From c011d009ee51eb8e21902152560a50c32b7120b3 Mon Sep 17 00:00:00 2001
From: Roy Xiang <git@royxiang.me>
Date: Fri, 11 Mar 2022 17:24:32 +0800
Subject: [PATCH] refactor: lock playback session by session key

---
 handler/plex.go | 39 ++++++++++++++++++---------------------
 1 file changed, 18 insertions(+), 21 deletions(-)

diff --git a/handler/plex.go b/handler/plex.go
index 3ace3ec..70f8191 100644
--- a/handler/plex.go
+++ b/handler/plex.go
@@ -148,13 +148,12 @@ func (c *PlexClient) IsTokenSet() bool {
 	return c.client.Token != ""
 }
 
-func (c *PlexClient) GetUser(token string) (user *plexUser) {
-	if user = c.searchUser(token); user != nil {
-		return
+func (c *PlexClient) GetUser(token string) *plexUser {
+	if user := c.searchUser(token); user != nil {
+		return user
 	}
 	c.fetchUsers(token)
-	user = c.searchUser(token)
-	return
+	return c.searchUser(token)
 }
 
 func (c *PlexClient) searchUser(token string) *plexUser {
@@ -264,11 +263,11 @@ func (c *PlexClient) syncTimelineWithPlaxt(r *http.Request, user *plexUser) {
 		return
 	}
 
-	session := c.getPlayerSession(clientUuid, ratingKey)
+	sessionKey, session := c.getPlayerSession(clientUuid, ratingKey)
 	if session == nil || session.status == sessionWatched {
 		return
 	}
-	lockKey := fmt.Sprintf("plex:session:%d:%s:%s", user.Id, clientUuid, ratingKey)
+	lockKey := fmt.Sprintf("plex:session:%s", sessionKey)
 	c.MulLock.Lock(lockKey)
 	defer c.MulLock.Unlock(lockKey)
 
@@ -401,13 +400,12 @@ func (c *PlexClient) getServerIdentifier() string {
 	return *c.serverIdentifier
 }
 
-func (c *PlexClient) getLibrarySection(sectionKey string) (section *plex.Directory) {
-	if section = c.searchLibrarySection(sectionKey); section != nil {
-		return
+func (c *PlexClient) getLibrarySection(sectionKey string) *plex.Directory {
+	if section := c.searchLibrarySection(sectionKey); section != nil {
+		return section
 	}
 	c.fetchLibrarySections()
-	section = c.searchLibrarySection(sectionKey)
-	return
+	return c.searchLibrarySection(sectionKey)
 }
 
 func (c *PlexClient) searchLibrarySection(sectionKey string) *plex.Directory {
@@ -440,25 +438,24 @@ func (c *PlexClient) fetchLibrarySections() {
 	}
 }
 
-func (c *PlexClient) getPlayerSession(playerIdentifier, ratingKey string) (session *sessionData) {
-	if session = c.searchPlayerSession(playerIdentifier, ratingKey); session != nil {
-		return session
+func (c *PlexClient) getPlayerSession(playerIdentifier, ratingKey string) (string, *sessionData) {
+	if key, session := c.searchPlayerSession(playerIdentifier, ratingKey); session != nil {
+		return key, session
 	}
 	c.fetchPlayerSessions()
-	session = c.searchPlayerSession(playerIdentifier, ratingKey)
-	return
+	return c.searchPlayerSession(playerIdentifier, ratingKey)
 }
 
-func (c *PlexClient) searchPlayerSession(playerIdentifier, ratingKey string) *sessionData {
+func (c *PlexClient) searchPlayerSession(playerIdentifier, ratingKey string) (string, *sessionData) {
 	c.MulLock.RLock(lockKeySessions)
 	defer c.MulLock.RUnlock(lockKeySessions)
 
-	for _, session := range c.sessions {
+	for key, session := range c.sessions {
 		if session.metadata.Player.MachineIdentifier == playerIdentifier && session.metadata.RatingKey == ratingKey {
-			return session
+			return key, session
 		}
 	}
-	return nil
+	return "", nil
 }
 
 func (c *PlexClient) fetchPlayerSessions() {