urllib3

urllib3 is a powerful, sanity-friendly HTTP client for Python. Much of the Python ecosystem already uses urllib3 and you should too. urllib3 brings many critical features that are missing from the Python standard libraries:

Thread safety.
Connection pooling.
Client-side SSL/TLS verification.
File uploads with multipart encoding.
Helpers for retrying requests and dealing with HTTP redirects.
Support for gzip, deflate, and brotli encoding.
Proxy support for HTTP and SOCKS.
100% test coverage.

urllib3 is powerful and easy to use::

>>> import urllib3
>>> http = urllib3.PoolManager()
>>> r = http.request('GET', 'http://httpbin.org/robots.txt')
>>> r.status
200
>>> r.data
'User-agent: *\nDisallow: /deny\n'

Installing

urllib3 can be installed with pip <https://pip.pypa.io>_::

$ pip install urllib3

Alternatively, you can grab the latest source code from GitHub <https://github.com/urllib3/urllib3>_::

$ git clone git://github.com/urllib3/urllib3.git
$ python setup.py install

Documentation

urllib3 has usage and reference documentation at urllib3.readthedocs.io <https://urllib3.readthedocs.io>_.

Contributing

urllib3 happily accepts contributions. Please see our contributing documentation <https://urllib3.readthedocs.io/en/latest/contributing.html>_ for some tips on getting started.

Security Disclosures

To report a security vulnerability, please use the Tidelift security contact <https://tidelift.com/security>_. Tidelift will coordinate the fix and disclosure with maintainers.

Maintainers

@sethmlarson <https://github.com/sethmlarson>_ (Seth M. Larson)
@pquentin <https://github.com/pquentin>_ (Quentin Pradet)
@theacodes <https://github.com/theacodes>_ (Thea Flowers)
@haikuginger <https://github.com/haikuginger>_ (Jess Shapiro)
@lukasa <https://github.com/lukasa>_ (Cory Benfield)
@sigmavirus24 <https://github.com/sigmavirus24>_ (Ian Stapleton Cordasco)
@shazow <https://github.com/shazow>_ (Andrey Petrov)

👋

Sponsorship

.. |tideliftlogo| image:: https://nedbatchelder.com/pix/TideliftLogosRGBTideliftShorthandOn-Whitesmall.png :width: 75 :alt: Tidelift

.. list-table:: :widths: 10 100

- |tideliftlogo|
- Professional support for urllib3 is available as part of the Tidelift Subscription_. Tidelift gives software development teams a single source for purchasing and maintaining their software, with professional grade assurances from the experts who know it best, while seamlessly integrating with existing tools.

.. _Tidelift Subscription: https://tidelift.com/subscription/pkg/pypi-urllib3?utm_source=pypi-urllib3&utm_medium=referral&utm_campaign=readme If your company benefits from this library, please consider `sponsoring its development `_. Sponsors include:

Abbott (2018-2019), sponsored @sethmlarson <https://github.com/sethmlarson>'s work on urllib3.
Google Cloud Platform (2018-2019), sponsored @theacodes <https://github.com/theacodes>'s work on urllib3.
Akamai (2017-2018), sponsored @haikuginger <https://github.com/haikuginger>'s work on urllib3
Hewlett Packard Enterprise (2016-2017), sponsored @Lukasa’s <https://github.com/Lukasa> work on urllib3.

Changes

1.25.9 (2020-04-16)

Added InvalidProxyConfigurationWarning which is raised when erroneously specifying an HTTPS proxy URL. urllib3 doesn't currently support connecting to HTTPS proxies but will soon be able to and we would like users to migrate properly without much breakage.

See this GitHub issue <https://github.com/urllib3/urllib3/issues/1850>_ for more information on how to fix your proxy config. (Pull #1851)
Drain connection after PoolManager redirect (Pull #1817)
Ensure load_verify_locations raises SSLError for all backends (Pull #1812)
Rename VerifiedHTTPSConnection to HTTPSConnection (Pull #1805)
Allow the CA certificate data to be passed as a string (Pull #1804)
Raise ValueError if method contains control characters (Pull #1800)
Add __repr__ to Timeout (Pull #1795)

1.25.8 (2020-01-20)

Drop support for EOL Python 3.4 (Pull #1774)
Optimize encodeinvalid_chars (Pull #1787)

1.25.7 (2019-11-11)

Preserve chunked parameter on retries (Pull #1715, Pull #1734)
Allow unset SERVER_SOFTWARE in App Engine (Pull #1704, Issue #1470)
Fix issue where URL fragment was sent within the request target. (Pull #1732)
Fix issue where an empty query section in a URL would fail to parse. (Pull #1732)
Remove TLS 1.3 support in SecureTransport due to Apple removing support (Pull #1703)

1.25.6 (2019-09-24)

Fix issue where tilde (~) characters were incorrectly percent-encoded in the path. (Pull #1692)

1.25.5 (2019-09-19)

Add mitigation for BPO-37428 affecting Python <3.7.4 and OpenSSL 1.1.1+ which caused certificate verification to be enabled when using cert_reqs=CERT_NONE. (Issue #1682)

1.25.4 (2019-09-19)

Propagate Retry-After header settings to subsequent retries. (Pull #1607)
Fix edge case where Retry-After header was still respected even when explicitly opted out of. (Pull #1607)
Remove dependency on rfc3986 for URL parsing.
Fix issue where URLs containing invalid characters within Url.auth would raise an exception instead of percent-encoding those characters.
Add support for HTTPResponse.auto_close = False which makes HTTP responses work well with BufferedReaders and other io module features. (Pull #1652)
Percent-encode invalid characters in URL for HTTPConnectionPool.request() (Pull #1673)

1.25.3 (2019-05-23)

Change HTTPSConnection to load system CA certificates when ca_certs, ca_cert_dir, and ssl_context are unspecified. (Pull #1608, Issue #1603)
Upgrade bundled rfc3986 to v1.3.2. (Pull #1609, Issue #1605)

1.25.2 (2019-04-28)

Change is_ipaddress to not detect IPvFuture addresses. (Pull #1583)
Change parse_url to percent-encode invalid characters within the path, query, and target components. (Pull #1586)

1.25.1 (2019-04-24)

Add support for Google's Brotli package. (Pull #1572, Pull #1579)
Upgrade bundled rfc3986 to v1.3.1 (Pull #1578)

1.25 (2019-04-22)

Require and validate certificates by default when using HTTPS (Pull #1507)
Upgraded urllib3.utils.parse_url() to be RFC 3986 compliant. (Pull #1487)
Added support for key_password for HTTPSConnectionPool to use encrypted key_file without creating your own SSLContext object. (Pull #1489)
Add TLSv1.3 support to CPython, pyOpenSSL, and SecureTransport SSLContext implementations. (Pull #1496)
Switched the default multipart header encoder from RFC 2231 to HTML 5 working draft. (Issue #303, PR #1492)
Fixed issue where OpenSSL would block if an encrypted client private key was given and no password was given. Instead an SSLError is raised. (Pull #1489)
Added support for Brotli content encoding. It is enabled automatically if brotlipy package is installed which can be requested with urllib3[brotli] extra. (Pull #1532)
Drop ciphers using DSS key exchange from default TLS cipher suites. Improve default ciphers when using SecureTransport. (Pull #1496)
Implemented a more efficient HTTPResponse.__iter__() method. (Issue #1483)

1.24.3 (2019-05-01)

Apply fix for CVE-2019-9740. (Pull #1591)

1.24.2 (2019-04-17)

Don't load system certificates by default when any other ca_certs, ca_certs_dir or ssl_context parameters are specified.
Remove Authorization header regardless of case when redirecting to cross-site. (Issue #1510)
Add support for IPv6 addresses in subjectAltName section of certificates. (Issue #1269)

1.24.1 (2018-11-02)

Remove quadratic behavior within GzipDecoder.decompress() (Issue #1467)
Restored functionality of ciphers parameter for create_urllib3_context(). (Issue #1462)

1.24 (2018-10-16)

Allow keyserverhostname to be specified when initializing a PoolManager to allow custom SNI to be overridden. (Pull #1449)
Test against Python 3.7 on AppVeyor. (Pull #1453)
Early-out ipv6 checks when running on App Engine. (Pull #1450)
Change ambiguous description of backoff_factor (Pull #1436)
Add ability to handle multiple Content-Encodings (Issue #1441 and Pull #1442)
Skip DNS names that can't be idna-decoded when using pyOpenSSL (Issue #1405).
Add a server_hostname parameter to HTTPSConnection which allows for overriding the SNI hostname sent in the handshake. (Pull #1397)
Drop support for EOL Python 2.6 (Pull #1429 and Pull #1430)
Fixed bug where responses with header Content-Type: message/* erroneously raised HeaderParsingError, resulting in a warning being logged. (Pull #1439)
Move urllib3 to src/urllib3 (Pull #1409)

1.23 (2018-06-04)

Allow providing a list of headers to strip from requests when redirecting to a different host. Defaults to the Authorization header. Different headers can be set via Retry.remove_headers_on_redirect. (Issue #1316)
Fix util.selectors._fileobj_to_fd to accept long (Issue #1247).
Dropped Python 3.3 support. (Pull #1242)
Put the connection back in the pool when calling stream() or read_chunked() on a chunked HEAD response. (Issue #1234)
Fixed pyOpenSSL-specific ssl client authentication issue when clients attempted to auth via certificate + chain (Issue #1060)
Add the port to the connectionpool connect print (Pull #1251)
Don't use the uuid module to create multipart data boundaries. (Pull #1380)
read_chunked() on a closed response returns no chunks. (Issue #1088)
Add Python 2.6 support to contrib.securetransport (Pull #1359)
Added support for auth info in url for SOCKS proxy (Pull #1363)

1.22 (2017-07-20)

Fixed missing brackets in HTTP CONNECT when connecting to IPv6 address via IPv6 proxy. (Issue #1222)
Made the connection pool retry on SSLError. The original SSLError is available on MaxRetryError.reason. (Issue #1112)
Drain and release connection before recursing on retry/redirect. Fixes deadlocks with a blocking connectionpool. (Issue #1167)
Fixed compatibility for cookiejar. (Issue #1229)
pyopenssl: Use vendored version of six. (Issue #1231)

1.21.1 (2017-05-02)

Fixed SecureTransport issue that would cause long delays in response body delivery. (Pull #1154)
Fixed regression in 1.21 that threw exceptions when users passed the socket_options flag to the PoolManager. (Issue #1165)
Fixed regression in 1.21 that threw exceptions when users passed the assert_hostname or assert_fingerprint flag to the PoolManager. (Pull #1157)

1.21 (2017-04-25)

Improved performance of certain selector system calls on Python 3.5 and later. (Pull #1095)
Resolved issue where the PyOpenSSL backend would not wrap SysCallError exceptions appropriately when sending data. (Pull #1125)
Selectors now detects a monkey-patched select module after import for modules that patch the select module like eventlet, greenlet. (Pull #1128)
Reduced memory consumption when streaming zlib-compressed responses (as opposed to raw deflate streams). (Pull #1129)
Connection pools now use the entire request context when constructing the pool key. (Pull #1016)
PoolManager.connection_from_* methods now accept a new keyword argument, pool_kwargs, which are merged with the existing connection_pool_kw. (Pull #1016)
Add retry counter for status_forcelist. (Issue #1147)
Added contrib module for using SecureTransport on macOS: urllib3.contrib.securetransport. (Pull #1122)
urllib3 now only normalizes the case of http:// and https:// schemes: for schemes it does not recognise, it assumes they are case-sensitive and leaves them unchanged. (Issue #1080)

1.20 (2017-01-19)

Added support for waiting for I/O using selectors other than select, improving urllib3's behaviour with large numbers of concurrent connections. (Pull #1001)
Updated the date for the system clock check. (Issue #1005)
ConnectionPools now correctly consider hostnames to be case-insensitive. (Issue #1032)
Outdated versions of PyOpenSSL now cause the PyOpenSSL contrib module to fail when it is injected, rather than at first use. (Pull #1063)
Outdated versions of cryptography now cause the PyOpenSSL contrib module to fail when it is injected, rather than at first use. (Issue #1044)
Automatically attempt to rewind a file-like body object when a request is retried or redirected. (Pull #1039)
Fix some bugs that occur when modules incautiously patch the queue module. (Pull #1061)
Prevent retries from occurring on read timeouts for which the request method was not in the method whitelist. (Issue #1059)
Changed the PyOpenSSL contrib module to lazily load idna to avoid unnecessarily bloating the memory of programs that don't need it. (Pull

1076)
Add support for IPv6 literals with zone identifiers. (Pull #1013)
Added support for socks5h:// and socks4a:// schemes when working with SOCKS proxies, and controlled remote DNS appropriately. (Issue #1035)

1.19.1 (2016-11-16)

Fixed AppEngine import that didn't function on Python 3.5. (Pull #1025)

1.19 (2016-11-03)

urllib3 now respects Retry-After headers on 413, 429, and 503 responses when using the default retry logic. (Pull #955)
Remove markers from setup.py to assist ancient setuptools versions. (Issue

986)
Disallow superscripts and other integerish things in URL ports. (Issue #989)
Allow urllib3's HTTPResponse.stream() method to continue to work with non-httplib underlying FPs. (Pull #990)
Empty filenames in multipart headers are now emitted as such, rather than being suppressed. (Issue #1015)
Prefer user-supplied Host headers on chunked uploads. (Issue #1009)

1.18.1 (2016-10-27)

CVE-2016-9015. Users who are using urllib3 version 1.17 or 1.18 along with PyOpenSSL injection and OpenSSL 1.1.0 must upgrade to this version. This release fixes a vulnerability whereby urllib3 in the above configuration would silently fail to validate TLS certificates due to erroneously setting invalid flags in OpenSSL's SSL_CTX_set_verify function. These erroneous flags do not cause a problem in OpenSSL versions before 1.1.0, which interprets the presence of any flag as requesting certificate validation.

There is no PR for this patch, as it was prepared for simultaneous disclosure and release. The master branch received the same fix in PR #1010.

1.18 (2016-09-26)

Fixed incorrect message for IncompleteRead exception. (PR #973)
Accept iPAddress subject alternative name fields in TLS certificates. (Issue #258)
Fixed consistency of HTTPResponse.closed between Python 2 and 3. (Issue #977)
Fixed handling of wildcard certificates when using PyOpenSSL. (Issue #979)

1.17 (2016-09-06)

Accept SSLContext objects for use in SSL/TLS negotiation. (Issue #835)
ConnectionPool debug log now includes scheme, host, and port. (Issue #897)
Substantially refactored documentation. (Issue #887)
Used URLFetch default timeout on AppEngine, rather than hardcoding our own. (Issue #858)
Normalize the scheme and host in the URL parser (Issue #833)
HTTPResponse contains the last Retry object, which now also contains retries history. (Issue #848)
Timeout can no longer be set as boolean, and must be greater than zero. (PR #924)
Removed pyasn1 and ndg-httpsclient from dependencies used for PyOpenSSL. We now use cryptography and idna, both of which are already dependencies of PyOpenSSL. (PR #930)
Fixed infinite loop in stream when amt=None. (Issue #928)
Try to use the operating system's certificates when we are using an SSLContext. (PR #941)
Updated cipher suite list to allow ChaCha20+Poly1305. AES-GCM is preferred to ChaCha20, but ChaCha20 is then preferred to everything else. (PR #947)
Updated cipher suite list to remove 3DES-based cipher suites. (PR #958)
Removed the cipher suite fallback to allow HIGH ciphers. (PR #958)
Implemented length_remaining to determine remaining content to be read. (PR #949)
Implemented enforce_content_length to enable exceptions when incomplete data chunks are received. (PR #949)
Dropped connection start, dropped connection reset, redirect, forced retry, and new HTTPS connection log levels to DEBUG, from INFO. (PR #967)

1.16 (2016-06-11)

Disable IPv6 DNS when IPv6 connections are not possible. (Issue #840)
Provide key_fn_by_scheme pool keying mechanism that can be overridden. (Issue #830)
Normalize scheme and host to lowercase for pool keys, and include source_address. (Issue #830)
Cleaner exception chain in Python 3 for _make_request. (Issue #861)
Fixed installing urllib3[socks] extra. (Issue #864)
Fixed signature of ConnectionPool.close so it can actually safely be called by subclasses. (Issue #873)
Retain release_conn state across retries. (Issues #651, #866)
Add customizable HTTPConnectionPool.ResponseCls, which defaults to HTTPResponse but can be replaced with a subclass. (Issue #879)

1.15.1 (2016-04-11)

Fix packaging to include backports module. (Issue #841)

1.15 (2016-04-06)

Added Retry(raiseonstatus=False). (Issue #720)
Always use setuptools, no more distutils fallback. (Issue #785)
Dropped support for Python 3.2. (Issue #786)
Chunked transfer encoding when requesting with chunked=True. (Issue #790)
Fixed regression with IPv6 port parsing. (Issue #801)
Append SNIMissingWarning messages to allow users to specify it in the PYTHONWARNINGS environment variable. (Issue #816)
Handle unicode headers in Py2. (Issue #818)
Log certificate when there is a hostname mismatch. (Issue #820)
Preserve order of request/response headers. (Issue #821)

1.14 (2015-12-29)

contrib: SOCKS proxy support! (Issue #762)
Fixed AppEngine handling of transfer-encoding header and bug in Timeout defaults checking. (Issue #763)

1.13.1 (2015-12-18)

Fixed regression in IPv6 + SSL for match_hostname. (Issue #761)

1.13 (2015-12-14)

Fixed pip install urllib3[secure] on modern pip. (Issue #706)
pyopenssl: Fixed SSL3WRITEPENDING error. (Issue #717)
pyopenssl: Support for TLSv1.1 and TLSv1.2. (Issue #696)
Close connections more defensively on exception. (Issue #734)
Adjusted read_chunked to handle gzipped, chunk-encoded bodies without repeatedly flushing the decoder, to function better on Jython. (Issue #743)
Accept ca_cert_dir for SSL-related PoolManager configuration. (Issue #758)

1.12 (2015-09-03)

Rely on six for importing httplib to work around conflicts with other Python 3 shims. (Issue #688)
Add support for directories of certificate authorities, as supported by OpenSSL. (Issue #701)
New exception: NewConnectionError, raised when we fail to establish a new connection, usually ECONNREFUSED socket error.

1.11 (2015-07-21)

When ca_certs is given, cert_reqs defaults to 'CERT_REQUIRED'. (Issue #650)
pip install urllib3[secure] will install Certifi and PyOpenSSL as dependencies. (Issue #678)
Made HTTPHeaderDict usable as a headers input value (Issues #632, #679)
Added urllib3.contrib.appengine <https://urllib3.readthedocs.io/en/latest/contrib.html#google-app-engine>_ which has an AppEngineManager for using URLFetch in a Google AppEngine environment. (Issue #664)
Dev: Added test suite for AppEngine. (Issue #631)
Fix performance regression when using PyOpenSSL. (Issue #626)
Passing incorrect scheme (e.g. foo://) will raise ValueError instead of AssertionError (backwards compatible for now, but please migrate). (Issue #640)
Fix pools not getting replenished when an error occurs during a request using release_conn=False. (Issue #644)
Fix pool-default headers not applying for url-encoded requests like GET. (Issue #657)
log.warning in Python 3 when headers are skipped due to parsing errors. (Issue #642)
Close and discard connections if an error occurs during read. (Issue #660)
Fix host parsing for IPv6 proxies. (Issue #668)
Separate warning type SubjectAltNameWarning, now issued once per host. (Issue #671)
Fix httplib.IncompleteRead not getting converted to ProtocolError when using HTTPResponse.stream() (Issue #674)

1.10.4 (2015-05-03)

Migrate tests to Tornado 4. (Issue #594)
Append default warning configuration rather than overwrite. (Issue #603)
Fix streaming decoding regression. (Issue #595)
Fix chunked requests losing state across keep-alive connections. (Issue #599)
Fix hanging when chunked HEAD response has no body. (Issue #605)

1.10.3 (2015-04-21)

Emit InsecurePlatformWarning when SSLContext object is missing. (Issue #558)
Fix regression of duplicate header keys being discarded. (Issue #563)
Response.stream() returns a generator for chunked responses. (Issue #560)
Set upper-bound timeout when waiting for a socket in PyOpenSSL. (Issue #585)
Work on platforms without ssl module for plain HTTP requests. (Issue #587)
Stop relying on the stdlib's default cipher list. (Issue #588)

1.10.2 (2015-02-25)

Fix file descriptor leakage on retries. (Issue #548)
Removed RC4 from default cipher list. (Issue #551)
Header performance improvements. (Issue #544)
Fix PoolManager not obeying redirect retry settings. (Issue #553)

1.10.1 (2015-02-10)

Pools can be used as context managers. (Issue #545)
Don't re-use connections which experienced an SSLError. (Issue #529)
Don't fail when gzip decoding an empty stream. (Issue #535)
Add sha256 support for fingerprint verification. (Issue #540)
Fixed handling of header values containing commas. (Issue #533)

1.10 (2014-12-14)

Disabled SSLv3. (Issue #473)
Add Url.url property to return the composed url string. (Issue #394)
Fixed PyOpenSSL + gevent WantWriteError. (Issue #412)
MaxRetryError.reason will always be an exception, not string. (Issue #481)
Fixed SSL-related timeouts not being detected as timeouts. (Issue #492)
Py3: Use ssl.create_default_context() when available. (Issue #473)
Emit InsecureRequestWarning for every insecure HTTPS request. (Issue #496)
Emit SecurityWarning when certificate has no subjectAltName. (Issue #499)
Close and discard sockets which experienced SSL-related errors. (Issue #501)
Handle body param in .request(...). (Issue #513)
Respect timeout with HTTPS proxy. (Issue #505)
PyOpenSSL: Handle ZeroReturnError exception. (Issue #520)

1.9.1 (2014-09-13)

Apply socket arguments before binding. (Issue #427)
More careful checks if fp-like object is closed. (Issue #435)
Fixed packaging issues of some development-related files not getting included. (Issue #440)
Allow performing only fingerprint verification. (Issue #444)
Emit SecurityWarning if system clock is waaay off. (Issue #445)
Fixed PyOpenSSL compatibility with PyPy. (Issue #450)
Fixed BrokenPipeError and ConnectionError handling in Py3. (Issue #443)

1.9 (2014-07-04)

Shuffled around development-related files. If you're maintaining a distro package of urllib3, you may need to tweak things. (Issue #415)
Unverified HTTPS requests will trigger a warning on the first request. See our new security documentation <https://urllib3.readthedocs.io/en/latest/security.html>_ for details. (Issue #426)
New retry logic and urllib3.util.retry.Retry configuration object. (Issue #326)
All raised exceptions should now wrapped in a urllib3.exceptions.HTTPException-extending exception. (Issue #326)
All errors during a retry-enabled request should be wrapped in urllib3.exceptions.MaxRetryError, including timeout-related exceptions which were previously exempt. Underlying error is accessible from the .reason property. (Issue #326)
urllib3.exceptions.ConnectionError renamed to urllib3.exceptions.ProtocolError. (Issue #326)
Errors during response read (such as IncompleteRead) are now wrapped in urllib3.exceptions.ProtocolError. (Issue #418)
Requesting an empty host will raise urllib3.exceptions.LocationValueError. (Issue #417)
Catch read timeouts over SSL connections as urllib3.exceptions.ReadTimeoutError. (Issue #419)
Apply socket arguments before connecting. (Issue #427)

1.8.3 (2014-06-23)

Fix TLS verification when using a proxy in Python 3.4.1. (Issue #385)
Add disable_cache option to urllib3.util.make_headers. (Issue #393)
Wrap socket.timeout exception with urllib3.exceptions.ReadTimeoutError. (Issue #399)
Fixed proxy-related bug where connections were being reused incorrectly. (Issues #366, #369)
Added socket_options keyword parameter which allows to define setsockopt configuration of new sockets. (Issue #397)
Removed HTTPConnection.tcp_nodelay in favor of HTTPConnection.default_socket_options. (Issue #397)
Fixed TypeError bug in Python 2.6.4. (Issue #411)

1.8.2 (2014-04-17)

Fix urllib3.util not being included in the package.

1.8.1 (2014-04-17)

Fix AppEngine bug of HTTPS requests going out as HTTP. (Issue #356)
Don't install dummyserver into site-packages as it's only needed for the test suite. (Issue #362)
Added support for specifying source_address. (Issue #352)

1.8 (2014-03-04)

Improved url parsing in urllib3.util.parse_url (properly parse '@' in username, and blank ports like 'hostname:').
New urllib3.connection module which contains all the HTTPConnection objects.
Several urllib3.util.Timeout-related fixes. Also changed constructor signature to a more sensible order. [Backwards incompatible] (Issues #252, #262, #263)
Use backports.ssl_match_hostname if it's installed. (Issue #274)
Added .tell() method to urllib3.response.HTTPResponse which returns the number of bytes read so far. (Issue #277)
Support for platforms without threading. (Issue #289)
Expand default-port comparison in HTTPConnectionPool.is_same_host to allow a pool with no specified port to be considered equal to to an HTTP/HTTPS url with port 80/443 explicitly provided. (Issue #305)
Improved default SSL/TLS settings to avoid vulnerabilities. (Issue #309)
Fixed urllib3.poolmanager.ProxyManager not retrying on connect errors. (Issue #310)
Disable Nagle's Algorithm on the socket for non-proxies. A subset of requests will send the entire HTTP request ~200 milliseconds faster; however, some of the resulting TCP packets will be smaller. (Issue #254)
Increased maximum number of SubjectAltNames in urllib3.contrib.pyopenssl from the default 64 to 1024 in a single certificate. (Issue #318)
Headers are now passed and stored as a custom urllib3.collections_.HTTPHeaderDict object rather than a plain dict. (Issue #329, #333)
Headers no longer lose their case on Python 3. (Issue #236)
urllib3.contrib.pyopenssl now uses the operating system's default CA certificates on inject. (Issue #332)
Requests with retries=False will immediately raise any exceptions without wrapping them in MaxRetryError. (Issue #348)
Fixed open socket leak with SSL-related failures. (Issue #344, #348)

1.7.1 (2013-09-25)

Added granular timeout support with new urllib3.util.Timeout class. (Issue #231)
Fixed Python 3.4 support. (Issue #238)

1.7 (2013-08-14)

More exceptions are now pickle-able, with tests. (Issue #174)
Fixed redirecting with relative URLs in Location header. (Issue #178)
Support for relative urls in Location: ... header. (Issue #179)
urllib3.response.HTTPResponse now inherits from io.IOBase for bonus file-like functionality. (Issue #187)
Passing assert_hostname=False when creating a HTTPSConnectionPool will skip hostname verification for SSL connections. (Issue #194)
New method urllib3.response.HTTPResponse.stream(...) which acts as a generator wrapped around .read(...). (Issue #198)
IPv6 url parsing enforces brackets around the hostname. (Issue #199)
Fixed thread race condition in urllib3.poolmanager.PoolManager.connection_from_host(...) (Issue #204)
ProxyManager requests now include non-default port in Host: ... header. (Issue #217)
Added HTTPS proxy support in ProxyManager. (Issue #170 #139)
New RequestField object can be passed to the fields=... param which can specify headers. (Issue #220)
Raise urllib3.exceptions.ProxyError when connecting to proxy fails. (Issue #221)
Use international headers when posting file names. (Issue #119)
Improved IPv6 support. (Issue #203)

1.6 (2013-04-25)

Contrib: Optional SNI support for Py2 using PyOpenSSL. (Issue #156)
ProxyManager automatically adds Host: ... header if not given.
Improved SSL-related code. cert_req now optionally takes a string like "REQUIRED" or "NONE". Same with ssl_version takes strings like "SSLv23" The string values reflect the suffix of the respective constant variable. (Issue #130)
Vendored socksipy now based on Anorov's fork which handles unexpectedly closed proxy connections and larger read buffers. (Issue #135)
Ensure the connection is closed if no data is received, fixes connection leak on some platforms. (Issue #133)
Added SNI support for SSL/TLS connections on Py32+. (Issue #89)
Tests fixed to be compatible with Py26 again. (Issue #125)
Added ability to choose SSL version by passing an ssl.PROTOCOL_* constant to the ssl_version parameter of HTTPSConnectionPool. (Issue #109)
Allow an explicit content type to be specified when encoding file fields. (Issue #126)
Exceptions are now pickleable, with tests. (Issue #101)
Fixed default headers not getting passed in some cases. (Issue #99)
Treat "content-encoding" header value as case-insensitive, per RFC 2616 Section 3.5. (Issue #110)
"Connection Refused" SocketErrors will get retried rather than raised. (Issue #92)
Updated vendored six, no longer overrides the global six module namespace. (Issue #113)
urllib3.exceptions.MaxRetryError contains a reason property holding the exception that prompted the final retry. If reason is None then it was due to a redirect. (Issue #92, #114)
Fixed PoolManager.urlopen() from not redirecting more than once. (Issue #149)
Don't assume Content-Type: text/plain for multi-part encoding parameters that are not files. (Issue #111)
Pass strict param down to httplib.HTTPConnection. (Issue #122)
Added mechanism to verify SSL certificates by fingerprint (md5, sha1) or against an arbitrary hostname (when connecting by IP or for misconfigured servers). (Issue #140)
Streaming decompression support. (Issue #159)

1.5 (2012-08-02)

Added urllib3.add_stderr_logger() for quickly enabling STDERR debug logging in urllib3.
Native full URL parsing (including auth, path, query, fragment) available in urllib3.util.parse_url(url).
Built-in redirect will switch method to 'GET' if status code is 303. (Issue #11)
urllib3.PoolManager strips the scheme and host before sending the request uri. (Issue #8)
New urllib3.exceptions.DecodeError exception for when automatic decoding, based on the Content-Type header, fails.
Fixed bug with pool depletion and leaking connections (Issue #76). Added explicit connection closing on pool eviction. Added urllib3.PoolManager.clear().
99% -> 100% unit test coverage.

1.4 (2012-06-16)

Minor AppEngine-related fixes.
Switched from mimetools.choose_boundary to uuid.uuid4().
Improved url parsing. (Issue #73)
IPv6 url support. (Issue #72)

1.3 (2012-03-25)

Removed pre-1.0 deprecated API.
Refactored helpers into a urllib3.util submodule.
Fixed multipart encoding to support list-of-tuples for keys with multiple values. (Issue #48)
Fixed multiple Set-Cookie headers in response not getting merged properly in Python 3. (Issue #53)
AppEngine support with Py27. (Issue #61)
Minor encode_multipart_formdata fixes related to Python 3 strings vs bytes.

1.2.2 (2012-02-06)

Fixed packaging bug of not shipping test-requirements.txt. (Issue #47)

1.2.1 (2012-02-05)

Fixed another bug related to when ssl module is not available. (Issue #41)
Location parsing errors now raise urllib3.exceptions.LocationParseError which inherits from ValueError.

1.2 (2012-01-29)

Added Python 3 support (tested on 3.2.2)
Dropped Python 2.5 support (tested on 2.6.7, 2.7.2)
Use select.poll instead of select.select for platforms that support it.
Use Queue.LifoQueue instead of Queue.Queue for more aggressive connection reusing. Configurable by overriding ConnectionPool.QueueCls.
Fixed ImportError during install when ssl module is not available. (Issue #41)
Fixed PoolManager redirects between schemes (such as HTTP -> HTTPS) not completing properly. (Issue #28, uncovered by Issue #10 in v1.1)
Ported dummyserver to use tornado instead of webob + eventlet. Removed extraneous unsupported dummyserver testing backends. Added socket-level tests.
More tests. Achievement Unlocked: 99% Coverage.

1.1 (2012-01-07)

Refactored dummyserver to its own root namespace module (used for testing).
Added hostname verification for VerifiedHTTPSConnection by vendoring in Py32's ssl_match_hostname. (Issue #25)
Fixed cross-host HTTP redirects when using PoolManager. (Issue #10)
Fixed decode_content being ignored when set through urlopen. (Issue

27)
Fixed timeout-related bugs. (Issues #17, #23)

1.0.2 (2011-11-04)

Fixed typo in VerifiedHTTPSConnection which would only present as a bug if you're using the object manually. (Thanks pyos)
Made RecentlyUsedContainer (and consequently PoolManager) more thread-safe by wrapping the access log in a mutex. (Thanks @christer)
Made RecentlyUsedContainer more dict-like (corrected __delitem__ and __getitem__ behaviour), with tests. Shouldn't affect core urllib3 code.

1.0.1 (2011-10-10)

Fixed a bug where the same connection would get returned into the pool twice, causing extraneous "HttpConnectionPool is full" log warnings.

1.0 (2011-10-08)

Added PoolManager with LRU expiration of connections (tested and documented).
Added ProxyManager (needs tests, docs, and confirmation that it works with HTTPS proxies).
Added optional partial-read support for responses when preload_content=False. You can now make requests and just read the headers without loading the content.
Made response decoding optional (default on, same as before).
Added optional explicit boundary string for encode_multipart_formdata.
Convenience request methods are now inherited from RequestMethods. Old helpers like get_url and post_url should be abandoned in favour of the new request(method, url, ...).
Refactored code to be even more decoupled, reusable, and extendable.
License header added to .py files.
Embiggened the documentation: Lots of Sphinx-friendly docstrings in the code and docs in docs/ and on https://urllib3.readthedocs.io/.
Embettered all the things!
Started writing this file.

0.4.1 (2011-07-17)

Minor bug fixes, code cleanup.

0.4 (2011-03-01)

Better unicode support.
Added VerifiedHTTPSConnection.
Added NTLMConnectionPool in contrib.
Minor improvements.

0.3.1 (2010-07-13)

Added assert_host_name optional parameter. Now compatible with proxies.

0.3 (2009-12-10)

Added HTTPS support.
Minor bug fixes.
Refactored, broken backwards compatibility with 0.2.
API to be treated as stable from this version forward.

0.2 (2008-11-17)

Added unit tests.
Bug fixes.

0.1 (2008-11-16)

First release.