From 248d44cc4a47edcafb4aff86978b800973fd3a74 Mon Sep 17 00:00:00 2001
From: Serra Allgood <serra@allgood.dev>
Date: Mon, 20 May 2019 22:56:58 -0700
Subject: [PATCH] roomserver/alias: don't call appserviceAPI in
 GetRoomIDForAlias if local alias found

The existing implementation will always make a call to appserviceAPI,
regardless of whether a local alias is found in the database.

Fixes #631

Signed-off-by: Serra Allgood <serra@allgood.dev>
---
 .../dendrite/roomserver/alias/alias.go        | 14 +--
 .../dendrite/roomserver/alias/alias_test.go   | 90 +++++++++++++++++++
 2 files changed, 98 insertions(+), 6 deletions(-)
 create mode 100644 src/github.com/matrix-org/dendrite/roomserver/alias/alias_test.go

diff --git a/src/github.com/matrix-org/dendrite/roomserver/alias/alias.go b/src/github.com/matrix-org/dendrite/roomserver/alias/alias.go
index 27279aad8..e6602c743 100644
--- a/src/github.com/matrix-org/dendrite/roomserver/alias/alias.go
+++ b/src/github.com/matrix-org/dendrite/roomserver/alias/alias.go
@@ -96,12 +96,14 @@ func (r *RoomserverAliasAPI) GetRoomIDForAlias(
 		return err
 	}
 
-	// No rooms 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 len(roomID) == 0 {
+		// No rooms 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
+		}
 	}
 
 	response.RoomID = roomID
diff --git a/src/github.com/matrix-org/dendrite/roomserver/alias/alias_test.go b/src/github.com/matrix-org/dendrite/roomserver/alias/alias_test.go
new file mode 100644
index 000000000..4bbff9846
--- /dev/null
+++ b/src/github.com/matrix-org/dendrite/roomserver/alias/alias_test.go
@@ -0,0 +1,90 @@
+// 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 alias
+
+import (
+	"context"
+	"fmt"
+	"testing"
+
+	appserviceAPI "github.com/matrix-org/dendrite/appservice/api"
+	roomserverAPI "github.com/matrix-org/dendrite/roomserver/api"
+)
+
+type MockRoomserverAliasAPIDatabase struct{}
+
+func (db MockRoomserverAliasAPIDatabase) SetRoomAlias(ctx context.Context, alias string, roomID string) error {
+	return nil
+}
+
+func (db MockRoomserverAliasAPIDatabase) GetRoomIDForAlias(ctx context.Context, alias string) (string, error) {
+	return "123", nil
+}
+
+func (db MockRoomserverAliasAPIDatabase) GetAliasesForRoomID(ctx context.Context, roomID string) ([]string, error) {
+	aliases := make([]string, 0)
+	return aliases, nil
+}
+
+func (db MockRoomserverAliasAPIDatabase) RemoveRoomAlias(ctx context.Context, alias string) error {
+	return nil
+}
+
+type MockAppServiceQueryAPI struct{}
+
+func (q MockAppServiceQueryAPI) UserIDExists(
+	ctx context.Context,
+	req *appserviceAPI.UserIDExistsRequest,
+	resp *appserviceAPI.UserIDExistsResponse,
+) error {
+	return nil
+}
+
+func (q MockAppServiceQueryAPI) RoomAliasExists(
+	ctx context.Context,
+	req *appserviceAPI.RoomAliasExistsRequest,
+	resp *appserviceAPI.RoomAliasExistsResponse,
+) error {
+	return fmt.Errorf("Should not have called this")
+}
+
+func TestGetRoomIDForAlias(t *testing.T) {
+	type args struct {
+		ctx      context.Context
+		request  *roomserverAPI.GetRoomIDForAliasRequest
+		response *roomserverAPI.GetRoomIDForAliasResponse
+	}
+
+	t.Run("Found local alias", func(t *testing.T) {
+		aliasAPI := &RoomserverAliasAPI{
+			DB:            MockRoomserverAliasAPIDatabase{},
+			AppserviceAPI: MockAppServiceQueryAPI{},
+		}
+		args := args{
+			context.Background(),
+			&roomserverAPI.GetRoomIDForAliasRequest{},
+			&roomserverAPI.GetRoomIDForAliasResponse{},
+		}
+
+		err := aliasAPI.GetRoomIDForAlias(args.ctx, args.request, args.response)
+		if err != nil {
+			t.Errorf("Got %s; wanted no error", err)
+		}
+
+		if args.response.RoomID != "123" {
+			t.Errorf("Got %s; wanted 123", args.response.RoomID)
+		}
+	})
+}