python-requests-toolbelt/docs/adapters.rst

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.. _adapters:
Transport Adapters
==================
The toolbelt comes with several different transport adapters for you to use
with requests. The transport adapters are all kept in
:mod:`requests_toolbelt.adapters` and include
- :class:`requests_toolbelt.adapters.appengine.AppEngineAdapter`
- :class:`requests_toolbelt.adapters.fingerprint.FingerprintAdapter`
- :class:`requests_toolbelt.adapters.socket_options.SocketOptionsAdapter`
- :class:`requests_toolbelt.adapters.socket_options.TCPKeepAliveAdapter`
- :class:`requests_toolbelt.adapters.source.SourceAddressAdapter`
- :class:`requests_toolbelt.adapters.ssl.SSLAdapter`
- :class:`requests_toolbelt.adapters.host_header_ssl.HostHeaderSSLAdapter`
- :class:`requests_toolbelt.adapters.x509.X509Adapter`
AppEngineAdapter
----------------
.. versionadded:: 0.6.0
As of version 2.10.0, Requests will be capable of supporting Google's App
Engine platform. In order to use Requests on GAE, however, you will need a
custom adapter found here as
:class:`~requests_toolbelt.adapters.appengine.AppEngineAdapter`. There are two
ways to take advantage of this support at the moment:
#. Using the :class:`~requests_toolbelt.adapters.appengine.AppEngineAdapter`
like every other adapter, e.g.,
.. code-block:: python
import requests
from requests_toolbelt.adapters import appengine
s = requests.Session()
s.mount('http://', appengine.AppEngineAdapter())
s.mount('https://', appengine.AppEngineAdapter())
#. By monkey-patching requests to always use the provided adapter:
.. code-block:: python
import requests
from requests_toolbelt.adapters import appengine
appengine.monkeypatch()
.. _insecure_appengine:
If you should need to disable certificate validation when monkeypatching (to
force third-party libraries that use Requests to not validate certificates, if
they do not provide API surface to do so, for example), you can disable it:
.. code-block:: python
from requests_toolbelt.adapters import appengine
appengine.monkeypatch(validate_certificate=False)
.. warning::
If ``validate_certificate`` is ``False``, the monkeypatched adapter
will *not* validate certificates. This effectively sets the
``validate_certificate`` argument to urlfetch.Fetch() to ``False``. You
should avoid using this wherever possible. Details can be found in the
`documentation for urlfetch.Fetch()`_.
.. _documentation for urlfetch.Fetch(): https://cloud.google.com/appengine/docs/python/refdocs/google.appengine.api.urlfetch
.. autoclass:: requests_toolbelt.adapters.appengine.AppEngineAdapter
FingerprintAdapter
------------------
.. versionadded:: 0.4.0
By default, requests will validate a server's certificate to ensure a
connection is secure. In addition to this, the user can provide a fingerprint
of the certificate they're expecting to receive. Unfortunately, the requests
API does not support this fairly rare use-case. When a user needs this extra
validation, they should use the
:class:`~requests_toolbelt.adapters.fingerprint.FingerprintAdapter` class to
perform the validation.
.. autoclass:: requests_toolbelt.adapters.fingerprint.FingerprintAdapter
SSLAdapter
----------
The ``SSLAdapter`` is the canonical implementation of the adapter proposed on
Cory Benfield's blog, `here`_. This adapter allows the user to choose one of
the SSL/TLS protocols made available in Python's ``ssl`` module for outgoing
HTTPS connections.
In principle, this shouldn't be necessary: compliant SSL servers should be able
to negotiate the required SSL version. In practice there have been bugs in some
versions of OpenSSL that mean that this negotiation doesn't go as planned. It
can be useful to be able to simply plug in a Transport Adapter that can paste
over the problem.
For example, suppose you're having difficulty with the server that provides TLS
for GitHub. You can work around it by using the following code::
from requests_toolbelt.adapters.ssl import SSLAdapter
import requests
import ssl
s = requests.Session()
s.mount('https://github.com/', SSLAdapter(ssl.PROTOCOL_TLSv1))
Any future requests to GitHub made through that adapter will automatically
attempt to negotiate TLSv1, and hopefully will succeed.
.. autoclass:: requests_toolbelt.adapters.ssl.SSLAdapter
.. _here: https://lukasa.co.uk/2013/01/Choosing_SSL_Version_In_Requests/
HostHeaderSSLAdapter
--------------------
.. versionadded:: 0.7.0
Requests supports SSL Verification by default. However, it relies on
the user making a request with the URL that has the hostname in it. If,
however, the user needs to make a request with the IP address, they cannot
actually verify a certificate against the hostname they want to request.
To accomodate this very rare need, we've added
:class:`~requests_toolbelt.adapters.host_header_ssl.HostHeaderSSLAdapter`.
Example usage:
.. code-block:: python
import requests
from requests_toolbelt.adapters import host_header_ssl
s = requests.Session()
s.mount('https://', host_header_ssl.HostHeaderSSLAdapter())
s.get("https://93.184.216.34", headers={"Host": "example.org"})
.. autoclass:: requests_toolbelt.adapters.host_header_ssl.HostHeaderSSLAdapter
SourceAddressAdapter
--------------------
.. versionadded:: 0.3.0
The :class:`~requests_toolbelt.adapters.source.SourceAddressAdapter` allows a
user to specify a source address for their connnection.
.. autoclass:: requests_toolbelt.adapters.source.SourceAddressAdapter
SocketOptionsAdapter
--------------------
.. versionadded:: 0.4.0
.. note::
This adapter will only work with requests 2.4.0 or newer. The ability to
set arbitrary socket options does not exist prior to requests 2.4.0.
The ``SocketOptionsAdapter`` allows a user to pass specific options to be set
on created sockets when constructing the Adapter without subclassing. The
adapter takes advantage of ``urllib3``'s `support`_ for setting arbitrary
socket options for each ``urllib3.connection.HTTPConnection`` (and
``HTTPSConnection``).
To pass socket options, you need to send a list of three-item tuples. For
example, ``requests`` and ``urllib3`` disable `Nagle's Algorithm`_ by default.
If you need to re-enable it, you would do the following:
.. code-block:: python
import socket
import requests
from requests_toolbelt.adapters.socket_options import SocketOptionsAdapter
nagles = [(socket.IPPROTO_TCP, socket.TCP_NODELAY, 0)]
session = requests.Session()
for scheme in session.adapters.keys():
session.mount(scheme, SocketOptionsAdapter(socket_options=nagles))
This would re-enable Nagle's Algorithm for all ``http://`` and ``https://``
connections made with that session.
.. autoclass:: requests_toolbelt.adapters.socket_options.SocketOptionsAdapter
.. _support: https://urllib3.readthedocs.org/en/latest/pools.html?highlight=socket_options#urllib3.connection.HTTPConnection.socket_options
.. _Nagle's Algorithm: https://en.wikipedia.org/wiki/Nagle%27s_algorithm
TCPKeepAliveAdapter
-------------------
.. versionadded:: 0.4.0
.. note::
This adapter will only work with requests 2.4.0 or newer. The ability to
set arbitrary socket options does not exist prior to requests 2.4.0.
The ``TCPKeepAliveAdapter`` allows a user to pass specific keep-alive related
options as keyword parameters as well as arbitrary socket options.
.. note::
Different keep-alive related socket options may not be available for your
platform. Check the socket module for the availability of the following
constants:
- ``socket.TCP_KEEPIDLE``
- ``socket.TCP_KEEPCNT``
- ``socket.TCP_KEEPINTVL``
The adapter will silently ignore any option passed for a non-existent
option.
An example usage of the adapter:
.. code-block:: python
import requests
from requests_toolbelt.adapters.socket_options import TCPKeepAliveAdapter
session = requests.Session()
keep_alive = TCPKeepAliveAdapter(idle=120, count=20, interval=30)
session.mount('https://region-a.geo-1.compute.hpcloudsvc.com', keep_alive)
session.post('https://region-a.geo-1.compute.hpcloudsvc.com/v2/1234abcdef/servers',
# ...
)
In this case we know that creating a server on HP Public Cloud can cause
requests to hang without using TCP Keep-Alive. So we mount the adapter
specifically for that domain, instead of adding it to every ``https://`` and
``http://`` request.
.. autoclass:: requests_toolbelt.adapters.socket_options.TCPKeepAliveAdapter
X509Adapter
-----------
Requests supports SSL Verification using a certificate in .pem format by default.
In some cases it is necessary to pass a full cert chain as part of a request or it
is deemed too great a risk to decrypt the certificate into a .pem file.
For such use cases we have created
:class:`~requests_toolbelt.adapters.x509.X509Adapter`.
Example usage:
.. code-block:: python
import requests
from requests_toolbelt.adapters.x509 import X509Adapter
s = requests.Session()
a = X509Adapter(max_retries=3,
cert_bytes=b'...', pk_bytes=b'...', encoding='...')
s.mount('https://', a)
.. autoclass:: requests_toolbelt.adapters.x509.X509Adapter