symbian-qemu-0.9.1-12/python-win32-2.6.1/lib/cgi.py
changeset 1 2fb8b9db1c86
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/symbian-qemu-0.9.1-12/python-win32-2.6.1/lib/cgi.py	Fri Jul 31 15:01:17 2009 +0100
@@ -0,0 +1,1039 @@
+#! /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.
+"""
+
+# XXX Perhaps there should be a slimmed version that doesn't contain
+# all those backwards compatible and debugging classes and functions?
+
+# 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 operator import attrgetter
+import sys
+import os
+import urllib
+import UserDict
+import urlparse
+
+from warnings import filterwarnings, catch_warnings, warn
+with catch_warnings():
+    if sys.py3kwarning:
+        filterwarnings("ignore", ".*mimetools has been removed",
+                        DeprecationWarning)
+    import mimetools
+    if sys.py3kwarning:
+        filterwarnings("ignore", ".*rfc822 has been removed", DeprecationWarning)
+    import rfc822
+
+try:
+    from cStringIO import StringIO
+except ImportError:
+    from StringIO import StringIO
+
+__all__ = ["MiniFieldStorage", "FieldStorage", "FormContentDict",
+           "SvFormContentDict", "InterpFormContentDict", "FormContent",
+           "parse", "parse_qs", "parse_qsl", "parse_multipart",
+           "parse_header", "print_exception", "print_environ",
+           "print_form", "print_directory", "print_arguments",
+           "print_environ_usage", "escape"]
+
+# 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 logfp, log
+    if logfile and not logfp:
+        try:
+            logfp = open(logfile, "a")
+        except IOError:
+            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
+
+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):
+    """Parse a query in the environment or from a file (default stdin)
+
+        Arguments, all optional:
+
+        fp              : file pointer; default: sys.stdin
+
+        environ         : environment dictionary; default: os.environ
+
+        keep_blank_values: flag indicating whether blank values in
+            URL 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.
+    """
+    if fp is None:
+        fp = sys.stdin
+    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)
+        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)
+        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 parse_qs(qs, keep_blank_values, strict_parsing)
+
+
+# parse query string function called from urlparse,
+# this is done in order to maintain backward compatiblity.
+
+def parse_qs(qs, keep_blank_values=0, strict_parsing=0):
+    """Parse a query given as a string argument."""
+    warn("cgi.parse_qs is deprecated, use urlparse.parse_qs \
+            instead",PendingDeprecationWarning)
+    return urlparse.parse_qs(qs, keep_blank_values, strict_parsing)
+
+
+def parse_qsl(qs, keep_blank_values=0, strict_parsing=0):
+    """Parse a query given as a string argument."""
+    warn("cgi.parse_qsl is deprecated, use urlparse.parse_qsl instead",
+            PendingDeprecationWarning)
+    return urlparse.parse_qsl(qs, keep_blank_values, strict_parsing)
+
+def parse_multipart(fp, pdict):
+    """Parse multipart input.
+
+    Arguments:
+    fp   : input file
+    pdict: dictionary containing other parameters of content-type header
+
+    Returns a dictionary just like parse_qs(): keys are the field names, each
+    value is a list of values for that field.  This is easy to use but not
+    much good if you are expecting megabytes to be uploaded -- in that case,
+    use the FieldStorage class instead which is much more flexible.  Note
+    that content-type is the raw, unparsed contents of the content-type
+    header.
+
+    XXX This does not parse nested multipart parts -- use FieldStorage for
+    that.
+
+    XXX This should really be subsumed by FieldStorage altogether -- no
+    point in having two implementations of the same parsing algorithm.
+    Also, FieldStorage protects itself better against certain DoS attacks
+    by limiting the size of the data read in one chunk.  The API here
+    does not support that kind of protection.  This also affects parse()
+    since it can call parse_multipart().
+
+    """
+    boundary = ""
+    if 'boundary' in pdict:
+        boundary = pdict['boundary']
+    if not valid_boundary(boundary):
+        raise ValueError,  ('Invalid boundary in multipart form: %r'
+                            % (boundary,))
+
+    nextpart = "--" + boundary
+    lastpart = "--" + boundary + "--"
+    partdict = {}
+    terminator = ""
+
+    while terminator != lastpart:
+        bytes = -1
+        data = None
+        if terminator:
+            # At start of next part.  Read headers first.
+            headers = mimetools.Message(fp)
+            clength = headers.getheader('content-length')
+            if clength:
+                try:
+                    bytes = int(clength)
+                except ValueError:
+                    pass
+            if bytes > 0:
+                if maxlen and bytes > maxlen:
+                    raise ValueError, 'Maximum content length exceeded'
+                data = fp.read(bytes)
+            else:
+                data = ""
+        # Read lines until end of part.
+        lines = []
+        while 1:
+            line = fp.readline()
+            if not line:
+                terminator = lastpart # End outer loop
+                break
+            if line[:2] == "--":
+                terminator = line.strip()
+                if terminator in (nextpart, lastpart):
+                    break
+            lines.append(line)
+        # Done with part.
+        if data is None:
+            continue
+        if bytes < 0:
+            if lines:
+                # Strip final line terminator
+                line = lines[-1]
+                if line[-2:] == "\r\n":
+                    line = line[:-2]
+                elif line[-1:] == "\n":
+                    line = line[:-1]
+                lines[-1] = line
+                data = "".join(lines)
+        line = headers['content-disposition']
+        if not line:
+            continue
+        key, params = parse_header(line)
+        if key != 'form-data':
+            continue
+        if 'name' in params:
+            name = params['name']
+        else:
+            continue
+        if name in partdict:
+            partdict[name].append(data)
+        else:
+            partdict[name] = [data]
+
+    return partdict
+
+
+def parse_header(line):
+    """Parse a Content-type like header.
+
+    Return the main content-type and a dictionary of options.
+
+    """
+    plist = [x.strip() for x in line.split(';')]
+    key = plist.pop(0).lower()
+    pdict = {}
+    for p in plist:
+        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
+
+    file: the file(-like) object from which you can read the data;
+        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 rfc822.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="",
+                 environ=os.environ, keep_blank_values=0, strict_parsing=0):
+        """Constructor.  Read multipart/* until last part.
+
+        Arguments, all optional:
+
+        fp              : file pointer; default: sys.stdin
+            (not used when the request method is GET)
+
+        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
+            URL 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.
+
+        """
+        method = 'GET'
+        self.keep_blank_values = keep_blank_values
+        self.strict_parsing = strict_parsing
+        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 = ""
+            fp = StringIO(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']
+        self.fp = fp or sys.stdin
+        self.headers = headers
+        self.outerboundary = outerboundary
+
+        # 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']
+
+        # 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
+        self.innerboundary = ""
+        if 'boundary' in pdict:
+            self.innerboundary = pdict['boundary']
+        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
+
+        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 __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 type(value) is type([]):
+                return map(attrgetter('value'), 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 type(value) is type([]):
+                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 type(value) is type([]):
+                return map(attrgetter('value'), 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 has_key(self, key):
+        """Dictionary style has_key() method."""
+        if self.list is None:
+            raise TypeError, "not indexable"
+        return any(item.name == key 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 __nonzero__(self):
+        return bool(self.list)
+
+    def read_urlencoded(self):
+        """Internal: read data in query string format."""
+        qs = self.fp.read(self.length)
+        if self.qs_on_post:
+            qs += '&' + self.qs_on_post
+        self.list = list = []
+        for key, value in urlparse.parse_qsl(qs, self.keep_blank_values,
+                                            self.strict_parsing):
+            list.append(MiniFieldStorage(key, value))
+        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:
+            for key, value in urlparse.parse_qsl(self.qs_on_post,
+                                self.keep_blank_values, self.strict_parsing):
+                self.list.append(MiniFieldStorage(key, value))
+            FieldStorageClass = None
+
+        klass = self.FieldStorageClass or self.__class__
+        part = klass(self.fp, {}, ib,
+                     environ, keep_blank_values, strict_parsing)
+        # Throw first part away
+        while not part.done:
+            headers = rfc822.Message(self.fp)
+            part = klass(self.fp, headers, ib,
+                         environ, keep_blank_values, strict_parsing)
+            self.list.append(part)
+        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('b')
+        todo = self.length
+        if todo >= 0:
+            while todo > 0:
+                data = self.fp.read(min(todo, self.bufsize))
+                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."""
+        self.file = self.__file = StringIO()
+        if self.outerboundary:
+            self.read_lines_to_outerboundary()
+        else:
+            self.read_lines_to_eof()
+
+    def __write(self, line):
+        if self.__file is not None:
+            if self.__file.tell() + len(line) > 1000:
+                self.file = self.make_file('')
+                self.file.write(self.__file.getvalue())
+                self.__file = None
+        self.file.write(line)
+
+    def read_lines_to_eof(self):
+        """Internal: read lines until EOF."""
+        while 1:
+            line = self.fp.readline(1<<16)
+            if not line:
+                self.done = -1
+                break
+            self.__write(line)
+
+    def read_lines_to_outerboundary(self):
+        """Internal: read lines until outerboundary."""
+        next = "--" + self.outerboundary
+        last = next + "--"
+        delim = ""
+        last_line_lfend = True
+        while 1:
+            line = self.fp.readline(1<<16)
+            if not line:
+                self.done = -1
+                break
+            if line[:2] == "--" and last_line_lfend:
+                strippedline = line.strip()
+                if strippedline == next:
+                    break
+                if strippedline == last:
+                    self.done = 1
+                    break
+            odelim = delim
+            if line[-2:] == "\r\n":
+                delim = "\r\n"
+                line = line[:-2]
+                last_line_lfend = True
+            elif line[-1] == "\n":
+                delim = "\n"
+                line = line[:-1]
+                last_line_lfend = True
+            else:
+                delim = ""
+                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 = "--" + self.outerboundary
+        last = next + "--"
+        last_line_lfend = True
+        while 1:
+            line = self.fp.readline(1<<16)
+            if not line:
+                self.done = -1
+                break
+            if line[:2] == "--" and last_line_lfend:
+                strippedline = line.strip()
+                if strippedline == next:
+                    break
+                if strippedline == last:
+                    self.done = 1
+                    break
+            last_line_lfend = line.endswith('\n')
+
+    def make_file(self, binary=None):
+        """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 'binary' argument is unused -- the file is always opened
+        in binary mode.
+
+        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.
+
+        """
+        import tempfile
+        return tempfile.TemporaryFile("w+b")
+
+
+
+# Backwards Compatibility Classes
+# ===============================
+
+class FormContentDict(UserDict.UserDict):
+    """Form content as dictionary with a list of values per field.
+
+    form = FormContentDict()
+
+    form[key] -> [value, value, ...]
+    key in form -> Boolean
+    form.keys() -> [key, key, ...]
+    form.values() -> [[val, val, ...], [val, val, ...], ...]
+    form.items() ->  [(key, [val, val, ...]), (key, [val, val, ...]), ...]
+    form.dict == {key: [val, val, ...], ...}
+
+    """
+    def __init__(self, environ=os.environ, keep_blank_values=0, strict_parsing=0):
+        self.dict = self.data = parse(environ=environ,
+                                      keep_blank_values=keep_blank_values,
+                                      strict_parsing=strict_parsing)
+        self.query_string = environ['QUERY_STRING']
+
+
+class SvFormContentDict(FormContentDict):
+    """Form content as dictionary expecting a single value per field.
+
+    If you only expect a single value for each field, then form[key]
+    will return that single value.  It will raise an IndexError if
+    that expectation is not true.  If you expect a field to have
+    possible multiple values, than you can use form.getlist(key) to
+    get all of the values.  values() and items() are a compromise:
+    they return single strings where there is a single value, and
+    lists of strings otherwise.
+
+    """
+    def __getitem__(self, key):
+        if len(self.dict[key]) > 1:
+            raise IndexError, 'expecting a single value'
+        return self.dict[key][0]
+    def getlist(self, key):
+        return self.dict[key]
+    def values(self):
+        result = []
+        for value in self.dict.values():
+            if len(value) == 1:
+                result.append(value[0])
+            else: result.append(value)
+        return result
+    def items(self):
+        result = []
+        for key, value in self.dict.items():
+            if len(value) == 1:
+                result.append((key, value[0]))
+            else: result.append((key, value))
+        return result
+
+
+class InterpFormContentDict(SvFormContentDict):
+    """This class is present for backwards compatibility only."""
+    def __getitem__(self, key):
+        v = SvFormContentDict.__getitem__(self, key)
+        if v[0] in '0123456789+-.':
+            try: return int(v)
+            except ValueError:
+                try: return float(v)
+                except ValueError: pass
+        return v.strip()
+    def values(self):
+        result = []
+        for key in self.keys():
+            try:
+                result.append(self[key])
+            except IndexError:
+                result.append(self.dict[key])
+        return result
+    def items(self):
+        result = []
+        for key in self.keys():
+            try:
+                result.append((key, self[key]))
+            except IndexError:
+                result.append((key, self.dict[key]))
+        return result
+
+
+class FormContent(FormContentDict):
+    """This class is present for backwards compatibility only."""
+    def values(self, key):
+        if key in self.dict :return self.dict[key]
+        else: return None
+    def indexed_value(self, key, location):
+        if key in self.dict:
+            if len(self.dict[key]) > location:
+                return self.dict[key][location]
+            else: return None
+        else: return None
+    def value(self, key):
+        if key in self.dict: return self.dict[key][0]
+        else: return None
+    def length(self, key):
+        return len(self.dict[key])
+    def stripped(self, key):
+        if key in self.dict: return self.dict[key][0].strip()
+        else: return None
+    def pars(self):
+        return self.dict
+
+
+# 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>" % (
+        escape("".join(list[:-1])),
+        escape(list[-1]),
+        )
+    del tb
+
+def print_environ(environ=os.environ):
+    """Dump the shell environment as HTML."""
+    keys = environ.keys()
+    keys.sort()
+    print
+    print "<H3>Shell Environment:</H3>"
+    print "<DL>"
+    for key in keys:
+        print "<DT>", escape(key), "<DD>", escape(environ[key])
+    print "</DL>"
+    print
+
+def print_form(form):
+    """Dump the contents of a form as HTML."""
+    keys = form.keys()
+    keys.sort()
+    print
+    print "<H3>Form Contents:</H3>"
+    if not keys:
+        print "<P>No form fields."
+    print "<DL>"
+    for key in keys:
+        print "<DT>" + escape(key) + ":",
+        value = form[key]
+        print "<i>" + escape(repr(type(value))) + "</i>"
+        print "<DD>" + 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 os.error, msg:
+        print "os.error:", escape(str(msg))
+    else:
+        print 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 escape(s, quote=None):
+    '''Replace special characters "&", "<" and ">" to HTML-safe sequences.
+    If the optional flag quote is true, the quotation mark character (")
+    is also translated.'''
+    s = s.replace("&", "&amp;") # Must be done first!
+    s = s.replace("<", "&lt;")
+    s = s.replace(">", "&gt;")
+    if quote:
+        s = s.replace('"', "&quot;")
+    return s
+
+def valid_boundary(s, _vb_pattern="^[ -~]{0,200}[!-~]$"):
+    import re
+    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()