:mod:`http.client` --- HTTP protocol client
===========================================

.. module:: http.client
   :synopsis: HTTP and HTTPS protocol client (requires sockets).


.. index::
   pair: HTTP; protocol
   single: HTTP; http.client (standard module)

.. index:: module: urllib.request

**Source code:** :source:`Lib/http/client.py`

--------------

This module defines classes which implement the client side of the HTTP and
HTTPS protocols.  It is normally not used directly --- the module
:mod:`urllib.request` uses it to handle URLs that use HTTP and HTTPS.

.. note::

   HTTPS support is only available if Python was compiled with SSL support
   (through the :mod:`ssl` module).

The module provides the following classes:


.. class:: HTTPConnection(host, port=None[, strict[, timeout[, source_address]]])

   An :class:`HTTPConnection` instance represents one transaction with an HTTP
   server.  It should be instantiated passing it a host and optional port
   number.  If no port number is passed, the port is extracted from the host
   string if it has the form ``host:port``, else the default HTTP port (80) is
   used.  If the optional *timeout* parameter is given, blocking
   operations (like connection attempts) will timeout after that many seconds
   (if it is not given, the global default timeout setting is used).
   The optional *source_address* parameter may be a tuple of a (host, port)
   to use as the source address the HTTP connection is made from.

   For example, the following calls all create instances that connect to the server
   at the same host and port::

      >>> h1 = http.client.HTTPConnection('www.cwi.nl')
      >>> h2 = http.client.HTTPConnection('www.cwi.nl:80')
      >>> h3 = http.client.HTTPConnection('www.cwi.nl', 80)
      >>> h3 = http.client.HTTPConnection('www.cwi.nl', 80, timeout=10)

   .. versionchanged:: 3.2
      *source_address* was added.

   .. versionchanged:: 3.2
      The *strict* parameter is deprecated.  HTTP 0.9-style "Simple Responses"
      are not supported anymore.


.. class:: HTTPSConnection(host, port=None, key_file=None, cert_file=None[, strict[, timeout[, source_address]]], *, context=None, check_hostname=None)

   A subclass of :class:`HTTPConnection` that uses SSL for communication with
   secure servers.  Default port is ``443``.  If *context* is specified, it
   must be a :class:`ssl.SSLContext` instance describing the various SSL
   options.  If *context* is specified and has a :attr:`~ssl.SSLContext.verify_mode`
   of either :data:`~ssl.CERT_OPTIONAL` or :data:`~ssl.CERT_REQUIRED`, then
   by default *host* is matched against the host name(s) allowed by the
   server's certificate.  If you want to change that behaviour, you can
   explicitly set *check_hostname* to False.

   *key_file* and *cert_file* are deprecated, please use
   :meth:`ssl.SSLContext.load_cert_chain` instead.

   If you access arbitrary hosts on the Internet, it is recommended to
   require certificate checking and feed the *context* with a set of
   trusted CA certificates::

      context = ssl.SSLContext(ssl.PROTOCOL_TLSv1)
      context.verify_mode = ssl.CERT_REQUIRED
      context.load_verify_locations('/etc/pki/tls/certs/ca-bundle.crt')
      h = client.HTTPSConnection('svn.python.org', 443, context=context)

   .. versionchanged:: 3.2
      *source_address*, *context* and *check_hostname* were added.

   .. versionchanged:: 3.2
      This class now supports HTTPS virtual hosts if possible (that is,
      if :data:`ssl.HAS_SNI` is true).

   .. versionchanged:: 3.2
      The *strict* parameter is deprecated.  HTTP 0.9-style "Simple Responses"
      are not supported anymore.


.. class:: HTTPResponse(sock, debuglevel=0[, strict], method=None, url=None)

   Class whose instances are returned upon successful connection.  Not
   instantiated directly by user.

   .. versionchanged:: 3.2
      The *strict* parameter is deprecated.  HTTP 0.9-style "Simple Responses"
      are not supported anymore.


The following exceptions are raised as appropriate:


.. exception:: HTTPException

   The base class of the other exceptions in this module.  It is a subclass of
   :exc:`Exception`.


.. exception:: NotConnected

   A subclass of :exc:`HTTPException`.


.. exception:: InvalidURL

   A subclass of :exc:`HTTPException`, raised if a port is given and is either
   non-numeric or empty.


.. exception:: UnknownProtocol

   A subclass of :exc:`HTTPException`.


.. exception:: UnknownTransferEncoding

   A subclass of :exc:`HTTPException`.


.. exception:: UnimplementedFileMode

   A subclass of :exc:`HTTPException`.


.. exception:: IncompleteRead

   A subclass of :exc:`HTTPException`.


.. exception:: ImproperConnectionState

   A subclass of :exc:`HTTPException`.


.. exception:: CannotSendRequest

   A subclass of :exc:`ImproperConnectionState`.


.. exception:: CannotSendHeader

   A subclass of :exc:`ImproperConnectionState`.


.. exception:: ResponseNotReady

   A subclass of :exc:`ImproperConnectionState`.


.. exception:: BadStatusLine

   A subclass of :exc:`HTTPException`.  Raised if a server responds with a HTTP
   status code that we don't understand.

The constants defined in this module are:


.. data:: HTTP_PORT

   The default port for the HTTP protocol (always ``80``).


.. data:: HTTPS_PORT

   The default port for the HTTPS protocol (always ``443``).

and also the following constants for integer status codes:

+------------------------------------------+---------+-----------------------------------------------------------------------+
| Constant                                 | Value   | Definition                                                            |
+==========================================+=========+=======================================================================+
| :const:`CONTINUE`                        | ``100`` | HTTP/1.1, `RFC 2616, Section                                          |
|                                          |         | 10.1.1                                                                |
|                                          |         | <http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html#sec10.1.1>`_  |
+------------------------------------------+---------+-----------------------------------------------------------------------+
| :const:`SWITCHING_PROTOCOLS`             | ``101`` | HTTP/1.1, `RFC 2616, Section                                          |
|                                          |         | 10.1.2                                                                |
|                                          |         | <http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html#sec10.1.2>`_  |
+------------------------------------------+---------+-----------------------------------------------------------------------+
| :const:`PROCESSING`                      | ``102`` | WEBDAV, `RFC 2518, Section 10.1                                       |
|                                          |         | <http://www.webdav.org/specs/rfc2518.html#STATUS_102>`_               |
+------------------------------------------+---------+-----------------------------------------------------------------------+
| :const:`OK`                              | ``200`` | HTTP/1.1, `RFC 2616, Section                                          |
|                                          |         | 10.2.1                                                                |
|                                          |         | <http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html#sec10.2.1>`_  |
+------------------------------------------+---------+-----------------------------------------------------------------------+
| :const:`CREATED`                         | ``201`` | HTTP/1.1, `RFC 2616, Section                                          |
|                                          |         | 10.2.2                                                                |
|                                          |         | <http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html#sec10.2.2>`_  |
+------------------------------------------+---------+-----------------------------------------------------------------------+
| :const:`ACCEPTED`                        | ``202`` | HTTP/1.1, `RFC 2616, Section                                          |
|                                          |         | 10.2.3                                                                |
|                                          |         | <http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html#sec10.2.3>`_  |
+------------------------------------------+---------+-----------------------------------------------------------------------+
| :const:`NON_AUTHORITATIVE_INFORMATION`   | ``203`` | HTTP/1.1, `RFC 2616, Section                                          |
|                                          |         | 10.2.4                                                                |
|                                          |         | <http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html#sec10.2.4>`_  |
+------------------------------------------+---------+-----------------------------------------------------------------------+
| :const:`NO_CONTENT`                      | ``204`` | HTTP/1.1, `RFC 2616, Section                                          |
|                                          |         | 10.2.5                                                                |
|                                          |         | <http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html#sec10.2.5>`_  |
+------------------------------------------+---------+-----------------------------------------------------------------------+
| :const:`RESET_CONTENT`                   | ``205`` | HTTP/1.1, `RFC 2616, Section                                          |
|                                          |         | 10.2.6                                                                |
|                                          |         | <http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html#sec10.2.6>`_  |
+------------------------------------------+---------+-----------------------------------------------------------------------+
| :const:`PARTIAL_CONTENT`                 | ``206`` | HTTP/1.1, `RFC 2616, Section                                          |
|                                          |         | 10.2.7                                                                |
|                                          |         | <http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html#sec10.2.7>`_  |
+------------------------------------------+---------+-----------------------------------------------------------------------+
| :const:`MULTI_STATUS`                    | ``207`` | WEBDAV `RFC 2518, Section 10.2                                        |
|                                          |         | <http://www.webdav.org/specs/rfc2518.html#STATUS_207>`_               |
+------------------------------------------+---------+-----------------------------------------------------------------------+
| :const:`IM_USED`                         | ``226`` | Delta encoding in HTTP,                                               |
|                                          |         | :rfc:`3229`, Section 10.4.1                                           |
+------------------------------------------+---------+-----------------------------------------------------------------------+
| :const:`MULTIPLE_CHOICES`                | ``300`` | HTTP/1.1, `RFC 2616, Section                                          |
|                                          |         | 10.3.1                                                                |
|                                          |         | <http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html#sec10.3.1>`_  |
+------------------------------------------+---------+-----------------------------------------------------------------------+
| :const:`MOVED_PERMANENTLY`               | ``301`` | HTTP/1.1, `RFC 2616, Section                                          |
|                                          |         | 10.3.2                                                                |
|                                          |         | <http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html#sec10.3.2>`_  |
+------------------------------------------+---------+-----------------------------------------------------------------------+
| :const:`FOUND`                           | ``302`` | HTTP/1.1, `RFC 2616, Section                                          |
|                                          |         | 10.3.3                                                                |
|                                          |         | <http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html#sec10.3.3>`_  |
+------------------------------------------+---------+-----------------------------------------------------------------------+
| :const:`SEE_OTHER`                       | ``303`` | HTTP/1.1, `RFC 2616, Section                                          |
|                                          |         | 10.3.4                                                                |
|                                          |         | <http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html#sec10.3.4>`_  |
+------------------------------------------+---------+-----------------------------------------------------------------------+
| :const:`NOT_MODIFIED`                    | ``304`` | HTTP/1.1, `RFC 2616, Section                                          |
|                                          |         | 10.3.5                                                                |
|                                          |         | <http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html#sec10.3.5>`_  |
+------------------------------------------+---------+-----------------------------------------------------------------------+
| :const:`USE_PROXY`                       | ``305`` | HTTP/1.1, `RFC 2616, Section                                          |
|                                          |         | 10.3.6                                                                |
|                                          |         | <http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html#sec10.3.6>`_  |
+------------------------------------------+---------+-----------------------------------------------------------------------+
| :const:`TEMPORARY_REDIRECT`              | ``307`` | HTTP/1.1, `RFC 2616, Section                                          |
|                                          |         | 10.3.8                                                                |
|                                          |         | <http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html#sec10.3.8>`_  |
+------------------------------------------+---------+-----------------------------------------------------------------------+
| :const:`BAD_REQUEST`                     | ``400`` | HTTP/1.1, `RFC 2616, Section                                          |
|                                          |         | 10.4.1                                                                |
|                                          |         | <http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html#sec10.4.1>`_  |
+------------------------------------------+---------+-----------------------------------------------------------------------+
| :const:`UNAUTHORIZED`                    | ``401`` | HTTP/1.1, `RFC 2616, Section                                          |
|                                          |         | 10.4.2                                                                |
|                                          |         | <http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html#sec10.4.2>`_  |
+------------------------------------------+---------+-----------------------------------------------------------------------+
| :const:`PAYMENT_REQUIRED`                | ``402`` | HTTP/1.1, `RFC 2616, Section                                          |
|                                          |         | 10.4.3                                                                |
|                                          |         | <http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html#sec10.4.3>`_  |
+------------------------------------------+---------+-----------------------------------------------------------------------+
| :const:`FORBIDDEN`                       | ``403`` | HTTP/1.1, `RFC 2616, Section                                          |
|                                          |         | 10.4.4                                                                |
|                                          |         | <http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html#sec10.4.4>`_  |
+------------------------------------------+---------+-----------------------------------------------------------------------+
| :const:`NOT_FOUND`                       | ``404`` | HTTP/1.1, `RFC 2616, Section                                          |
|                                          |         | 10.4.5                                                                |
|                                          |         | <http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html#sec10.4.5>`_  |
+------------------------------------------+---------+-----------------------------------------------------------------------+
| :const:`METHOD_NOT_ALLOWED`              | ``405`` | HTTP/1.1, `RFC 2616, Section                                          |
|                                          |         | 10.4.6                                                                |
|                                          |         | <http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html#sec10.4.6>`_  |
+------------------------------------------+---------+-----------------------------------------------------------------------+
| :const:`NOT_ACCEPTABLE`                  | ``406`` | HTTP/1.1, `RFC 2616, Section                                          |
|                                          |         | 10.4.7                                                                |
|                                          |         | <http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html#sec10.4.7>`_  |
+------------------------------------------+---------+-----------------------------------------------------------------------+
| :const:`PROXY_AUTHENTICATION_REQUIRED`   | ``407`` | HTTP/1.1, `RFC 2616, Section                                          |
|                                          |         | 10.4.8                                                                |
|                                          |         | <http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html#sec10.4.8>`_  |
+------------------------------------------+---------+-----------------------------------------------------------------------+
| :const:`REQUEST_TIMEOUT`                 | ``408`` | HTTP/1.1, `RFC 2616, Section                                          |
|                                          |         | 10.4.9                                                                |
|                                          |         | <http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html#sec10.4.9>`_  |
+------------------------------------------+---------+-----------------------------------------------------------------------+
| :const:`CONFLICT`                        | ``409`` | HTTP/1.1, `RFC 2616, Section                                          |
|                                          |         | 10.4.10                                                               |
|                                          |         | <http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html#sec10.4.10>`_ |
+------------------------------------------+---------+-----------------------------------------------------------------------+
| :const:`GONE`                            | ``410`` | HTTP/1.1, `RFC 2616, Section                                          |
|                                          |         | 10.4.11                                                               |
|                                          |         | <http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html#sec10.4.11>`_ |
+------------------------------------------+---------+-----------------------------------------------------------------------+
| :const:`LENGTH_REQUIRED`                 | ``411`` | HTTP/1.1, `RFC 2616, Section                                          |
|                                          |         | 10.4.12                                                               |
|                                          |         | <http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html#sec10.4.12>`_ |
+------------------------------------------+---------+-----------------------------------------------------------------------+
| :const:`PRECONDITION_FAILED`             | ``412`` | HTTP/1.1, `RFC 2616, Section                                          |
|                                          |         | 10.4.13                                                               |
|                                          |         | <http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html#sec10.4.13>`_ |
+------------------------------------------+---------+-----------------------------------------------------------------------+
| :const:`REQUEST_ENTITY_TOO_LARGE`        | ``413`` | HTTP/1.1, `RFC 2616, Section                                          |
|                                          |         | 10.4.14                                                               |
|                                          |         | <http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html#sec10.4.14>`_ |
+------------------------------------------+---------+-----------------------------------------------------------------------+
| :const:`REQUEST_URI_TOO_LONG`            | ``414`` | HTTP/1.1, `RFC 2616, Section                                          |
|                                          |         | 10.4.15                                                               |
|                                          |         | <http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html#sec10.4.15>`_ |
+------------------------------------------+---------+-----------------------------------------------------------------------+
| :const:`UNSUPPORTED_MEDIA_TYPE`          | ``415`` | HTTP/1.1, `RFC 2616, Section                                          |
|                                          |         | 10.4.16                                                               |
|                                          |         | <http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html#sec10.4.16>`_ |
+------------------------------------------+---------+-----------------------------------------------------------------------+
| :const:`REQUESTED_RANGE_NOT_SATISFIABLE` | ``416`` | HTTP/1.1, `RFC 2616, Section                                          |
|                                          |         | 10.4.17                                                               |
|                                          |         | <http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html#sec10.4.17>`_ |
+------------------------------------------+---------+-----------------------------------------------------------------------+
| :const:`EXPECTATION_FAILED`              | ``417`` | HTTP/1.1, `RFC 2616, Section                                          |
|                                          |         | 10.4.18                                                               |
|                                          |         | <http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html#sec10.4.18>`_ |
+------------------------------------------+---------+-----------------------------------------------------------------------+
| :const:`UNPROCESSABLE_ENTITY`            | ``422`` | WEBDAV, `RFC 2518, Section 10.3                                       |
|                                          |         | <http://www.webdav.org/specs/rfc2518.html#STATUS_422>`_               |
+------------------------------------------+---------+-----------------------------------------------------------------------+
| :const:`LOCKED`                          | ``423`` | WEBDAV `RFC 2518, Section 10.4                                        |
|                                          |         | <http://www.webdav.org/specs/rfc2518.html#STATUS_423>`_               |
+------------------------------------------+---------+-----------------------------------------------------------------------+
| :const:`FAILED_DEPENDENCY`               | ``424`` | WEBDAV, `RFC 2518, Section 10.5                                       |
|                                          |         | <http://www.webdav.org/specs/rfc2518.html#STATUS_424>`_               |
+------------------------------------------+---------+-----------------------------------------------------------------------+
| :const:`UPGRADE_REQUIRED`                | ``426`` | HTTP Upgrade to TLS,                                                  |
|                                          |         | :rfc:`2817`, Section 6                                                |
+------------------------------------------+---------+-----------------------------------------------------------------------+
| :const:`INTERNAL_SERVER_ERROR`           | ``500`` | HTTP/1.1, `RFC 2616, Section                                          |
|                                          |         | 10.5.1                                                                |
|                                          |         | <http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html#sec10.5.1>`_  |
+------------------------------------------+---------+-----------------------------------------------------------------------+
| :const:`NOT_IMPLEMENTED`                 | ``501`` | HTTP/1.1, `RFC 2616, Section                                          |
|                                          |         | 10.5.2                                                                |
|                                          |         | <http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html#sec10.5.2>`_  |
+------------------------------------------+---------+-----------------------------------------------------------------------+
| :const:`BAD_GATEWAY`                     | ``502`` | HTTP/1.1 `RFC 2616, Section                                           |
|                                          |         | 10.5.3                                                                |
|                                          |         | <http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html#sec10.5.3>`_  |
+------------------------------------------+---------+-----------------------------------------------------------------------+
| :const:`SERVICE_UNAVAILABLE`             | ``503`` | HTTP/1.1, `RFC 2616, Section                                          |
|                                          |         | 10.5.4                                                                |
|                                          |         | <http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html#sec10.5.4>`_  |
+------------------------------------------+---------+-----------------------------------------------------------------------+
| :const:`GATEWAY_TIMEOUT`                 | ``504`` | HTTP/1.1 `RFC 2616, Section                                           |
|                                          |         | 10.5.5                                                                |
|                                          |         | <http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html#sec10.5.5>`_  |
+------------------------------------------+---------+-----------------------------------------------------------------------+
| :const:`HTTP_VERSION_NOT_SUPPORTED`      | ``505`` | HTTP/1.1, `RFC 2616, Section                                          |
|                                          |         | 10.5.6                                                                |
|                                          |         | <http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html#sec10.5.6>`_  |
+------------------------------------------+---------+-----------------------------------------------------------------------+
| :const:`INSUFFICIENT_STORAGE`            | ``507`` | WEBDAV, `RFC 2518, Section 10.6                                       |
|                                          |         | <http://www.webdav.org/specs/rfc2518.html#STATUS_507>`_               |
+------------------------------------------+---------+-----------------------------------------------------------------------+
| :const:`NOT_EXTENDED`                    | ``510`` | An HTTP Extension Framework,                                          |
|                                          |         | :rfc:`2774`, Section 7                                                |
+------------------------------------------+---------+-----------------------------------------------------------------------+


.. data:: responses

   This dictionary maps the HTTP 1.1 status codes to the W3C names.

   Example: ``http.client.responses[http.client.NOT_FOUND]`` is ``'Not Found'``.


.. _httpconnection-objects:

HTTPConnection Objects
----------------------

:class:`HTTPConnection` instances have the following methods:


.. method:: HTTPConnection.request(method, url, body=None, headers={})

   This will send a request to the server using the HTTP request
   method *method* and the selector *url*.  If the *body* argument is
   present, it should be string or bytes object of data to send after
   the headers are finished.  Strings are encoded as ISO-8859-1, the
   default charset for HTTP.  To use other encodings, pass a bytes
   object.  The Content-Length header is set to the length of the
   string.

   The *body* may also be an open :term:`file object`, in which case the
   contents of the file is sent; this file object should support ``fileno()``
   and ``read()`` methods. The header Content-Length is automatically set to
   the length of the file as reported by stat. The *body* argument may also be
   an iterable and Content-Length header should be explicitly provided when the
   body is an iterable.

   The *headers* argument should be a mapping of extra HTTP
   headers to send with the request.

   .. versionadded:: 3.2
      *body* can now be an iterable.

.. method:: HTTPConnection.getresponse()

   Should be called after a request is sent to get the response from the server.
   Returns an :class:`HTTPResponse` instance.

   .. note::

      Note that you must have read the whole response before you can send a new
      request to the server.


.. method:: HTTPConnection.set_debuglevel(level)

   Set the debugging level.  The default debug level is ``0``, meaning no
   debugging output is printed.  Any value greater than ``0`` will cause all
   currently defined debug output to be printed to stdout.  The ``debuglevel``
   is passed to any new :class:`HTTPResponse` objects that are created.

   .. versionadded:: 3.1


.. method:: HTTPConnection.set_tunnel(host, port=None, headers=None)

   Set the host and the port for HTTP Connect Tunnelling. Normally used when it
   is required to a HTTPS Connection through a proxy server.

   The headers argument should be a mapping of extra HTTP headers to to sent
   with the CONNECT request.

   .. versionadded:: 3.2


.. method:: HTTPConnection.connect()

   Connect to the server specified when the object was created.


.. method:: HTTPConnection.close()

   Close the connection to the server.

As an alternative to using the :meth:`request` method described above, you can
also send your request step by step, by using the four functions below.


.. method:: HTTPConnection.putrequest(request, selector, skip_host=False, skip_accept_encoding=False)

   This should be the first call after the connection to the server has been made.
   It sends a line to the server consisting of the *request* string, the *selector*
   string, and the HTTP version (``HTTP/1.1``).  To disable automatic sending of
   ``Host:`` or ``Accept-Encoding:`` headers (for example to accept additional
   content encodings), specify *skip_host* or *skip_accept_encoding* with non-False
   values.


.. method:: HTTPConnection.putheader(header, argument[, ...])

   Send an :rfc:`822`\ -style header to the server.  It sends a line to the server
   consisting of the header, a colon and a space, and the first argument.  If more
   arguments are given, continuation lines are sent, each consisting of a tab and
   an argument.


.. method:: HTTPConnection.endheaders(message_body=None)

   Send a blank line to the server, signalling the end of the headers. The
   optional message_body argument can be used to pass message body
   associated with the request.  The message body will be sent in
   the same packet as the message headers if possible.  The
   message_body should be a string.


.. method:: HTTPConnection.send(data)

   Send data to the server.  This should be used directly only after the
   :meth:`endheaders` method has been called and before :meth:`getresponse` is
   called.


.. _httpresponse-objects:

HTTPResponse Objects
--------------------

An :class:`HTTPResponse` instance wraps the HTTP response from the
server.  It provides access to the request headers and the entity
body.  The response is an iterable object and can be used in a with
statement.


.. method:: HTTPResponse.read([amt])

   Reads and returns the response body, or up to the next *amt* bytes.


.. method:: HTTPResponse.getheader(name, default=None)

   Return the value of the header *name*, or *default* if there is no header
   matching *name*.  If there is more than one  header with the name *name*,
   return all of the values joined by ', '.  If 'default' is any iterable other
   than a single string, its elements are similarly returned joined by commas.


.. method:: HTTPResponse.getheaders()

   Return a list of (header, value) tuples.

.. method:: HTTPResponse.fileno()

   Return the ``fileno`` of the underlying socket.

.. attribute:: HTTPResponse.msg

   A :class:`http.client.HTTPMessage` instance containing the response
   headers.  :class:`http.client.HTTPMessage` is a subclass of
   :class:`email.message.Message`.


.. attribute:: HTTPResponse.version

   HTTP protocol version used by server.  10 for HTTP/1.0, 11 for HTTP/1.1.


.. attribute:: HTTPResponse.status

   Status code returned by server.


.. attribute:: HTTPResponse.reason

   Reason phrase returned by server.


.. attribute:: HTTPResponse.debuglevel

   A debugging hook.  If :attr:`debuglevel` is greater than zero, messages
   will be printed to stdout as the response is read and parsed.

.. attribute:: HTTPResponse.closed

   Is True if the stream is closed.

Examples
--------

Here is an example session that uses the ``GET`` method::

   >>> import http.client
   >>> conn = http.client.HTTPConnection("www.python.org")
   >>> conn.request("GET", "/index.html")
   >>> r1 = conn.getresponse()
   >>> print(r1.status, r1.reason)
   200 OK
   >>> data1 = r1.read()  # This will return entire content.
   >>> # The following example demonstrates reading data in chunks.
   >>> conn.request("GET", "/index.html")
   >>> r1 = conn.getresponse()
   >>> while not r1.closed:
   ...     print(r1.read(200)) # 200 bytes
   b'<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"...
   ...
   >>> # Example of an invalid request
   >>> conn.request("GET", "/parrot.spam")
   >>> r2 = conn.getresponse()
   >>> print(r2.status, r2.reason)
   404 Not Found
   >>> data2 = r2.read()
   >>> conn.close()

Here is an example session that uses the ``HEAD`` method.  Note that the
``HEAD`` method never returns any data. ::

   >>> import http.client
   >>> conn = http.client.HTTPConnection("www.python.org")
   >>> conn.request("HEAD","/index.html")
   >>> res = conn.getresponse()
   >>> print(res.status, res.reason)
   200 OK
   >>> data = res.read()
   >>> print(len(data))
   0
   >>> data == b''
   True

Here is an example session that shows how to ``POST`` requests::

   >>> import http.client, urllib.parse
   >>> params = urllib.parse.urlencode({'@number': 12524, '@type': 'issue', '@action': 'show'})
   >>> headers = {"Content-type": "application/x-www-form-urlencoded",
   ...            "Accept": "text/plain"}
   >>> conn = http.client.HTTPConnection("bugs.python.org")
   >>> conn.request("POST", "", params, headers)
   >>> response = conn.getresponse()
   >>> print(response.status, response.reason)
   302 Found
   >>> data = response.read()
   >>> data
   b'Redirecting to <a href="http://bugs.python.org/issue12524">http://bugs.python.org/issue12524</a>'
   >>> conn.close()


.. _httpmessage-objects:

HTTPMessage Objects
-------------------

An :class:`http.client.HTTPMessage` instance holds the headers from an HTTP
response.  It is implemented using the :class:`email.message.Message` class.

.. XXX Define the methods that clients can depend upon between versions.
