias.go
new file mode 100644
index 00000000..4139582b
--- /dev/null
+++ b/roomserver/internal/alias.go
@@ -0,0 +1,271 @@
+// Copyright 2017 Vector Creations 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 internal
+
+import (
+	"context"
+	"encoding/json"
+	"errors"
+	"time"
+
+	"github.com/matrix-org/dendrite/roomserver/api"
+	"github.com/matrix-org/gomatrixserverlib"
+)
+
+// RoomserverInternalAPIDatabase has the storage APIs needed to implement the alias API.
+type RoomserverInternalAPIDatabase interface {
+	// Save a given room alias with the room ID it refers to.
+	// Returns an error if there was a problem talking to the database.
+	SetRoomAlias(ctx context.Context, alias string, roomID string, creatorUserID string) error
+	// Look up the room ID a given alias refers to.
+	// Returns an error if there was a problem talking to the database.
+	GetRoomIDForAlias(ctx context.Context, alias string) (string, error)
+	// Look up all aliases referring to a given room ID.
+	// Returns an error if there was a problem talking to the database.
+	GetAliasesForRoomID(ctx context.Context, roomID string) ([]string, error)
+	// Get the user ID of the creator of an alias.
+	// Returns an error if there was a problem talking to the database.
+	GetCreatorIDForAlias(ctx context.Context, alias string) (string, error)
+	// Remove a given room alias.
+	// Returns an error if there was a problem talking to the database.
+	RemoveRoomAlias(ctx context.Context, alias string) error
+	// Look up the room version for a given room.
+	GetRoomVersionForRoom(
+		ctx context.Context, roomID string,
+	) (gomatrixserverlib.RoomVersion, error)
+}
+
+// SetRoomAlias implements alias.RoomserverInternalAPI
+func (r *RoomserverInternalAPI) SetRoomAlias(
+	ctx context.Context,
+	request *api.SetRoomAliasRequest,
+	response *api.SetRoomAliasResponse,
+) error {
+	// Check if the alias isn't already referring to a room
+	roomID, err := r.DB.GetRoomIDForAlias(ctx, request.Alias)
+	if err != nil {
+		return err
+	}
+	if len(roomID) > 0 {
+		// If the alias already exists, stop the process
+		response.AliasExists = true
+		return nil
+	}
+	response.AliasExists = false
+
+	// Save the new alias
+	if err := r.DB.SetRoomAlias(ctx, request.Alias, request.RoomID, request.UserID); err != nil {
+		return err
+	}
+
+	// Send a m.room.aliases event with the updated list of aliases for this room
+	// At this point we've already committed the alias to the database so we
+	// shouldn't cancel this request.
+	// TODO: Ensure that we send unsent events when if server restarts.
+	return r.sendUpdatedAliasesEvent(context.TODO(), request.UserID, request.RoomID)
+}
+
+// GetRoomIDForAlias implements alias.RoomserverInternalAPI
+func (r *RoomserverInternalAPI) GetRoomIDForAlias(
+	ctx context.Context,
+	request *api.GetRoomIDForAliasRequest,
+	response *api.GetRoomIDForAliasResponse,
+) error {
+	// Look up the room ID in the database
+	roomID, err := r.DB.GetRoomIDForAlias(ctx, request.Alias)
+	if err != nil {
+		return err
+	}
+
+	/*
+		TODO: Why is this here? It creates an unnecessary dependency
+		from the roomserver to the appservice component, which should be
+		altogether optional.
+
+		if roomID == "" {
+			// No room found locally, try our application services by making a call to
+			// the appservice component
+			aliasReq := appserviceAPI.RoomAliasExistsRequest{Alias: request.Alias}
+			var aliasResp appserviceAPI.RoomAliasExistsResponse
+			if err = r.AppserviceAPI.RoomAliasExists(ctx, &aliasReq, &aliasResp); err != nil {
+				return err
+			}
+
+			if aliasResp.AliasExists {
+				roomID, err = r.DB.GetRoomIDForAlias(ctx, request.Alias)
+				if err != nil {
+					return err
+				}
+			}
+		}
+	*/
+
+	response.RoomID = roomID
+	return nil
+}
+
+// GetAliasesForRoomID implements alias.RoomserverInternalAPI
+func (r *RoomserverInternalAPI) GetAliasesForRoomID(
+	ctx context.Context,
+	request *api.GetAliasesForRoomIDRequest,
+	response *api.GetAliasesForRoomIDResponse,
+) error {
+	// Look up the aliases in the database for the given RoomID
+	aliases, err := r.DB.GetAliasesForRoomID(ctx, request.RoomID)
+	if err != nil {
+		return err
+	}
+
+	response.Aliases = aliases
+	return nil
+}
+
+// GetCreatorIDForAlias implements alias.RoomserverInternalAPI
+func (r *RoomserverInternalAPI) GetCreatorIDForAlias(
+	ctx context.Context,
+	request *api.GetCreatorIDForAliasRequest,
+	response *api.GetCreatorIDForAliasResponse,
+) error {
+	// Look up the aliases in the database for the given RoomID
+	creatorID, err := r.DB.GetCreatorIDForAlias(ctx, request.Alias)
+	if err != nil {
+		return err
+	}
+
+	response.UserID = creatorID
+	return nil
+}
+
+// RemoveRoomAlias implements alias.RoomserverInternalAPI
+func (r *RoomserverInternalAPI) RemoveRoomAlias(
+	ctx context.Context,
+	request *api.RemoveRoomAliasRequest,
+	response *api.RemoveRoomAliasResponse,
+) error {
+	// Look up the room ID in the database
+	roomID, err := r.DB.GetRoomIDForAlias(ctx, request.Alias)
+	if err != nil {
+		return err
+	}
+
+	// Remove the dalias from the database
+	if err := r.DB.RemoveRoomAlias(ctx, request.Alias); err != nil {
+		return err
+	}
+
+	// Send an updated m.room.aliases event
+	// At this point we've already committed the alias to the database so we
+	// shouldn't cancel this request.
+	// TODO: Ensure that we send unsent events when if server restarts.
+	return r.sendUpdatedAliasesEvent(context.TODO(), request.UserID, roomID)
+}
+
+type roomAliasesContent struct {
+	Aliases []string `json:"aliases"`
+}
+
+// Build the updated m.room.aliases event to send to the room after addition or
+// removal of an alias
+func (r *RoomserverInternalAPI) sendUpdatedAliasesEvent(
+	ctx context.Context, userID string, roomID string,
+) error {
+	serverName := string(r.Cfg.Matrix.ServerName)
+
+	builder := gomatrixserverlib.EventBuilder{
+		Sender:   userID,
+		RoomID:   roomID,
+		Type:     "m.room.aliases",
+		StateKey: &serverName,
+	}
+
+	// Retrieve the updated list of aliases, marhal it and set it as the
+	// event's content
+	aliases, err := r.DB.GetAliasesForRoomID(ctx, roomID)
+	if err != nil {
+		return err
+	}
+	content := roomAliasesContent{Aliases: aliases}
+	rawContent, err := json.Marshal(content)
+	if err != nil {
+		return err
+	}
+	err = builder.SetContent(json.RawMessage(rawContent))
+	if err != nil {
+		return err
+	}
+
+	// Get needed state events and depth
+	eventsNeeded, err := gomatrixserverlib.StateNeededForEventBuilder(&builder)
+	if err != nil {
+		return err
+	}
+	if len(eventsNeeded.Tuples()) == 0 {
+		return errors.New("expecting state tuples for event builder, got none")
+	}
+	req := api.QueryLatestEventsAndStateRequest{
+		RoomID:       roomID,
+		StateToFetch: eventsNeeded.Tuples(),
+	}
+	var res api.QueryLatestEventsAndStateResponse
+	if err = r.QueryLatestEventsAndState(ctx, &req, &res); err != nil {
+		return err
+	}
+	builder.Depth = res.Depth
+	builder.PrevEvents = res.LatestEvents
+
+	// Add auth events
+	authEvents := gomatrixserverlib.NewAuthEvents(nil)
+	for i := range res.StateEvents {
+		err = authEvents.AddEvent(&res.StateEvents[i].Event)
+		if err != nil {
+			return err
+		}
+	}
+	refs, err := eventsNeeded.AuthEventReferences(&authEvents)
+	if err != nil {
+		return err
+	}
+	builder.AuthEvents = refs
+
+	roomVersion, err := r.DB.GetRoomVersionForRoom(ctx, roomID)
+	if err != nil {
+		return err
+	}
+
+	// Build the event
+	now := time.Now()
+	event, err := builder.Build(
+		now, r.Cfg.Matrix.ServerName, r.Cfg.Matrix.KeyID,
+		r.Cfg.Matrix.PrivateKey, roomVersion,
+	)
+	if err != nil {
+		return err
+	}
+
+	// Create the request
+	ire := api.InputRoomEvent{
+		Kind:         api.KindNew,
+		Event:        event.Headered(roomVersion),
+		AuthEventIDs: event.AuthEventIDs(),
+		SendAsServer: serverName,
+	}
+	inputReq := api.InputRoomEventsRequest{
+		InputRoomEvents: []api.InputRoomEvent{ire},
+	}
+	var inputRes api.InputRoomEventsResponse
+
+	// Send the request
+	return r.InputRoomEvents(ctx, &inputReq, &inputRes)
+}