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.
pip install djproxy
djproxy requires requests >= 1.0.0, django >= 1.11 and python >= 2.7. The goal is to maintain compatibility with all versions of Django that are still officially supported. However, djproxy may still work with older versions.
If you encounter issues using djproxy with a supported version of django, please report it.
Start by defining a new proxy:
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:
urlpatterns = [
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, urls.
HttpProxy view's behavior can be further customized by overriding
the following class attributes.
base_url: The proxy url is formed byurlparse.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'sProxyPassReversedirective).verify_ssl*: This attribute corresponds to requests' verify parameter. 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. 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. 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.
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:
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/
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:
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_urlprefix
Optional configuration keys:
verify_ssl: defaults toTrue.csrf_exempt: defaults toTrue.cert: defaults toNone.timeout: defaults toNone.middleware: Defaults toNone. SpecifyingNonecauses 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 toNone.Noneresults 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.
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:
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 to make this process easier.
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.
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.