"""Generic socket server classes. This module tries to capture the various aspects of defining a server: For socket-based servers: - address family:
- AF_INET{,6}: IP (Internet Protocol) sockets (default)
- AF_UNIX: Unix domain sockets
- others, e.g. AF_DECNET are conceivable (see <socket.h>
- socket type:
- SOCK_STREAM (reliable stream, e.g. TCP)
- SOCK_DGRAM (datagrams, e.g. UDP) For request-based servers (including socket-based): - client address verification before further looking at the request
(This is actually a hook for any processing that needs to look
at the request before anything else, e.g. logging)
- how to handle multiple requests:
- synchronous (one request is handled at a time)
- forking (each request is handled by a new process)
- threading (each request is handled by a new thread) The classes in this module favor the server type that is simplest to
write: a synchronous TCP/IP server. This is bad class design, but
save some typing. (There's also the issue that a deep class hierarchy
slows down method lookups.) There are five classes in an inheritance diagram, four of which represent
synchronous servers of four types: +------------+
| BaseServer |
+------------+
|
v
+-----------+ +------------------+
| TCPServer |------->| UnixStreamServer |
+-----------+ +------------------+
|
v
+-----------+ +--------------------+
| UDPServer |------->| UnixDatagramServer |
+-----------+ +--------------------+ Note that UnixDatagramServer derives from UDPServer, not from
UnixStreamServer -- the only difference between an IP and a Unix
stream server is the address family, which is simply repeated in both
unix server classes. Forking and threading versions of each type of server can be created
using the ForkingMixIn and ThreadingMixIn mix-in classes. For
instance, a threading UDP server class is created as follows: class ThreadingUDPServer(ThreadingMixIn, UDPServer): pass The Mix-in class must come first, since it overrides a method defined
in UDPServer! Setting the various member variables also changes
the behavior of the underlying server mechanism. To implement a service, you must derive a class from
BaseRequestHandler and redefine its handle() method. You can then run
various versions of the service by combining one of the server classes
with your request handler class. The request handler class must be different for datagram or stream
services. This can be hidden by using the request handler
subclasses StreamRequestHandler or DatagramRequestHandler. Of course, you still have to use your head! For instance, it makes no sense to use a forking server if the service
contains state in memory that can be modified by requests (since the
modifications in the child process would never reach the initial state
kept in the parent process and passed to each child). In this case,
you can use a threading server, but you will probably have to use
locks to avoid two requests that come in nearly simultaneous to apply
conflicting changes to the server state. On the other hand, if you are building e.g. an HTTP server, where all
data is stored externally (e.g. in the file system), a synchronous
class will essentially render the service "deaf" while one request is
being handled -- which may be for a very long time if a client is slow
to read all the data it has requested. Here a threading or forking
server is appropriate. In some cases, it may be appropriate to process part of a request
synchronously, but to finish processing in a forked child depending on
the request data. This can be implemented by using a synchronous
server and doing an explicit fork in the request handler class
handle() method. Another approach to handling multiple simultaneous requests in an
environment that supports neither threads nor fork (or where these are
too expensive or inappropriate for the service) is to maintain an
explicit table of partially finished requests and to use select() to
decide which request to work on next (or whether to handle a new
incoming request). This is particularly important for stream services
where each client can potentially be connected for a long time (if
threads or subprocesses cannot be used). Future work:
- Standard classes for Sun RPC (which uses either UDP or TCP)
- Standard mix-in classes to implement various authentication
and encryption schemes
- Standard framework for select-based multiplexing XXX Open problems:
- What to do with out-of-band data? BaseServer:
- split generic "request" functionality out into BaseServer class.
Copyright (C) 2000 Luke Kenneth Casson Leighton <[email protected]> example: read entries from a SQL database (requires overriding
get_request() to return a table entry from the database).
entry is processed by a RequestHandlerClass. """ # Author of the BaseServer patch: Luke Kenneth Casson Leighton # XXX Warning!
# There is a test suite for this module, but it cannot be run by the
# standard regression test.
# To run it manually, run Lib/test/test_socketserver.py. __version__ = "0.4" import socket
import select
import sys
import os
import errno
try:
import threading
except ImportError:
import dummy_threading as threading __all__ = ["TCPServer","UDPServer","ForkingUDPServer","ForkingTCPServer",
"ThreadingUDPServer","ThreadingTCPServer","BaseRequestHandler",
"StreamRequestHandler","DatagramRequestHandler",
"ThreadingMixIn", "ForkingMixIn"]
if hasattr(socket, "AF_UNIX"):
__all__.extend(["UnixStreamServer","UnixDatagramServer",
"ThreadingUnixStreamServer",
"ThreadingUnixDatagramServer"]) def _eintr_retry(func, *args):
"""restart a system call interrupted by EINTR"""
while True:
try:
return func(*args)
except (OSError, select.error) as e:
if e.args[0] != errno.EINTR:
raise class BaseServer: """Base class for server classes. Methods for the caller: - __init__(server_address, RequestHandlerClass)
- serve_forever(poll_interval=0.5)
- shutdown()
- handle_request() # if you do not use serve_forever()
- fileno() -> int # for select() Methods that may be overridden: - server_bind()
- server_activate()
- get_request() -> request, client_address
- handle_timeout()
- verify_request(request, client_address)
- server_close()
- process_request(request, client_address)
- shutdown_request(request)
- close_request(request)
- handle_error() Methods for derived classes: - finish_request(request, client_address) Class variables that may be overridden by derived classes or
instances: - timeout
- address_family
- socket_type
- allow_reuse_address Instance variables: - RequestHandlerClass
- socket """ timeout = None def __init__(self, server_address, RequestHandlerClass):
"""Constructor. May be extended, do not override."""
self.server_address = server_address
self.RequestHandlerClass = RequestHandlerClass
self.__is_shut_down = threading.Event()
self.__shutdown_request = False def server_activate(self):
"""Called by constructor to activate the server. May be overridden. """
pass def serve_forever(self, poll_interval=0.5):
"""Handle one request at a time until shutdown. Polls for shutdown every poll_interval seconds. Ignores
self.timeout. If you need to do periodic tasks, do them in
another thread.
"""
self.__is_shut_down.clear()
try:
while not self.__shutdown_request:
# XXX: Consider using another file descriptor or
# connecting to the socket to wake this up instead of
# polling. Polling reduces our responsiveness to a
# shutdown request and wastes cpu at all other times.
r, w, e = _eintr_retry(select.select, [self], [], [],
poll_interval)
if self in r:
self._handle_request_noblock()
finally:
self.__shutdown_request = False
self.__is_shut_down.set() def shutdown(self):
"""Stops the serve_forever loop. Blocks until the loop has finished. This must be called while
serve_forever() is running in another thread, or it will
deadlock.
"""
self.__shutdown_request = True
self.__is_shut_down.wait() # The distinction between handling, getting, processing and
# finishing a request is fairly arbitrary. Remember:
#
# - handle_request() is the top-level call. It calls
# select, get_request(), verify_request() and process_request()
# - get_request() is different for stream or datagram sockets
# - process_request() is the place that may fork a new process
# or create a new thread to finish the request
# - finish_request() instantiates the request handler class;
# this constructor will handle the request all by itself def handle_request(self):
"""Handle one request, possibly blocking. Respects self.timeout.
"""
# Support people who used socket.settimeout() to escape
# handle_request before self.timeout was available.
timeout = self.socket.gettimeout()
if timeout is None:
timeout = self.timeout
elif self.timeout is not None:
timeout = min(timeout, self.timeout)
fd_sets = _eintr_retry(select.select, [self], [], [], timeout)
if not fd_sets[0]:
self.handle_timeout()
return
self._handle_request_noblock() def _handle_request_noblock(self):
"""Handle one request, without blocking. I assume that select.select has returned that the socket is
readable before this function was called, so there should be
no risk of blocking in get_request().
"""
try:
request, client_address = self.get_request()
except socket.error:
return
if self.verify_request(request, client_address):
try:
self.process_request(request, client_address)
except:
self.handle_error(request, client_address)
self.shutdown_request(request) def handle_timeout(self):
"""Called if no new request arrives within self.timeout. Overridden by ForkingMixIn.
"""
pass def verify_request(self, request, client_address):
"""Verify the request. May be overridden. Return True if we should proceed with this request. """
return True def process_request(self, request, client_address):
"""Call finish_request. Overridden by ForkingMixIn and ThreadingMixIn. """
self.finish_request(request, client_address)
self.shutdown_request(request) def server_close(self):
"""Called to clean-up the server. May be overridden. """
pass def finish_request(self, request, client_address):
"""Finish one request by instantiating RequestHandlerClass."""
self.RequestHandlerClass(request, client_address, self) def shutdown_request(self, request):
"""Called to shutdown and close an individual request."""
self.close_request(request) def close_request(self, request):
"""Called to clean up an individual request."""
pass def handle_error(self, request, client_address):
"""Handle an error gracefully. May be overridden. The default is to print a traceback and continue. """
print '-'*40
print 'Exception happened during processing of request from',
print client_address
import traceback
traceback.print_exc() # XXX But this goes to stderr!
print '-'*40 class TCPServer(BaseServer): """Base class for various socket-based server classes. Defaults to synchronous IP stream (i.e., TCP). Methods for the caller: - __init__(server_address, RequestHandlerClass, bind_and_activate=True)
- serve_forever(poll_interval=0.5)
- shutdown()
- handle_request() # if you don't use serve_forever()
- fileno() -> int # for select() Methods that may be overridden: - server_bind()
- server_activate()
- get_request() -> request, client_address
- handle_timeout()
- verify_request(request, client_address)
- process_request(request, client_address)
- shutdown_request(request)
- close_request(request)
- handle_error() Methods for derived classes: - finish_request(request, client_address) Class variables that may be overridden by derived classes or
instances: - timeout
- address_family
- socket_type
- request_queue_size (only for stream sockets)
- allow_reuse_address Instance variables: - server_address
- RequestHandlerClass
- socket """ address_family = socket.AF_INET socket_type = socket.SOCK_STREAM request_queue_size = 5 allow_reuse_address = False def __init__(self, server_address, RequestHandlerClass, bind_and_activate=True):
"""Constructor. May be extended, do not override."""
BaseServer.__init__(self, server_address, RequestHandlerClass)
self.socket = socket.socket(self.address_family,
self.socket_type)
if bind_and_activate:
try:
self.server_bind()
self.server_activate()
except:
self.server_close()
raise def server_bind(self):
"""Called by constructor to bind the socket. May be overridden. """
if self.allow_reuse_address:
self.socket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
self.socket.bind(self.server_address)
self.server_address = self.socket.getsockname() def server_activate(self):
"""Called by constructor to activate the server. May be overridden. """
self.socket.listen(self.request_queue_size) def server_close(self):
"""Called to clean-up the server. May be overridden. """
self.socket.close() def fileno(self):
"""Return socket file number. Interface required by select(). """
return self.socket.fileno() def get_request(self):
"""Get the request and client address from the socket. May be overridden. """
return self.socket.accept() def shutdown_request(self, request):
"""Called to shutdown and close an individual request."""
try:
#explicitly shutdown. socket.close() merely releases
#the socket and waits for GC to perform the actual close.
request.shutdown(socket.SHUT_WR)
except socket.error:
pass #some platforms may raise ENOTCONN here
self.close_request(request) def close_request(self, request):
"""Called to clean up an individual request."""
request.close()
__version__ = "0.3" __all__ = ["HTTPServer", "BaseHTTPRequestHandler"] import sys
import time
import socket # For gethostbyaddr()
from warnings import filterwarnings, catch_warnings
with catch_warnings():
if sys.py3kwarning:
filterwarnings("ignore", ".*mimetools has been removed",
DeprecationWarning)
import mimetools
import SocketServer # Default error message template
DEFAULT_ERROR_MESSAGE = """\
<head>
<title>Error response</title>
</head>
<body>
<h1>Error response</h1>
<p>Error code %(code)d.
<p>Message: %(message)s.
<p>Error code explanation: %(code)s = %(explain)s.
</body>
""" DEFAULT_ERROR_CONTENT_TYPE = "text/html" def _quote_html(html):
return html.replace("&", "&").replace("<", "<").replace(">", ">") class HTTPServer(SocketServer.TCPServer): allow_reuse_address = 1 # Seems to make sense in testing environment def server_bind(self):
"""Override server_bind to store the server name."""
SocketServer.TCPServer.server_bind(self)
host, port = self.socket.getsockname()[:2]
self.server_name = socket.getfqdn(host)
self.server_port = port SocketServer.StreamRequestHandler
class BaseRequestHandler: """Base class for request handler classes. This class is instantiated for each request to be handled. The
constructor sets the instance variables request, client_address
and server, and then calls the handle() method. To implement a
specific service, all you need to do is to derive a class which
defines a handle() method. The handle() method can find the request as self.request, the
client address as self.client_address, and the server (in case it
needs access to per-server information) as self.server. Since a
separate instance is created for each request, the handle() method
can define arbitrary other instance variariables. """ def __init__(self, request, client_address, server):
self.request = request
self.client_address = client_address
self.server = server
self.setup()
try:
self.handle()
finally:
self.finish() def setup(self):
pass def handle(self):
pass def finish(self):
pass # The following two classes make it possible to use the same service
# class for stream or datagram servers.
# Each class sets up these instance variables:
# - rfile: a file object from which receives the request is read
# - wfile: a file object to which the reply is written
# When the handle() method returns, wfile is flushed properly class StreamRequestHandler(BaseRequestHandler): """Define self.rfile and self.wfile for stream sockets.""" # Default buffer sizes for rfile, wfile.
# We default rfile to buffered because otherwise it could be
# really slow for large data (a getc() call per byte); we make
# wfile unbuffered because (a) often after a write() we want to
# read and we need to flush the line; (b) big writes to unbuffered
# files are typically optimized by stdio even when big reads
# aren't.
rbufsize = -1
wbufsize = 0 # A timeout to apply to the request socket, if not None.
timeout = None # Disable nagle algorithm for this socket, if True.
# Use only when wbufsize != 0, to avoid small packets.
disable_nagle_algorithm = False def setup(self):
self.connection = self.request#是一个socket对象
if self.timeout is not None:
self.connection.settimeout(self.timeout)
if self.disable_nagle_algorithm:
self.connection.setsockopt(socket.IPPROTO_TCP,
socket.TCP_NODELAY, True)
self.rfile = self.connection.makefile('rb', self.rbufsize) #makefile([mode, [bufsize]]) -- return a file object for the socket [*]
self.wfile = self.connection.makefile('wb', self.wbufsize) def finish(self):
if not self.wfile.closed:
try:
self.wfile.flush()
except socket.error:
# An final socket error may have occurred here, such as
# the local error ECONNABORTED.
pass
self.wfile.close()
self.rfile.close() class BaseHTTPRequestHandler(SocketServer.StreamRequestHandler): """HTTP request handler base class. The following explanation of HTTP serves to guide you through the
code as well as to expose any misunderstandings I may have about
HTTP (so you don't need to read the code to figure out I'm wrong
:-). HTTP (HyperText Transfer Protocol) is an extensible protocol on
top of a reliable stream transport (e.g. TCP/IP). The protocol
recognizes three parts to a request: 1. One line identifying the request type and path
2. An optional set of RFC-822-style headers
3. An optional data part The headers and data are separated by a blank line. The first line of the request has the form <command> <path> <version> where <command> is a (case-sensitive) keyword such as GET or POST,
<path> is a string containing path information for the request,
and <version> should be the string "HTTP/1.0" or "HTTP/1.1".
<path> is encoded using the URL encoding scheme (using %xx to signify
the ASCII character with hex code xx). The specification specifies that lines are separated by CRLF but
for compatibility with the widest range of clients recommends
servers also handle LF. Similarly, whitespace in the request line
is treated sensibly (allowing multiple spaces between components
and allowing trailing whitespace). Similarly, for output, lines ought to be separated by CRLF pairs
but most clients grok LF characters just fine. If the first line of the request has the form <command> <path> (i.e. <version> is left out) then this is assumed to be an HTTP
0.9 request; this form has no optional headers and data part and
the reply consists of just the data. The reply form of the HTTP 1.x protocol again has three parts: 1. One line giving the response code
2. An optional set of RFC-822-style headers
3. The data Again, the headers and data are separated by a blank line. The response code line has the form <version> <responsecode> <responsestring> where <version> is the protocol version ("HTTP/1.0" or "HTTP/1.1"),
<responsecode> is a 3-digit response code indicating success or
failure of the request, and <responsestring> is an optional
human-readable string explaining what the response code means. This server parses the request and the headers, and then calls a
function specific to the request type (<command>). Specifically,
a request SPAM will be handled by a method do_SPAM(). If no
such method exists the server sends an error response to the
client. If it exists, it is called with no arguments: do_SPAM() Note that the request name is case sensitive (i.e. SPAM and spam
are different requests). The various request details are stored in instance variables: - client_address is the client IP address in the form (host,
port); - command, path and version are the broken-down request line; - headers is an instance of mimetools.Message (or a derived
class) containing the header information; - rfile is a file object open for reading positioned at the
start of the optional input data part; - wfile is a file object open for writing. IT IS IMPORTANT TO ADHERE TO THE PROTOCOL FOR WRITING! The first thing to be written must be the response line. Then
follow 0 or more header lines, then a blank line, and then the
actual data (if any). The meaning of the header lines depends on
the command executed by the server; in most cases, when data is
returned, there should be at least one header line of the form Content-type: <type>/<subtype> where <type> and <subtype> should be registered MIME types,
e.g. "text/html" or "text/plain". """ # The Python system version, truncated to its first component.
sys_version = "Python/" + sys.version.split()[0] # 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].
server_version = "BaseHTTP/" + __version__ # The default request version. This only affects responses up until
# the point where the request line is parsed, so it mainly decides what
# the client gets back when sending a malformed request line.
# Most web servers default to HTTP 0.9, i.e. don't send a status line.
default_request_version = "HTTP/0.9" def parse_request(self):
"""Parse a request (internal). The request should be stored in self.raw_requestline; the results
are in self.command, self.path, self.request_version and
self.headers. Return True for success, False for failure; on failure, an
error is sent back. """
self.command = None # set in case of error on the first line
self.request_version = version = self.default_request_version
self.close_connection = 1
requestline = self.raw_requestline
requestline = requestline.rstrip('\r\n')
self.requestline = requestline
words = requestline.split()
if len(words) == 3:
command, path, version = words
if version[:5] != 'HTTP/':
self.send_error(400, "Bad request version (%r)" % version)
return False
try:
base_version_number = version.split('/', 1)[1]
version_number = base_version_number.split(".")
# RFC 2145 section 3.1 says there can be only one "." and
# - major and minor numbers MUST be treated as
# separate integers;
# - HTTP/2.4 is a lower version than HTTP/2.13, which in
# turn is lower than HTTP/12.3;
# - Leading zeros MUST be ignored by recipients.
if len(version_number) != 2:
raise ValueError
version_number = int(version_number[0]), int(version_number[1])
except (ValueError, IndexError):
self.send_error(400, "Bad request version (%r)" % version)
return False
if version_number >= (1, 1) and self.protocol_version >= "HTTP/1.1":
self.close_connection = 0
if version_number >= (2, 0):
self.send_error(505,
"Invalid HTTP Version (%s)" % base_version_number)
return False
elif len(words) == 2:
command, path = words
self.close_connection = 1
if command != 'GET':
self.send_error(400,
"Bad HTTP/0.9 request type (%r)" % command)
return False
elif not words:
return False
else:
self.send_error(400, "Bad request syntax (%r)" % requestline)
return False
self.command, self.path, self.request_version = command, path, version # Examine the headers and look for a Connection directive
self.headers = self.MessageClass(self.rfile, 0) conntype = self.headers.get('Connection', "")
if conntype.lower() == 'close':
self.close_connection = 1
elif (conntype.lower() == 'keep-alive' and
self.protocol_version >= "HTTP/1.1"):
self.close_connection = 0
return True def handle_one_request(self):
"""Handle a single HTTP request. You normally don't need to override this method; see the class
__doc__ string for information on how to handle specific HTTP
commands such as GET and POST. """
try:
self.raw_requestline = self.rfile.readline(65537)#读取一行，这行最多为65537B
if len(self.raw_requestline) > 65536:#溢出处理
self.requestline = ''
self.request_version = ''
self.command = ''
self.send_error(414)
return
if not self.raw_requestline:#读取数据为空，关闭连接
self.close_connection = 1
return
if not self.parse_request():#分析请求，出错则返回
# An error code has been sent, just exit
return
mname = 'do_' + self.command#生成动作，例如do_post
if not hasattr(self, mname):
self.send_error(501, "Unsupported method (%r)" % self.command)
return
method = getattr(self, mname)
method()
self.wfile.flush() #actually send the response if not already done.
except socket.timeout, e:
#a read or a write timed out. Discard this connection
self.log_error("Request timed out: %r", e)
self.close_connection = 1
return def handle(self):
"""Handle multiple requests if necessary."""
self.close_connection = 1 self.handle_one_request()
while not self.close_connection:
self.handle_one_request() def send_error(self, code, message=None):
"""Send and log an error reply. Arguments are the error code, and a detailed message.
The detailed message defaults to the short entry matching the
response code. This sends an error response (so it must be called before any
output has been generated), logs the error, and finally sends
a piece of HTML explaining the error to the user. """ try:
short, long = self.responses[code]
except KeyError:
short, long = '???', '???'
if message is None:
message = short
explain = long
self.log_error("code %d, message %s", code, message)
# using _quote_html to prevent Cross Site Scripting attacks (see bug #1100201)
content = (self.error_message_format %
{'code': code, 'message': _quote_html(message), 'explain': explain})
self.send_response(code, message)
self.send_header("Content-Type", self.error_content_type)
self.send_header('Connection', 'close')
self.end_headers()
if self.command != 'HEAD' and code >= 200 and code not in (204, 304):
self.wfile.write(content) error_message_format = DEFAULT_ERROR_MESSAGE
error_content_type = DEFAULT_ERROR_CONTENT_TYPE def send_response(self, code, message=None):
"""Send the response header and log the response code. Also send two standard headers with the server software
version and the current date. """
self.log_request(code)
if message is None:
if code in self.responses:
message = self.responses[code][0]
else:
message = ''
if self.request_version != 'HTTP/0.9':
self.wfile.write("%s %d %s\r\n" %
(self.protocol_version, code, message))
# print (self.protocol_version, code, message)
self.send_header('Server', self.version_string())
self.send_header('Date', self.date_time_string()) def send_header(self, keyword, value):
"""Send a MIME header."""
if self.request_version != 'HTTP/0.9':
self.wfile.write("%s: %s\r\n" % (keyword, value)) if keyword.lower() == 'connection':
if value.lower() == 'close':
self.close_connection = 1
elif value.lower() == 'keep-alive':
self.close_connection = 0 def end_headers(self):
"""Send the blank line ending the MIME headers."""
if self.request_version != 'HTTP/0.9':
self.wfile.write("\r\n") def log_request(self, code='-', size='-'):
"""Log an accepted request. This is called by send_response(). """ self.log_message('"%s" %s %s',
self.requestline, str(code), str(size)) def log_error(self, format, *args):
"""Log an error. This is called when a request cannot be fulfilled. By
default it passes the message on to log_message(). Arguments are the same as for log_message(). XXX This should go to the separate error log. """ self.log_message(format, *args) def log_message(self, format, *args):
"""Log an arbitrary message. This is used by all other logging functions. Override
it if you have specific logging wishes. The first argument, FORMAT, is a format string for the
message to be logged. If the format string contains
any % escapes requiring parameters, they should be
specified as subsequent arguments (it's just like
printf!). The client ip address and current date/time are prefixed to every
message. """ sys.stderr.write("%s - - [%s] %s\n" %
(self.client_address[0],
self.log_date_time_string(),
format%args)) def version_string(self):
"""Return the server software version string."""
return self.server_version + ' ' + self.sys_version def date_time_string(self, timestamp=None):
"""Return the current date and time formatted for a message header."""
if timestamp is None:
timestamp = time.time()
year, month, day, hh, mm, ss, wd, y, z = time.gmtime(timestamp)
s = "%s, %02d %3s %4d %02d:%02d:%02d GMT" % (
self.weekdayname[wd],
day, self.monthname[month], year,
hh, mm, ss)
return s def log_date_time_string(self):
"""Return the current time formatted for logging."""
now = time.time()
year, month, day, hh, mm, ss, x, y, z = time.localtime(now)
s = "%02d/%3s/%04d %02d:%02d:%02d" % (
day, self.monthname[month], year, hh, mm, ss)
return s weekdayname = ['Mon', 'Tue', 'Wed', 'Thu', 'Fri', 'Sat', 'Sun'] monthname = [None,
'Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun',
'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec'] def address_string(self):
"""Return the client address formatted for logging. This version looks up the full hostname using gethostbyaddr(),
and tries to find a name that contains at least one dot. """ host, port = self.client_address[:2]
return socket.getfqdn(host) # Essentially static class variables # The version of the HTTP protocol we support.
# Set this to HTTP/1.1 to enable automatic keepalive
protocol_version = "HTTP/1.0" # The Message-like class used to parse headers
MessageClass = mimetools.Message # Table mapping response codes to messages; entries have the
# form {code: (shortmessage, longmessage)}.
# See RFC 2616.
responses = {
100: ('Continue', 'Request received, please continue'),
101: ('Switching Protocols',
'Switching to new protocol; obey Upgrade header'), 200: ('OK', 'Request fulfilled, document follows'),
201: ('Created', 'Document created, URL follows'),
202: ('Accepted',
'Request accepted, processing continues off-line'),
203: ('Non-Authoritative Information', 'Request fulfilled from cache'),
204: ('No Content', 'Request fulfilled, nothing follows'),
205: ('Reset Content', 'Clear input form for further input.'),
206: ('Partial Content', 'Partial content follows.'), 300: ('Multiple Choices',
'Object has several resources -- see URI list'),
301: ('Moved Permanently', 'Object moved permanently -- see URI list'),
302: ('Found', 'Object moved temporarily -- see URI list'),
303: ('See Other', 'Object moved -- see Method and URL list'),
304: ('Not Modified',
'Document has not changed since given time'),
305: ('Use Proxy',
'You must use proxy specified in Location to access this '
'resource.'),
307: ('Temporary Redirect',
'Object moved temporarily -- see URI list'), 400: ('Bad Request',
'Bad request syntax or unsupported method'),
401: ('Unauthorized',
'No permission -- see authorization schemes'),
402: ('Payment Required',
'No payment -- see charging schemes'),
403: ('Forbidden',
'Request forbidden -- authorization will not help'),
404: ('Not Found', 'Nothing matches the given URI'),
405: ('Method Not Allowed',
'Specified method is invalid for this resource.'),
406: ('Not Acceptable', 'URI not available in preferred format.'),
407: ('Proxy Authentication Required', 'You must authenticate with '
'this proxy before proceeding.'),
408: ('Request Timeout', 'Request timed out; try again later.'),
409: ('Conflict', 'Request conflict.'),
410: ('Gone',
'URI no longer exists and has been permanently removed.'),
411: ('Length Required', 'Client must specify Content-Length.'),
412: ('Precondition Failed', 'Precondition in headers is false.'),
413: ('Request Entity Too Large', 'Entity is too large.'),
414: ('Request-URI Too Long', 'URI is too long.'),
415: ('Unsupported Media Type', 'Entity body in unsupported format.'),
416: ('Requested Range Not Satisfiable',
'Cannot satisfy request range.'),
417: ('Expectation Failed',
'Expect condition could not be satisfied.'), 500: ('Internal Server Error', 'Server got itself in trouble'),
501: ('Not Implemented',
'Server does not support this operation'),
502: ('Bad Gateway', 'Invalid responses from another server/proxy.'),
503: ('Service Unavailable',
'The server cannot process the request due to a high load'),
504: ('Gateway Timeout',
'The gateway server did not receive a timely response'),
505: ('HTTP Version Not Supported', 'Cannot fulfill request.'),
}
class BaseHandler:
"""Manage the invocation of a WSGI application""" # Configuration parameters; can override per-subclass or per-instance
wsgi_version = (1,0)
wsgi_multithread = True
wsgi_multiprocess = True
wsgi_run_once = False origin_server = True # We are transmitting direct to client
http_version = "1.0" # Version that should be used for response
server_software = None # String name of server software, if any # os_environ is used to supply configuration from the OS environment:
# by default it's a copy of 'os.environ' as of import time, but you can
# override this in e.g. your __init__ method.
os_environ = dict(os.environ.items()) # Collaborator classes
wsgi_file_wrapper = FileWrapper # set to None to disable
headers_class = Headers # must be a Headers-like class # Error handling (also per-subclass or per-instance)
traceback_limit = None # Print entire traceback to self.get_stderr()
error_status = "500 Internal Server Error"
error_headers = [('Content-Type','text/plain')]
error_body = "A server error occurred. Please contact the administrator." # State variables (don't mess with these)
status = result = None
headers_sent = False
headers = None
bytes_sent = 0 def run(self, application):
"""Invoke the application"""
# Note to self: don't move the close()! Asynchronous servers shouldn't
# call close() from finish_response(), so if you close() anywhere but
# the double-error branch here, you'll break asynchronous servers by
# prematurely closing. Async servers must return from 'run()' without
# closing if there might still be output to iterate over.
try:
self.setup_environ()
self.result = application(self.environ, self.start_response)
self.finish_response()
except:
try:
self.handle_error()
except:
# If we get an error handling an error, just give up already!
self.close()
raise # ...and let the actual server figure it out. def setup_environ(self):
"""Set up the environment for one request""" env = self.environ = self.os_environ.copy()
self.add_cgi_vars() env['wsgi.input'] = self.get_stdin()
env['wsgi.errors'] = self.get_stderr()
env['wsgi.version'] = self.wsgi_version
env['wsgi.run_once'] = self.wsgi_run_once
env['wsgi.url_scheme'] = self.get_scheme()
env['wsgi.multithread'] = self.wsgi_multithread
env['wsgi.multiprocess'] = self.wsgi_multiprocess if self.wsgi_file_wrapper is not None:
env['wsgi.file_wrapper'] = self.wsgi_file_wrapper if self.origin_server and self.server_software:
env.setdefault('SERVER_SOFTWARE',self.server_software) def finish_response(self):
"""Send any iterable data, then close self and the iterable Subclasses intended for use in asynchronous servers will
want to redefine this method, such that it sets up callbacks
in the event loop to iterate over the data, and to call
'self.close()' once the response is finished.
"""
try:
if not self.result_is_file() or not self.sendfile():
for data in self.result:
self.write(data)
self.finish_content()
finally:
self.close() def get_scheme(self):
"""Return the URL scheme being used"""
return guess_scheme(self.environ) def set_content_length(self):
"""Compute Content-Length or switch to chunked encoding if possible"""
try:
blocks = len(self.result)
except (TypeError,AttributeError,NotImplementedError):
pass
else:
if blocks==1:
self.headers['Content-Length'] = str(self.bytes_sent)
return
# XXX Try for chunked encoding if origin server and client is 1.1 def cleanup_headers(self):
"""Make any necessary header changes or defaults Subclasses can extend this to add other defaults.
"""
if 'Content-Length' not in self.headers:
self.set_content_length() def start_response(self, status, headers,exc_info=None):
"""'start_response()' callable as specified by PEP 333""" if exc_info:
try:
if self.headers_sent:
# Re-raise original exception if headers sent
raise exc_info[0], exc_info[1], exc_info[2]
finally:
exc_info = None # avoid dangling circular ref
elif self.headers is not None:
raise AssertionError("Headers already set!") assert type(status) is StringType,"Status must be a string"
assert len(status)>=4,"Status must be at least 4 characters"
assert int(status[:3]),"Status message must begin w/3-digit code"
assert status[3]==" ", "Status message must have a space after code"
if __debug__:
for name,val in headers:
assert type(name) is StringType,"Header names must be strings"
assert type(val) is StringType,"Header values must be strings"
assert not is_hop_by_hop(name),"Hop-by-hop headers not allowed"
self.status = status
self.headers = self.headers_class(headers)
return self.write def send_preamble(self):
"""Transmit version/status/date/server, via self._write()"""
if self.origin_server:
if self.client_is_modern():
self._write('HTTP/%s %s\r\n' % (self.http_version,self.status))
if 'Date' not in self.headers:
self._write(
'Date: %s\r\n' % format_date_time(time.time())
)
if self.server_software and 'Server' not in self.headers:
self._write('Server: %s\r\n' % self.server_software)
else:
self._write('Status: %s\r\n' % self.status) def write(self, data):
"""'write()' callable as specified by PEP 333""" assert type(data) is StringType,"write() argument must be string" if not self.status:
raise AssertionError("write() before start_response()") elif not self.headers_sent:
# Before the first output, send the stored headers
self.bytes_sent = len(data) # make sure we know content-length
self.send_headers()
else:
self.bytes_sent += len(data) # XXX check Content-Length and truncate if too many bytes written?
self._write(data)
self._flush() def sendfile(self):
"""Platform-specific file transmission Override this method in subclasses to support platform-specific
file transmission. It is only called if the application's
return iterable ('self.result') is an instance of
'self.wsgi_file_wrapper'. This method should return a true value if it was able to actually
transmit the wrapped file-like object using a platform-specific
approach. It should return a false value if normal iteration
should be used instead. An exception can be raised to indicate
that transmission was attempted, but failed. NOTE: this method should call 'self.send_headers()' if
'self.headers_sent' is false and it is going to attempt direct
transmission of the file.
"""
return False # No platform-specific transmission by default def finish_content(self):
"""Ensure headers and content have both been sent"""
if not self.headers_sent:
# Only zero Content-Length if not set by the application (so
# that HEAD requests can be satisfied properly, see #3839)
self.headers.setdefault('Content-Length', "")
self.send_headers()
else:
pass # XXX check if content-length was too short? def close(self):
"""Close the iterable (if needed) and reset all instance vars Subclasses may want to also drop the client connection.
"""
try:
if hasattr(self.result,'close'):
self.result.close()
finally:
self.result = self.headers = self.status = self.environ = None
self.bytes_sent = 0; self.headers_sent = False def send_headers(self):
"""Transmit headers to the client, via self._write()"""
self.cleanup_headers()
self.headers_sent = True
if not self.origin_server or self.client_is_modern():
self.send_preamble()
self._write(str(self.headers)) def result_is_file(self):
"""True if 'self.result' is an instance of 'self.wsgi_file_wrapper'"""
wrapper = self.wsgi_file_wrapper
return wrapper is not None and isinstance(self.result,wrapper) def client_is_modern(self):
"""True if client can accept status and headers"""
return self.environ['SERVER_PROTOCOL'].upper() != 'HTTP/0.9' def log_exception(self,exc_info):
"""Log the 'exc_info' tuple in the server log Subclasses may override to retarget the output or change its format.
"""
try:
from traceback import print_exception
stderr = self.get_stderr()
print_exception(
exc_info[0], exc_info[1], exc_info[2],
self.traceback_limit, stderr
)
stderr.flush()
finally:
exc_info = None def handle_error(self):
"""Log current error, and send error output to client if possible"""
self.log_exception(sys.exc_info())
if not self.headers_sent:
self.result = self.error_output(self.environ, self.start_response)
self.finish_response()
# XXX else: attempt advanced recovery techniques for HTML or text? def error_output(self, environ, start_response):
"""WSGI mini-app to create error output By default, this just uses the 'error_status', 'error_headers',
and 'error_body' attributes to generate an output page. It can
be overridden in a subclass to dynamically generate diagnostics,
choose an appropriate message for the user's preferred language, etc. Note, however, that it's not recommended from a security perspective to
spit out diagnostics to any old user; ideally, you should have to do
something special to enable diagnostic output, which is why we don't
include any here!
"""
start_response(self.error_status,self.error_headers[:],sys.exc_info())
return [self.error_body] # Pure abstract methods; *must* be overridden in subclasses def _write(self,data):
"""Override in subclass to buffer data for send to client It's okay if this method actually transmits the data; BaseHandler
just separates write and flush operations for greater efficiency
when the underlying system actually has such a distinction.
"""
raise NotImplementedError def _flush(self):
"""Override in subclass to force sending of recent '_write()' calls It's okay if this method is a no-op (i.e., if '_write()' actually
sends the data.
"""
raise NotImplementedError def get_stdin(self):
"""Override in subclass to return suitable 'wsgi.input'"""
raise NotImplementedError def get_stderr(self):
"""Override in subclass to return suitable 'wsgi.errors'"""
raise NotImplementedError def add_cgi_vars(self):
"""Override in subclass to insert CGI variables in 'self.environ'"""
raise NotImplementedError class SimpleHandler(BaseHandler):
"""Handler that's just initialized with streams, environment, etc. This handler subclass is intended for synchronous HTTP/1.0 origin servers,
and handles sending the entire response output, given the correct inputs. Usage:: handler = SimpleHandler(
inp,out,err,env, multithread=False, multiprocess=True
)
handler.run(app)""" def __init__(self,stdin,stdout,stderr,environ,
multithread=True, multiprocess=False
):
self.stdin = stdin
self.stdout = stdout
self.stderr = stderr
self.base_env = environ
self.wsgi_multithread = multithread
self.wsgi_multiprocess = multiprocess def get_stdin(self):
return self.stdin def get_stderr(self):
return self.stderr def add_cgi_vars(self):
self.environ.update(self.base_env) def _write(self,data):
self.stdout.write(data)
self._write = self.stdout.write def _flush(self):
self.stdout.flush()
self._flush = self.stdout.flush class BaseCGIHandler(SimpleHandler): """CGI-like systems using input/output/error streams and environ mapping Usage:: handler = BaseCGIHandler(inp,out,err,env)
handler.run(app) This handler class is useful for gateway protocols like ReadyExec and
FastCGI, that have usable input/output/error streams and an environment
mapping. It's also the base class for CGIHandler, which just uses
sys.stdin, os.environ, and so on. The constructor also takes keyword arguments 'multithread' and
'multiprocess' (defaulting to 'True' and 'False' respectively) to control
the configuration sent to the application. It sets 'origin_server' to
False (to enable CGI-like output), and assumes that 'wsgi.run_once' is
False.
""" origin_server = False """BaseHTTPServer that implements the Python WSGI protocol (PEP 333, rev 1.21) This is both an example of how WSGI can be implemented, and a basis for running
simple web applications on a local machine, such as might be done when testing
or debugging an application. It has not been reviewed for security issues,
however, and we strongly recommend that you use a "real" web server for
production use. For example usage, see the 'if __name__=="__main__"' block at the end of the
module. See also the BaseHTTPServer module docs for other API information.
""" from BaseHTTPServer import BaseHTTPRequestHandler, HTTPServer
import urllib, sys
from wsgiref.handlers import SimpleHandler __version__ = "0.1"
__all__ = ['WSGIServer', 'WSGIRequestHandler', 'demo_app', 'make_server'] server_version = "WSGIServer/" + __version__
sys_version = "Python/" + sys.version.split()[0]
software_version = server_version + ' ' + sys_version class ServerHandler(SimpleHandler): server_software = software_version def close(self):
try:
self.request_handler.log_request(
self.status.split(' ',1)[0], self.bytes_sent
)
finally:
SimpleHandler.close(self) class WSGIServer(HTTPServer): """BaseHTTPServer that implements the Python WSGI protocol""" application = None def server_bind(self):
"""Override server_bind to store the server name."""
HTTPServer.server_bind(self)
self.setup_environ() def setup_environ(self):
# Set up base environment
env = self.base_environ = {}
env['SERVER_NAME'] = self.server_name
env['GATEWAY_INTERFACE'] = 'CGI/1.1'
env['SERVER_PORT'] = str(self.server_port)
env['REMOTE_HOST']=''
env['CONTENT_LENGTH']=''
env['SCRIPT_NAME'] = '' def get_app(self):
return self.application def set_app(self,application):
self.application = application class WSGIRequestHandler(BaseHTTPRequestHandler): server_version = "WSGIServer/" + __version__ def get_environ(self):
env = self.server.base_environ.copy()
env['SERVER_PROTOCOL'] = self.request_version
env['REQUEST_METHOD'] = self.command
if '?' in self.path:
path,query = self.path.split('?',1)
else:
path,query = self.path,'' env['PATH_INFO'] = urllib.unquote(path)
env['QUERY_STRING'] = query host = self.address_string()
if host != self.client_address[0]:
env['REMOTE_HOST'] = host
env['REMOTE_ADDR'] = self.client_address[0] if self.headers.typeheader is None:
env['CONTENT_TYPE'] = self.headers.type
else:
env['CONTENT_TYPE'] = self.headers.typeheader length = self.headers.getheader('content-length')
if length:
env['CONTENT_LENGTH'] = length for h in self.headers.headers:
k,v = h.split(':',1)
k=k.replace('-','_').upper(); v=v.strip()
if k in env:
continue # skip content length, type,etc.
if 'HTTP_'+k in env:
env['HTTP_'+k] += ','+v # comma-separate multiple headers
else:
env['HTTP_'+k] = v
return env def get_stderr(self):
return sys.stderr def handle(self):#处理一个request，构造server时，要传入一个requesthandler
"""Handle a single HTTP request""" self.raw_requestline = self.rfile.readline(65537)
if len(self.raw_requestline) > 65536:
self.requestline = ''
self.request_version = ''
self.command = ''
self.send_error(414)
return if not self.parse_request(): # An error code has been sent, just exit
return handler = ServerHandler(
self.rfile, self.wfile, self.get_stderr(), self.get_environ()
)
handler.request_handler = self # backpointer for logging
handler.run(self.server.get_app()) def demo_app(environ,start_response):#相当于django框架，处理request时会调用它
from StringIO import StringIO
stdout = StringIO()
print >>stdout, "Hello world!"
print >>stdout
h = environ.items(); h.sort()
for k,v in h:
print >>stdout, k,'=', repr(v)
start_response("200 OK", [('Content-Type','text/plain')])
return [stdout.getvalue()] def make_server(
host, port, app, server_class=WSGIServer, handler_class=WSGIRequestHandler
):
"""Create a new WSGI server listening on `host` and `port` for `app`"""
server = server_class((host, port), handler_class)
server.set_app(app)
return server if __name__ == '__main__':
httpd = make_server('', 8000, demo_app)
sa = httpd.socket.getsockname()
print "Serving HTTP on", sa[0], "port", sa[1], "..."
import webbrowser
webbrowser.open('http://localhost:8000/xyz?abc')
httpd.handle_request() # serve one request, then exit
httpd.server_close() server执行监听，accept，server对象有个成员为requesthandler，服务器在serv_forever时，会通过select函数来判断有无客户连接，有就调用_handle_request _noblock ->get_request ->process_request ->finish_request ->RequestHandlerClass生成一个RequestHandler对象，该对象又会调用自己的handle()->handle_one_request->parse_request->找到相应的处理方法，然后调用方法，完成一个请求。在wsgirequesthandler中重载了handle函数，它构造了serverhandler对象，serverhandler调用run来完成请求，run又调用到app对象，由app干活，返回response。