Hi all,

OK this is pretty much the best one Ive got....Ill re-iterate the usage 
points from the previous so this email may be considered definitive.

Fixes:

1. Memory fault when streaming extremely large files to disk when 
filename is sent from client.
2. Fixed headers being overwritten by headers for last field. Headers 
are now available for all fields (assumed as original intention).
3. Fixed filename being overwritten by last file sent in postings with 
multiple files.
4. Fixed error where MSIE returns invalid MIME type/subtype when the 
file has no extension (duh!) so default of application/octet-stream is 
used instead.

Enhancements:

1. Added file creation callback, allowing client to override both file 
creation/deletion semantics and location - examples of ways to use this 
are provided.
2. Added StringField creation callback, allowing client to override both 
the creation/deletion semantics and behaviour - this may be used in a 
similar manner as the file creation callback above.

Both these callbacks can be ignored in general use - additionally cgi 
style inheritence and overriding of make_file and make_field is possible 
- or you can supply the callback instead of inheriting.

These behaviours allow the following functionality to be implemented by 
the client (no implementation is given here)

a. When string reaches a given size it is placed in a file.
b. control of maximum file actions such as error or truncate after 
maximum is reached.

I have tested the above with MSIE, Firefox and Opera. I can sucessfully 
upload files of 1.94GB (but IE then times out)...Firefox can cope with 
much above 1.29GB and opera a similar figure - thus - the new util.py 
out-performs the browsers that are out there currently!

If you were to fire data at the server using an app such as a python 
program and the HTTPConnection class then I reckon you could pretty much 
fill any disk space you wish at your leisure!

Mission (should have been) accomplished - comments please!!!!

Obviously I am putting the code forward for inclusion in a future 
release of mod_python.

---------------------
Examples for new file callback usage - 2 techniques are shown. The first 
uses the class constructor to create the file object and uses simple 
control. It is not advisable to add class variables to this if serving 
multiple sites from apache - in this case to provide greater control 
over the constructor parameters use the factory method. It should be 
noted that the code shown here is used purely for example usage. The 
issue of temporary file location and security must be considered when 
providing such overrides with mod_python.

Both methods are common in that they derive from FileType. Thereby 
providing extended file functionality.

Indeed. It is possible to subclass tempfile.TemporaryFile and gain the 
same security semantics.

-----------------------------------------------------------------
Technique 1: Simple file control using class constructor.

class Storage(file):

     def __init__(self, advisoryFilename):
         self.m_advisoryFilename = advisoryFilename
         self.m_deleteOnClose    = True
         self.m_deletedAlready   = False
     self.m_realFilename     = '/someTempDir/thingy-unique-thingy'
         super(Storage, self).__init__(self.m_realFilename, 'w+b')

     def close(self):
         if self.m_deletedAlready:
             return
         super(Storage, self).close()
         if self.m_deleteOnClose:
             self.m_deletedAlready = True
             os.remove(self.m_realFilename)
         return

requestData = util.FieldStorage(request, True, file_callback = Storage)

-----------------------------------------------------------------
Technique 2: Advanced file control using object factory.

class Storage(file):

     def __init__(self, directory, advisoryFilename):
         self.m_advisoryFilename = advisoryFilename
         self.m_deleteOnClose    = True
         self.m_deletedAlready   = False
     self.m_realFilename     = directory + '/thingy-unique-thingy'
         super(Storage, self).__init__(self.m_realFilename, 'w+b')

     def close(self):
         if self.m_deletedAlready:
             return
         super(Storage, self).close()
         if self.m_deleteOnClose:
             self.m_deletedAlready = True
             os.remove(self.m_realFilename)
         return

class StorageFactory:

     def __init__(self, directory):
         self.m_dir = directory

     def create(self, advisoryFilename):
         return Storage(self.m_dir, advisoryFilename)

fileFactory = StorageFactory(someDirectory)
[...sometime later...]
requestData = util.FieldStorage(request, True, file_callback = 
fileFactory.create)
-----------------------------------------------------------------

Hope this helps,
Barry Pearce

 #
 # Copyright 2004 Apache Software Foundation 
 # 
 # Licensed under the Apache License, Version 2.0 (the "License"); you
 # may not use this file except in compliance with the License.  You
 # may obtain a copy of the License at
 #
 #      http://www.apache.org/licenses/LICENSE-2.0

 #
 # Unless required by applicable law or agreed to in writing, software
 # distributed under the License is distributed on an "AS IS" BASIS,
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
 # implied.  See the License for the specific language governing
 # permissions and limitations under the License.
 #
 # Originally developed by Gregory Trubetskoy.
 #
 # $Id: util.py 149056 2005-01-29 18:26:00Z nlehuen $

import _apache
import apache
import cStringIO
import tempfile

from types import *
from exceptions import *

parse_qs = _apache.parse_qs
parse_qsl = _apache.parse_qsl

# Maximum line length for reading. (64KB)
# Fixes memory error when upload large files such as 700+MB ISOs.
readBlockSize = 65368

""" The classes below are a (almost) a drop-in replacement for the
    standard cgi.py FieldStorage class. They should have pretty much the
    same functionality.

    These classes differ in that unlike cgi.FieldStorage, they are not
    recursive. The class FieldStorage contains a list of instances of
    Field class. Field class is incapable of storing anything in it.

    These objects should be considerably faster than the ones in cgi.py
    because they do not expect CGI environment, and are
    optimized specifically for Apache and mod_python.
"""

class Field:

    filename = None
    headers = {}

    def __init__(self, name, file, ctype, type_options,
                 disp, disp_options, headers = {}):
        self.name = name
        self.file = file
        self.type = ctype
        self.type_options = type_options
        self.disposition = disp
        self.disposition_options = disp_options
        if disp_options.has_key("filename"):
            self.filename = disp_options["filename"]
        else:
            self.filename = None
        self.headers = headers

    def __repr__(self):
        """Return printable representation."""
        return "Field(%s, %s)" % (`self.name`, `self.value`)

    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)
        else:
            value = None
        return value

    def __del__(self):
        self.file.close()

class StringField(str):
    """ This class is basically a string with
    a value attribute for compatibility with std lib cgi.py
    """
    
    def __init__(self, str=""):
        str.__init__(self, str)
        self.value = self.__str__()

class FieldStorage:

    def __init__(self, req, keep_blank_values=0, strict_parsing=0, file_callback=None, field_callback=None):
        #
        # Whenever readline is called ALWAYS use the max size EVEN when not expecting a long line.
        # - this helps protect against malformed content from exhausting memory.
        #

        self.list = []

        # always process GET-style parameters
        if req.args:
            pairs = parse_qsl(req.args, keep_blank_values)
            for pair in pairs:
                file = cStringIO.StringIO(pair[1])
                self.list.append(Field(pair[0], file, "text/plain", {}, None, {}))

        if req.method != "POST":
            return

        try:
            clen = int(req.headers_in["content-length"])
        except (KeyError, ValueError):
            # absent content-length is not acceptable
            raise apache.SERVER_RETURN, apache.HTTP_LENGTH_REQUIRED

        if not req.headers_in.has_key("content-type"):
            ctype = "application/x-www-form-urlencoded"
        else:
            ctype = req.headers_in["content-type"]
            
        if ctype == "application/x-www-form-urlencoded":
            pairs = parse_qsl(req.read(clen), keep_blank_values)
            for pair in pairs:
                file = cStringIO.StringIO(pair[1])
                self.list.append(Field(pair[0], file, "text/plain", {}, None, {}))
            return
            
        if ctype[:10] != "multipart/":
            # we don't understand this content-type
            raise apache.SERVER_RETURN, apache.HTTP_NOT_IMPLEMENTED
            
        # figure out boundary
        try:
            i = ctype.lower().rindex("boundary=")
            boundary = ctype[i+9:]
            if len(boundary) >= 2 and boundary[0] == boundary[-1] == '"':
                boundary = boundary[1:-1]
            boundary = "--" + boundary
        except ValueError:
            raise apache.SERVER_RETURN, apache.HTTP_BAD_REQUEST

        #read until boundary
        self.skip_to_boundary(req, boundary)

        while True:

            ## parse headers
            
            ctype, type_options = "text/plain", {}
            disp, disp_options = None, {}
            headers = apache.make_table()

            line = req.readline(readBlockSize)
            sline = line.strip()
            if not line or sline == (boundary + "--"):
                break
            
            while line and line not in ["\n", "\r\n"]:
                h, v = line.split(":", 1)
                headers.add(h, v)
                h = h.lower()
                if h == "content-disposition":
                    disp, disp_options = parse_header(v)
                elif h == "content-type":
                    ctype, type_options = parse_header(v)
                    #
                    # NOTE: FIX up binary rubbish sent as content type from Microsoft IE 6.0
                    # when sending a file which does not have a suffix.
                    #
                    if ctype.find('/') == -1:
                        ctype = 'application/octet-stream'
                line = req.readline(readBlockSize)
                sline = line.strip()

            if disp_options.has_key("name"):
                name = disp_options["name"]
            else:
                name = None

            # is this a file?
            if disp_options.has_key("filename"):
                if file_callback and callable(file_callback):
                    file = file_callback(disp_options["filename"])
                else:
                    file = self.make_file()
            else:
                if field_callback and callable(field_callback):
                    file = field_callback()
                else:
                    file = self.make_field()

            # read it in
            self.read_to_boundary(req, boundary, file)
            file.seek(0)

            # make a Field
            field = Field(name, file, ctype, type_options, disp, disp_options, headers)

            self.list.append(field)

    def make_file(self):
        return tempfile.TemporaryFile("w+b")
        
    def make_field(self):
        return cStringIO.StringIO()

    def skip_to_boundary(self, req, boundary):
        last_bound = boundary + "--"
        roughBoundaryLength = len(last_bound) + 128
        line = req.readline(readBlockSize)
        lineLength = len(line)
        if lineLength < roughBoundaryLength:
            sline = line.strip()
        else:
            sline = ''
        while line and sline != boundary and sline != last_bound:
            line = req.readline(readBlockSize)
            lineLength = len(line)
            if lineLength < roughBoundaryLength:
                sline = line.strip()
            else:
                sline = ''

    def read_to_boundary(self, req, boundary, file):
        #
        # Although technically possible for the boundary to be split by the read, this will
        # not happen because the readBlockSize is set quite high - far longer than any boundary line
        # will ever contain.
        #
        # lastCharCarried is used to detect the situation where the \r\n is split across the end of
        # a read block.
        #
        delim = ''
        lastCharCarried = False
        last_bound = boundary + '--'
        roughBoundaryLength = len(last_bound) + 128
        line = req.readline(readBlockSize)
        lineLength = len(line)
        if lineLength < roughBoundaryLength:
            sline = line.strip()
        else:
            sline = ''
        while lineLength > 0 and sline != boundary and sline != last_bound:
            if not lastCharCarried:
                file.write(delim)
                delim = ''
            else:
                lastCharCarried = False
            cutLength = 0
            if lineLength == readBlockSize:
                if line[-1:] == '\r':
                    delim = '\r'
                    cutLength = -1
                    lastCharCarried = True
            if line[-2:] == '\r\n':
                delim += '\r\n'
                cutLength = -2
            elif line[-1:] == '\n':
                delim += '\n'
                cutLength = -1
            if cutLength != 0:
                file.write(line[:cutLength])
            else:
                file.write(line)
            line = req.readline(readBlockSize)
            lineLength = len(line)
            if lineLength < roughBoundaryLength:
                sline = line.strip()
            else:
                sline = ''

    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:
                if isinstance(item.file, FileType) or \
                       isinstance(getattr(item.file, 'file', None), FileType):
                    found.append(item)
                else:
                    found.append(StringField(item.value))
        if not found:
            raise KeyError, key
        if len(found) == 1:
            return found[0]
        else:
            return found

    def get(self, key, default):
        try:
            return self.__getitem__(key)
        except KeyError:
            return default

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

    def has_key(self, key):
        """Dictionary style has_key() method."""
        if self.list is None:
            raise TypeError, "not indexable"
        for item in self.list:
            if item.name == key: return 1
        return 0

    __contains__ = has_key

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

    def getfirst(self, key, default=None):
        """ return the first value received """
        for item in self.list:
            if item.name == key:
                if isinstance(item.file, FileType) or \
                       isinstance(getattr(item.file, 'file', None), FileType):
                    return item
                else:
                    return StringField(item.value)
        return default
                                                                    
    def getlist(self, key):
        """ return a list of received values """
        if self.list is None:
            raise TypeError, "not indexable"
        found = []
        for item in self.list:
            if item.name == key:
                if isinstance(item.file, FileType) or \
                       isinstance(getattr(item.file, 'file', None), FileType):
                    found.append(item)
                else:
                    found.append(StringField(item.value))
        return found

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

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

    """
    
    plist = map(lambda a: a.strip(), line.split(';'))
    key = plist[0].lower()
    del plist[0]
    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]
            pdict[name] = value
    return key, pdict

def apply_fs_data(object, fs, **args):
    """
    Apply FieldStorage data to an object - the object must be
    callable. Examine the args, and match then with fs data,
    then call the object, return the result.
    """

    # add form data to args
    for field in fs.list:
        if field.filename:
            val = field
        else:
            val = field.value
        args.setdefault(field.name, []).append(val)

    # replace lists with single values
    for arg in args:
        if ((type(args[arg]) is ListType) and
            (len(args[arg]) == 1)):
            args[arg] = args[arg][0]

    # we need to weed out unexpected keyword arguments
    # and for that we need to get a list of them. There
    # are a few options for callable objects here:

    fc = None
    expected = []
    if hasattr(object, "func_code"):
        # function
        fc = object.func_code
        expected = fc.co_varnames[0:fc.co_argcount]
    elif hasattr(object, 'im_func'):
        # method
        fc = object.im_func.func_code
        expected = fc.co_varnames[1:fc.co_argcount]
    elif type(object) is ClassType:
        # class
        fc = object.__init__.im_func.func_code
        expected = fc.co_varnames[1:fc.co_argcount]
    elif type(object) is BuiltinFunctionType:
        # builtin
        fc = None
        expected = []
    elif hasattr(object, '__call__'):
        # callable object
        fc = object.__call__.im_func.func_code
        expected = fc.co_varnames[1:fc.co_argcount]
    
    # remove unexpected args unless co_flags & 0x08,
    # meaning function accepts **kw syntax
    if fc is None:
        args = {}
    elif not (fc.co_flags & 0x08):
        for name in args.keys():
            if name not in expected:
                del args[name] 

    return object(**args)

def redirect(req, location, permanent=0, text=None):
    """
    A convenience function to provide redirection
    """

    if req.sent_bodyct:
        raise IOError, "Cannot redirect after headers have already been sent."

    req.err_headers_out["Location"] = location
    if permanent:
        req.status = apache.HTTP_MOVED_PERMANENTLY
    else:
        req.status = apache.HTTP_MOVED_TEMPORARILY

    if text is None:
        req.write('<p>The document has moved' 
                  ' <a href="%s">here</a></p>\n'
                  % location)
    else:
        req.write(text)

    raise apache.SERVER_RETURN, apache.OK