# thread_local_timezones.rb

Path: | lib/sequel/extensions/thread_local_timezones.rb
Last Update: | Sun May 19 07:59:58 +0000 2013

The thread_local_timezones extension allows you to set a per-thread timezone that will override the default global timezone while the thread is executing. The main use case is for web applications that execute each request in its own thread, and want to set the timezones based on the request.

To load the extension:

      Sequel.extension :thread_local_timezones

The most common example is having the database always store time in UTC, but have the application deal with the timezone of the current user. That can be done with:

      Sequel.database_timezone = :utc
      # In each thread:
      Sequel.thread_application_timezone = current_user.timezone

This extension is designed to work with the named_timezones extension.

This extension adds the thread_application_timezone=, thread_database_timezone=, and thread_typecast_timezone= methods to the Sequel module. It overrides the application_timezone, database_timezone, and typecast_timezone methods to check the related thread local timezone first, and use it if present. If the related thread local timezone is not present, it falls back to the default global timezone.

There is one special case of note. If you have a default global timezone and you want to have a nil thread local timezone, you have to set the thread local value to :nil instead of nil:

      Sequel.application_timezone = :utc
      Sequel.thread_application_timezone = nil
      Sequel.application_timezone # => :utc
      Sequel.thread_application_timezone = :nil
      Sequel.application_timezone # => nil

[Validate]