:mod:`http.client` --- HTTP protocol client =========================================== .. module:: http.client :synopsis: HTTP and HTTPS protocol client (requires sockets). **Source code:** :source:`Lib/http/client.py` .. index:: pair: HTTP; protocol single: HTTP; http.client (standard module) .. index:: pair: module; urllib.request -------------- This module defines classes that 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. .. seealso:: The `Requests package `_ is recommended for a higher-level HTTP client interface. .. note:: HTTPS support is only available if Python was compiled with SSL support (through the :mod:`ssl` module). .. include:: ../includes/wasm-notavail.rst The module provides the following classes: .. class:: HTTPConnection(host, port=None[, timeout], source_address=None, \ blocksize=8192) An :class:`HTTPConnection` instance represents one transaction with an HTTP server. It should be instantiated by 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. The optional *blocksize* parameter sets the buffer size in bytes for sending a file-like message body. For example, the following calls all create instances that connect to the server at the same host and port:: >>> h1 = http.client.HTTPConnection('www.python.org') >>> h2 = http.client.HTTPConnection('www.python.org:80') >>> h3 = http.client.HTTPConnection('www.python.org', 80) >>> h4 = http.client.HTTPConnection('www.python.org', 80, timeout=10) .. versionchanged:: 3.2 *source_address* was added. .. versionchanged:: 3.4 The *strict* parameter was removed. HTTP 0.9-style "Simple Responses" are no longer supported. .. versionchanged:: 3.7 *blocksize* parameter was added. .. class:: HTTPSConnection(host, port=None, *[, timeout], \ source_address=None, context=None, \ blocksize=8192) 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. Please read :ref:`ssl-security` for more information on best practices. .. 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:: 3.4 The *strict* parameter was removed. HTTP 0.9-style "Simple Responses" are no longer supported. .. versionchanged:: 3.4.3 This class now performs all the necessary certificate and hostname checks by default. To revert to the previous, unverified, behavior :func:`ssl._create_unverified_context` can be passed to the *context* parameter. .. versionchanged:: 3.8 This class now enables TLS 1.3 :attr:`ssl.SSLContext.post_handshake_auth` for the default *context* or when *cert_file* is passed with a custom *context*. .. versionchanged:: 3.10 This class now sends an ALPN extension with protocol indicator ``http/1.1`` when no *context* is given. Custom *context* should set ALPN protocols with :meth:`~ssl.SSLContext.set_alpn_protocol`. .. versionchanged:: 3.12 The deprecated *key_file*, *cert_file* and *check_hostname* parameters have been removed. .. class:: HTTPResponse(sock, debuglevel=0, method=None, url=None) Class whose instances are returned upon successful connection. Not instantiated directly by user. .. versionchanged:: 3.4 The *strict* parameter was removed. HTTP 0.9 style "Simple Responses" are no longer supported. This module provides the following function: .. function:: parse_headers(fp) Parse the headers from a file pointer *fp* representing a HTTP request/response. The file has to be a :class:`BufferedIOBase` reader (i.e. not text) and must provide a valid :rfc:`2822` style header. This function returns an instance of :class:`http.client.HTTPMessage` that holds the header fields, but no payload (the same as :attr:`HTTPResponse.msg` and :attr:`http.server.BaseHTTPRequestHandler.headers`). After returning, the file pointer *fp* is ready to read the HTTP body. .. note:: :meth:`parse_headers` does not parse the start-line of a HTTP message; it only parses the ``Name: value`` lines. The file has to be ready to read these field lines, so the first line should already be consumed before calling the function. 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. .. exception:: LineTooLong A subclass of :exc:`HTTPException`. Raised if an excessively long line is received in the HTTP protocol from the server. .. exception:: RemoteDisconnected A subclass of :exc:`ConnectionResetError` and :exc:`BadStatusLine`. Raised by :meth:`HTTPConnection.getresponse` when the attempt to read the response results in no data read from the connection, indicating that the remote end has closed the connection. .. versionadded:: 3.5 Previously, :exc:`BadStatusLine`\ ``('')`` was raised. 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``). .. 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'``. See :ref:`http-status-codes` for a list of HTTP status codes that are available in this module as constants. .. _httpconnection-objects: HTTPConnection Objects ---------------------- :class:`HTTPConnection` instances have the following methods: .. method:: HTTPConnection.request(method, url, body=None, headers={}, *, \ encode_chunked=False) This will send a request to the server using the HTTP request method *method* and the request URI *url*. The provided *url* must be an absolute path to conform with :rfc:`RFC 2616 §5.1.2 <2616#section-5.1.2>` (unless connecting to an HTTP proxy server or using the ``OPTIONS`` or ``CONNECT`` methods). If *body* is specified, the specified data is sent after the headers are finished. It may be a :class:`str`, a :term:`bytes-like object`, an open :term:`file object`, or an iterable of :class:`bytes`. If *body* is a string, it is encoded as ISO-8859-1, the default for HTTP. If it is a bytes-like object, the bytes are sent as is. If it is a :term:`file object`, the contents of the file is sent; this file object should support at least the ``read()`` method. If the file object is an instance of :class:`io.TextIOBase`, the data returned by the ``read()`` method will be encoded as ISO-8859-1, otherwise the data returned by ``read()`` is sent as is. If *body* is an iterable, the elements of the iterable are sent as is until the iterable is exhausted. The *headers* argument should be a mapping of extra HTTP headers to send with the request. A :rfc:`Host header <2616#section-14.23>` must be provided to conform with :rfc:`RFC 2616 §5.1.2 <2616#section-5.1.2>` (unless connecting to an HTTP proxy server or using the ``OPTIONS`` or ``CONNECT`` methods). If *headers* contains neither Content-Length nor Transfer-Encoding, but there is a request body, one of those header fields will be added automatically. If *body* is ``None``, the Content-Length header is set to ``0`` for methods that expect a body (``PUT``, ``POST``, and ``PATCH``). If *body* is a string or a bytes-like object that is not also a :term:`file `, the Content-Length header is set to its length. Any other type of *body* (files and iterables in general) will be chunk-encoded, and the Transfer-Encoding header will automatically be set instead of Content-Length. The *encode_chunked* argument is only relevant if Transfer-Encoding is specified in *headers*. If *encode_chunked* is ``False``, the HTTPConnection object assumes that all encoding is handled by the calling code. If it is ``True``, the body will be chunk-encoded. For example, to perform a ``GET`` request to ``https://docs.python.org/3/``:: >>> import http.client >>> host = "docs.python.org" >>> conn = http.client.HTTPSConnection(host) >>> conn.request("GET", "/3/", headers={"Host": host}) >>> response = conn.getresponse() >>> print(response.status, response.reason) 200 OK .. note:: Chunked transfer encoding has been added to the HTTP protocol version 1.1. Unless the HTTP server is known to handle HTTP 1.1, the caller must either specify the Content-Length, or must pass a :class:`str` or bytes-like object that is not also a file as the body representation. .. versionadded:: 3.2 *body* can now be an iterable. .. versionchanged:: 3.6 If neither Content-Length nor Transfer-Encoding are set in *headers*, file and iterable *body* objects are now chunk-encoded. The *encode_chunked* argument was added. No attempt is made to determine the Content-Length for file objects. .. 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. .. versionchanged:: 3.5 If a :exc:`ConnectionError` or subclass is raised, the :class:`HTTPConnection` object will be ready to reconnect when a new request is sent. .. 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. This allows running the connection through a proxy server. The *host* and *port* arguments specify the endpoint of the tunneled connection (i.e. the address included in the CONNECT request, *not* the address of the proxy server). The *headers* argument should be a mapping of extra HTTP headers to send with the CONNECT request. As HTTP/1.1 is used for HTTP CONNECT tunnelling request, `as per the RFC `_, a HTTP ``Host:`` header must be provided, matching the authority-form of the request target provided as the destination for the CONNECT request. If a HTTP ``Host:`` header is not provided via the headers argument, one is generated and transmitted automatically. For example, to tunnel through a HTTPS proxy server running locally on port 8080, we would pass the address of the proxy to the :class:`HTTPSConnection` constructor, and the address of the host that we eventually want to reach to the :meth:`~HTTPConnection.set_tunnel` method:: >>> import http.client >>> conn = http.client.HTTPSConnection("localhost", 8080) >>> conn.set_tunnel("www.python.org") >>> conn.request("HEAD","/index.html") .. versionadded:: 3.2 .. versionchanged:: 3.12 HTTP CONNECT tunnelling requests use protocol HTTP/1.1, upgraded from protocol HTTP/1.0. ``Host:`` HTTP headers are mandatory for HTTP/1.1, so one will be automatically generated and transmitted if not provided in the headers argument. .. method:: HTTPConnection.get_proxy_response_headers() Returns a dictionary with the headers of the response received from the proxy server to the CONNECT request. If the CONNECT request was not sent, the method returns an empty dictionary. .. versionadded:: 3.12 .. method:: HTTPConnection.connect() Connect to the server specified when the object was created. By default, this is called automatically when making a request if the client does not already have a connection. .. audit-event:: http.client.connect self,host,port http.client.HTTPConnection.connect .. method:: HTTPConnection.close() Close the connection to the server. .. attribute:: HTTPConnection.blocksize Buffer size in bytes for sending a file-like message body. .. versionadded:: 3.7 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(method, url, 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 *method* string, the *url* 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, *, encode_chunked=False) Send a blank line to the server, signalling the end of the headers. The optional *message_body* argument can be used to pass a message body associated with the request. If *encode_chunked* is ``True``, the result of each iteration of *message_body* will be chunk-encoded as specified in :rfc:`7230`, Section 3.3.1. How the data is encoded is dependent on the type of *message_body*. If *message_body* implements the :ref:`buffer interface ` the encoding will result in a single chunk. If *message_body* is a :class:`collections.abc.Iterable`, each iteration of *message_body* will result in a chunk. If *message_body* is a :term:`file object`, each call to ``.read()`` will result in a chunk. The method automatically signals the end of the chunk-encoded data immediately after *message_body*. .. note:: Due to the chunked encoding specification, empty chunks yielded by an iterator body will be ignored by the chunk-encoder. This is to avoid premature termination of the read of the request by the target server due to malformed encoding. .. versionadded:: 3.6 Chunked encoding support. The *encode_chunked* parameter was added. .. 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. .. audit-event:: http.client.send self,data http.client.HTTPConnection.send .. _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. .. versionchanged:: 3.5 The :class:`io.BufferedIOBase` interface is now implemented and all of its reader operations are supported. .. method:: HTTPResponse.read([amt]) Reads and returns the response body, or up to the next *amt* bytes. .. method:: HTTPResponse.readinto(b) Reads up to the next len(b) bytes of the response body into the buffer *b*. Returns the number of bytes read. .. versionadded:: 3.3 .. 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.url URL of the resource retrieved, commonly used to determine if a redirect was followed. .. attribute:: HTTPResponse.headers Headers of the response in the form of an :class:`email.message.EmailMessage` instance. .. 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. .. method:: HTTPResponse.geturl() .. deprecated:: 3.9 Deprecated in favor of :attr:`~HTTPResponse.url`. .. method:: HTTPResponse.info() .. deprecated:: 3.9 Deprecated in favor of :attr:`~HTTPResponse.headers`. .. method:: HTTPResponse.getcode() .. deprecated:: 3.9 Deprecated in favor of :attr:`~HTTPResponse.status`. Examples -------- Here is an example session that uses the ``GET`` method:: >>> import http.client >>> conn = http.client.HTTPSConnection("www.python.org") >>> conn.request("GET", "/") >>> 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", "/") >>> r1 = conn.getresponse() >>> while chunk := r1.read(200): ... print(repr(chunk)) b'\n