djproxy 2.3.0

djproxy is a simple reverse proxy class-based generic view for Django apps.

If an application depends on a proxy (to get around Same Origin Policy issues
in JavaScript, perhaps), djproxy can be used to provide that functionality in
a web server agnostic way. This allows developers to keep local development
environments for proxy dependent applications fully functional without needing
to run anything other than the django development server.

djproxy is also suitable for use in production environments and has been proven
to be performant in large scale deployments. However, a web server's proxy
capabilities will be *more* performant in many cases. If one needs to use this
in production, it should be fine as long as upstream responses aren't large.
Performance can be further increased by aggressively caching upstream
responses.

Home-page: https://github.com/thomasw/djproxy
Author: Thomas Welfley
Author-email: thomas.welfley+djproxy@gmail.com
License: MIT
Description: djproxy
=======

|Build Status| |Coverage Status| |Latest Version| |Downloads|

djproxy is a class-based generic view reverse HTTP proxy for Django.

Why?
----

If an application depends on a proxy (to get around Same Origin Policy
issues in JavaScript, perhaps), djproxy can be used to provide that
functionality in a web server agnostic way. This allows developers to
keep local development environments for proxy dependent applications
fully functional without needing to run anything other than the django
development server.

djproxy is also suitable for use in production environments and has been
proven to be performant in large scale deployments. However, a web
server's proxy capabilities will be *more* performant in many cases. If
one needs to use this in production, it should be fine as long as
upstream responses aren't large. Performance can be further increased by
aggressively caching upstream responses.

Note that djproxy doesn't currently support websockets because django
doesn't support them. I will investigate adding websocket support as
soon as django has it.

Installation
------------

::

pip install djproxy

djproxy requires requests >= 1.0.0, django >= 1.4.0 and python >= 2.6.

Usage
-----

Start by defining a new proxy:

.. code:: python

from djproxy.views import HttpProxy

class LocalProxy(HttpProxy):
base_url = 'https://google.com/'

Add a url pattern that points at the proxy view. The ``url`` kwarg will
be urljoined with base\_url:

.. code:: python

urlpatterns = patterns(
'',
url(r'^local_proxy/(?P<url>.*)$', LocalProxy.as_view(), name='proxy')
)

``/local_proxy/some/content`` will now proxy
``https://google.com/some/content/``.

Additional examples can be found here:
`views <https://github.com/yola/djproxy/blob/master/tests/test_views.py>`__,
`urls <https://github.com/yola/djproxy/blob/master/tests/test_urls.py>`__.

HttpProxy configuration:
~~~~~~~~~~~~~~~~~~~~~~~~

``HttpProxy`` view's behavior can be further customized by overriding
the following class attributes.

- ``base_url``: The proxy url is formed by
``urlparse.urljoin(base_url, url_kwarg)``
- ``ignored_upstream_headers``: A list of headers that shouldn't be
forwarded to the browser from the proxied endpoint.
- ``ignored_request_headers``: A list of headers that shouldn't be
forwarded to the proxied endpoint from the browser.
- ``proxy_middleware``: A list of proxy middleware to apply to request
and response data.
- ``pass_query_string``: A boolean indicating whether the query string
should be sent to the proxied endpoint.
- ``reverse_urls``: An iterable of location header replacements to be
made on the constructed response (similar to Apache's
``ProxyPassReverse`` directive).
- ``verify_ssl``\ \*: This attribute corresponds to `requests' verify
parameter <http://docs.python-requests.org/en/latest/user/advanced/?highlight=verify#ssl-cert-verification>`__.
It may be either a boolean, which toggles SSL certificate
verification on or off, or the path to a CA\_BUNDLE file for private
certificates.
- ``cert``\ \*: This attribute corresponds to `requests' cert
parameter <http://docs.python-requests.org/en/latest/user/advanced/?highlight=verify#ssl-cert-verification>`__.
If a string is specified, it will be treated as a path to an ssl
client cert file (.pem). If a tuple is specified, it will be treated
as a ('cert', 'key') pair.
- ``timeout``\ \*: This attribute corresponds to `requests' timeout
parameter <http://docs.python-requests.org/en/master/api/#requests.request>`__.
It is used to specify how long to wait for the upstream server to
send data before giving up. The value must be either a float
representing the total timeout time in seconds, or a (connect timeout
float, read timeout float) tuple.

\* The behavior changes that result from configuring ``verify_ssl``,
``cert``, and ``timeout`` will ultimately be dependent on the specific
version of requests that's installed. For example, in older versions of
requests, tuple values are not supported for the ``cert`` and
``timeout`` properties.

Adjusting location headers (ProxyPassReverse)
---------------------------------------------

Apache has a directive called ``ProxyPassReverse`` that makes
replacements to three location headers: ``URI``, ``Location``, and
``Content-Location``. Without this functionality, proxying an endpoint
that returns a redirect with a ``Location`` header of
``http://foo.bar/go/cats/`` would cause a downstream requestor to be
redirected away from the proxy. djproxy has a similar mechanism which is
exposed via the ``reverse_urls`` class variable. The following proxies
are equivalent:

Djproxy:

.. code:: python


class ReverseProxy(HttpProxy):
base_url = 'https://google.com/'
reverse_urls = [
('/google/', 'https://google.com/')
]

urlpatterns = patterns(
'',
url(r'^google/(?P<url>.*)$', ReverseProxy.as_view(), name='gproxy')

Apache:

::

<Proxy https://google.com/*>
Order deny,allow
Allow from all
</Proxy>
ProxyPass /google/ https://google.com/
ProxyPassReverse /google/ https://google.com/

HttpProxy dynamic configuration and route generation helper:
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

To specify the configuration for a set of proxies, without having to
maintain specific classes and url routes, one can use
``djproxy.helpers.generate_routes`` as follows:

In ``urls.py``, pass ``generate_routes`` a ``configuration`` dict to
configure a set of proxies:

.. code:: python

from djproxy.urls import generate_routes

configuration = {
'test_proxy': {
'base_url': 'https://google.com/',
'prefix': '/test_prefix/',
},
'service_name': {
'base_url': 'https://service.com/',
'prefix': '/service_prefix/',
'verify_ssl': False,
'append_middlware': ['myapp.proxy_middleware.add_headers']
}
}

urlpatterns += generate_routes(configuration)

Using the snippet above will enable a Django app to proxy
``https://google.com/X`` at ``/test_prefix/X`` and
``https://service.com/Y`` at ``/service_prefix/Y``.

These correspond to the following production Apache proxy configuration:

::

<Proxy https://google.com/*>
Order deny,allow
Allow from all
</Proxy>
ProxyPass /test_prefix/ https://google.com/
ProxyPassReverse /test_prefix/ https://google.com/


<Proxy https://service.com/*>
Order deny,allow
Allow from all
</Proxy>
ProxyPass /service_prefix/ http://service.com/
ProxyPassReverse /service_prefix/ http://service.com/

Required configuration keys:

- ``base_url``
- ``prefix``

Optional configuration keys:

- ``verify_ssl``: defaults to ``True``.
- ``csrf_exempt``: defaults to ``True``.
- ``cert``: defaults to ``None``.
- ``timeout``: defaults to ``None``.
- ``middleware``: Defaults to ``None``. Specifying ``None`` causes
djproxy to use the default middleware set. If a list is passed, the
default middleware list specified by the HttpProxy definition will be
replaced with the provided list.
- ``append_middleware``: Defaults to ``None``. ``None`` results in no
changes to the default middleware set. If a list is specified, the
list will be appended to the default middleware list specified in the
HttpProxy definition or, if provided, the middleware key specified in
the config dict.

Proxy middleware
----------------

HttpProxys support custom middleware for preprocessing data from
downstream to be sent to upstream endpoints and for preprocessing
response data before it is sent back downstream. ``X-Forwarded-Host``,
``X-Forwarded-For``, ``X-Forwarded-Proto`` and the ``ProxyPassRevere``
functionality area all implemented as middleware.

HttProxy views are configured to execute particular middleware by
setting their ``proxy_middleware`` attribute. The following HttpProxy
would attach XFF and XFH headers, but not preform the ProxyPassReverse
header translation or attach an XFP header:

.. code:: python

class ReverseProxy(HttpProxy):
base_url = 'https://google.com/'
reverse_urls = [
('/google/', 'https://google.com/')
]
proxy_middleware = [
'djproxy.proxy_middleware.AddXFF',
'djproxy.proxy_middleware.AddXFH'
]

If a custom middleware is needed to modify content, headers, cookies,
etc before the content is sent upstream of if one needs to make similar
modifications before the content is sent back downstream, a custom
middleware can be written and proxy views can be configured to use it.
djproxy contains a `middleware
template <https://github.com/thomasw/djproxy/blob/master/djproxy/proxy_middleware.py#L32>`__
to make this process easier.

Terminology
-----------

It is important to understand the meaning of these terms in the context
of this project:

**upstream**: The destination that is being proxied.

**downstream**: The agent that initiated the request to djproxy.

Contributing
------------

To run the tests, first install development dependencies:

::

pip install -r requirements.txt

To test this against a version of Django other than the latest supported
on the test environment's Python version, wipe out the
``requirements.txt`` installation by pip installing the desired version.

Run ``nosetests`` to execute the test suite.

To automatically run the test suite, flake8, and pep257 checks whenever python
files change use testtube by executing ``stir`` in the top level djproxy
directory.

To run a Django dev server that proxies itself, execute the following:

::

django-admin.py runserver --settings=tests.test_settings --pythonpath="./"

Similarly, to run a configure Django shell, execute the following:

::

django-admin.py shell --settings=tests.test_settings --pythonpath="./"

See ``tests/test_settings.py`` and ``tests/test_urls.py`` for
configuration information.

.. |Build Status| image:: https://img.shields.io/travis/thomasw/djproxy.svg
:target: https://travis-ci.org/thomasw/djproxy
.. |Coverage Status| image:: https://img.shields.io/coveralls/thomasw/djproxy.svg
:target: https://coveralls.io/r/thomasw/djproxy
.. |Latest Version| image:: https://img.shields.io/pypi/v/djproxy.svg
:target: https://pypi.python.org/pypi/djproxy/
.. |Downloads| image:: https://img.shields.io/pypi/dm/djproxy.svg
:target: https://pypi.python.org/pypi/djproxy/

Platform: UNKNOWN
Classifier: Development Status :: 5 - Production/Stable
Classifier: Intended Audience :: Developers
Classifier: License :: OSI Approved :: MIT License
Classifier: Topic :: Software Development :: Libraries
Classifier: Framework :: Django :: 1.4
Classifier: Framework :: Django :: 1.5
Classifier: Framework :: Django :: 1.6
Classifier: Framework :: Django :: 1.7
Classifier: Framework :: Django :: 1.8
Classifier: Framework :: Django :: 1.9
Classifier: Programming Language :: Python
Classifier: Programming Language :: Python :: 2.6
Classifier: Programming Language :: Python :: 2.7
Classifier: Programming Language :: Python :: 3.4
Classifier: Programming Language :: Python :: 3.5
Classifier: Programming Language :: Python :: Implementation :: PyPy