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cpython/Doc/library/http.client.rst
Senthil Kumaran 2e910fd0b7 versionadded: 3.2. not 3.1.
2009-07-25 04:27:38 +00:00

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: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
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 the :mod:`socket` module was compiled with
SSL support.
The module provides the following classes:
.. class:: HTTPConnection(host, port=None, strict=None[, timeout])
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. When True, the optional parameter *strict* (which defaults to a false
value) causes ``BadStatusLine`` to
be raised if the status line can't be parsed as a valid HTTP/1.0 or 1.1
status line. 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).
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)
.. class:: HTTPSConnection(host, port=None, key_file=None, cert_file=None, strict=None[, timeout])
A subclass of :class:`HTTPConnection` that uses SSL for communication with
secure servers. Default port is ``443``. *key_file* is the name of a PEM
formatted file that contains your private key. *cert_file* is a PEM formatted
certificate chain file.
.. note::
This does not do any certificate verification.
.. class:: HTTPResponse(sock, debuglevel=0, strict=0, method=None, url=None)
Class whose instances are returned upon successful connection. Not
instantiated directly by user.
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 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 *headers* argument should be a mapping of extra HTTP
headers to send with the request.
.. 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 amount of debugging output printed). The default
debug level is ``0``, meaning no debugging output is printed.
.. versionadded:: 2.7
.. method:: HTTPConnection.set_tunnel(host, port=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.
.. 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()
Send a blank line to the server, signalling the end of the headers.
.. 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)
Get the contents of the header *name*, or *default* if there is no matching
header.
.. method:: HTTPResponse.getheaders()
Return a list of (header, value) tuples.
.. 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 `debuglevel` is greater than zero, messages
will be printed to stdout as the response is read and parsed.
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()
>>> 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 shows how to ``POST`` requests::
>>> import http.client, urllib.parse
>>> params = urllib.parse.urlencode({'spam': 1, 'eggs': 2, 'bacon': 0})
>>> headers = {"Content-type": "application/x-www-form-urlencoded",
... "Accept": "text/plain"}
>>> conn = http.client.HTTPConnection("musi-cal.mojam.com:80")
>>> conn.request("POST", "/cgi-bin/query", params, headers)
>>> response = conn.getresponse()
>>> print(response.status, response.reason)
200 OK
>>> data = response.read()
>>> 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.
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