cpython/Lib/http/server.py at 3.12 · python/cpython · GitHub

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"""HTTP server classes.

Note: BaseHTTPRequestHandler doesn't implement any HTTP request; see
SimpleHTTPRequestHandler for simple implementations of GET, HEAD and POST,
and CGIHTTPRequestHandler for CGI scripts.

It does, however, optionally implement HTTP/1.1 persistent connections,
as of version 0.3.

Notes on CGIHTTPRequestHandler
------------------------------

This class implements GET and POST requests to cgi-bin scripts.

If the os.fork() function is not present (e.g. on Windows),
subprocess.Popen() is used as a fallback, with slightly altered semantics.

In all cases, the implementation is intentionally naive -- all
requests are executed synchronously.

SECURITY WARNING: DON'T USE THIS CODE UNLESS YOU ARE INSIDE A FIREWALL
-- it may execute arbitrary Python code or external programs.

Note that status code 200 is sent prior to execution of a CGI script, so
scripts cannot send other status codes such as 302 (redirect).

XXX To do:

- log requests even later (to capture byte count)
- log user-agent header and other interesting goodies
- send error log to separate file
"""


# See also:
#
# HTTP Working Group T. Berners-Lee
# INTERNET-DRAFT R. T. Fielding
# <draft-ietf-http-v10-spec-00.txt> H. Frystyk Nielsen
# Expires September 8, 1995 March 8, 1995
#
# URL: http://www.ics.uci.edu/pub/ietf/http/draft-ietf-http-v10-spec-00.txt
#
# and
#
# Network Working Group R. Fielding
# Request for Comments: 2616 et al
# Obsoletes: 2068 June 1999
# Category: Standards Track
#
# URL: http://www.faqs.org/rfcs/rfc2616.html

# Log files
# ---------
#
# Here's a quote from the NCSA httpd docs about log file format.
#
# | The logfile format is as follows. Each line consists of:
# |
# | host rfc931 authuser [DD/Mon/YYYY:hh:mm:ss] "request" ddd bbbb
# |
# | host: Either the DNS name or the IP number of the remote client
# | rfc931: Any information returned by identd for this person,
# | - otherwise.
# | authuser: If user sent a userid for authentication, the user name,
# | - otherwise.
# | DD: Day
# | Mon: Month (calendar name)
# | YYYY: Year
# | hh: hour (24-hour format, the machine's timezone)
# | mm: minutes
# | ss: seconds
# | request: The first line of the HTTP request as sent by the client.
# | ddd: the status code returned by the server, - if not available.
# | bbbb: the total number of bytes sent,
# | *not including the HTTP/1.0 header*, - if not available
# |
# | You can determine the name of the file accessed through request.
#
# (Actually, the latter is only true if you know the server configuration
# at the time the request was made!)

__version__="0.6"

__all__= [
"HTTPServer", "ThreadingHTTPServer", "BaseHTTPRequestHandler",
"SimpleHTTPRequestHandler", "CGIHTTPRequestHandler",
]

importcopy
importdatetime
importemail.utils
importhtml
importhttp.client
importio
importitertools
importmimetypes
importos
importposixpath
importselect
importshutil
importsocket# For gethostbyaddr()
importsocketserver
importsys
importtime
importurllib.parse

fromhttpimportHTTPStatus


# Default error message template
DEFAULT_ERROR_MESSAGE="""\
<!DOCTYPE HTML>
<html lang="en">
 <head>
 <meta charset="utf-8">
 <title>Error response</title>
 </head>
 <body>
 <h1>Error response</h1>
 <p>Error code: %(code)d</p>
 <p>Message: %(message)s.</p>
 <p>Error code explanation: %(code)s - %(explain)s.</p>
 </body>
</html>
"""

DEFAULT_ERROR_CONTENT_TYPE="text/html;charset=utf-8"

# Data larger than this will be read in chunks, to prevent extreme
# overallocation.
_MIN_READ_BUF_SIZE=1<<20

classHTTPServer(socketserver.TCPServer):

allow_reuse_address=1# Seems to make sense in testing environment

defserver_bind(self):
"""Override server_bind to store the server name."""
socketserver.TCPServer.server_bind(self)
host, port=self.server_address[:2]
self.server_name=socket.getfqdn(host)
self.server_port=port


classThreadingHTTPServer(socketserver.ThreadingMixIn, HTTPServer):
daemon_threads=True


classBaseHTTPRequestHandler(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 email.message.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__

error_message_format=DEFAULT_ERROR_MESSAGE
error_content_type=DEFAULT_ERROR_CONTENT_TYPE

# 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"

defparse_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, any relevant
 error response has already been 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=True
requestline=str(self.raw_requestline, 'iso-8859-1')
requestline=requestline.rstrip('\r\n')
self.requestline=requestline
words=requestline.split()
iflen(words) ==0:
returnFalse

iflen(words) >=3: # Enough to determine protocol version
version=words[-1]
try:
ifnotversion.startswith('HTTP/'):
raiseValueError
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.
iflen(version_number) !=2:
raiseValueError
ifany(notcomponent.isdigit() forcomponentinversion_number):
raiseValueError("non digit in http version")
ifany(len(component) >10forcomponentinversion_number):
raiseValueError("unreasonable length http version")
version_number=int(version_number[0]), int(version_number[1])
except (ValueError, IndexError):
self.send_error(
HTTPStatus.BAD_REQUEST,
"Bad request version (%r)"%version)
returnFalse
ifversion_number>= (1, 1) andself.protocol_version>="HTTP/1.1":
self.close_connection=False
ifversion_number>= (2, 0):
self.send_error(
HTTPStatus.HTTP_VERSION_NOT_SUPPORTED,
"Invalid HTTP version (%s)"%base_version_number)
returnFalse
self.request_version=version

ifnot2<=len(words) <=3:
self.send_error(
HTTPStatus.BAD_REQUEST,
"Bad request syntax (%r)"%requestline)
returnFalse
command, path=words[:2]
iflen(words) ==2:
self.close_connection=True
ifcommand!='GET':
self.send_error(
HTTPStatus.BAD_REQUEST,
"Bad HTTP/0.9 request type (%r)"%command)
returnFalse
self.command, self.path=command, path

# gh-87389: The purpose of replacing '//' with '/' is to protect
# against open redirect attacks possibly triggered if the path starts
# with '//' because http clients treat //path as an absolute URI
# without scheme (similar to http://path) rather than a path.
ifself.path.startswith('//'):
self.path='/'+self.path.lstrip('/') # Reduce to a single /

# Examine the headers and look for a Connection directive.
try:
self.headers=http.client.parse_headers(self.rfile,
_class=self.MessageClass)
excepthttp.client.LineTooLongaserr:
self.send_error(
HTTPStatus.REQUEST_HEADER_FIELDS_TOO_LARGE,
"Line too long",
str(err))
returnFalse
excepthttp.client.HTTPExceptionaserr:
self.send_error(
HTTPStatus.REQUEST_HEADER_FIELDS_TOO_LARGE,
"Too many headers",
str(err)
 )
returnFalse

conntype=self.headers.get('Connection', "")
ifconntype.lower() =='close':
self.close_connection=True
elif (conntype.lower() =='keep-alive'and
self.protocol_version>="HTTP/1.1"):
self.close_connection=False
# Examine the headers and look for an Expect directive
expect=self.headers.get('Expect', "")
if (expect.lower() =="100-continue"and
self.protocol_version>="HTTP/1.1"and
self.request_version>="HTTP/1.1"):
ifnotself.handle_expect_100():
returnFalse
returnTrue

defhandle_expect_100(self):
"""Decide what to do with an "Expect: 100-continue" header.

 If the client is expecting a 100 Continue response, we must
 respond with either a 100 Continue or a final response before
 waiting for the request body. The default is to always respond
 with a 100 Continue. You can behave differently (for example,
 reject unauthorized requests) by overriding this method.

 This method should either return True (possibly after sending
 a 100 Continue response) or send an error response and return
 False.

 """
self.send_response_only(HTTPStatus.CONTINUE)
self.end_headers()
returnTrue

defhandle_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)
iflen(self.raw_requestline) >65536:
self.requestline=''
self.request_version=''
self.command=''
self.send_error(HTTPStatus.REQUEST_URI_TOO_LONG)
return
ifnotself.raw_requestline:
self.close_connection=True
return
ifnotself.parse_request():
# An error code has been sent, just exit
return
mname='do_'+self.command
ifnothasattr(self, mname):
self.send_error(
HTTPStatus.NOT_IMPLEMENTED,
"Unsupported method (%r)"%self.command)
return
method=getattr(self, mname)
method()
self.wfile.flush() #actually send the response if not already done.
exceptTimeoutErrorase:
#a read or a write timed out. Discard this connection
self.log_error("Request timed out: %r", e)
self.close_connection=True
return

defhandle(self):
"""Handle multiple requests if necessary."""
self.close_connection=True

self.handle_one_request()
whilenotself.close_connection:
self.handle_one_request()

defsend_error(self, code, message=None, explain=None):
"""Send and log an error reply.

 Arguments are
 * code: an HTTP error code
 3 digits
 * message: a simple optional 1 line reason phrase.
 *( HTAB / SP / VCHAR / %x80-FF )
 defaults to short entry matching the response code
 * explain: a detailed message defaults to the long 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:
shortmsg, longmsg=self.responses[code]
exceptKeyError:
shortmsg, longmsg='???', '???'
ifmessageisNone:
message=shortmsg
ifexplainisNone:
explain=longmsg
self.log_error("code %d, message %s", code, message)
self.send_response(code, message)
self.send_header('Connection', 'close')

# Message body is omitted for cases described in:
# - RFC7230: 3.3. 1xx, 204(No Content), 304(Not Modified)
# - RFC7231: 6.3.6. 205(Reset Content)
body=None
if (code>=200and
codenotin (HTTPStatus.NO_CONTENT,
HTTPStatus.RESET_CONTENT,
HTTPStatus.NOT_MODIFIED)):
# HTML encode to prevent Cross Site Scripting attacks
# (see bug #1100201)
content= (self.error_message_format% {
'code': code,
'message': html.escape(message, quote=False),
'explain': html.escape(explain, quote=False)
 })
body=content.encode('UTF-8', 'replace')
self.send_header("Content-Type", self.error_content_type)
self.send_header('Content-Length', str(len(body)))
self.end_headers()

ifself.command!='HEAD'andbody:
self.wfile.write(body)

defsend_response(self, code, message=None):
"""Add the response header to the headers buffer and log the
 response code.

 Also send two standard headers with the server software
 version and the current date.

 """
self.log_request(code)
self.send_response_only(code, message)
self.send_header('Server', self.version_string())
self.send_header('Date', self.date_time_string())

defsend_response_only(self, code, message=None):
"""Send the response header only."""
ifself.request_version!='HTTP/0.9':
ifmessageisNone:
ifcodeinself.responses:
message=self.responses[code][0]
else:
message=''
ifnothasattr(self, '_headers_buffer'):
self._headers_buffer= []
self._headers_buffer.append(("%s %d %s\r\n"%
 (self.protocol_version, code, message)).encode(
'latin-1', 'strict'))

defsend_header(self, keyword, value):
"""Send a MIME header to the headers buffer."""
ifself.request_version!='HTTP/0.9':
ifnothasattr(self, '_headers_buffer'):
self._headers_buffer= []
self._headers_buffer.append(
 ("%s: %s\r\n"% (keyword, value)).encode('latin-1', 'strict'))

ifkeyword.lower() =='connection':
ifvalue.lower() =='close':
self.close_connection=True
elifvalue.lower() =='keep-alive':
self.close_connection=False

defend_headers(self):
"""Send the blank line ending the MIME headers."""
ifself.request_version!='HTTP/0.9':
self._headers_buffer.append(b"\r\n")
self.flush_headers()

defflush_headers(self):
ifhasattr(self, '_headers_buffer'):
self.wfile.write(b"".join(self._headers_buffer))
self._headers_buffer= []

deflog_request(self, code='-', size='-'):
"""Log an accepted request.

 This is called by send_response().

 """
ifisinstance(code, HTTPStatus):
code=code.value
self.log_message('"%s" %s %s',
self.requestline, str(code), str(size))

deflog_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)

# https://en.wikipedia.org/wiki/List_of_Unicode_characters#Control_codes
_control_char_table=str.maketrans(
 {c: fr'\x{c:02x}'forcinitertools.chain(range(0x20), range(0x7f,0xa0))})
_control_char_table[ord('\\')] =r'\\'

deflog_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 and current date/time are prefixed to
 every message.

 Unicode control characters are replaced with escaped hex
 before writing the output to stderr.

 """

message=format%args
sys.stderr.write("%s - - [%s] %s\n"%
 (self.address_string(),
self.log_date_time_string(),
message.translate(self._control_char_table)))

defversion_string(self):
"""Return the server software version string."""
returnself.server_version+' '+self.sys_version

defdate_time_string(self, timestamp=None):
"""Return the current date and time formatted for a message header."""
iftimestampisNone:
timestamp=time.time()
returnemail.utils.formatdate(timestamp, usegmt=True)

deflog_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)
returns

weekdayname= ['Mon', 'Tue', 'Wed', 'Thu', 'Fri', 'Sat', 'Sun']

monthname= [None,
'Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun',
'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec']

defaddress_string(self):
"""Return the client address."""

returnself.client_address[0]

# 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"

# MessageClass used to parse headers
MessageClass=http.client.HTTPMessage

# hack to maintain backwards compatibility
responses= {
v: (v.phrase, v.description)
forvinHTTPStatus.__members__.values()
 }


classSimpleHTTPRequestHandler(BaseHTTPRequestHandler):

"""Simple HTTP request handler with GET and HEAD commands.

 This serves files from the current directory and any of its
 subdirectories. The MIME type for files is determined by
 calling the .guess_type() method.

 The GET and HEAD requests are identical except that the HEAD
 request omits the actual contents of the file.

 """

server_version="SimpleHTTP/"+__version__
index_pages= ("index.html", "index.htm")
extensions_map=_encodings_map_default= {
'.gz': 'application/gzip',
'.Z': 'application/octet-stream',
'.bz2': 'application/x-bzip2',
'.xz': 'application/x-xz',
 }

def__init__(self, *args, directory=None, **kwargs):
ifdirectoryisNone:
directory=os.getcwd()
self.directory=os.fspath(directory)
super().__init__(*args, **kwargs)

defdo_GET(self):
"""Serve a GET request."""
f=self.send_head()
iff:
try:
self.copyfile(f, self.wfile)
finally:
f.close()

defdo_HEAD(self):
"""Serve a HEAD request."""
f=self.send_head()
iff:
f.close()

defsend_head(self):
"""Common code for GET and HEAD commands.

 This sends the response code and MIME headers.

 Return value is either a file object (which has to be copied
 to the outputfile by the caller unless the command was HEAD,
 and must be closed by the caller under all circumstances), or
 None, in which case the caller has nothing further to do.

 """
path=self.translate_path(self.path)
f=None
ifos.path.isdir(path):
parts=urllib.parse.urlsplit(self.path)
ifnotparts.path.endswith('/'):
# redirect browser - doing basically what apache does
self.send_response(HTTPStatus.MOVED_PERMANENTLY)
new_parts= (parts[0], parts[1], parts[2] +'/',
parts[3], parts[4])
new_url=urllib.parse.urlunsplit(new_parts)
self.send_header("Location", new_url)
self.send_header("Content-Length", "0")
self.end_headers()
returnNone
forindexinself.index_pages:
index=os.path.join(path, index)
ifos.path.isfile(index):
path=index
break
else:
returnself.list_directory(path)
ctype=self.guess_type(path)
# check for trailing "/" which should return 404. See Issue17324
# The test for this was added in test_httpserver.py
# However, some OS platforms accept a trailingSlash as a filename
# See discussion on python-dev and Issue34711 regarding
# parsing and rejection of filenames with a trailing slash
ifpath.endswith("/"):
self.send_error(HTTPStatus.NOT_FOUND, "File not found")
returnNone
try:
f=open(path, 'rb')
exceptOSError:
self.send_error(HTTPStatus.NOT_FOUND, "File not found")
returnNone

try:
fs=os.fstat(f.fileno())
# Use browser cache if possible
if ("If-Modified-Since"inself.headers
and"If-None-Match"notinself.headers):
# compare If-Modified-Since and time of last file modification
try:
ims=email.utils.parsedate_to_datetime(
self.headers["If-Modified-Since"])
except (TypeError, IndexError, OverflowError, ValueError):
# ignore ill-formed values
pass
else:
ifims.tzinfoisNone:
# obsolete format with no timezone, cf.
# https://tools.ietf.org/html/rfc7231#section-7.1.1.1
ims=ims.replace(tzinfo=datetime.timezone.utc)
ifims.tzinfoisdatetime.timezone.utc:
# compare to UTC datetime of last modification
last_modif=datetime.datetime.fromtimestamp(
fs.st_mtime, datetime.timezone.utc)
# remove microseconds, like in If-Modified-Since
last_modif=last_modif.replace(microsecond=0)

iflast_modif<=ims:
self.send_response(HTTPStatus.NOT_MODIFIED)
self.end_headers()
f.close()
returnNone

self.send_response(HTTPStatus.OK)
self.send_header("Content-type", ctype)
self.send_header("Content-Length", str(fs[6]))
self.send_header("Last-Modified",
self.date_time_string(fs.st_mtime))
self.end_headers()
returnf
except:
f.close()
raise

deflist_directory(self, path):
"""Helper to produce a directory listing (absent index.html).

 Return value is either a file object, or None (indicating an
 error). In either case, the headers are sent, making the
 interface the same as for send_head().

 """
try:
list=os.listdir(path)
exceptOSError:
self.send_error(
HTTPStatus.NOT_FOUND,
"No permission to list directory")
returnNone
list.sort(key=lambdaa: a.lower())
r= []
try:
displaypath=urllib.parse.unquote(self.path,
errors='surrogatepass')
exceptUnicodeDecodeError:
displaypath=urllib.parse.unquote(self.path)
displaypath=html.escape(displaypath, quote=False)
enc=sys.getfilesystemencoding()
title=f'Directory listing for {displaypath}'
r.append('<!DOCTYPE HTML>')
r.append('<html lang="en">')
r.append('<head>')
r.append(f'<meta charset="{enc}">')
r.append(f'<title>{title}</title>\n</head>')
r.append(f'<body>\n<h1>{title}</h1>')
r.append('<hr>\n<ul>')
fornameinlist:
fullname=os.path.join(path, name)
displayname=linkname=name
# Append / for directories or @ for symbolic links
ifos.path.isdir(fullname):
displayname=name+"/"
linkname=name+"/"
ifos.path.islink(fullname):
displayname=name+"@"
# Note: a link to a directory displays with @ and links with /
r.append('<li><a href="%s">%s</a></li>'
% (urllib.parse.quote(linkname,
errors='surrogatepass'),
html.escape(displayname, quote=False)))
r.append('</ul>\n<hr>\n</body>\n</html>\n')
encoded='\n'.join(r).encode(enc, 'surrogateescape')
f=io.BytesIO()
f.write(encoded)
f.seek(0)
self.send_response(HTTPStatus.OK)
self.send_header("Content-type", "text/html; charset=%s"%enc)
self.send_header("Content-Length", str(len(encoded)))
self.end_headers()
returnf

deftranslate_path(self, path):
"""Translate a /-separated PATH to the local filename syntax.

 Components that mean special things to the local file system
 (e.g. drive or directory names) are ignored. (XXX They should
 probably be diagnosed.)

 """
# abandon query parameters
path=path.split('?',1)[0]
path=path.split('#',1)[0]
# Don't forget explicit trailing slash when normalizing. Issue17324
trailing_slash=path.rstrip().endswith('/')
try:
path=urllib.parse.unquote(path, errors='surrogatepass')
exceptUnicodeDecodeError:
path=urllib.parse.unquote(path)
path=posixpath.normpath(path)
words=path.split('/')
words=filter(None, words)
path=self.directory
forwordinwords:
ifos.path.dirname(word) orwordin (os.curdir, os.pardir):
# Ignore components that are not a simple file/directory name
continue
path=os.path.join(path, word)
iftrailing_slash:
path+='/'
returnpath

defcopyfile(self, source, outputfile):
"""Copy all data between two file objects.

 The SOURCE argument is a file object open for reading
 (or anything with a read() method) and the DESTINATION
 argument is a file object open for writing (or
 anything with a write() method).

 The only reason for overriding this would be to change
 the block size or perhaps to replace newlines by CRLF
 -- note however that this the default server uses this
 to copy binary data as well.

 """
shutil.copyfileobj(source, outputfile)

defguess_type(self, path):
"""Guess the type of a file.

 Argument is a PATH (a filename).

 Return value is a string of the form type/subtype,
 usable for a MIME Content-type header.

 The default implementation looks the file's extension
 up in the table self.extensions_map, using application/octet-stream
 as a default; however it would be permissible (if
 slow) to look inside the data to make a better guess.

 """
base, ext=posixpath.splitext(path)
ifextinself.extensions_map:
returnself.extensions_map[ext]
ext=ext.lower()
ifextinself.extensions_map:
returnself.extensions_map[ext]
guess, _=mimetypes.guess_type(path)
ifguess:
returnguess
return'application/octet-stream'


# Utilities for CGIHTTPRequestHandler

def_url_collapse_path(path):
"""
 Given a URL path, remove extra '/'s and '.' path elements and collapse
 any '..' references and returns a collapsed path.

 Implements something akin to RFC-2396 5.2 step 6 to parse relative paths.
 The utility of this function is limited to is_cgi method and helps
 preventing some security attacks.

 Returns: The reconstituted URL, which will always start with a '/'.

 Raises: IndexError if too many '..' occur within the path.

 """
# Query component should not be involved.
path, _, query=path.partition('?')
path=urllib.parse.unquote(path)

# Similar to os.path.split(os.path.normpath(path)) but specific to URL
# path semantics rather than local operating system semantics.
path_parts=path.split('/')
head_parts= []
forpartinpath_parts[:-1]:
ifpart=='..':
head_parts.pop() # IndexError if more '..' than prior parts
elifpartandpart!='.':
head_parts.append( part )
ifpath_parts:
tail_part=path_parts.pop()
iftail_part:
iftail_part=='..':
head_parts.pop()
tail_part=''
eliftail_part=='.':
tail_part=''
else:
tail_part=''

ifquery:
tail_part='?'.join((tail_part, query))

splitpath= ('/'+'/'.join(head_parts), tail_part)
collapsed_path="/".join(splitpath)

returncollapsed_path


nobody=None

defnobody_uid():
"""Internal routine to get nobody's uid"""
globalnobody
ifnobody:
returnnobody
try:
importpwd
exceptImportError:
return-1
try:
nobody=pwd.getpwnam('nobody')[2]
exceptKeyError:
nobody=1+max(x[2] forxinpwd.getpwall())
returnnobody


defexecutable(path):
"""Test for executable file."""
returnos.access(path, os.X_OK)


classCGIHTTPRequestHandler(SimpleHTTPRequestHandler):

"""Complete HTTP server with GET, HEAD and POST commands.

 GET and HEAD also support running CGI scripts.

 The POST command is *only* implemented for CGI scripts.

 """

# Determine platform specifics
have_fork=hasattr(os, 'fork')

# Make rfile unbuffered -- we need to read one line and then pass
# the rest to a subprocess, so we can't use buffered input.
rbufsize=0

defdo_POST(self):