2 files changed, 51 insertions, 6 deletions

diff --git a/appservice/account.go b/appservice/account.go
index 2df2930..3791ee3 100644
--- a/appservice/account.go
+++ b/appservice/account.go
@@ -137,9 +137,13 @@ func (a *Account) userInfoUpdatedInternal(user UserID, info *UserInfo) error {
 	}
 
 	if info.Avatar != nil {
-		err2 := mx.ProfileAvatar(mx_user_id, info.Avatar)
-		if err2 != nil {
-			err = err2
+		cache_key := fmt.Sprintf("%s/user_avatar/%s", a.Protocol, user)
+		cache_val := info.Avatar.Filename()
+		if cache_val == "" || dbCacheTestAndSet(cache_key, cache_val) {
+			err2 := mx.ProfileAvatar(mx_user_id, info.Avatar)
+			if err2 != nil {
+				err = err2
+			}
 		}
 	}
 
@@ -185,9 +189,13 @@ func (a *Account) roomInfoUpdatedInternal(roomId RoomID, author UserID, info *Ro
 	}
 
 	if info.Picture != nil {
-		err2 := mx.RoomAvatarAs(mx_room_id, info.Picture, as_mxid)
-		if err2 != nil {
-			err = err2
+		cache_key := fmt.Sprintf("%s/room_picture/%s", a.Protocol, roomId)
+		cache_val := info.Picture.Filename()
+		if cache_val == "" || dbCacheTestAndSet(cache_key, cache_val) {
+			err2 := mx.RoomAvatarAs(mx_room_id, info.Picture, as_mxid)
+			if err2 != nil {
+				err = err2
+			}
 		}
 	}
 
@@ -204,6 +212,9 @@ func (a *Account) Event(event *Event) {
 }
 
 func (a *Account) eventInternal(event *Event) error {
+	// TODO: automatically ignore events that come from one of our bridged matrix users
+	// TODO: deduplicate events if we have several matrix users joined the same room (hard problem)
+
 	mx_user_id, err := dbGetMxUser(a.Protocol, event.Author)
 	if err != nil {
 		return err
diff --git a/appservice/db.go b/appservice/db.go
index 5cefd30..646dae3 100644
--- a/appservice/db.go
+++ b/appservice/db.go
@@ -23,6 +23,8 @@ func InitDb() error {
 		return err
 	}
 
+	db.AutoMigrate(&DbCache{})
+
 	db.AutoMigrate(&DbUserMap{})
 	db.Model(&DbUserMap{}).AddIndex("idx_protocol_user", "protocol", "user_id")
 
@@ -35,6 +37,14 @@ func InitDb() error {
 	return nil
 }
 
+// Long-term cache entries
+type DbCache struct {
+	gorm.Model
+
+	Key string `gorm:"unique_index"`
+	Value string
+}
+
 // User mapping between protocol user IDs and puppeted matrix ids
 type DbUserMap struct {
 	gorm.Model
@@ -76,6 +86,30 @@ type DbPmRoomMap struct {
 
 // ----
 
+func dbCacheGet(key string) string {
+	var entry DbCache
+	if db.Where(&DbCache{Key: key}).First(&entry).RecordNotFound() {
+		return ""
+	} else {
+		return entry.Value
+	}
+}
+
+func dbCachePut(key string, value string) {
+	var entry DbCache
+	db.Where(&DbCache{Key: key}).Assign(&DbCache{Value: value}).FirstOrCreate(&entry)
+}
+
+func dbCacheTestAndSet(key string, value string) bool {
+	// TODO make this really an atomic operation
+	// True if value was changed, false if was already set
+	if dbCacheGet(key) != value {
+		dbCachePut(key, value)
+		return true
+	}
+	return false
+}
+
 func dbGetMxRoom(protocol string, roomId connector.RoomID) (string, error) {
 	var room DbRoomMap