openstack/python-keystoneclient
Code Issues Proposed changes

Controllable redirect handling

Browse Source 
The requests library handles redirects as a browser would, which has the problem
that forwarding a POST will convert it to a GET. This is not necessarily
intuitive for an API. Handle all redirection manually and provide some
control over how far redirection can go.

Closes-Bug: 1267286
Change-Id: I24596a9c39cc29db28a66c3053ef3954b33abf90
This commit is contained in:
Jamie Lennox
2013-12-05 18:11:39 +10:00
parent 0b25aa7c80
commit 165da791af
3 changed files with 146 additions and 17 deletions
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78
keystoneclient/session.py
View File

@@ -33,8 +33,12 @@ class Session(object):
user_agent = None
REDIRECT_STATUSES = (301, 302, 303, 305, 307)
DEFAULT_REDIRECT_LIMIT = 30
def __init__(self, session=None, original_ip=None, verify=True, cert=None,
timeout=None, user_agent=None):
timeout=None, user_agent=None,
redirect=DEFAULT_REDIRECT_LIMIT):
"""Maintains client communication state and common functionality.
As much as possible the parameters to this class reflect and are passed
@@ -61,6 +65,10 @@ class Session(object):
request. If not provided a default is used.
(optional, defaults to
'python-keystoneclient')
:param int/bool redirect: Controls the maximum number of redirections
that can be followed by a request. Either an
integer for a specific count or True/False
for forever/never. (optional, default to 30)
"""
if not session:
session = requests.Session()
@@ -70,6 +78,7 @@ class Session(object):
self.verify = verify
self.cert = cert
self.timeout = None
self.redirect = redirect
if timeout is not None:
self.timeout = float(timeout)
@@ -79,7 +88,7 @@ class Session(object):
self.user_agent = user_agent
def request(self, url, method, json=None, original_ip=None,
user_agent=None, **kwargs):
user_agent=None, redirect=None, **kwargs):
"""Send an HTTP request with the specified characteristics.
Wrapper around `requests.Session.request` to handle tasks such as
@@ -93,13 +102,19 @@ class Session(object):
:param string original_ip: Mark this request as forwarded for this ip.
(optional)
:param dict headers: Headers to be included in the request. (optional)
:param kwargs: any other parameter that can be passed to
requests.Session.request (such as `headers`) or `json`
that will be encoded as JSON and used as `data` argument
:param json: Some data to be represented as JSON. (optional)
:param string user_agent: A user_agent to use for the request. If
present will override one present in headers.
(optional)
:param int/bool redirect: the maximum number of redirections that
can be followed by a request. Either an
integer for a specific count or True/False
for forever/never. (optional)
:param kwargs: any other parameter that can be passed to
requests.Session.request (such as `headers`). Except:
'data' will be overwritten by the data in 'json' param.
'allow_redirects' is ignored as redirects are handled
by the session.
:raises exceptions.ClientException: For connection failure, or to
indicate an error response code.
@@ -149,7 +164,17 @@ class Session(object):
if data:
_logger.debug('REQ BODY: %s', data)
resp = self._send_request(url, method, **kwargs)
# Force disable requests redirect handling. We will manage this below.
kwargs['allow_redirects'] = False
if redirect is None:
redirect = self.redirect
resp = self._send_request(url, method, redirect, **kwargs)
# NOTE(jamielennox): we create a tuple here to be the same as what is
# returned by the requests library.
resp.history = tuple(resp.history)
if resp.status_code >= 400:
_logger.debug('Request returned failure status: %s',
@@ -158,7 +183,12 @@ class Session(object):
return resp
def _send_request(self, url, method, **kwargs):
def _send_request(self, url, method, redirect, **kwargs):
# NOTE(jamielennox): We handle redirection manually because the
# requests lib follows some browser patterns where it will redirect
# POSTs as GETs for certain statuses which is not want we want for an
# API. See: https://en.wikipedia.org/wiki/Post/Redirect/Get
try:
resp = self.session.request(method, url, **kwargs)
except requests.exceptions.SSLError:
@@ -174,16 +204,30 @@ class Session(object):
_logger.debug('RESP: [%s] %s\nRESP BODY: %s\n',
resp.status_code, resp.headers, resp.text)
# NOTE(jamielennox): The requests lib will handle the majority of
# redirections. Where it fails is when POSTs are redirected which
# is apparently something handled differently by each browser which
# requests forces us to do the most compliant way (which we don't want)
# see: https://en.wikipedia.org/wiki/Post/Redirect/Get
# Nova and other direct users don't do this. Is it still relevant?
if resp.status_code in (301, 302, 305):
# Redirected. Reissue the request to the new location.
return self._send_request(resp.headers['location'],
method, **kwargs)
if resp.status_code in self.REDIRECT_STATUSES:
# be careful here in python True == 1 and False == 0
if isinstance(redirect, bool):
redirect_allowed = redirect
else:
redirect -= 1
redirect_allowed = redirect >= 0
if not redirect_allowed:
return resp
try:
location = resp.headers['location']
except KeyError:
_logger.warn("Failed to redirect request to %s as new "
"location was not provided.", resp.url)
else:
new_resp = self._send_request(location, method, redirect,
**kwargs)
if not isinstance(new_resp.history, list):
new_resp.history = list(new_resp.history)
new_resp.history.insert(0, resp)
resp = new_resp
return resp

84
keystoneclient/tests/test_session.py
View File

@@ -15,6 +15,7 @@
import httpretty
import mock
import requests
from keystoneclient import exceptions
from keystoneclient import session as client_session
@@ -138,3 +139,86 @@ class SessionTests(utils.TestCase):
self.stub_url(httpretty.GET, status=500)
self.assertRaises(exceptions.InternalServerError,
session.get, self.TEST_URL)
class RedirectTests(utils.TestCase):
REDIRECT_CHAIN = ['http://myhost:3445/',
'http://anotherhost:6555/',
'http://thirdhost/',
'http://finaldestination:55/']
DEFAULT_REDIRECT_BODY = 'Redirect'
DEFAULT_RESP_BODY = 'Found'
def setup_redirects(self, method=httpretty.GET, status=305,
redirect_kwargs={}, final_kwargs={}):
redirect_kwargs.setdefault('body', self.DEFAULT_REDIRECT_BODY)
for s, d in zip(self.REDIRECT_CHAIN, self.REDIRECT_CHAIN[1:]):
httpretty.register_uri(method, s, status=status, location=d,
**redirect_kwargs)
final_kwargs.setdefault('status', 200)
final_kwargs.setdefault('body', self.DEFAULT_RESP_BODY)
httpretty.register_uri(method, self.REDIRECT_CHAIN[-1], **final_kwargs)
def assertResponse(self, resp):
self.assertEqual(resp.status_code, 200)
self.assertEqual(resp.text, self.DEFAULT_RESP_BODY)
@httpretty.activate
def test_basic_get(self):
session = client_session.Session()
self.setup_redirects()
resp = session.get(self.REDIRECT_CHAIN[-2])
self.assertResponse(resp)
@httpretty.activate
def test_basic_post_keeps_correct_method(self):
session = client_session.Session()
self.setup_redirects(method=httpretty.POST, status=301)
resp = session.post(self.REDIRECT_CHAIN[-2])
self.assertResponse(resp)
@httpretty.activate
def test_redirect_forever(self):
session = client_session.Session(redirect=True)
self.setup_redirects()
resp = session.get(self.REDIRECT_CHAIN[0])
self.assertResponse(resp)
self.assertTrue(len(resp.history), len(self.REDIRECT_CHAIN))
@httpretty.activate
def test_no_redirect(self):
session = client_session.Session(redirect=False)
self.setup_redirects()
resp = session.get(self.REDIRECT_CHAIN[0])
self.assertEqual(resp.status_code, 305)
self.assertEqual(resp.url, self.REDIRECT_CHAIN[0])
@httpretty.activate
def test_redirect_limit(self):
self.setup_redirects()
for i in (1, 2):
session = client_session.Session(redirect=i)
resp = session.get(self.REDIRECT_CHAIN[0])
self.assertEqual(resp.status_code, 305)
self.assertEqual(resp.url, self.REDIRECT_CHAIN[i])
self.assertEqual(resp.text, self.DEFAULT_REDIRECT_BODY)
@httpretty.activate
def test_history_matches_requests(self):
self.setup_redirects(status=301)
session = client_session.Session(redirect=True)
req_resp = requests.get(self.REDIRECT_CHAIN[0],
allow_redirects=True)
ses_resp = session.get(self.REDIRECT_CHAIN[0])
self.assertEqual(type(req_resp.history), type(ses_resp.history))
self.assertEqual(len(req_resp.history), len(ses_resp.history))
for r, s in zip(req_resp.history, ses_resp.history):
self.assertEqual(r.url, s.url)
self.assertEqual(r.status_code, s.status_code)

1
keystoneclient/tests/test_shell.py
View File

@@ -445,6 +445,7 @@ class ShellTest(utils.TestCase):
' --os-auth-url=blah.com endpoint-list'))
request_mock.assert_called_with(mock.ANY, mock.ANY,
timeout=2,
allow_redirects=False,
headers=mock.ANY,
verify=mock.ANY)