Accessing session data
Session data in GitLab is stored in Redis and can be accessed in a variety of ways.
During a web request, for example:
- Rails provides access to the session from within controllers through
ActionDispatch::Session
. - Outside of controllers, it is possible to access the session through
Gitlab::Session
.
Outside of a web request it is still possible to access sessions stored in Redis. For example:
- Session IDs and contents can be looked up directly in Redis.
- Data about the UserAgent associated with the session can be accessed through
ActiveSession
.
When storing values in a session it is best to:
- Use simple primitives and avoid storing objects to avoid marshaling complications.
- Clean up after unneeded variables to keep memory usage in Redis down.
GitLab::Session
Sometimes you might want to persist data in the session instead of another store like the database. Gitlab::Session
lets you access this without passing the session around extensively. For example, you could access it from within a policy without having to pass the session through to each place permissions are checked from.
The session has a hash-like interface, just like when using it from a controller. There is also NamespacedSessionStore
for storing key-value data in a hash.
# Lookup a value stored in the current session
Gitlab::Session.current[:my_feature]
# Modify the current session stored in redis
Gitlab::Session.current[:my_feature] = value
# Store key-value data namespaced under a key
Gitlab::NamespacedSessionStore.new(:my_feature)[some_key] = value
# Set the session for a block of code, such as for tests
Gitlab::Session.with_session(my_feature: value) do
# Code that uses Session.current[:my_feature]
end
Redis
Session data can be accessed directly through Redis. This can let you check up on a browser session when debugging.
# Get a list of sessions
session_ids = Gitlab::Redis::Sessions.with do |redis|
redis.smembers("#{Gitlab::Redis::Sessions::USER_SESSIONS_LOOKUP_NAMESPACE}:#{user.id}")
end
# Retrieve a specific session
session_data = Gitlab::Redis::Sessions.with { |redis| redis.get("#{Gitlab::Redis::Sessions::SESSION_NAMESPACE}:#{session_id}") }
Marshal.load(session_data)
Getting device information with ActiveSession
The Active Sessions page on a user's profile displays information about the device used to access each session. The methods used there to list sessions can also be useful for development.
# Get list of sessions for a given user
# Includes session_id and data from the UserAgent
ActiveSession.list(user)