456 lines
16 KiB
Python
456 lines
16 KiB
Python
import typing as t
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from functools import update_wrapper
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from io import BytesIO
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from itertools import chain
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from typing import Union
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from . import exceptions
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from .datastructures import FileStorage
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from .datastructures import Headers
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from .datastructures import MultiDict
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from .http import parse_options_header
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from .sansio.multipart import Data
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from .sansio.multipart import Epilogue
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from .sansio.multipart import Field
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from .sansio.multipart import File
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from .sansio.multipart import MultipartDecoder
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from .sansio.multipart import NeedData
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from .urls import url_decode_stream
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from .wsgi import _make_chunk_iter
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from .wsgi import get_content_length
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from .wsgi import get_input_stream
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# there are some platforms where SpooledTemporaryFile is not available.
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# In that case we need to provide a fallback.
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try:
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from tempfile import SpooledTemporaryFile
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except ImportError:
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from tempfile import TemporaryFile
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SpooledTemporaryFile = None # type: ignore
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if t.TYPE_CHECKING:
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import typing as te
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from _typeshed.wsgi import WSGIEnvironment
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t_parse_result = t.Tuple[t.IO[bytes], MultiDict, MultiDict]
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class TStreamFactory(te.Protocol):
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def __call__(
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self,
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total_content_length: t.Optional[int],
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content_type: t.Optional[str],
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filename: t.Optional[str],
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content_length: t.Optional[int] = None,
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) -> t.IO[bytes]:
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...
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F = t.TypeVar("F", bound=t.Callable[..., t.Any])
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def _exhaust(stream: t.IO[bytes]) -> None:
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bts = stream.read(64 * 1024)
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while bts:
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bts = stream.read(64 * 1024)
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def default_stream_factory(
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total_content_length: t.Optional[int],
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content_type: t.Optional[str],
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filename: t.Optional[str],
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content_length: t.Optional[int] = None,
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) -> t.IO[bytes]:
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max_size = 1024 * 500
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if SpooledTemporaryFile is not None:
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return t.cast(t.IO[bytes], SpooledTemporaryFile(max_size=max_size, mode="rb+"))
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elif total_content_length is None or total_content_length > max_size:
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return t.cast(t.IO[bytes], TemporaryFile("rb+"))
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return BytesIO()
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def parse_form_data(
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environ: "WSGIEnvironment",
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stream_factory: t.Optional["TStreamFactory"] = None,
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charset: str = "utf-8",
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errors: str = "replace",
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max_form_memory_size: t.Optional[int] = None,
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max_content_length: t.Optional[int] = None,
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cls: t.Optional[t.Type[MultiDict]] = None,
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silent: bool = True,
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) -> "t_parse_result":
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"""Parse the form data in the environ and return it as tuple in the form
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``(stream, form, files)``. You should only call this method if the
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transport method is `POST`, `PUT`, or `PATCH`.
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If the mimetype of the data transmitted is `multipart/form-data` the
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files multidict will be filled with `FileStorage` objects. If the
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mimetype is unknown the input stream is wrapped and returned as first
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argument, else the stream is empty.
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This is a shortcut for the common usage of :class:`FormDataParser`.
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Have a look at :doc:`/request_data` for more details.
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.. versionadded:: 0.5
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The `max_form_memory_size`, `max_content_length` and
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`cls` parameters were added.
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.. versionadded:: 0.5.1
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The optional `silent` flag was added.
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:param environ: the WSGI environment to be used for parsing.
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:param stream_factory: An optional callable that returns a new read and
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writeable file descriptor. This callable works
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the same as :meth:`Response._get_file_stream`.
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:param charset: The character set for URL and url encoded form data.
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:param errors: The encoding error behavior.
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:param max_form_memory_size: the maximum number of bytes to be accepted for
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in-memory stored form data. If the data
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exceeds the value specified an
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:exc:`~exceptions.RequestEntityTooLarge`
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exception is raised.
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:param max_content_length: If this is provided and the transmitted data
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is longer than this value an
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:exc:`~exceptions.RequestEntityTooLarge`
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exception is raised.
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:param cls: an optional dict class to use. If this is not specified
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or `None` the default :class:`MultiDict` is used.
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:param silent: If set to False parsing errors will not be caught.
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:return: A tuple in the form ``(stream, form, files)``.
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"""
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return FormDataParser(
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stream_factory,
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charset,
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errors,
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max_form_memory_size,
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max_content_length,
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cls,
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silent,
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).parse_from_environ(environ)
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def exhaust_stream(f: F) -> F:
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"""Helper decorator for methods that exhausts the stream on return."""
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def wrapper(self, stream, *args, **kwargs): # type: ignore
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try:
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return f(self, stream, *args, **kwargs)
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finally:
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exhaust = getattr(stream, "exhaust", None)
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if exhaust is not None:
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exhaust()
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else:
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while True:
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chunk = stream.read(1024 * 64)
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if not chunk:
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break
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return update_wrapper(t.cast(F, wrapper), f)
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class FormDataParser:
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"""This class implements parsing of form data for Werkzeug. By itself
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it can parse multipart and url encoded form data. It can be subclassed
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and extended but for most mimetypes it is a better idea to use the
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untouched stream and expose it as separate attributes on a request
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object.
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.. versionadded:: 0.8
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:param stream_factory: An optional callable that returns a new read and
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writeable file descriptor. This callable works
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the same as :meth:`Response._get_file_stream`.
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:param charset: The character set for URL and url encoded form data.
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:param errors: The encoding error behavior.
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:param max_form_memory_size: the maximum number of bytes to be accepted for
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in-memory stored form data. If the data
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exceeds the value specified an
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:exc:`~exceptions.RequestEntityTooLarge`
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exception is raised.
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:param max_content_length: If this is provided and the transmitted data
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is longer than this value an
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:exc:`~exceptions.RequestEntityTooLarge`
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exception is raised.
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:param cls: an optional dict class to use. If this is not specified
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or `None` the default :class:`MultiDict` is used.
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:param silent: If set to False parsing errors will not be caught.
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"""
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def __init__(
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self,
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stream_factory: t.Optional["TStreamFactory"] = None,
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charset: str = "utf-8",
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errors: str = "replace",
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max_form_memory_size: t.Optional[int] = None,
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max_content_length: t.Optional[int] = None,
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cls: t.Optional[t.Type[MultiDict]] = None,
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silent: bool = True,
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) -> None:
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if stream_factory is None:
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stream_factory = default_stream_factory
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self.stream_factory = stream_factory
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self.charset = charset
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self.errors = errors
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self.max_form_memory_size = max_form_memory_size
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self.max_content_length = max_content_length
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if cls is None:
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cls = MultiDict
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self.cls = cls
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self.silent = silent
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def get_parse_func(
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self, mimetype: str, options: t.Dict[str, str]
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) -> t.Optional[
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t.Callable[
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["FormDataParser", t.IO[bytes], str, t.Optional[int], t.Dict[str, str]],
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"t_parse_result",
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]
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]:
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return self.parse_functions.get(mimetype)
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def parse_from_environ(self, environ: "WSGIEnvironment") -> "t_parse_result":
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"""Parses the information from the environment as form data.
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:param environ: the WSGI environment to be used for parsing.
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:return: A tuple in the form ``(stream, form, files)``.
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"""
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content_type = environ.get("CONTENT_TYPE", "")
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content_length = get_content_length(environ)
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mimetype, options = parse_options_header(content_type)
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return self.parse(get_input_stream(environ), mimetype, content_length, options)
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def parse(
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self,
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stream: t.IO[bytes],
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mimetype: str,
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content_length: t.Optional[int],
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options: t.Optional[t.Dict[str, str]] = None,
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) -> "t_parse_result":
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"""Parses the information from the given stream, mimetype,
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content length and mimetype parameters.
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:param stream: an input stream
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:param mimetype: the mimetype of the data
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:param content_length: the content length of the incoming data
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:param options: optional mimetype parameters (used for
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the multipart boundary for instance)
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:return: A tuple in the form ``(stream, form, files)``.
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"""
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if (
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self.max_content_length is not None
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and content_length is not None
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and content_length > self.max_content_length
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):
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# if the input stream is not exhausted, firefox reports Connection Reset
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_exhaust(stream)
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raise exceptions.RequestEntityTooLarge()
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if options is None:
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options = {}
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parse_func = self.get_parse_func(mimetype, options)
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if parse_func is not None:
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try:
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return parse_func(self, stream, mimetype, content_length, options)
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except ValueError:
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if not self.silent:
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raise
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return stream, self.cls(), self.cls()
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@exhaust_stream
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def _parse_multipart(
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self,
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stream: t.IO[bytes],
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mimetype: str,
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content_length: t.Optional[int],
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options: t.Dict[str, str],
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) -> "t_parse_result":
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parser = MultiPartParser(
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self.stream_factory,
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self.charset,
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self.errors,
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max_form_memory_size=self.max_form_memory_size,
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cls=self.cls,
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)
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boundary = options.get("boundary", "").encode("ascii")
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if not boundary:
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raise ValueError("Missing boundary")
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form, files = parser.parse(stream, boundary, content_length)
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return stream, form, files
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@exhaust_stream
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def _parse_urlencoded(
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self,
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stream: t.IO[bytes],
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mimetype: str,
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content_length: t.Optional[int],
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options: t.Dict[str, str],
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) -> "t_parse_result":
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if (
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self.max_form_memory_size is not None
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and content_length is not None
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and content_length > self.max_form_memory_size
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):
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# if the input stream is not exhausted, firefox reports Connection Reset
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_exhaust(stream)
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raise exceptions.RequestEntityTooLarge()
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form = url_decode_stream(stream, self.charset, errors=self.errors, cls=self.cls)
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return stream, form, self.cls()
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#: mapping of mimetypes to parsing functions
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parse_functions: t.Dict[
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str,
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t.Callable[
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["FormDataParser", t.IO[bytes], str, t.Optional[int], t.Dict[str, str]],
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"t_parse_result",
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],
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] = {
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"multipart/form-data": _parse_multipart,
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"application/x-www-form-urlencoded": _parse_urlencoded,
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"application/x-url-encoded": _parse_urlencoded,
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}
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def _line_parse(line: str) -> t.Tuple[str, bool]:
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"""Removes line ending characters and returns a tuple (`stripped_line`,
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`is_terminated`).
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"""
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if line[-2:] == "\r\n":
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return line[:-2], True
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elif line[-1:] in {"\r", "\n"}:
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return line[:-1], True
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return line, False
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class MultiPartParser:
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def __init__(
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self,
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stream_factory: t.Optional["TStreamFactory"] = None,
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charset: str = "utf-8",
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errors: str = "replace",
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max_form_memory_size: t.Optional[int] = None,
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cls: t.Optional[t.Type[MultiDict]] = None,
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buffer_size: int = 64 * 1024,
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) -> None:
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self.charset = charset
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self.errors = errors
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self.max_form_memory_size = max_form_memory_size
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if stream_factory is None:
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stream_factory = default_stream_factory
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self.stream_factory = stream_factory
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if cls is None:
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cls = MultiDict
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self.cls = cls
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self.buffer_size = buffer_size
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def fail(self, message: str) -> "te.NoReturn":
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raise ValueError(message)
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def get_part_charset(self, headers: Headers) -> str:
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# Figure out input charset for current part
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content_type = headers.get("content-type")
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if content_type:
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mimetype, ct_params = parse_options_header(content_type)
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return ct_params.get("charset", self.charset)
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return self.charset
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def start_file_streaming(
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self, event: File, total_content_length: t.Optional[int]
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) -> t.IO[bytes]:
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content_type = event.headers.get("content-type")
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try:
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content_length = int(event.headers["content-length"])
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except (KeyError, ValueError):
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content_length = 0
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container = self.stream_factory(
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total_content_length=total_content_length,
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filename=event.filename,
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content_type=content_type,
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content_length=content_length,
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)
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return container
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def parse(
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self, stream: t.IO[bytes], boundary: bytes, content_length: t.Optional[int]
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) -> t.Tuple[MultiDict, MultiDict]:
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container: t.Union[t.IO[bytes], t.List[bytes]]
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_write: t.Callable[[bytes], t.Any]
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iterator = chain(
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_make_chunk_iter(
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stream,
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limit=content_length,
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buffer_size=self.buffer_size,
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),
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[None],
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)
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parser = MultipartDecoder(boundary, self.max_form_memory_size)
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fields = []
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files = []
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current_part: Union[Field, File]
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for data in iterator:
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parser.receive_data(data)
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event = parser.next_event()
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while not isinstance(event, (Epilogue, NeedData)):
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if isinstance(event, Field):
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current_part = event
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container = []
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_write = container.append
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elif isinstance(event, File):
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current_part = event
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container = self.start_file_streaming(event, content_length)
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_write = container.write
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elif isinstance(event, Data):
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_write(event.data)
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if not event.more_data:
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if isinstance(current_part, Field):
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value = b"".join(container).decode(
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self.get_part_charset(current_part.headers), self.errors
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)
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fields.append((current_part.name, value))
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else:
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container = t.cast(t.IO[bytes], container)
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container.seek(0)
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files.append(
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(
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current_part.name,
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FileStorage(
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container,
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current_part.filename,
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current_part.name,
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headers=current_part.headers,
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),
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)
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)
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event = parser.next_event()
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return self.cls(fields), self.cls(files)
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