#! /usr/local/bin/python

# NOTE: the above "/usr/local/bin/python" is NOT a mistake. It is
# intentionally NOT "/usr/bin/env python". On many systems
# (e.g. Solaris), /usr/local/bin is not in $PATH as passed to CGI
# scripts, and /usr/local/bin is the default directory where Python is
# installed, so /usr/bin/env would be unable to find python. Granted,
# binary installations by Linux vendors often install Python in
# /usr/bin. So let those vendors patch cgi.py to match their choice
# of installation.

"""Support module for CGI (Common Gateway Interface) scripts.

This module defines a number of utilities for use by CGI scripts
written in Python.
"""

# History
# -------
#
# Michael McLay started this module. Steve Majewski changed the
# interface to SvFormContentDict and FormContentDict. The multipart
# parsing was inspired by code submitted by Andreas Paepcke. Guido van
# Rossum rewrote, reformatted and documented the module and is currently
# responsible for its maintenance.
#

__version__ = "2.6"


# Imports
# =======

from io import StringIO, BytesIO, TextIOWrapper
from collections.abc import Mapping
import sys
import os
import urllib.parse
from email.parser import FeedParser
from email.message import Message
import html
import locale
import tempfile

__all__ = ["MiniFieldStorage", "FieldStorage", "parse", "parse_multipart",
 "parse_header", "test", "print_exception", "print_environ",
 "print_form", "print_directory", "print_arguments",
 "print_environ_usage"]

# Logging support
# ===============

logfile = "" # Filename to log to, if not empty
logfp = None # File object to log to, if not None

def initlog(*allargs):
 """Write a log message, if there is a log file.

 Even though this function is called initlog(), you should always
 use log(); log is a variable that is set either to initlog
 (initially), to dolog (once the log file has been opened), or to
 nolog (when logging is disabled).

 The first argument is a format string; the remaining arguments (if
 any) are arguments to the % operator, so e.g.
 log("%s: %s", "a", "b")
 will write "a: b" to the log file, followed by a newline.

 If the global logfp is not None, it should be a file object to
 which log data is written.

 If the global logfp is None, the global logfile may be a string
 giving a filename to open, in append mode. This file should be
 world writable!!! If the file can't be opened, logging is
 silently disabled (since there is no safe place where we could
 send an error message).

 """
 global log, logfile, logfp
 if logfile and not logfp:
 try:
 logfp = open(logfile, "a")
 except OSError:
 pass
 if not logfp:
 log = nolog
 else:
 log = dolog
 log(*allargs)

def dolog(fmt, *args):
 """Write a log message to the log file. See initlog() for docs."""
 logfp.write(fmt%args + "\n")

def nolog(*allargs):
 """Dummy function, assigned to log when logging is disabled."""
 pass

def closelog():
 """Close the log file."""
 global log, logfile, logfp
 logfile = ''
 if logfp:
 logfp.close()
 logfp = None
 log = initlog

log = initlog # The current logging function


# Parsing functions
# =================

# Maximum input we will accept when REQUEST_METHOD is POST
# 0 ==> unlimited input
maxlen = 0

def parse(fp=None, environ=os.environ, keep_blank_values=0,
 strict_parsing=0, separator='&'):
 """Parse a query in the environment or from a file (default stdin)

 Arguments, all optional:

 fp : file pointer; default: sys.stdin.buffer

 environ : environment dictionary; default: os.environ

 keep_blank_values: flag indicating whether blank values in
 percent-encoded forms should be treated as blank strings.
 A true value indicates that blanks should be retained as
 blank strings. The default false value indicates that
 blank values are to be ignored and treated as if they were
 not included.

 strict_parsing: flag indicating what to do with parsing errors.
 If false (the default), errors are silently ignored.
 If true, errors raise a ValueError exception.

 separator: str. The symbol to use for separating the query arguments.
 Defaults to &.
 """
 if fp is None:
 fp = sys.stdin

 # field keys and values (except for files) are returned as strings
 # an encoding is required to decode the bytes read from self.fp
 if hasattr(fp,'encoding'):
 encoding = fp.encoding
 else:
 encoding = 'latin-1'

 # fp.read() must return bytes
 if isinstance(fp, TextIOWrapper):
 fp = fp.buffer

 if not 'REQUEST_METHOD' in environ:
 environ['REQUEST_METHOD'] = 'GET' # For testing stand-alone
 if environ['REQUEST_METHOD'] == 'POST':
 ctype, pdict = parse_header(environ['CONTENT_TYPE'])
 if ctype == 'multipart/form-data':
 return parse_multipart(fp, pdict, separator=separator)
 elif ctype == 'application/x-www-form-urlencoded':
 clength = int(environ['CONTENT_LENGTH'])
 if maxlen and clength > maxlen:
 raise ValueError('Maximum content length exceeded')
 qs = fp.read(clength).decode(encoding)
 else:
 qs = '' # Unknown content-type
 if 'QUERY_STRING' in environ:
 if qs: qs = qs + '&'
 qs = qs + environ['QUERY_STRING']
 elif sys.argv[1:]:
 if qs: qs = qs + '&'
 qs = qs + sys.argv[1]
 environ['QUERY_STRING'] = qs # XXX Shouldn't, really
 elif 'QUERY_STRING' in environ:
 qs = environ['QUERY_STRING']
 else:
 if sys.argv[1:]:
 qs = sys.argv[1]
 else:
 qs = ""
 environ['QUERY_STRING'] = qs # XXX Shouldn't, really
 return urllib.parse.parse_qs(qs, keep_blank_values, strict_parsing,
 encoding=encoding, separator=separator)


def parse_multipart(fp, pdict, encoding="utf-8", errors="replace", separator='&'):
 """Parse multipart input.

 Arguments:
 fp : input file
 pdict: dictionary containing other parameters of content-type header
 encoding, errors: request encoding and error handler, passed to
 FieldStorage

 Returns a dictionary just like parse_qs(): keys are the field names, each
 value is a list of values for that field. For non-file fields, the value
 is a list of strings.
 """
 # RFC 2026, Section 5.1 : The "multipart" boundary delimiters are always
 # represented as 7bit US-ASCII.
 boundary = pdict['boundary'].decode('ascii')
 ctype = "multipart/form-data; boundary={}".format(boundary)
 headers = Message()
 headers.set_type(ctype)
 try:
 headers['Content-Length'] = pdict['CONTENT-LENGTH']
 except KeyError:
 pass
 fs = FieldStorage(fp, headers=headers, encoding=encoding, errors=errors,
 environ={'REQUEST_METHOD': 'POST'}, separator=separator)
 return {k: fs.getlist(k) for k in fs}

def _parseparam(s):
 while s[:1] == ';':
 s = s[1:]
 end = s.find(';')
 while end > 0 and (s.count('"', 0, end) - s.count('\\"', 0, end)) % 2:
 end = s.find(';', end + 1)
 if end < 0:
 end = len(s)
 f = s[:end]
 yield f.strip()
 s = s[end:]

def parse_header(line):
 """Parse a Content-type like header.

 Return the main content-type and a dictionary of options.

 """
 parts = _parseparam(';' + line)
 key = parts.__next__()
 pdict = {}
 for p in parts:
 i = p.find('=')
 if i >= 0:
 name = p[:i].strip().lower()
 value = p[i+1:].strip()
 if len(value) >= 2 and value[0] == value[-1] == '"':
 value = value[1:-1]
 value = value.replace('\\\\', '\\').replace('\\"', '"')
 pdict[name] = value
 return key, pdict


# Classes for field storage
# =========================

class MiniFieldStorage:

 """Like FieldStorage, for use when no file uploads are possible."""

 # Dummy attributes
 filename = None
 list = None
 type = None
 file = None
 type_options = {}
 disposition = None
 disposition_options = {}
 headers = {}

 def __init__(self, name, value):
 """Constructor from field name and value."""
 self.name = name
 self.value = value
 # self.file = StringIO(value)

 def __repr__(self):
 """Return printable representation."""
 return "MiniFieldStorage(%r, %r)" % (self.name, self.value)


class FieldStorage:

 """Store a sequence of fields, reading multipart/form-data.

 This class provides naming, typing, files stored on disk, and
 more. At the top level, it is accessible like a dictionary, whose
 keys are the field names. (Note: None can occur as a field name.)
 The items are either a Python list (if there's multiple values) or
 another FieldStorage or MiniFieldStorage object. If it's a single
 object, it has the following attributes:

 name: the field name, if specified; otherwise None

 filename: the filename, if specified; otherwise None; this is the
 client side filename, *not* the file name on which it is
 stored (that's a temporary file you don't deal with)

 value: the value as a *string*; for file uploads, this
 transparently reads the file every time you request the value
 and returns *bytes*

 file: the file(-like) object from which you can read the data *as
 bytes* ; None if the data is stored a simple string

 type: the content-type, or None if not specified

 type_options: dictionary of options specified on the content-type
 line

 disposition: content-disposition, or None if not specified

 disposition_options: dictionary of corresponding options

 headers: a dictionary(-like) object (sometimes email.message.Message or a
 subclass thereof) containing *all* headers

 The class is subclassable, mostly for the purpose of overriding
 the make_file() method, which is called internally to come up with
 a file open for reading and writing. This makes it possible to
 override the default choice of storing all files in a temporary
 directory and unlinking them as soon as they have been opened.

 """
 def __init__(self, fp=None, headers=None, outerboundary=b'',
 environ=os.environ, keep_blank_values=0, strict_parsing=0,
 limit=None, encoding='utf-8', errors='replace',
 max_num_fields=None, separator='&'):
 """Constructor. Read multipart/* until last part.

 Arguments, all optional:

 fp : file pointer; default: sys.stdin.buffer
 (not used when the request method is GET)
 Can be :
 1. a TextIOWrapper object
 2. an object whose read() and readline() methods return bytes

 headers : header dictionary-like object; default:
 taken from environ as per CGI spec

 outerboundary : terminating multipart boundary
 (for internal use only)

 environ : environment dictionary; default: os.environ

 keep_blank_values: flag indicating whether blank values in
 percent-encoded forms should be treated as blank strings.
 A true value indicates that blanks should be retained as
 blank strings. The default false value indicates that
 blank values are to be ignored and treated as if they were
 not included.

 strict_parsing: flag indicating what to do with parsing errors.
 If false (the default), errors are silently ignored.
 If true, errors raise a ValueError exception.

 limit : used internally to read parts of multipart/form-data forms,
 to exit from the reading loop when reached. It is the difference
 between the form content-length and the number of bytes already
 read

 encoding, errors : the encoding and error handler used to decode the
 binary stream to strings. Must be the same as the charset defined
 for the page sending the form (content-type : meta http-equiv or
 header)

 max_num_fields: int. If set, then __init__ throws a ValueError
 if there are more than n fields read by parse_qsl().

 """
 method = 'GET'
 self.keep_blank_values = keep_blank_values
 self.strict_parsing = strict_parsing
 self.max_num_fields = max_num_fields
 self.separator = separator
 if 'REQUEST_METHOD' in environ:
 method = environ['REQUEST_METHOD'].upper()
 self.qs_on_post = None
 if method == 'GET' or method == 'HEAD':
 if 'QUERY_STRING' in environ:
 qs = environ['QUERY_STRING']
 elif sys.argv[1:]:
 qs = sys.argv[1]
 else:
 qs = ""
 qs = qs.encode(locale.getpreferredencoding(), 'surrogateescape')
 fp = BytesIO(qs)
 if headers is None:
 headers = {'content-type':
 "application/x-www-form-urlencoded"}
 if headers is None:
 headers = {}
 if method == 'POST':
 # Set default content-type for POST to what's traditional
 headers['content-type'] = "application/x-www-form-urlencoded"
 if 'CONTENT_TYPE' in environ:
 headers['content-type'] = environ['CONTENT_TYPE']
 if 'QUERY_STRING' in environ:
 self.qs_on_post = environ['QUERY_STRING']
 if 'CONTENT_LENGTH' in environ:
 headers['content-length'] = environ['CONTENT_LENGTH']
 else:
 if not (isinstance(headers, (Mapping, Message))):
 raise TypeError("headers must be mapping or an instance of "
 "email.message.Message")
 self.headers = headers
 if fp is None:
 self.fp = sys.stdin.buffer
 # self.fp.read() must return bytes
 elif isinstance(fp, TextIOWrapper):
 self.fp = fp.buffer
 else:
 if not (hasattr(fp, 'read') and hasattr(fp, 'readline')):
 raise TypeError("fp must be file pointer")
 self.fp = fp

 self.encoding = encoding
 self.errors = errors

 if not isinstance(outerboundary, bytes):
 raise TypeError('outerboundary must be bytes, not %s'
 % type(outerboundary).__name__)
 self.outerboundary = outerboundary

 self.bytes_read = 0
 self.limit = limit

 # Process content-disposition header
 cdisp, pdict = "", {}
 if 'content-disposition' in self.headers:
 cdisp, pdict = parse_header(self.headers['content-disposition'])
 self.disposition = cdisp
 self.disposition_options = pdict
 self.name = None
 if 'name' in pdict:
 self.name = pdict['name']
 self.filename = None
 if 'filename' in pdict:
 self.filename = pdict['filename']
 self._binary_file = self.filename is not None

 # Process content-type header
 #
 # Honor any existing content-type header. But if there is no
 # content-type header, use some sensible defaults. Assume
 # outerboundary is "" at the outer level, but something non-false
 # inside a multi-part. The default for an inner part is text/plain,
 # but for an outer part it should be urlencoded. This should catch
 # bogus clients which erroneously forget to include a content-type
 # header.
 #
 # See below for what we do if there does exist a content-type header,
 # but it happens to be something we don't understand.
 if 'content-type' in self.headers:
 ctype, pdict = parse_header(self.headers['content-type'])
 elif self.outerboundary or method != 'POST':
 ctype, pdict = "text/plain", {}
 else:
 ctype, pdict = 'application/x-www-form-urlencoded', {}
 self.type = ctype
 self.type_options = pdict
 if 'boundary' in pdict:
 self.innerboundary = pdict['boundary'].encode(self.encoding,
 self.errors)
 else:
 self.innerboundary = b""

 clen = -1
 if 'content-length' in self.headers:
 try:
 clen = int(self.headers['content-length'])
 except ValueError:
 pass
 if maxlen and clen > maxlen:
 raise ValueError('Maximum content length exceeded')
 self.length = clen
 if self.limit is None and clen >= 0:
 self.limit = clen

 self.list = self.file = None
 self.done = 0
 if ctype == 'application/x-www-form-urlencoded':
 self.read_urlencoded()
 elif ctype[:10] == 'multipart/':
 self.read_multi(environ, keep_blank_values, strict_parsing)
 else:
 self.read_single()

 def __del__(self):
 try:
 self.file.close()
 except AttributeError:
 pass

 def __enter__(self):
 return self

 def __exit__(self, *args):
 self.file.close()

 def __repr__(self):
 """Return a printable representation."""
 return "FieldStorage(%r, %r, %r)" % (
 self.name, self.filename, self.value)

 def __iter__(self):
 return iter(self.keys())

 def __getattr__(self, name):
 if name != 'value':
 raise AttributeError(name)
 if self.file:
 self.file.seek(0)
 value = self.file.read()
 self.file.seek(0)
 elif self.list is not None:
 value = self.list
 else:
 value = None
 return value

 def __getitem__(self, key):
 """Dictionary style indexing."""
 if self.list is None:
 raise TypeError("not indexable")
 found = []
 for item in self.list:
 if item.name == key: found.append(item)
 if not found:
 raise KeyError(key)
 if len(found) == 1:
 return found[0]
 else:
 return found

 def getvalue(self, key, default=None):
 """Dictionary style get() method, including 'value' lookup."""
 if key in self:
 value = self[key]
 if isinstance(value, list):
 return [x.value for x in value]
 else:
 return value.value
 else:
 return default

 def getfirst(self, key, default=None):
 """ Return the first value received."""
 if key in self:
 value = self[key]
 if isinstance(value, list):
 return value[0].value
 else:
 return value.value
 else:
 return default

 def getlist(self, key):
 """ Return list of received values."""
 if key in self:
 value = self[key]
 if isinstance(value, list):
 return [x.value for x in value]
 else:
 return [value.value]
 else:
 return []

 def keys(self):
 """Dictionary style keys() method."""
 if self.list is None:
 raise TypeError("not indexable")
 return list(set(item.name for item in self.list))

 def __contains__(self, key):
 """Dictionary style __contains__ method."""
 if self.list is None:
 raise TypeError("not indexable")
 return any(item.name == key for item in self.list)

 def __len__(self):
 """Dictionary style len(x) support."""
 return len(self.keys())

 def __bool__(self):
 if self.list is None:
 raise TypeError("Cannot be converted to bool.")
 return bool(self.list)

 def read_urlencoded(self):
 """Internal: read data in query string format."""
 qs = self.fp.read(self.length)
 if not isinstance(qs, bytes):
 raise ValueError("%s should return bytes, got %s" \
 % (self.fp, type(qs).__name__))
 qs = qs.decode(self.encoding, self.errors)
 if self.qs_on_post:
 qs += '&' + self.qs_on_post
 query = urllib.parse.parse_qsl(
 qs, self.keep_blank_values, self.strict_parsing,
 encoding=self.encoding, errors=self.errors,
 max_num_fields=self.max_num_fields, separator=self.separator)
 self.list = [MiniFieldStorage(key, value) for key, value in query]
 self.skip_lines()

 FieldStorageClass = None

 def read_multi(self, environ, keep_blank_values, strict_parsing):
 """Internal: read a part that is itself multipart."""
 ib = self.innerboundary
 if not valid_boundary(ib):
 raise ValueError('Invalid boundary in multipart form: %r' % (ib,))
 self.list = []
 if self.qs_on_post:
 query = urllib.parse.parse_qsl(
 self.qs_on_post, self.keep_blank_values, self.strict_parsing,
 encoding=self.encoding, errors=self.errors,
 max_num_fields=self.max_num_fields, separator=self.separator)
 self.list.extend(MiniFieldStorage(key, value) for key, value in query)

 klass = self.FieldStorageClass or self.__class__
 first_line = self.fp.readline() # bytes
 if not isinstance(first_line, bytes):
 raise ValueError("%s should return bytes, got %s" \
 % (self.fp, type(first_line).__name__))
 self.bytes_read += len(first_line)

 # Ensure that we consume the file until we've hit our inner boundary
 while (first_line.strip() != (b"--" + self.innerboundary) and
 first_line):
 first_line = self.fp.readline()
 self.bytes_read += len(first_line)

 # Propagate max_num_fields into the sub class appropriately
 max_num_fields = self.max_num_fields
 if max_num_fields is not None:
 max_num_fields -= len(self.list)

 while True:
 parser = FeedParser()
 hdr_text = b""
 while True:
 data = self.fp.readline()
 hdr_text += data
 if not data.strip():
 break
 if not hdr_text:
 break
 # parser takes strings, not bytes
 self.bytes_read += len(hdr_text)
 parser.feed(hdr_text.decode(self.encoding, self.errors))
 headers = parser.close()

 # Some clients add Content-Length for part headers, ignore them
 if 'content-length' in headers:
 del headers['content-length']

 limit = None if self.limit is None \
 else self.limit - self.bytes_read
 part = klass(self.fp, headers, ib, environ, keep_blank_values,
 strict_parsing, limit,
 self.encoding, self.errors, max_num_fields, self.separator)

 if max_num_fields is not None:
 max_num_fields -= 1
 if part.list:
 max_num_fields -= len(part.list)
 if max_num_fields < 0:
 raise ValueError('Max number of fields exceeded')

 self.bytes_read += part.bytes_read
 self.list.append(part)
 if part.done or self.bytes_read >= self.length > 0:
 break
 self.skip_lines()

 def read_single(self):
 """Internal: read an atomic part."""
 if self.length >= 0:
 self.read_binary()
 self.skip_lines()
 else:
 self.read_lines()
 self.file.seek(0)

 bufsize = 8*1024 # I/O buffering size for copy to file

 def read_binary(self):
 """Internal: read binary data."""
 self.file = self.make_file()
 todo = self.length
 if todo >= 0:
 while todo > 0:
 data = self.fp.read(min(todo, self.bufsize)) # bytes
 if not isinstance(data, bytes):
 raise ValueError("%s should return bytes, got %s"
 % (self.fp, type(data).__name__))
 self.bytes_read += len(data)
 if not data:
 self.done = -1
 break
 self.file.write(data)
 todo = todo - len(data)

 def read_lines(self):
 """Internal: read lines until EOF or outerboundary."""
 if self._binary_file:
 self.file = self.__file = BytesIO() # store data as bytes for files
 else:
 self.file = self.__file = StringIO() # as strings for other fields
 if self.outerboundary:
 self.read_lines_to_outerboundary()
 else:
 self.read_lines_to_eof()

 def __write(self, line):
 """line is always bytes, not string"""
 if self.__file is not None:
 if self.__file.tell() + len(line) > 1000:
 self.file = self.make_file()
 data = self.__file.getvalue()
 self.file.write(data)
 self.__file = None
 if self._binary_file:
 # keep bytes
 self.file.write(line)
 else:
 # decode to string
 self.file.write(line.decode(self.encoding, self.errors))

 def read_lines_to_eof(self):
 """Internal: read lines until EOF."""
 while 1:
 line = self.fp.readline(1<<16) # bytes
 self.bytes_read += len(line)
 if not line:
 self.done = -1
 break
 self.__write(line)

 def read_lines_to_outerboundary(self):
 """Internal: read lines until outerboundary.
 Data is read as bytes: boundaries and line ends must be converted
 to bytes for comparisons.
 """
 next_boundary = b"--" + self.outerboundary
 last_boundary = next_boundary + b"--"
 delim = b""
 last_line_lfend = True
 _read = 0
 while 1:

 if self.limit is not None and 0 <= self.limit <= _read:
 break
 line = self.fp.readline(1<<16) # bytes
 self.bytes_read += len(line)
 _read += len(line)
 if not line:
 self.done = -1
 break
 if delim == b"\r":
 line = delim + line
 delim = b""
 if line.startswith(b"--") and last_line_lfend:
 strippedline = line.rstrip()
 if strippedline == next_boundary:
 break
 if strippedline == last_boundary:
 self.done = 1
 break
 odelim = delim
 if line.endswith(b"\r\n"):
 delim = b"\r\n"
 line = line[:-2]
 last_line_lfend = True
 elif line.endswith(b"\n"):
 delim = b"\n"
 line = line[:-1]
 last_line_lfend = True
 elif line.endswith(b"\r"):
 # We may interrupt \r\n sequences if they span the 2**16
 # byte boundary
 delim = b"\r"
 line = line[:-1]
 last_line_lfend = False
 else:
 delim = b""
 last_line_lfend = False
 self.__write(odelim + line)

 def skip_lines(self):
 """Internal: skip lines until outer boundary if defined."""
 if not self.outerboundary or self.done:
 return
 next_boundary = b"--" + self.outerboundary
 last_boundary = next_boundary + b"--"
 last_line_lfend = True
 while True:
 line = self.fp.readline(1<<16)
 self.bytes_read += len(line)
 if not line:
 self.done = -1
 break
 if line.endswith(b"--") and last_line_lfend:
 strippedline = line.strip()
 if strippedline == next_boundary:
 break
 if strippedline == last_boundary:
 self.done = 1
 break
 last_line_lfend = line.endswith(b'\n')

 def make_file(self):
 """Overridable: return a readable & writable file.

 The file will be used as follows:
 - data is written to it
 - seek(0)
 - data is read from it

 The file is opened in binary mode for files, in text mode
 for other fields

 This version opens a temporary file for reading and writing,
 and immediately deletes (unlinks) it. The trick (on Unix!) is
 that the file can still be used, but it can't be opened by
 another process, and it will automatically be deleted when it
 is closed or when the current process terminates.

 If you want a more permanent file, you derive a class which
 overrides this method. If you want a visible temporary file
 that is nevertheless automatically deleted when the script
 terminates, try defining a __del__ method in a derived class
 which unlinks the temporary files you have created.

 """
 if self._binary_file:
 return tempfile.TemporaryFile("wb+")
 else:
 return tempfile.TemporaryFile("w+",
 encoding=self.encoding, newline = '\n')


# Test/debug code
# ===============

def test(environ=os.environ):
 """Robust test CGI script, usable as main program.

 Write minimal HTTP headers and dump all information provided to
 the script in HTML form.

 """
 print("Content-type: text/html")
 print()
 sys.stderr = sys.stdout
 try:
 form = FieldStorage() # Replace with other classes to test those
 print_directory()
 print_arguments()
 print_form(form)
 print_environ(environ)
 print_environ_usage()
 def f():
 exec("testing print_exception() -- <I>italics?</I>")
 def g(f=f):
 f()
 print("<H3>What follows is a test, not an actual exception:</H3>")
 g()
 except:
 print_exception()

 print("<H1>Second try with a small maxlen...</H1>")

 global maxlen
 maxlen = 50
 try:
 form = FieldStorage() # Replace with other classes to test those
 print_directory()
 print_arguments()
 print_form(form)
 print_environ(environ)
 except:
 print_exception()

def print_exception(type=None, value=None, tb=None, limit=None):
 if type is None:
 type, value, tb = sys.exc_info()
 import traceback
 print()
 print("<H3>Traceback (most recent call last):</H3>")
 list = traceback.format_tb(tb, limit) + \
 traceback.format_exception_only(type, value)
 print("<PRE>%s<B>%s</B></PRE>" % (
 html.escape("".join(list[:-1])),
 html.escape(list[-1]),
 ))
 del tb

def print_environ(environ=os.environ):
 """Dump the shell environment as HTML."""
 keys = sorted(environ.keys())
 print()
 print("<H3>Shell Environment:</H3>")
 print("<DL>")
 for key in keys:
 print("<DT>", html.escape(key), "<DD>", html.escape(environ[key]))
 print("</DL>")
 print()

def print_form(form):
 """Dump the contents of a form as HTML."""
 keys = sorted(form.keys())
 print()
 print("<H3>Form Contents:</H3>")
 if not keys:
 print("<P>No form fields.")
 print("<DL>")
 for key in keys:
 print("<DT>" + html.escape(key) + ":", end=' ')
 value = form[key]
 print("<i>" + html.escape(repr(type(value))) + "</i>")
 print("<DD>" + html.escape(repr(value)))
 print("</DL>")
 print()

def print_directory():
 """Dump the current directory as HTML."""
 print()
 print("<H3>Current Working Directory:</H3>")
 try:
 pwd = os.getcwd()
 except OSError as msg:
 print("OSError:", html.escape(str(msg)))
 else:
 print(html.escape(pwd))
 print()

def print_arguments():
 print()
 print("<H3>Command Line Arguments:</H3>")
 print()
 print(sys.argv)
 print()

def print_environ_usage():
 """Dump a list of environment variables used by CGI as HTML."""
 print("""
<H3>These environment variables could have been set:</H3>
<UL>
<LI>AUTH_TYPE
<LI>CONTENT_LENGTH
<LI>CONTENT_TYPE
<LI>DATE_GMT
<LI>DATE_LOCAL
<LI>DOCUMENT_NAME
<LI>DOCUMENT_ROOT
<LI>DOCUMENT_URI
<LI>GATEWAY_INTERFACE
<LI>LAST_MODIFIED
<LI>PATH
<LI>PATH_INFO
<LI>PATH_TRANSLATED
<LI>QUERY_STRING
<LI>REMOTE_ADDR
<LI>REMOTE_HOST
<LI>REMOTE_IDENT
<LI>REMOTE_USER
<LI>REQUEST_METHOD
<LI>SCRIPT_NAME
<LI>SERVER_NAME
<LI>SERVER_PORT
<LI>SERVER_PROTOCOL
<LI>SERVER_ROOT
<LI>SERVER_SOFTWARE
</UL>
In addition, HTTP headers sent by the server may be passed in the
environment as well. Here are some common variable names:
<UL>
<LI>HTTP_ACCEPT
<LI>HTTP_CONNECTION
<LI>HTTP_HOST
<LI>HTTP_PRAGMA
<LI>HTTP_REFERER
<LI>HTTP_USER_AGENT
</UL>
""")


# Utilities
# =========

def valid_boundary(s):
 import re
 if isinstance(s, bytes):
 _vb_pattern = b"^[ -~]{0,200}[!-~]$"
 else:
 _vb_pattern = "^[ -~]{0,200}[!-~]$"
 return re.match(_vb_pattern, s)

# Invoke mainline
# ===============

# Call test() when this file is run as a script (not imported as a module)
if __name__ == '__main__':
 test()