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98 lines
3.1 KiB
98 lines
3.1 KiB
6 years ago
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"""
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This module provides the API for ``requests_toolbelt.threaded``.
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The module provides a clean and simple API for making requests via a thread
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pool. The thread pool will use sessions for increased performance.
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A simple use-case is:
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.. code-block:: python
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from requests_toolbelt import threaded
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urls_to_get = [{
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'url': 'https://api.github.com/users/sigmavirus24',
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'method': 'GET',
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}, {
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'url': 'https://api.github.com/repos/requests/toolbelt',
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'method': 'GET',
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}, {
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'url': 'https://google.com',
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'method': 'GET',
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}]
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responses, errors = threaded.map(urls_to_get)
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By default, the threaded submodule will detect the number of CPUs your
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computer has and use that if no other number of processes is selected. To
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change this, always use the keyword argument ``num_processes``. Using the
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above example, we would expand it like so:
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.. code-block:: python
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responses, errors = threaded.map(urls_to_get, num_processes=10)
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You can also customize how a :class:`requests.Session` is initialized by
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creating a callback function:
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.. code-block:: python
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from requests_toolbelt import user_agent
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def initialize_session(session):
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session.headers['User-Agent'] = user_agent('my-scraper', '0.1')
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session.headers['Accept'] = 'application/json'
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responses, errors = threaded.map(urls_to_get,
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initializer=initialize_session)
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.. autofunction:: requests_toolbelt.threaded.map
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Inspiration is blatantly drawn from the standard library's multiprocessing
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library. See the following references:
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- multiprocessing's `pool source`_
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- map and map_async `inspiration`_
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.. _pool source:
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https://hg.python.org/cpython/file/8ef4f75a8018/Lib/multiprocessing/pool.py
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.. _inspiration:
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https://hg.python.org/cpython/file/8ef4f75a8018/Lib/multiprocessing/pool.py#l340
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"""
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from . import pool
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from .._compat import queue
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def map(requests, **kwargs):
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r"""Simple interface to the threaded Pool object.
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This function takes a list of dictionaries representing requests to make
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using Sessions in threads and returns a tuple where the first item is
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a generator of successful responses and the second is a generator of
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exceptions.
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:param list requests:
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Collection of dictionaries representing requests to make with the Pool
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object.
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:param \*\*kwargs:
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Keyword arguments that are passed to the
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:class:`~requests_toolbelt.threaded.pool.Pool` object.
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:returns: Tuple of responses and exceptions from the pool
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:rtype: (:class:`~requests_toolbelt.threaded.pool.ThreadResponse`,
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:class:`~requests_toolbelt.threaded.pool.ThreadException`)
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"""
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if not (requests and all(isinstance(r, dict) for r in requests)):
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raise ValueError('map expects a list of dictionaries.')
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# Build our queue of requests
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job_queue = queue.Queue()
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for request in requests:
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job_queue.put(request)
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# Ensure the user doesn't try to pass their own job_queue
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kwargs['job_queue'] = job_queue
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threadpool = pool.Pool(**kwargs)
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threadpool.join_all()
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return threadpool.responses(), threadpool.exceptions()
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