1---
2stage: none
3group: unassigned
4info: To determine the technical writer assigned to the Stage/Group associated with this page, see https://about.gitlab.com/handbook/engineering/ux/technical-writing/#assignments
5---
6
7# Accessing session data
8
9Session data in GitLab is stored in Redis and can be accessed in a variety of ways.
10
11During a web request, for example:
12
13- Rails provides access to the session from within controllers through [`ActionDispatch::Session`](https://guides.rubyonrails.org/action_controller_overview.html#session).
14- Outside of controllers, it is possible to access the session through `Gitlab::Session`.
15
16Outside of a web request it is still possible to access sessions stored in Redis. For example:
17
18- Session IDs and contents can be [looked up directly in Redis](#redis).
19- Data about the UserAgent associated with the session can be accessed through `ActiveSession`.
20
21When storing values in a session it is best to:
22
23- Use simple primitives and avoid storing objects to avoid marshaling complications.
24- Clean up after unneeded variables to keep memory usage in Redis down.
25
26## GitLab::Session
27
28Sometimes 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.
29
30The 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.
31
32```ruby
33# Lookup a value stored in the current session
34Gitlab::Session.current[:my_feature]
35
36# Modify the current session stored in redis
37Gitlab::Session.current[:my_feature] = value
38
39# Store key-value data namespaced under a key
40Gitlab::NamespacedSessionStore.new(:my_feature)[some_key] = value
41
42# Set the session for a block of code, such as for tests
43Gitlab::Session.with_session(my_feature: value) do
44  # Code that uses Session.current[:my_feature]
45end
46```
47
48## Redis
49
50Session data can be accessed directly through Redis. This can let you check up on a browser session when debugging.
51
52```ruby
53# Get a list of sessions
54session_ids = Gitlab::Redis::Sessions.with do |redis|
55  redis.smembers("#{Gitlab::Redis::Sessions::USER_SESSIONS_LOOKUP_NAMESPACE}:#{user.id}")
56end
57
58# Retrieve a specific session
59session_data = Gitlab::Redis::Sessions.with { |redis| redis.get("#{Gitlab::Redis::Sessions::SESSION_NAMESPACE}:#{session_id}") }
60Marshal.load(session_data)
61```
62
63## Getting device information with ActiveSession
64
65The [**Active Sessions** page on a user's profile](../user/profile/active_sessions.md) displays information about the device used to access each session. The methods used there to list sessions can also be useful for development.
66
67```ruby
68# Get list of sessions for a given user
69# Includes session_id and data from the UserAgent
70ActiveSession.list(user)
71```
72