:mod:`BaseHTTPServer` --- Basic HTTP server
===========================================
.. module:: BaseHTTPServer
:synopsis: Basic HTTP server (base class for SimpleHTTPServer and CGIHTTPServer).
.. note::
The :mod:`BaseHTTPServer` module has been merged into :mod:`http.server` in
Python 3. The :term:`2to3` tool will automatically adapt imports when
converting your sources to Python 3.
.. index::
pair: WWW; server
pair: HTTP; protocol
single: URL
single: httpd
module: SimpleHTTPServer
module: CGIHTTPServer
**Source code:** :source:`Lib/BaseHTTPServer.py`
--------------
This module defines two classes for implementing HTTP servers (Web servers).
Usually, this module isn't used directly, but is used as a basis for building
functioning Web servers. See the :mod:`SimpleHTTPServer` and
:mod:`CGIHTTPServer` modules.
The first class, :class:`HTTPServer`, is a :class:`SocketServer.TCPServer`
subclass, and therefore implements the :class:`SocketServer.BaseServer`
interface. It creates and listens at the HTTP socket, dispatching the requests
to a handler. Code to create and run the server looks like this::
def run(server_class=BaseHTTPServer.HTTPServer,
handler_class=BaseHTTPServer.BaseHTTPRequestHandler):
server_address = ('', 8000)
httpd = server_class(server_address, handler_class)
httpd.serve_forever()
.. class:: HTTPServer(server_address, RequestHandlerClass)
This class builds on the :class:`TCPServer` class by storing the server
address as instance variables named :attr:`server_name` and
:attr:`server_port`. The server is accessible by the handler, typically
through the handler's :attr:`server` instance variable.
.. class:: BaseHTTPRequestHandler(request, client_address, server)
This class is used to handle the HTTP requests that arrive at the server. By
itself, it cannot respond to any actual HTTP requests; it must be subclassed
to handle each request method (e.g. GET or
POST). :class:`BaseHTTPRequestHandler` provides a number of class and
instance variables, and methods for use by subclasses.
The handler will parse the request and the headers, then call a method
specific to the request type. The method name is constructed from the
request. For example, for the request method ``SPAM``, the :meth:`do_SPAM`
method will be called with no arguments. All of the relevant information is
stored in instance variables of the handler. Subclasses should not need to
override or extend the :meth:`__init__` method.
:class:`BaseHTTPRequestHandler` has the following instance variables:
.. attribute:: client_address
Contains a tuple of the form ``(host, port)`` referring to the client's
address.
.. attribute:: server
Contains the server instance.
.. attribute:: command
Contains the command (request type). For example, ``'GET'``.
.. attribute:: path
Contains the request path.
.. attribute:: request_version
Contains the version string from the request. For example, ``'HTTP/1.0'``.
.. attribute:: headers
Holds an instance of the class specified by the :attr:`MessageClass` class
variable. This instance parses and manages the headers in the HTTP
request.
.. attribute:: rfile
Contains an input stream, positioned at the start of the optional input
data.
.. attribute:: wfile
Contains the output stream for writing a response back to the
client. Proper adherence to the HTTP protocol must be used when writing to
this stream.
:class:`BaseHTTPRequestHandler` has the following class variables:
.. attribute:: server_version
Specifies the server software version. You may want to override this. The
format is multiple whitespace-separated strings, where each string is of
the form name[/version]. For example, ``'BaseHTTP/0.2'``.
.. attribute:: sys_version
Contains the Python system version, in a form usable by the
:attr:`version_string` method and the :attr:`server_version` class
variable. For example, ``'Python/1.4'``.
.. attribute:: error_message_format
Specifies a format string for building an error response to the client. It
uses parenthesized, keyed format specifiers, so the format operand must be
a dictionary. The *code* key should be an integer, specifying the numeric
HTTP error code value. *message* should be a string containing a
(detailed) error message of what occurred, and *explain* should be an
explanation of the error code number. Default *message* and *explain*
values can found in the *responses* class variable.
.. attribute:: error_content_type
Specifies the Content-Type HTTP header of error responses sent to the
client. The default value is ``'text/html'``.
.. versionadded:: 2.6
Previously, the content type was always ``'text/html'``.
.. attribute:: protocol_version
This specifies the HTTP protocol version used in responses. If set to
``'HTTP/1.1'``, the server will permit HTTP persistent connections;
however, your server *must* then include an accurate ``Content-Length``
header (using :meth:`send_header`) in all of its responses to clients.
For backwards compatibility, the setting defaults to ``'HTTP/1.0'``.
.. attribute:: MessageClass
.. index:: single: Message (in module mimetools)
Specifies a :class:`rfc822.Message`\ -like class to parse HTTP headers.
Typically, this is not overridden, and it defaults to
:class:`mimetools.Message`.
.. attribute:: responses
This variable contains a mapping of error code integers to two-element tuples
containing a short and long message. For example, ``{code: (shortmessage,
longmessage)}``. The *shortmessage* is usually used as the *message* key in an
error response, and *longmessage* as the *explain* key (see the
:attr:`error_message_format` class variable).
A :class:`BaseHTTPRequestHandler` instance has the following methods:
.. method:: handle()
Calls :meth:`handle_one_request` once (or, if persistent connections are
enabled, multiple times) to handle incoming HTTP requests. You should
never need to override it; instead, implement appropriate :meth:`do_\*`
methods.
.. method:: handle_one_request()
This method will parse and dispatch the request to the appropriate
:meth:`do_\*` method. You should never need to override it.
.. method:: send_error(code[, message])
Sends and logs a complete error reply to the client. The numeric *code*
specifies the HTTP error code, with *message* as optional, more specific text. A
complete set of headers is sent, followed by text composed using the
:attr:`error_message_format` class variable.
.. method:: send_response(code[, message])
Sends a response header and logs the accepted request. The HTTP response
line is sent, followed by *Server* and *Date* headers. The values for
these two headers are picked up from the :meth:`version_string` and
:meth:`date_time_string` methods, respectively.
.. method:: send_header(keyword, value)
Writes a specific HTTP header to the output stream. *keyword* should
specify the header keyword, with *value* specifying its value.
.. method:: end_headers()
Sends a blank line, indicating the end of the HTTP headers in the
response.
.. method:: log_request([code[, size]])
Logs an accepted (successful) request. *code* should specify the numeric
HTTP code associated with the response. If a size of the response is
available, then it should be passed as the *size* parameter.
.. method:: log_error(...)
Logs an error when a request cannot be fulfilled. By default, it passes
the message to :meth:`log_message`, so it takes the same arguments
(*format* and additional values).
.. method:: log_message(format, ...)
Logs an arbitrary message to ``sys.stderr``. This is typically overridden
to create custom error logging mechanisms. The *format* argument is a
standard printf-style format string, where the additional arguments to
:meth:`log_message` are applied as inputs to the formatting. The client
ip address and current date and time are prefixed to every message logged.
.. method:: version_string()
Returns the server software's version string. This is a combination of the
:attr:`server_version` and :attr:`sys_version` class variables.
.. method:: date_time_string([timestamp])
Returns the date and time given by *timestamp* (which must be in the
format returned by :func:`time.time`), formatted for a message header. If
*timestamp* is omitted, it uses the current date and time.
The result looks like ``'Sun, 06 Nov 1994 08:49:37 GMT'``.
.. versionadded:: 2.5
The *timestamp* parameter.
.. method:: log_date_time_string()
Returns the current date and time, formatted for logging.
.. method:: address_string()
Returns the client address, formatted for logging. A name lookup is
performed on the client's IP address.
More examples
-------------
To create a server that doesn't run forever, but until some condition is
fulfilled::
def run_while_true(server_class=BaseHTTPServer.HTTPServer,
handler_class=BaseHTTPServer.BaseHTTPRequestHandler):
"""
This assumes that keep_running() is a function of no arguments which
is tested initially and after each request. If its return value
is true, the server continues.
"""
server_address = ('', 8000)
httpd = server_class(server_address, handler_class)
while keep_running():
httpd.handle_request()
.. seealso::
Module :mod:`CGIHTTPServer`
Extended request handler that supports CGI scripts.
Module :mod:`SimpleHTTPServer`
Basic request handler that limits response to files actually under the
document root.
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