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
SimpleHTTPServer and
CGIHTTPServer modules.
The first class, HTTPServer, is a
SocketServer.TCPServer subclass. It creates and listens at the
web 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 TCPServer class by
storing the server address as instance
variables named server_name and server_port. The
server is accessible by the handler, typically through the handler's
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).
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
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
__init__() method.
BaseHTTPRequestHandler has the following instance variables:
- client_address
-
Contains a tuple of the form
(host, port) referring
to the client's address.
- command
-
Contains the command (request type). For example,
'GET'.
- path
-
Contains the request path.
- request_version
-
Contains the version string from the request. For example,
'HTTP/1.0'.
- headers
-
Holds an instance of the class specified by the MessageClass
class variable. This instance parses and manages the headers in
the HTTP request.
- rfile
-
Contains an input stream, positioned at the start of the optional
input data.
- 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.
BaseHTTPRequestHandler has the following class variables:
- 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'.
- sys_version
-
Contains the Python system version, in a form usable by the
version_string method and the server_version class
variable. For example,
'Python/1.4'.
- 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.
- protocol_version
-
This specifies the HTTP protocol version used in responses.
Typically, this should not be overridden. Defaults to
'HTTP/1.0'.
- MessageClass
-
Specifies a rfc822.Message-like class to parse HTTP
headers. Typically, this is not overridden, and it defaults to
mimetools.Message.
- 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 error_message_format class variable).
A BaseHTTPRequestHandler instance has the following methods:
- handle()
-
Overrides the superclass' handle() method to provide the
specific handler behavior. This method will parse and dispatch
the request to the appropriate do_*() 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 error_message_format
class variable.
- 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
version_string() and date_time_string() methods,
respectively.
- send_header(keyword, value)
-
Writes a specific MIME header to the output stream. keyword
should specify the header keyword, with value specifying
its value.
- end_headers()
-
Sends a blank line, indicating the end of the MIME headers in
the response.
- 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.
- log_error(...)
-
Logs an error when a request cannot be fulfilled. By default,
it passes the message to log_message(), so it takes the
same arguments (format and additional values).
- 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 log_message() are applied
as inputs to the formatting. The client address and current date
and time are prefixed to every message logged.
- version_string()
-
Returns the server software's version string. This is a combination
of the server_version and sys_version class variables.
- date_time_string()
-
Returns the current date and time, formatted for a message header.
- log_data_time_string()
-
Returns the current date and time, formatted for logging.
- address_string()
-
Returns the client address, formatted for logging. A name lookup
is performed on the client's IP address.
See Also:
- Module CGIHTTPServer:
- Extended request handler that supports CGI
scripts.
- Module SimpleHTTPServer:
- Basic request handler that limits response
to files actually under the document root.
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