from __future__ import annotations import typing as t from io import BytesIO from urllib.parse import parse_qsl from ._internal import _plain_int from .datastructures import FileStorage from .datastructures import Headers from .datastructures import MultiDict from .exceptions import RequestEntityTooLarge from .http import parse_options_header from .sansio.multipart import Data from .sansio.multipart import Epilogue from .sansio.multipart import Field from .sansio.multipart import File from .sansio.multipart import MultipartDecoder from .sansio.multipart import NeedData from .wsgi import get_content_length from .wsgi import get_input_stream # 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 # type: ignore if t.TYPE_CHECKING: import typing as te from _typeshed.wsgi import WSGIEnvironment t_parse_result = t.Tuple[t.IO[bytes], MultiDict, MultiDict] class TStreamFactory(te.Protocol): def __call__( self, total_content_length: int | None, content_type: str | None, filename: str | None, content_length: int | None = None, ) -> t.IO[bytes]: ... F = t.TypeVar("F", bound=t.Callable[..., t.Any]) def default_stream_factory( total_content_length: int | None, content_type: str | None, filename: str | None, content_length: int | None = None, ) -> t.IO[bytes]: max_size = 1024 * 500 if SpooledTemporaryFile is not None: return t.cast(t.IO[bytes], SpooledTemporaryFile(max_size=max_size, mode="rb+")) elif total_content_length is None or total_content_length > max_size: return t.cast(t.IO[bytes], TemporaryFile("rb+")) return BytesIO() def parse_form_data( environ: WSGIEnvironment, stream_factory: TStreamFactory | None = None, max_form_memory_size: int | None = None, max_content_length: int | None = None, cls: type[MultiDict] | None = None, silent: bool = True, *, max_form_parts: int | None = None, ) -> t_parse_result: """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`. :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:`Response._get_file_stream`. :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. :param max_form_parts: The maximum number of multipart parts to be parsed. If this is exceeded, a :exc:`~exceptions.RequestEntityTooLarge` exception is raised. :return: A tuple in the form ``(stream, form, files)``. .. versionchanged:: 3.0 The ``charset`` and ``errors`` parameters were removed. .. versionchanged:: 2.3 Added the ``max_form_parts`` parameter. .. versionadded:: 0.5.1 Added the ``silent`` parameter. .. versionadded:: 0.5 Added the ``max_form_memory_size``, ``max_content_length``, and ``cls`` parameters. """ return FormDataParser( stream_factory=stream_factory, max_form_memory_size=max_form_memory_size, max_content_length=max_content_length, max_form_parts=max_form_parts, silent=silent, cls=cls, ).parse_from_environ(environ) class FormDataParser: """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. :param stream_factory: An optional callable that returns a new read and writeable file descriptor. This callable works the same as :meth:`Response._get_file_stream`. :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. :param max_form_parts: The maximum number of multipart parts to be parsed. If this is exceeded, a :exc:`~exceptions.RequestEntityTooLarge` exception is raised. .. versionchanged:: 3.0 The ``charset`` and ``errors`` parameters were removed. .. versionchanged:: 3.0 The ``parse_functions`` attribute and ``get_parse_func`` methods were removed. .. versionchanged:: 2.2.3 Added the ``max_form_parts`` parameter. .. versionadded:: 0.8 """ def __init__( self, stream_factory: TStreamFactory | None = None, max_form_memory_size: int | None = None, max_content_length: int | None = None, cls: type[MultiDict] | None = None, silent: bool = True, *, max_form_parts: int | None = None, ) -> None: if stream_factory is None: stream_factory = default_stream_factory self.stream_factory = stream_factory self.max_form_memory_size = max_form_memory_size self.max_content_length = max_content_length self.max_form_parts = max_form_parts if cls is None: cls = MultiDict self.cls = cls self.silent = silent def parse_from_environ(self, environ: WSGIEnvironment) -> t_parse_result: """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)``. """ stream = get_input_stream(environ, max_content_length=self.max_content_length) content_length = get_content_length(environ) mimetype, options = parse_options_header(environ.get("CONTENT_TYPE")) return self.parse( stream, content_length=content_length, mimetype=mimetype, options=options, ) def parse( self, stream: t.IO[bytes], mimetype: str, content_length: int | None, options: dict[str, str] | None = None, ) -> t_parse_result: """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)``. .. versionchanged:: 3.0 The invalid ``application/x-url-encoded`` content type is not treated as ``application/x-www-form-urlencoded``. """ if mimetype == "multipart/form-data": parse_func = self._parse_multipart elif mimetype == "application/x-www-form-urlencoded": parse_func = self._parse_urlencoded else: return stream, self.cls(), self.cls() if options is None: options = {} try: return parse_func(stream, mimetype, content_length, options) except ValueError: if not self.silent: raise return stream, self.cls(), self.cls() def _parse_multipart( self, stream: t.IO[bytes], mimetype: str, content_length: int | None, options: dict[str, str], ) -> t_parse_result: parser = MultiPartParser( stream_factory=self.stream_factory, max_form_memory_size=self.max_form_memory_size, max_form_parts=self.max_form_parts, cls=self.cls, ) boundary = options.get("boundary", "").encode("ascii") if not boundary: raise ValueError("Missing boundary") form, files = parser.parse(stream, boundary, content_length) return stream, form, files def _parse_urlencoded( self, stream: t.IO[bytes], mimetype: str, content_length: int | None, options: dict[str, str], ) -> t_parse_result: if ( self.max_form_memory_size is not None and content_length is not None and content_length > self.max_form_memory_size ): raise RequestEntityTooLarge() try: items = parse_qsl( stream.read().decode(), keep_blank_values=True, errors="werkzeug.url_quote", ) except ValueError as e: raise RequestEntityTooLarge() from e return stream, self.cls(items), self.cls() class MultiPartParser: def __init__( self, stream_factory: TStreamFactory | None = None, max_form_memory_size: int | None = None, cls: type[MultiDict] | None = None, buffer_size: int = 64 * 1024, max_form_parts: int | None = None, ) -> None: self.max_form_memory_size = max_form_memory_size self.max_form_parts = max_form_parts if stream_factory is None: stream_factory = default_stream_factory self.stream_factory = stream_factory if cls is None: cls = MultiDict self.cls = cls self.buffer_size = buffer_size def fail(self, message: str) -> te.NoReturn: raise ValueError(message) def get_part_charset(self, headers: Headers) -> str: # Figure out input charset for current part content_type = headers.get("content-type") if content_type: parameters = parse_options_header(content_type)[1] ct_charset = parameters.get("charset", "").lower() # A safe list of encodings. Modern clients should only send ASCII or UTF-8. # This list will not be extended further. if ct_charset in {"ascii", "us-ascii", "utf-8", "iso-8859-1"}: return ct_charset return "utf-8" def start_file_streaming( self, event: File, total_content_length: int | None ) -> t.IO[bytes]: content_type = event.headers.get("content-type") try: content_length = _plain_int(event.headers["content-length"]) except (KeyError, ValueError): content_length = 0 container = self.stream_factory( total_content_length=total_content_length, filename=event.filename, content_type=content_type, content_length=content_length, ) return container def parse( self, stream: t.IO[bytes], boundary: bytes, content_length: int | None ) -> tuple[MultiDict[str, str], MultiDict[str, FileStorage]]: current_part: Field | File container: t.IO[bytes] | list[bytes] _write: t.Callable[[bytes], t.Any] parser = MultipartDecoder( boundary, max_form_memory_size=self.max_form_memory_size, max_parts=self.max_form_parts, ) fields = [] files = [] for data in _chunk_iter(stream.read, self.buffer_size): parser.receive_data(data) event = parser.next_event() while not isinstance(event, (Epilogue, NeedData)): if isinstance(event, Field): current_part = event container = [] _write = container.append elif isinstance(event, File): current_part = event container = self.start_file_streaming(event, content_length) _write = container.write elif isinstance(event, Data): _write(event.data) if not event.more_data: if isinstance(current_part, Field): value = b"".join(container).decode( self.get_part_charset(current_part.headers), "replace" ) fields.append((current_part.name, value)) else: container = t.cast(t.IO[bytes], container) container.seek(0) files.append( ( current_part.name, FileStorage( container, current_part.filename, current_part.name, headers=current_part.headers, ), ) ) event = parser.next_event() return self.cls(fields), self.cls(files) def _chunk_iter(read: t.Callable[[int], bytes], size: int) -> t.Iterator[bytes | None]: """Read data in chunks for multipart/form-data parsing. Stop if no data is read. Yield ``None`` at the end to signal end of parsing. """ while True: data = read(size) if not data: break yield data yield None