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596 lines
20 KiB
596 lines
20 KiB
from __future__ import annotations
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import io
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import typing as t
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from functools import partial
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from functools import update_wrapper
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from .exceptions import ClientDisconnected
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from .exceptions import RequestEntityTooLarge
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from .sansio import utils as _sansio_utils
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from .sansio.utils import host_is_trusted # noqa: F401 # Imported as part of API
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if t.TYPE_CHECKING:
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from _typeshed.wsgi import WSGIApplication
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from _typeshed.wsgi import WSGIEnvironment
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def responder(f: t.Callable[..., WSGIApplication]) -> WSGIApplication:
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"""Marks a function as responder. Decorate a function with it and it
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will automatically call the return value as WSGI application.
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Example::
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@responder
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def application(environ, start_response):
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return Response('Hello World!')
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"""
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return update_wrapper(lambda *a: f(*a)(*a[-2:]), f)
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def get_current_url(
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environ: WSGIEnvironment,
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root_only: bool = False,
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strip_querystring: bool = False,
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host_only: bool = False,
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trusted_hosts: t.Iterable[str] | None = None,
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) -> str:
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"""Recreate the URL for a request from the parts in a WSGI
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environment.
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The URL is an IRI, not a URI, so it may contain Unicode characters.
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Use :func:`~werkzeug.urls.iri_to_uri` to convert it to ASCII.
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:param environ: The WSGI environment to get the URL parts from.
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:param root_only: Only build the root path, don't include the
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remaining path or query string.
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:param strip_querystring: Don't include the query string.
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:param host_only: Only build the scheme and host.
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:param trusted_hosts: A list of trusted host names to validate the
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host against.
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"""
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parts = {
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"scheme": environ["wsgi.url_scheme"],
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"host": get_host(environ, trusted_hosts),
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}
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if not host_only:
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parts["root_path"] = environ.get("SCRIPT_NAME", "")
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if not root_only:
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parts["path"] = environ.get("PATH_INFO", "")
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if not strip_querystring:
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parts["query_string"] = environ.get("QUERY_STRING", "").encode("latin1")
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return _sansio_utils.get_current_url(**parts)
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def _get_server(
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environ: WSGIEnvironment,
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) -> tuple[str, int | None] | None:
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name = environ.get("SERVER_NAME")
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if name is None:
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return None
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try:
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port: int | None = int(environ.get("SERVER_PORT", None))
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except (TypeError, ValueError):
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# unix socket
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port = None
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return name, port
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def get_host(
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environ: WSGIEnvironment, trusted_hosts: t.Iterable[str] | None = None
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) -> str:
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"""Return the host for the given WSGI environment.
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The ``Host`` header is preferred, then ``SERVER_NAME`` if it's not
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set. The returned host will only contain the port if it is different
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than the standard port for the protocol.
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Optionally, verify that the host is trusted using
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:func:`host_is_trusted` and raise a
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:exc:`~werkzeug.exceptions.SecurityError` if it is not.
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:param environ: A WSGI environment dict.
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:param trusted_hosts: A list of trusted host names.
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:return: Host, with port if necessary.
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:raise ~werkzeug.exceptions.SecurityError: If the host is not
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trusted.
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"""
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return _sansio_utils.get_host(
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environ["wsgi.url_scheme"],
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environ.get("HTTP_HOST"),
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_get_server(environ),
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trusted_hosts,
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)
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def get_content_length(environ: WSGIEnvironment) -> int | None:
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"""Return the ``Content-Length`` header value as an int. If the header is not given
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or the ``Transfer-Encoding`` header is ``chunked``, ``None`` is returned to indicate
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a streaming request. If the value is not an integer, or negative, 0 is returned.
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:param environ: The WSGI environ to get the content length from.
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.. versionadded:: 0.9
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"""
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return _sansio_utils.get_content_length(
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http_content_length=environ.get("CONTENT_LENGTH"),
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http_transfer_encoding=environ.get("HTTP_TRANSFER_ENCODING"),
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)
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def get_input_stream(
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environ: WSGIEnvironment,
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safe_fallback: bool = True,
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max_content_length: int | None = None,
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) -> t.IO[bytes]:
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"""Return the WSGI input stream, wrapped so that it may be read safely without going
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past the ``Content-Length`` header value or ``max_content_length``.
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If ``Content-Length`` exceeds ``max_content_length``, a
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:exc:`RequestEntityTooLarge`` ``413 Content Too Large`` error is raised.
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If the WSGI server sets ``environ["wsgi.input_terminated"]``, it indicates that the
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server handles terminating the stream, so it is safe to read directly. For example,
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a server that knows how to handle chunked requests safely would set this.
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If ``max_content_length`` is set, it can be enforced on streams if
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``wsgi.input_terminated`` is set. Otherwise, an empty stream is returned unless the
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user explicitly disables this safe fallback.
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If the limit is reached before the underlying stream is exhausted (such as a file
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that is too large, or an infinite stream), the remaining contents of the stream
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cannot be read safely. Depending on how the server handles this, clients may show a
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"connection reset" failure instead of seeing the 413 response.
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:param environ: The WSGI environ containing the stream.
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:param safe_fallback: Return an empty stream when ``Content-Length`` is not set.
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Disabling this allows infinite streams, which can be a denial-of-service risk.
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:param max_content_length: The maximum length that content-length or streaming
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requests may not exceed.
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.. versionchanged:: 2.3.2
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``max_content_length`` is only applied to streaming requests if the server sets
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``wsgi.input_terminated``.
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.. versionchanged:: 2.3
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Check ``max_content_length`` and raise an error if it is exceeded.
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.. versionadded:: 0.9
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"""
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stream = t.cast(t.IO[bytes], environ["wsgi.input"])
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content_length = get_content_length(environ)
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if content_length is not None and max_content_length is not None:
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if content_length > max_content_length:
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raise RequestEntityTooLarge()
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# A WSGI server can set this to indicate that it terminates the input stream. In
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# that case the stream is safe without wrapping, or can enforce a max length.
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if "wsgi.input_terminated" in environ:
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if max_content_length is not None:
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# If this is moved above, it can cause the stream to hang if a read attempt
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# is made when the client sends no data. For example, the development server
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# does not handle buffering except for chunked encoding.
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return t.cast(
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t.IO[bytes], LimitedStream(stream, max_content_length, is_max=True)
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)
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return stream
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# No limit given, return an empty stream unless the user explicitly allows the
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# potentially infinite stream. An infinite stream is dangerous if it's not expected,
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# as it can tie up a worker indefinitely.
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if content_length is None:
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return io.BytesIO() if safe_fallback else stream
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return t.cast(t.IO[bytes], LimitedStream(stream, content_length))
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def get_path_info(environ: WSGIEnvironment) -> str:
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"""Return ``PATH_INFO`` from the WSGI environment.
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:param environ: WSGI environment to get the path from.
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.. versionchanged:: 3.0
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The ``charset`` and ``errors`` parameters were removed.
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.. versionadded:: 0.9
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"""
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path: bytes = environ.get("PATH_INFO", "").encode("latin1")
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return path.decode(errors="replace")
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class ClosingIterator:
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"""The WSGI specification requires that all middlewares and gateways
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respect the `close` callback of the iterable returned by the application.
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Because it is useful to add another close action to a returned iterable
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and adding a custom iterable is a boring task this class can be used for
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that::
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return ClosingIterator(app(environ, start_response), [cleanup_session,
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cleanup_locals])
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If there is just one close function it can be passed instead of the list.
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A closing iterator is not needed if the application uses response objects
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and finishes the processing if the response is started::
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try:
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return response(environ, start_response)
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finally:
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cleanup_session()
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cleanup_locals()
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"""
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def __init__(
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self,
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iterable: t.Iterable[bytes],
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callbacks: None
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| (t.Callable[[], None] | t.Iterable[t.Callable[[], None]]) = None,
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) -> None:
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iterator = iter(iterable)
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self._next = t.cast(t.Callable[[], bytes], partial(next, iterator))
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if callbacks is None:
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callbacks = []
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elif callable(callbacks):
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callbacks = [callbacks]
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else:
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callbacks = list(callbacks)
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iterable_close = getattr(iterable, "close", None)
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if iterable_close:
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callbacks.insert(0, iterable_close)
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self._callbacks = callbacks
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def __iter__(self) -> ClosingIterator:
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return self
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def __next__(self) -> bytes:
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return self._next()
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def close(self) -> None:
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for callback in self._callbacks:
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callback()
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def wrap_file(
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environ: WSGIEnvironment, file: t.IO[bytes], buffer_size: int = 8192
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) -> t.Iterable[bytes]:
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"""Wraps a file. This uses the WSGI server's file wrapper if available
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or otherwise the generic :class:`FileWrapper`.
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.. versionadded:: 0.5
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If the file wrapper from the WSGI server is used it's important to not
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iterate over it from inside the application but to pass it through
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unchanged. If you want to pass out a file wrapper inside a response
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object you have to set :attr:`Response.direct_passthrough` to `True`.
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More information about file wrappers are available in :pep:`333`.
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:param file: a :class:`file`-like object with a :meth:`~file.read` method.
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:param buffer_size: number of bytes for one iteration.
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"""
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return environ.get("wsgi.file_wrapper", FileWrapper)( # type: ignore
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file, buffer_size
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)
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class FileWrapper:
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"""This class can be used to convert a :class:`file`-like object into
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an iterable. It yields `buffer_size` blocks until the file is fully
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read.
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You should not use this class directly but rather use the
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:func:`wrap_file` function that uses the WSGI server's file wrapper
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support if it's available.
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.. versionadded:: 0.5
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If you're using this object together with a :class:`Response` you have
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to use the `direct_passthrough` mode.
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:param file: a :class:`file`-like object with a :meth:`~file.read` method.
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:param buffer_size: number of bytes for one iteration.
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"""
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def __init__(self, file: t.IO[bytes], buffer_size: int = 8192) -> None:
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self.file = file
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self.buffer_size = buffer_size
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def close(self) -> None:
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if hasattr(self.file, "close"):
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self.file.close()
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def seekable(self) -> bool:
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if hasattr(self.file, "seekable"):
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return self.file.seekable()
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if hasattr(self.file, "seek"):
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return True
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return False
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def seek(self, *args: t.Any) -> None:
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if hasattr(self.file, "seek"):
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self.file.seek(*args)
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def tell(self) -> int | None:
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if hasattr(self.file, "tell"):
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return self.file.tell()
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return None
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def __iter__(self) -> FileWrapper:
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return self
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def __next__(self) -> bytes:
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data = self.file.read(self.buffer_size)
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if data:
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return data
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raise StopIteration()
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class _RangeWrapper:
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# private for now, but should we make it public in the future ?
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"""This class can be used to convert an iterable object into
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an iterable that will only yield a piece of the underlying content.
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It yields blocks until the underlying stream range is fully read.
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The yielded blocks will have a size that can't exceed the original
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iterator defined block size, but that can be smaller.
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If you're using this object together with a :class:`Response` you have
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to use the `direct_passthrough` mode.
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:param iterable: an iterable object with a :meth:`__next__` method.
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:param start_byte: byte from which read will start.
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:param byte_range: how many bytes to read.
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"""
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def __init__(
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self,
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iterable: t.Iterable[bytes] | t.IO[bytes],
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start_byte: int = 0,
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byte_range: int | None = None,
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):
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self.iterable = iter(iterable)
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self.byte_range = byte_range
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self.start_byte = start_byte
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self.end_byte = None
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if byte_range is not None:
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self.end_byte = start_byte + byte_range
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self.read_length = 0
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self.seekable = hasattr(iterable, "seekable") and iterable.seekable()
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self.end_reached = False
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def __iter__(self) -> _RangeWrapper:
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return self
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def _next_chunk(self) -> bytes:
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try:
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chunk = next(self.iterable)
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self.read_length += len(chunk)
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return chunk
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except StopIteration:
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self.end_reached = True
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raise
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def _first_iteration(self) -> tuple[bytes | None, int]:
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chunk = None
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if self.seekable:
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self.iterable.seek(self.start_byte) # type: ignore
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self.read_length = self.iterable.tell() # type: ignore
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contextual_read_length = self.read_length
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else:
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while self.read_length <= self.start_byte:
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chunk = self._next_chunk()
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if chunk is not None:
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chunk = chunk[self.start_byte - self.read_length :]
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contextual_read_length = self.start_byte
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return chunk, contextual_read_length
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def _next(self) -> bytes:
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if self.end_reached:
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raise StopIteration()
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chunk = None
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contextual_read_length = self.read_length
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if self.read_length == 0:
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chunk, contextual_read_length = self._first_iteration()
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if chunk is None:
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chunk = self._next_chunk()
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if self.end_byte is not None and self.read_length >= self.end_byte:
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self.end_reached = True
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return chunk[: self.end_byte - contextual_read_length]
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return chunk
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def __next__(self) -> bytes:
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chunk = self._next()
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if chunk:
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return chunk
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self.end_reached = True
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raise StopIteration()
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def close(self) -> None:
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if hasattr(self.iterable, "close"):
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self.iterable.close()
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class LimitedStream(io.RawIOBase):
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"""Wrap a stream so that it doesn't read more than a given limit. This is used to
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limit ``wsgi.input`` to the ``Content-Length`` header value or
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:attr:`.Request.max_content_length`.
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When attempting to read after the limit has been reached, :meth:`on_exhausted` is
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called. When the limit is a maximum, this raises :exc:`.RequestEntityTooLarge`.
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If reading from the stream returns zero bytes or raises an error,
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:meth:`on_disconnect` is called, which raises :exc:`.ClientDisconnected`. When the
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limit is a maximum and zero bytes were read, no error is raised, since it may be the
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end of the stream.
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If the limit is reached before the underlying stream is exhausted (such as a file
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that is too large, or an infinite stream), the remaining contents of the stream
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cannot be read safely. Depending on how the server handles this, clients may show a
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"connection reset" failure instead of seeing the 413 response.
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:param stream: The stream to read from. Must be a readable binary IO object.
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:param limit: The limit in bytes to not read past. Should be either the
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``Content-Length`` header value or ``request.max_content_length``.
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:param is_max: Whether the given ``limit`` is ``request.max_content_length`` instead
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of the ``Content-Length`` header value. This changes how exhausted and
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disconnect events are handled.
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|
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.. versionchanged:: 2.3
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Handle ``max_content_length`` differently than ``Content-Length``.
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.. versionchanged:: 2.3
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Implements ``io.RawIOBase`` rather than ``io.IOBase``.
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"""
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def __init__(self, stream: t.IO[bytes], limit: int, is_max: bool = False) -> None:
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self._stream = stream
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self._pos = 0
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self.limit = limit
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self._limit_is_max = is_max
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@property
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def is_exhausted(self) -> bool:
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"""Whether the current stream position has reached the limit."""
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return self._pos >= self.limit
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def on_exhausted(self) -> None:
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"""Called when attempting to read after the limit has been reached.
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The default behavior is to do nothing, unless the limit is a maximum, in which
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case it raises :exc:`.RequestEntityTooLarge`.
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.. versionchanged:: 2.3
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Raises ``RequestEntityTooLarge`` if the limit is a maximum.
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.. versionchanged:: 2.3
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Any return value is ignored.
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"""
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if self._limit_is_max:
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raise RequestEntityTooLarge()
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def on_disconnect(self, error: Exception | None = None) -> None:
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"""Called when an attempted read receives zero bytes before the limit was
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reached. This indicates that the client disconnected before sending the full
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request body.
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The default behavior is to raise :exc:`.ClientDisconnected`, unless the limit is
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a maximum and no error was raised.
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.. versionchanged:: 2.3
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Added the ``error`` parameter. Do nothing if the limit is a maximum and no
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error was raised.
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.. versionchanged:: 2.3
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Any return value is ignored.
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"""
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if not self._limit_is_max or error is not None:
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raise ClientDisconnected()
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# If the limit is a maximum, then we may have read zero bytes because the
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# streaming body is complete. There's no way to distinguish that from the
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# client disconnecting early.
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def exhaust(self) -> bytes:
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"""Exhaust the stream by reading until the limit is reached or the client
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disconnects, returning the remaining data.
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.. versionchanged:: 2.3
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Return the remaining data.
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.. versionchanged:: 2.2.3
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Handle case where wrapped stream returns fewer bytes than requested.
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"""
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|
if not self.is_exhausted:
|
|
return self.readall()
|
|
|
|
return b""
|
|
|
|
def readinto(self, b: bytearray) -> int | None: # type: ignore[override]
|
|
size = len(b)
|
|
remaining = self.limit - self._pos
|
|
|
|
if remaining <= 0:
|
|
self.on_exhausted()
|
|
return 0
|
|
|
|
if hasattr(self._stream, "readinto"):
|
|
# Use stream.readinto if it's available.
|
|
if size <= remaining:
|
|
# The size fits in the remaining limit, use the buffer directly.
|
|
try:
|
|
out_size: int | None = self._stream.readinto(b)
|
|
except (OSError, ValueError) as e:
|
|
self.on_disconnect(error=e)
|
|
return 0
|
|
else:
|
|
# Use a temp buffer with the remaining limit as the size.
|
|
temp_b = bytearray(remaining)
|
|
|
|
try:
|
|
out_size = self._stream.readinto(temp_b)
|
|
except (OSError, ValueError) as e:
|
|
self.on_disconnect(error=e)
|
|
return 0
|
|
|
|
if out_size:
|
|
b[:out_size] = temp_b
|
|
else:
|
|
# WSGI requires that stream.read is available.
|
|
try:
|
|
data = self._stream.read(min(size, remaining))
|
|
except (OSError, ValueError) as e:
|
|
self.on_disconnect(error=e)
|
|
return 0
|
|
|
|
out_size = len(data)
|
|
b[:out_size] = data
|
|
|
|
if not out_size:
|
|
# Read zero bytes from the stream.
|
|
self.on_disconnect()
|
|
return 0
|
|
|
|
self._pos += out_size
|
|
return out_size
|
|
|
|
def readall(self) -> bytes:
|
|
if self.is_exhausted:
|
|
self.on_exhausted()
|
|
return b""
|
|
|
|
out = bytearray()
|
|
|
|
# The parent implementation uses "while True", which results in an extra read.
|
|
while not self.is_exhausted:
|
|
data = self.read(1024 * 64)
|
|
|
|
# Stream may return empty before a max limit is reached.
|
|
if not data:
|
|
break
|
|
|
|
out.extend(data)
|
|
|
|
return bytes(out)
|
|
|
|
def tell(self) -> int:
|
|
"""Return the current stream position.
|
|
|
|
.. versionadded:: 0.9
|
|
"""
|
|
return self._pos
|
|
|
|
def readable(self) -> bool:
|
|
return True
|