PyPAC: Proxy auto-config for Python

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PyPAC is a Python library for finding proxy auto-config (PAC)_ files and making HTTP requests that respect them. PAC files are often used in organizations that need fine-grained and centralized control of proxy settings.

PyPAC can find PAC files according to the DNS portion of the Web Proxy Auto-Discovery (WPAD)_ protocol. On Windows, PyPAC will automatically get the PAC file URL from the Internet Options dialog. On macOS, PyPAC will automatically get the PAC file URL from System Preferences.

.. _proxy auto-config (PAC): https://en.wikipedia.org/wiki/Proxy_auto-config

PyPAC provides a subclass of a Requests <http://docs.python-requests.org/en/master/>_ Session, so you can start using it immediately, with any PAC file transparently discovered and honoured:

.. code-block:: python

>>> from pypac import PACSession
>>> session = PACSession()
>>> session.get('http://example.org')
...

If a PAC file isn’t found, then PACSession behaves like a regular Session.

.. _Web Proxy Auto-Discovery (WPAD): https://en.wikipedia.org/wiki/Web_Proxy_Autodiscovery_Protocol

If you’re looking to add basic PAC functionality to a library that you’re using, try the pac_context_for_url() context manager:

.. code-block:: python

from pypac import pac_context_for_url import boto3

with pac_context_for_url(‘https://example.amazonaws.com‘): client = boto3.client(‘sqs’) client.list_queues()

This sets up proxy environment variables at the start of the scope, based on any auto-discovered PAC and the given URL. pac_context_for_url() should work for any library that honours proxy environment variables.

Features

• The same Requests API that you already know and love
• Honour PAC setting from Windows Internet Options and macOS System Preferences
• Follow DNS Web Proxy Auto-Discovery protocol
• Proxy authentication pass-through
• Proxy failover and load balancing
• Generic components for adding PAC support to other code

PyPAC supports Python 2.7 and 3.5+.

Installation

Install PyPAC using pip <https://pip.pypa.io>_::

$ python -m pip install pypac

Documentation

PyPAC’s documentation is available at http://pypac.readthedocs.io/.