535 lines
21 KiB
Python
535 lines
21 KiB
Python
# -*- coding: utf-8 -*-
|
|
"""
|
|
werkzeug.formparser
|
|
~~~~~~~~~~~~~~~~~~~
|
|
|
|
This module implements the form parsing. It supports url-encoded forms
|
|
as well as non-nested multipart uploads.
|
|
|
|
:copyright: (c) 2014 by the Werkzeug Team, see AUTHORS for more details.
|
|
:license: BSD, see LICENSE for more details.
|
|
"""
|
|
import re
|
|
import codecs
|
|
|
|
# there are some platforms where SpooledTemporaryFile is not available.
|
|
# In that case we need to provide a fallback.
|
|
try:
|
|
from tempfile import SpooledTemporaryFile
|
|
except ImportError:
|
|
from tempfile import TemporaryFile
|
|
SpooledTemporaryFile = None
|
|
|
|
from itertools import chain, repeat, tee
|
|
from functools import update_wrapper
|
|
|
|
from werkzeug._compat import to_native, text_type, BytesIO
|
|
from werkzeug.urls import url_decode_stream
|
|
from werkzeug.wsgi import make_line_iter, \
|
|
get_input_stream, get_content_length
|
|
from werkzeug.datastructures import Headers, FileStorage, MultiDict
|
|
from werkzeug.http import parse_options_header
|
|
|
|
|
|
#: an iterator that yields empty strings
|
|
_empty_string_iter = repeat('')
|
|
|
|
#: a regular expression for multipart boundaries
|
|
_multipart_boundary_re = re.compile('^[ -~]{0,200}[!-~]$')
|
|
|
|
#: supported http encodings that are also available in python we support
|
|
#: for multipart messages.
|
|
_supported_multipart_encodings = frozenset(['base64', 'quoted-printable'])
|
|
|
|
|
|
def default_stream_factory(total_content_length, filename, content_type,
|
|
content_length=None):
|
|
"""The stream factory that is used per default."""
|
|
max_size = 1024 * 500
|
|
if SpooledTemporaryFile is not None:
|
|
return SpooledTemporaryFile(max_size=max_size, mode='wb+')
|
|
if total_content_length is None or total_content_length > max_size:
|
|
return TemporaryFile('wb+')
|
|
return BytesIO()
|
|
|
|
|
|
def parse_form_data(environ, stream_factory=None, charset='utf-8',
|
|
errors='replace', max_form_memory_size=None,
|
|
max_content_length=None, cls=None,
|
|
silent=True):
|
|
"""Parse the form data in the environ and return it as tuple in the form
|
|
``(stream, form, files)``. You should only call this method if the
|
|
transport method is `POST`, `PUT`, or `PATCH`.
|
|
|
|
If the mimetype of the data transmitted is `multipart/form-data` the
|
|
files multidict will be filled with `FileStorage` objects. If the
|
|
mimetype is unknown the input stream is wrapped and returned as first
|
|
argument, else the stream is empty.
|
|
|
|
This is a shortcut for the common usage of :class:`FormDataParser`.
|
|
|
|
Have a look at :ref:`dealing-with-request-data` for more details.
|
|
|
|
.. versionadded:: 0.5
|
|
The `max_form_memory_size`, `max_content_length` and
|
|
`cls` parameters were added.
|
|
|
|
.. versionadded:: 0.5.1
|
|
The optional `silent` flag was added.
|
|
|
|
:param environ: the WSGI environment to be used for parsing.
|
|
:param stream_factory: An optional callable that returns a new read and
|
|
writeable file descriptor. This callable works
|
|
the same as :meth:`~BaseResponse._get_file_stream`.
|
|
:param charset: The character set for URL and url encoded form data.
|
|
:param errors: The encoding error behavior.
|
|
:param max_form_memory_size: the maximum number of bytes to be accepted for
|
|
in-memory stored form data. If the data
|
|
exceeds the value specified an
|
|
:exc:`~exceptions.RequestEntityTooLarge`
|
|
exception is raised.
|
|
:param max_content_length: If this is provided and the transmitted data
|
|
is longer than this value an
|
|
:exc:`~exceptions.RequestEntityTooLarge`
|
|
exception is raised.
|
|
:param cls: an optional dict class to use. If this is not specified
|
|
or `None` the default :class:`MultiDict` is used.
|
|
:param silent: If set to False parsing errors will not be caught.
|
|
:return: A tuple in the form ``(stream, form, files)``.
|
|
"""
|
|
return FormDataParser(stream_factory, charset, errors,
|
|
max_form_memory_size, max_content_length,
|
|
cls, silent).parse_from_environ(environ)
|
|
|
|
|
|
def exhaust_stream(f):
|
|
"""Helper decorator for methods that exhausts the stream on return."""
|
|
|
|
def wrapper(self, stream, *args, **kwargs):
|
|
try:
|
|
return f(self, stream, *args, **kwargs)
|
|
finally:
|
|
exhaust = getattr(stream, 'exhaust', None)
|
|
if exhaust is not None:
|
|
exhaust()
|
|
else:
|
|
while 1:
|
|
chunk = stream.read(1024 * 64)
|
|
if not chunk:
|
|
break
|
|
return update_wrapper(wrapper, f)
|
|
|
|
|
|
class FormDataParser(object):
|
|
|
|
"""This class implements parsing of form data for Werkzeug. By itself
|
|
it can parse multipart and url encoded form data. It can be subclassed
|
|
and extended but for most mimetypes it is a better idea to use the
|
|
untouched stream and expose it as separate attributes on a request
|
|
object.
|
|
|
|
.. versionadded:: 0.8
|
|
|
|
:param stream_factory: An optional callable that returns a new read and
|
|
writeable file descriptor. This callable works
|
|
the same as :meth:`~BaseResponse._get_file_stream`.
|
|
:param charset: The character set for URL and url encoded form data.
|
|
:param errors: The encoding error behavior.
|
|
:param max_form_memory_size: the maximum number of bytes to be accepted for
|
|
in-memory stored form data. If the data
|
|
exceeds the value specified an
|
|
:exc:`~exceptions.RequestEntityTooLarge`
|
|
exception is raised.
|
|
:param max_content_length: If this is provided and the transmitted data
|
|
is longer than this value an
|
|
:exc:`~exceptions.RequestEntityTooLarge`
|
|
exception is raised.
|
|
:param cls: an optional dict class to use. If this is not specified
|
|
or `None` the default :class:`MultiDict` is used.
|
|
:param silent: If set to False parsing errors will not be caught.
|
|
"""
|
|
|
|
def __init__(self, stream_factory=None, charset='utf-8',
|
|
errors='replace', max_form_memory_size=None,
|
|
max_content_length=None, cls=None,
|
|
silent=True):
|
|
if stream_factory is None:
|
|
stream_factory = default_stream_factory
|
|
self.stream_factory = stream_factory
|
|
self.charset = charset
|
|
self.errors = errors
|
|
self.max_form_memory_size = max_form_memory_size
|
|
self.max_content_length = max_content_length
|
|
if cls is None:
|
|
cls = MultiDict
|
|
self.cls = cls
|
|
self.silent = silent
|
|
|
|
def get_parse_func(self, mimetype, options):
|
|
return self.parse_functions.get(mimetype)
|
|
|
|
def parse_from_environ(self, environ):
|
|
"""Parses the information from the environment as form data.
|
|
|
|
:param environ: the WSGI environment to be used for parsing.
|
|
:return: A tuple in the form ``(stream, form, files)``.
|
|
"""
|
|
content_type = environ.get('CONTENT_TYPE', '')
|
|
content_length = get_content_length(environ)
|
|
mimetype, options = parse_options_header(content_type)
|
|
return self.parse(get_input_stream(environ), mimetype,
|
|
content_length, options)
|
|
|
|
def parse(self, stream, mimetype, content_length, options=None):
|
|
"""Parses the information from the given stream, mimetype,
|
|
content length and mimetype parameters.
|
|
|
|
:param stream: an input stream
|
|
:param mimetype: the mimetype of the data
|
|
:param content_length: the content length of the incoming data
|
|
:param options: optional mimetype parameters (used for
|
|
the multipart boundary for instance)
|
|
:return: A tuple in the form ``(stream, form, files)``.
|
|
"""
|
|
if self.max_content_length is not None and \
|
|
content_length is not None and \
|
|
content_length > self.max_content_length:
|
|
raise exceptions.RequestEntityTooLarge()
|
|
if options is None:
|
|
options = {}
|
|
|
|
parse_func = self.get_parse_func(mimetype, options)
|
|
if parse_func is not None:
|
|
try:
|
|
return parse_func(self, stream, mimetype,
|
|
content_length, options)
|
|
except ValueError:
|
|
if not self.silent:
|
|
raise
|
|
|
|
return stream, self.cls(), self.cls()
|
|
|
|
@exhaust_stream
|
|
def _parse_multipart(self, stream, mimetype, content_length, options):
|
|
parser = MultiPartParser(self.stream_factory, self.charset, self.errors,
|
|
max_form_memory_size=self.max_form_memory_size,
|
|
cls=self.cls)
|
|
boundary = options.get('boundary')
|
|
if boundary is None:
|
|
raise ValueError('Missing boundary')
|
|
if isinstance(boundary, text_type):
|
|
boundary = boundary.encode('ascii')
|
|
form, files = parser.parse(stream, boundary, content_length)
|
|
return stream, form, files
|
|
|
|
@exhaust_stream
|
|
def _parse_urlencoded(self, stream, mimetype, content_length, options):
|
|
if self.max_form_memory_size is not None and \
|
|
content_length is not None and \
|
|
content_length > self.max_form_memory_size:
|
|
raise exceptions.RequestEntityTooLarge()
|
|
form = url_decode_stream(stream, self.charset,
|
|
errors=self.errors, cls=self.cls)
|
|
return stream, form, self.cls()
|
|
|
|
#: mapping of mimetypes to parsing functions
|
|
parse_functions = {
|
|
'multipart/form-data': _parse_multipart,
|
|
'application/x-www-form-urlencoded': _parse_urlencoded,
|
|
'application/x-url-encoded': _parse_urlencoded
|
|
}
|
|
|
|
|
|
def is_valid_multipart_boundary(boundary):
|
|
"""Checks if the string given is a valid multipart boundary."""
|
|
return _multipart_boundary_re.match(boundary) is not None
|
|
|
|
|
|
def _line_parse(line):
|
|
"""Removes line ending characters and returns a tuple (`stripped_line`,
|
|
`is_terminated`).
|
|
"""
|
|
if line[-2:] in ['\r\n', b'\r\n']:
|
|
return line[:-2], True
|
|
elif line[-1:] in ['\r', '\n', b'\r', b'\n']:
|
|
return line[:-1], True
|
|
return line, False
|
|
|
|
|
|
def parse_multipart_headers(iterable):
|
|
"""Parses multipart headers from an iterable that yields lines (including
|
|
the trailing newline symbol). The iterable has to be newline terminated.
|
|
|
|
The iterable will stop at the line where the headers ended so it can be
|
|
further consumed.
|
|
|
|
:param iterable: iterable of strings that are newline terminated
|
|
"""
|
|
result = []
|
|
for line in iterable:
|
|
line = to_native(line)
|
|
line, line_terminated = _line_parse(line)
|
|
if not line_terminated:
|
|
raise ValueError('unexpected end of line in multipart header')
|
|
if not line:
|
|
break
|
|
elif line[0] in ' \t' and result:
|
|
key, value = result[-1]
|
|
result[-1] = (key, value + '\n ' + line[1:])
|
|
else:
|
|
parts = line.split(':', 1)
|
|
if len(parts) == 2:
|
|
result.append((parts[0].strip(), parts[1].strip()))
|
|
|
|
# we link the list to the headers, no need to create a copy, the
|
|
# list was not shared anyways.
|
|
return Headers(result)
|
|
|
|
|
|
_begin_form = 'begin_form'
|
|
_begin_file = 'begin_file'
|
|
_cont = 'cont'
|
|
_end = 'end'
|
|
|
|
|
|
class MultiPartParser(object):
|
|
|
|
def __init__(self, stream_factory=None, charset='utf-8', errors='replace',
|
|
max_form_memory_size=None, cls=None, buffer_size=64 * 1024):
|
|
self.charset = charset
|
|
self.errors = errors
|
|
self.max_form_memory_size = max_form_memory_size
|
|
self.stream_factory = default_stream_factory if stream_factory is None else stream_factory
|
|
self.cls = MultiDict if cls is None else cls
|
|
|
|
# make sure the buffer size is divisible by four so that we can base64
|
|
# decode chunk by chunk
|
|
assert buffer_size % 4 == 0, 'buffer size has to be divisible by 4'
|
|
# also the buffer size has to be at least 1024 bytes long or long headers
|
|
# will freak out the system
|
|
assert buffer_size >= 1024, 'buffer size has to be at least 1KB'
|
|
|
|
self.buffer_size = buffer_size
|
|
|
|
def _fix_ie_filename(self, filename):
|
|
"""Internet Explorer 6 transmits the full file name if a file is
|
|
uploaded. This function strips the full path if it thinks the
|
|
filename is Windows-like absolute.
|
|
"""
|
|
if filename[1:3] == ':\\' or filename[:2] == '\\\\':
|
|
return filename.split('\\')[-1]
|
|
return filename
|
|
|
|
def _find_terminator(self, iterator):
|
|
"""The terminator might have some additional newlines before it.
|
|
There is at least one application that sends additional newlines
|
|
before headers (the python setuptools package).
|
|
"""
|
|
for line in iterator:
|
|
if not line:
|
|
break
|
|
line = line.strip()
|
|
if line:
|
|
return line
|
|
return b''
|
|
|
|
def fail(self, message):
|
|
raise ValueError(message)
|
|
|
|
def get_part_encoding(self, headers):
|
|
transfer_encoding = headers.get('content-transfer-encoding')
|
|
if transfer_encoding is not None and \
|
|
transfer_encoding in _supported_multipart_encodings:
|
|
return transfer_encoding
|
|
|
|
def get_part_charset(self, headers):
|
|
# Figure out input charset for current part
|
|
content_type = headers.get('content-type')
|
|
if content_type:
|
|
mimetype, ct_params = parse_options_header(content_type)
|
|
return ct_params.get('charset', self.charset)
|
|
return self.charset
|
|
|
|
def start_file_streaming(self, filename, headers, total_content_length):
|
|
if isinstance(filename, bytes):
|
|
filename = filename.decode(self.charset, self.errors)
|
|
filename = self._fix_ie_filename(filename)
|
|
content_type = headers.get('content-type')
|
|
try:
|
|
content_length = int(headers['content-length'])
|
|
except (KeyError, ValueError):
|
|
content_length = 0
|
|
container = self.stream_factory(total_content_length, content_type,
|
|
filename, content_length)
|
|
return filename, container
|
|
|
|
def in_memory_threshold_reached(self, bytes):
|
|
raise exceptions.RequestEntityTooLarge()
|
|
|
|
def validate_boundary(self, boundary):
|
|
if not boundary:
|
|
self.fail('Missing boundary')
|
|
if not is_valid_multipart_boundary(boundary):
|
|
self.fail('Invalid boundary: %s' % boundary)
|
|
if len(boundary) > self.buffer_size: # pragma: no cover
|
|
# this should never happen because we check for a minimum size
|
|
# of 1024 and boundaries may not be longer than 200. The only
|
|
# situation when this happens is for non debug builds where
|
|
# the assert is skipped.
|
|
self.fail('Boundary longer than buffer size')
|
|
|
|
def parse_lines(self, file, boundary, content_length, cap_at_buffer=True):
|
|
"""Generate parts of
|
|
``('begin_form', (headers, name))``
|
|
``('begin_file', (headers, name, filename))``
|
|
``('cont', bytestring)``
|
|
``('end', None)``
|
|
|
|
Always obeys the grammar
|
|
parts = ( begin_form cont* end |
|
|
begin_file cont* end )*
|
|
"""
|
|
next_part = b'--' + boundary
|
|
last_part = next_part + b'--'
|
|
|
|
iterator = chain(make_line_iter(file, limit=content_length,
|
|
buffer_size=self.buffer_size,
|
|
cap_at_buffer=cap_at_buffer),
|
|
_empty_string_iter)
|
|
|
|
terminator = self._find_terminator(iterator)
|
|
|
|
if terminator == last_part:
|
|
return
|
|
elif terminator != next_part:
|
|
self.fail('Expected boundary at start of multipart data')
|
|
|
|
while terminator != last_part:
|
|
headers = parse_multipart_headers(iterator)
|
|
|
|
disposition = headers.get('content-disposition')
|
|
if disposition is None:
|
|
self.fail('Missing Content-Disposition header')
|
|
disposition, extra = parse_options_header(disposition)
|
|
transfer_encoding = self.get_part_encoding(headers)
|
|
name = extra.get('name')
|
|
|
|
# Accept filename* to support non-ascii filenames as per rfc2231
|
|
filename = extra.get('filename') or extra.get('filename*')
|
|
|
|
# if no content type is given we stream into memory. A list is
|
|
# used as a temporary container.
|
|
if filename is None:
|
|
yield _begin_form, (headers, name)
|
|
|
|
# otherwise we parse the rest of the headers and ask the stream
|
|
# factory for something we can write in.
|
|
else:
|
|
yield _begin_file, (headers, name, filename)
|
|
|
|
buf = b''
|
|
for line in iterator:
|
|
if not line:
|
|
self.fail('unexpected end of stream')
|
|
|
|
if line[:2] == b'--':
|
|
terminator = line.rstrip()
|
|
if terminator in (next_part, last_part):
|
|
break
|
|
|
|
if transfer_encoding is not None:
|
|
if transfer_encoding == 'base64':
|
|
transfer_encoding = 'base64_codec'
|
|
try:
|
|
line = codecs.decode(line, transfer_encoding)
|
|
except Exception:
|
|
self.fail('could not decode transfer encoded chunk')
|
|
|
|
# we have something in the buffer from the last iteration.
|
|
# this is usually a newline delimiter.
|
|
if buf:
|
|
yield _cont, buf
|
|
buf = b''
|
|
|
|
# If the line ends with windows CRLF we write everything except
|
|
# the last two bytes. In all other cases however we write
|
|
# everything except the last byte. If it was a newline, that's
|
|
# fine, otherwise it does not matter because we will write it
|
|
# the next iteration. this ensures we do not write the
|
|
# final newline into the stream. That way we do not have to
|
|
# truncate the stream. However we do have to make sure that
|
|
# if something else than a newline is in there we write it
|
|
# out.
|
|
if line[-2:] == b'\r\n':
|
|
buf = b'\r\n'
|
|
cutoff = -2
|
|
else:
|
|
buf = line[-1:]
|
|
cutoff = -1
|
|
yield _cont, line[:cutoff]
|
|
|
|
else: # pragma: no cover
|
|
raise ValueError('unexpected end of part')
|
|
|
|
# if we have a leftover in the buffer that is not a newline
|
|
# character we have to flush it, otherwise we will chop of
|
|
# certain values.
|
|
if buf not in (b'', b'\r', b'\n', b'\r\n'):
|
|
yield _cont, buf
|
|
|
|
yield _end, None
|
|
|
|
def parse_parts(self, file, boundary, content_length):
|
|
"""Generate ``('file', (name, val))`` and
|
|
``('form', (name, val))`` parts.
|
|
"""
|
|
in_memory = 0
|
|
|
|
for ellt, ell in self.parse_lines(file, boundary, content_length):
|
|
if ellt == _begin_file:
|
|
headers, name, filename = ell
|
|
is_file = True
|
|
guard_memory = False
|
|
filename, container = self.start_file_streaming(
|
|
filename, headers, content_length)
|
|
_write = container.write
|
|
|
|
elif ellt == _begin_form:
|
|
headers, name = ell
|
|
is_file = False
|
|
container = []
|
|
_write = container.append
|
|
guard_memory = self.max_form_memory_size is not None
|
|
|
|
elif ellt == _cont:
|
|
_write(ell)
|
|
# if we write into memory and there is a memory size limit we
|
|
# count the number of bytes in memory and raise an exception if
|
|
# there is too much data in memory.
|
|
if guard_memory:
|
|
in_memory += len(ell)
|
|
if in_memory > self.max_form_memory_size:
|
|
self.in_memory_threshold_reached(in_memory)
|
|
|
|
elif ellt == _end:
|
|
if is_file:
|
|
container.seek(0)
|
|
yield ('file',
|
|
(name, FileStorage(container, filename, name,
|
|
headers=headers)))
|
|
else:
|
|
part_charset = self.get_part_charset(headers)
|
|
yield ('form',
|
|
(name, b''.join(container).decode(
|
|
part_charset, self.errors)))
|
|
|
|
def parse(self, file, boundary, content_length):
|
|
formstream, filestream = tee(
|
|
self.parse_parts(file, boundary, content_length), 2)
|
|
form = (p[1] for p in formstream if p[0] == 'form')
|
|
files = (p[1] for p in filestream if p[0] == 'file')
|
|
return self.cls(form), self.cls(files)
|
|
|
|
|
|
from werkzeug import exceptions
|