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: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:: 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. .. seealso:: The `Requests package <https://requests.readthedocs.io/en/master/>`_ 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). 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 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 not longer supported. .. versionchanged:: 3.7 *blocksize* parameter was added. .. class:: HTTPSConnection(host, port=None, key_file=None, \ cert_file=None[, timeout], \ source_address=None, *, context=None, \ check_hostname=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*. .. deprecated:: 3.6 *key_file* and *cert_file* are deprecated in favor of *context*. Please use :meth:`ssl.SSLContext.load_cert_chain` instead, or let :func:`ssl.create_default_context` select the system's trusted CA certificates for you. The *check_hostname* parameter is also deprecated; the :attr:`ssl.SSLContext.check_hostname` attribute of *context* should be used instead. .. 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 selector *url*. 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. 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 <file object>`, 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. .. 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. 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 .. 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. .. 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 <bufferobjects>` 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. .. _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.getstatus() .. 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'<!doctype html>\n<!--[if"... ... >>> # Example of an invalid request >>> conn = http.client.HTTPSConnection("docs.python.org") >>> 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.HTTPSConnection("www.python.org") >>> conn.request("HEAD", "/") >>> 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() Client side ``HTTP PUT`` requests are very similar to ``POST`` requests. The difference lies only the server side where HTTP server will allow resources to be created via ``PUT`` request. It should be noted that custom HTTP methods are also handled in :class:`urllib.request.Request` by setting the appropriate method attribute. Here is an example session that shows how to send a ``PUT`` request using http.client:: >>> # This creates an HTTP message >>> # with the content of BODY as the enclosed representation >>> # for the resource http://localhost:8080/file ... >>> import http.client >>> BODY = "***filecontents***" >>> conn = http.client.HTTPConnection("localhost", 8080) >>> conn.request("PUT", "/file", BODY) >>> response = conn.getresponse() >>> print(response.status, response.reason) 200, OK .. _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.