.. _topics-scheduler:

========= Scheduler

.. module:: scrapy.core.scheduler

The scheduler component receives requests from the :ref:engine <component-engine> and stores them into persistent and/or non-persistent data structures. It also gets those requests and feeds them back to the engine when it asks for a next request to be downloaded.

Overriding the default scheduler

You can use your own custom scheduler class by supplying its full Python path in the :setting:SCHEDULER setting.

Minimal scheduler interface

.. autoclass:: BaseScheduler :members:

Default scheduler

.. autoclass:: Scheduler() :members: :special-members: init, len

Priority queues

.. autoclass:: scrapy.pqueues.DownloaderAwarePriorityQueue .. autoclass:: scrapy.pqueues.ScrapyPriorityQueue