Mini Shell
import io
import re
import typing as t
from functools import partial
from functools import update_wrapper
from itertools import chain
from ._internal import _make_encode_wrapper
from ._internal import _to_bytes
from ._internal import _to_str
from .sansio import utils as _sansio_utils
from .sansio.utils import host_is_trusted # noqa: F401 # Imported as part of API
from .urls import _URLTuple
from .urls import uri_to_iri
from .urls import url_join
from .urls import url_parse
from .urls import url_quote
if t.TYPE_CHECKING:
from _typeshed.wsgi import WSGIApplication
from _typeshed.wsgi import WSGIEnvironment
def responder(f: t.Callable[..., "WSGIApplication"]) -> "WSGIApplication":
"""Marks a function as responder. Decorate a function with it and it
will automatically call the return value as WSGI application.
Example::
@responder
def application(environ, start_response):
return Response('Hello World!')
"""
return update_wrapper(lambda *a: f(*a)(*a[-2:]), f)
def get_current_url(
environ: "WSGIEnvironment",
root_only: bool = False,
strip_querystring: bool = False,
host_only: bool = False,
trusted_hosts: t.Optional[t.Iterable[str]] = None,
) -> str:
"""Recreate the URL for a request from the parts in a WSGI
environment.
The URL is an IRI, not a URI, so it may contain Unicode characters.
Use :func:`~werkzeug.urls.iri_to_uri` to convert it to ASCII.
:param environ: The WSGI environment to get the URL parts from.
:param root_only: Only build the root path, don't include the
remaining path or query string.
:param strip_querystring: Don't include the query string.
:param host_only: Only build the scheme and host.
:param trusted_hosts: A list of trusted host names to validate the
host against.
"""
parts = {
"scheme": environ["wsgi.url_scheme"],
"host": get_host(environ, trusted_hosts),
}
if not host_only:
parts["root_path"] = environ.get("SCRIPT_NAME", "")
if not root_only:
parts["path"] = environ.get("PATH_INFO", "")
if not strip_querystring:
parts["query_string"] = environ.get("QUERY_STRING", "").encode("latin1")
return _sansio_utils.get_current_url(**parts)
def _get_server(
environ: "WSGIEnvironment",
) -> t.Optional[t.Tuple[str, t.Optional[int]]]:
name = environ.get("SERVER_NAME")
if name is None:
return None
try:
port: t.Optional[int] = int(environ.get("SERVER_PORT", None))
except (TypeError, ValueError):
# unix socket
port = None
return name, port
def get_host(
environ: "WSGIEnvironment", trusted_hosts: t.Optional[t.Iterable[str]] = None
) -> str:
"""Return the host for the given WSGI environment.
The ``Host`` header is preferred, then ``SERVER_NAME`` if it's not
set. The returned host will only contain the port if it is different
than the standard port for the protocol.
Optionally, verify that the host is trusted using
:func:`host_is_trusted` and raise a
:exc:`~werkzeug.exceptions.SecurityError` if it is not.
:param environ: A WSGI environment dict.
:param trusted_hosts: A list of trusted host names.
:return: Host, with port if necessary.
:raise ~werkzeug.exceptions.SecurityError: If the host is not
trusted.
"""
return _sansio_utils.get_host(
environ["wsgi.url_scheme"],
environ.get("HTTP_HOST"),
_get_server(environ),
trusted_hosts,
)
def get_content_length(environ: "WSGIEnvironment") -> t.Optional[int]:
"""Returns the content length from the WSGI environment as
integer. If it's not available or chunked transfer encoding is used,
``None`` is returned.
.. versionadded:: 0.9
:param environ: the WSGI environ to fetch the content length from.
"""
if environ.get("HTTP_TRANSFER_ENCODING", "") == "chunked":
return None
content_length = environ.get("CONTENT_LENGTH")
if content_length is not None:
try:
return max(0, int(content_length))
except (ValueError, TypeError):
pass
return None
def get_input_stream(
environ: "WSGIEnvironment", safe_fallback: bool = True
) -> t.IO[bytes]:
"""Returns the input stream from the WSGI environment and wraps it
in the most sensible way possible. The stream returned is not the
raw WSGI stream in most cases but one that is safe to read from
without taking into account the content length.
If content length is not set, the stream will be empty for safety reasons.
If the WSGI server supports chunked or infinite streams, it should set
the ``wsgi.input_terminated`` value in the WSGI environ to indicate that.
.. versionadded:: 0.9
:param environ: the WSGI environ to fetch the stream from.
:param safe_fallback: use an empty stream as a safe fallback when the
content length is not set. Disabling this allows infinite streams,
which can be a denial-of-service risk.
"""
stream = t.cast(t.IO[bytes], environ["wsgi.input"])
content_length = get_content_length(environ)
# A wsgi extension that tells us if the input is terminated. In
# that case we return the stream unchanged as we know we can safely
# read it until the end.
if environ.get("wsgi.input_terminated"):
return stream
# If the request doesn't specify a content length, returning the stream is
# potentially dangerous because it could be infinite, malicious or not. If
# safe_fallback is true, return an empty stream instead for safety.
if content_length is None:
return io.BytesIO() if safe_fallback else stream
# Otherwise limit the stream to the content length
return t.cast(t.IO[bytes], LimitedStream(stream, content_length))
def get_query_string(environ: "WSGIEnvironment") -> str:
"""Returns the ``QUERY_STRING`` from the WSGI environment. This also
takes care of the WSGI decoding dance. The string returned will be
restricted to ASCII characters.
:param environ: WSGI environment to get the query string from.
.. versionadded:: 0.9
"""
qs = environ.get("QUERY_STRING", "").encode("latin1")
# QUERY_STRING really should be ascii safe but some browsers
# will send us some unicode stuff (I am looking at you IE).
# In that case we want to urllib quote it badly.
return url_quote(qs, safe=":&%=+$!*'(),")
def get_path_info(
environ: "WSGIEnvironment", charset: str = "utf-8", errors: str = "replace"
) -> str:
"""Return the ``PATH_INFO`` from the WSGI environment and decode it
unless ``charset`` is ``None``.
:param environ: WSGI environment to get the path from.
:param charset: The charset for the path info, or ``None`` if no
decoding should be performed.
:param errors: The decoding error handling.
.. versionadded:: 0.9
"""
path = environ.get("PATH_INFO", "").encode("latin1")
return _to_str(path, charset, errors, allow_none_charset=True) # type: ignore
def get_script_name(
environ: "WSGIEnvironment", charset: str = "utf-8", errors: str = "replace"
) -> str:
"""Return the ``SCRIPT_NAME`` from the WSGI environment and decode
it unless `charset` is set to ``None``.
:param environ: WSGI environment to get the path from.
:param charset: The charset for the path, or ``None`` if no decoding
should be performed.
:param errors: The decoding error handling.
.. versionadded:: 0.9
"""
path = environ.get("SCRIPT_NAME", "").encode("latin1")
return _to_str(path, charset, errors, allow_none_charset=True) # type: ignore
def pop_path_info(
environ: "WSGIEnvironment", charset: str = "utf-8", errors: str = "replace"
) -> t.Optional[str]:
"""Removes and returns the next segment of `PATH_INFO`, pushing it onto
`SCRIPT_NAME`. Returns `None` if there is nothing left on `PATH_INFO`.
If the `charset` is set to `None` bytes are returned.
If there are empty segments (``'/foo//bar``) these are ignored but
properly pushed to the `SCRIPT_NAME`:
>>> env = {'SCRIPT_NAME': '/foo', 'PATH_INFO': '/a/b'}
>>> pop_path_info(env)
'a'
>>> env['SCRIPT_NAME']
'/foo/a'
>>> pop_path_info(env)
'b'
>>> env['SCRIPT_NAME']
'/foo/a/b'
.. versionadded:: 0.5
.. versionchanged:: 0.9
The path is now decoded and a charset and encoding
parameter can be provided.
:param environ: the WSGI environment that is modified.
:param charset: The ``encoding`` parameter passed to
:func:`bytes.decode`.
:param errors: The ``errors`` paramater passed to
:func:`bytes.decode`.
"""
path = environ.get("PATH_INFO")
if not path:
return None
script_name = environ.get("SCRIPT_NAME", "")
# shift multiple leading slashes over
old_path = path
path = path.lstrip("/")
if path != old_path:
script_name += "/" * (len(old_path) - len(path))
if "/" not in path:
environ["PATH_INFO"] = ""
environ["SCRIPT_NAME"] = script_name + path
rv = path.encode("latin1")
else:
segment, path = path.split("/", 1)
environ["PATH_INFO"] = f"/{path}"
environ["SCRIPT_NAME"] = script_name + segment
rv = segment.encode("latin1")
return _to_str(rv, charset, errors, allow_none_charset=True) # type: ignore
def peek_path_info(
environ: "WSGIEnvironment", charset: str = "utf-8", errors: str = "replace"
) -> t.Optional[str]:
"""Returns the next segment on the `PATH_INFO` or `None` if there
is none. Works like :func:`pop_path_info` without modifying the
environment:
>>> env = {'SCRIPT_NAME': '/foo', 'PATH_INFO': '/a/b'}
>>> peek_path_info(env)
'a'
>>> peek_path_info(env)
'a'
If the `charset` is set to `None` bytes are returned.
.. versionadded:: 0.5
.. versionchanged:: 0.9
The path is now decoded and a charset and encoding
parameter can be provided.
:param environ: the WSGI environment that is checked.
"""
segments = environ.get("PATH_INFO", "").lstrip("/").split("/", 1)
if segments:
return _to_str( # type: ignore
segments[0].encode("latin1"), charset, errors, allow_none_charset=True
)
return None
def extract_path_info(
environ_or_baseurl: t.Union[str, "WSGIEnvironment"],
path_or_url: t.Union[str, _URLTuple],
charset: str = "utf-8",
errors: str = "werkzeug.url_quote",
collapse_http_schemes: bool = True,
) -> t.Optional[str]:
"""Extracts the path info from the given URL (or WSGI environment) and
path. The path info returned is a string. The URLs might also be IRIs.
If the path info could not be determined, `None` is returned.
Some examples:
>>> extract_path_info('http://example.com/app', '/app/hello')
'/hello'
>>> extract_path_info('http://example.com/app',
... 'https://example.com/app/hello')
'/hello'
>>> extract_path_info('http://example.com/app',
... 'https://example.com/app/hello',
... collapse_http_schemes=False) is None
True
Instead of providing a base URL you can also pass a WSGI environment.
:param environ_or_baseurl: a WSGI environment dict, a base URL or
base IRI. This is the root of the
application.
:param path_or_url: an absolute path from the server root, a
relative path (in which case it's the path info)
or a full URL.
:param charset: the charset for byte data in URLs
:param errors: the error handling on decode
:param collapse_http_schemes: if set to `False` the algorithm does
not assume that http and https on the
same server point to the same
resource.
.. versionchanged:: 0.15
The ``errors`` parameter defaults to leaving invalid bytes
quoted instead of replacing them.
.. versionadded:: 0.6
"""
def _normalize_netloc(scheme: str, netloc: str) -> str:
parts = netloc.split("@", 1)[-1].split(":", 1)
port: t.Optional[str]
if len(parts) == 2:
netloc, port = parts
if (scheme == "http" and port == "80") or (
scheme == "https" and port == "443"
):
port = None
else:
netloc = parts[0]
port = None
if port is not None:
netloc += f":{port}"
return netloc
# make sure whatever we are working on is a IRI and parse it
path = uri_to_iri(path_or_url, charset, errors)
if isinstance(environ_or_baseurl, dict):
environ_or_baseurl = get_current_url(environ_or_baseurl, root_only=True)
base_iri = uri_to_iri(environ_or_baseurl, charset, errors)
base_scheme, base_netloc, base_path = url_parse(base_iri)[:3]
cur_scheme, cur_netloc, cur_path = url_parse(url_join(base_iri, path))[:3]
# normalize the network location
base_netloc = _normalize_netloc(base_scheme, base_netloc)
cur_netloc = _normalize_netloc(cur_scheme, cur_netloc)
# is that IRI even on a known HTTP scheme?
if collapse_http_schemes:
for scheme in base_scheme, cur_scheme:
if scheme not in ("http", "https"):
return None
else:
if not (base_scheme in ("http", "https") and base_scheme == cur_scheme):
return None
# are the netlocs compatible?
if base_netloc != cur_netloc:
return None
# are we below the application path?
base_path = base_path.rstrip("/")
if not cur_path.startswith(base_path):
return None
return f"/{cur_path[len(base_path) :].lstrip('/')}"
class ClosingIterator:
"""The WSGI specification requires that all middlewares and gateways
respect the `close` callback of the iterable returned by the application.
Because it is useful to add another close action to a returned iterable
and adding a custom iterable is a boring task this class can be used for
that::
return ClosingIterator(app(environ, start_response), [cleanup_session,
cleanup_locals])
If there is just one close function it can be passed instead of the list.
A closing iterator is not needed if the application uses response objects
and finishes the processing if the response is started::
try:
return response(environ, start_response)
finally:
cleanup_session()
cleanup_locals()
"""
def __init__(
self,
iterable: t.Iterable[bytes],
callbacks: t.Optional[
t.Union[t.Callable[[], None], t.Iterable[t.Callable[[], None]]]
] = None,
) -> None:
iterator = iter(iterable)
self._next = t.cast(t.Callable[[], bytes], partial(next, iterator))
if callbacks is None:
callbacks = []
elif callable(callbacks):
callbacks = [callbacks]
else:
callbacks = list(callbacks)
iterable_close = getattr(iterable, "close", None)
if iterable_close:
callbacks.insert(0, iterable_close)
self._callbacks = callbacks
def __iter__(self) -> "ClosingIterator":
return self
def __next__(self) -> bytes:
return self._next()
def close(self) -> None:
for callback in self._callbacks:
callback()
def wrap_file(
environ: "WSGIEnvironment", file: t.IO[bytes], buffer_size: int = 8192
) -> t.Iterable[bytes]:
"""Wraps a file. This uses the WSGI server's file wrapper if available
or otherwise the generic :class:`FileWrapper`.
.. versionadded:: 0.5
If the file wrapper from the WSGI server is used it's important to not
iterate over it from inside the application but to pass it through
unchanged. If you want to pass out a file wrapper inside a response
object you have to set :attr:`Response.direct_passthrough` to `True`.
More information about file wrappers are available in :pep:`333`.
:param file: a :class:`file`-like object with a :meth:`~file.read` method.
:param buffer_size: number of bytes for one iteration.
"""
return environ.get("wsgi.file_wrapper", FileWrapper)( # type: ignore
file, buffer_size
)
class FileWrapper:
"""This class can be used to convert a :class:`file`-like object into
an iterable. It yields `buffer_size` blocks until the file is fully
read.
You should not use this class directly but rather use the
:func:`wrap_file` function that uses the WSGI server's file wrapper
support if it's available.
.. versionadded:: 0.5
If you're using this object together with a :class:`Response` you have
to use the `direct_passthrough` mode.
:param file: a :class:`file`-like object with a :meth:`~file.read` method.
:param buffer_size: number of bytes for one iteration.
"""
def __init__(self, file: t.IO[bytes], buffer_size: int = 8192) -> None:
self.file = file
self.buffer_size = buffer_size
def close(self) -> None:
if hasattr(self.file, "close"):
self.file.close()
def seekable(self) -> bool:
if hasattr(self.file, "seekable"):
return self.file.seekable()
if hasattr(self.file, "seek"):
return True
return False
def seek(self, *args: t.Any) -> None:
if hasattr(self.file, "seek"):
self.file.seek(*args)
def tell(self) -> t.Optional[int]:
if hasattr(self.file, "tell"):
return self.file.tell()
return None
def __iter__(self) -> "FileWrapper":
return self
def __next__(self) -> bytes:
data = self.file.read(self.buffer_size)
if data:
return data
raise StopIteration()
class _RangeWrapper:
# private for now, but should we make it public in the future ?
"""This class can be used to convert an iterable object into
an iterable that will only yield a piece of the underlying content.
It yields blocks until the underlying stream range is fully read.
The yielded blocks will have a size that can't exceed the original
iterator defined block size, but that can be smaller.
If you're using this object together with a :class:`Response` you have
to use the `direct_passthrough` mode.
:param iterable: an iterable object with a :meth:`__next__` method.
:param start_byte: byte from which read will start.
:param byte_range: how many bytes to read.
"""
def __init__(
self,
iterable: t.Union[t.Iterable[bytes], t.IO[bytes]],
start_byte: int = 0,
byte_range: t.Optional[int] = None,
):
self.iterable = iter(iterable)
self.byte_range = byte_range
self.start_byte = start_byte
self.end_byte = None
if byte_range is not None:
self.end_byte = start_byte + byte_range
self.read_length = 0
self.seekable = (
hasattr(iterable, "seekable") and iterable.seekable() # type: ignore
)
self.end_reached = False
def __iter__(self) -> "_RangeWrapper":
return self
def _next_chunk(self) -> bytes:
try:
chunk = next(self.iterable)
self.read_length += len(chunk)
return chunk
except StopIteration:
self.end_reached = True
raise
def _first_iteration(self) -> t.Tuple[t.Optional[bytes], int]:
chunk = None
if self.seekable:
self.iterable.seek(self.start_byte) # type: ignore
self.read_length = self.iterable.tell() # type: ignore
contextual_read_length = self.read_length
else:
while self.read_length <= self.start_byte:
chunk = self._next_chunk()
if chunk is not None:
chunk = chunk[self.start_byte - self.read_length :]
contextual_read_length = self.start_byte
return chunk, contextual_read_length
def _next(self) -> bytes:
if self.end_reached:
raise StopIteration()
chunk = None
contextual_read_length = self.read_length
if self.read_length == 0:
chunk, contextual_read_length = self._first_iteration()
if chunk is None:
chunk = self._next_chunk()
if self.end_byte is not None and self.read_length >= self.end_byte:
self.end_reached = True
return chunk[: self.end_byte - contextual_read_length]
return chunk
def __next__(self) -> bytes:
chunk = self._next()
if chunk:
return chunk
self.end_reached = True
raise StopIteration()
def close(self) -> None:
if hasattr(self.iterable, "close"):
self.iterable.close() # type: ignore
def _make_chunk_iter(
stream: t.Union[t.Iterable[bytes], t.IO[bytes]],
limit: t.Optional[int],
buffer_size: int,
) -> t.Iterator[bytes]:
"""Helper for the line and chunk iter functions."""
if isinstance(stream, (bytes, bytearray, str)):
raise TypeError(
"Passed a string or byte object instead of true iterator or stream."
)
if not hasattr(stream, "read"):
for item in stream:
if item:
yield item
return
stream = t.cast(t.IO[bytes], stream)
if not isinstance(stream, LimitedStream) and limit is not None:
stream = t.cast(t.IO[bytes], LimitedStream(stream, limit))
_read = stream.read
while True:
item = _read(buffer_size)
if not item:
break
yield item
def make_line_iter(
stream: t.Union[t.Iterable[bytes], t.IO[bytes]],
limit: t.Optional[int] = None,
buffer_size: int = 10 * 1024,
cap_at_buffer: bool = False,
) -> t.Iterator[bytes]:
"""Safely iterates line-based over an input stream. If the input stream
is not a :class:`LimitedStream` the `limit` parameter is mandatory.
This uses the stream's :meth:`~file.read` method internally as opposite
to the :meth:`~file.readline` method that is unsafe and can only be used
in violation of the WSGI specification. The same problem applies to the
`__iter__` function of the input stream which calls :meth:`~file.readline`
without arguments.
If you need line-by-line processing it's strongly recommended to iterate
over the input stream using this helper function.
.. versionchanged:: 0.8
This function now ensures that the limit was reached.
.. versionadded:: 0.9
added support for iterators as input stream.
.. versionadded:: 0.11.10
added support for the `cap_at_buffer` parameter.
:param stream: the stream or iterate to iterate over.
:param limit: the limit in bytes for the stream. (Usually
content length. Not necessary if the `stream`
is a :class:`LimitedStream`.
:param buffer_size: The optional buffer size.
:param cap_at_buffer: if this is set chunks are split if they are longer
than the buffer size. Internally this is implemented
that the buffer size might be exhausted by a factor
of two however.
"""
_iter = _make_chunk_iter(stream, limit, buffer_size)
first_item = next(_iter, "")
if not first_item:
return
s = _make_encode_wrapper(first_item)
empty = t.cast(bytes, s(""))
cr = t.cast(bytes, s("\r"))
lf = t.cast(bytes, s("\n"))
crlf = t.cast(bytes, s("\r\n"))
_iter = t.cast(t.Iterator[bytes], chain((first_item,), _iter))
def _iter_basic_lines() -> t.Iterator[bytes]:
_join = empty.join
buffer: t.List[bytes] = []
while True:
new_data = next(_iter, "")
if not new_data:
break
new_buf: t.List[bytes] = []
buf_size = 0
for item in t.cast(
t.Iterator[bytes], chain(buffer, new_data.splitlines(True))
):
new_buf.append(item)
buf_size += len(item)
if item and item[-1:] in crlf:
yield _join(new_buf)
new_buf = []
elif cap_at_buffer and buf_size >= buffer_size:
rv = _join(new_buf)
while len(rv) >= buffer_size:
yield rv[:buffer_size]
rv = rv[buffer_size:]
new_buf = [rv]
buffer = new_buf
if buffer:
yield _join(buffer)
# This hackery is necessary to merge 'foo\r' and '\n' into one item
# of 'foo\r\n' if we were unlucky and we hit a chunk boundary.
previous = empty
for item in _iter_basic_lines():
if item == lf and previous[-1:] == cr:
previous += item
item = empty
if previous:
yield previous
previous = item
if previous:
yield previous
def make_chunk_iter(
stream: t.Union[t.Iterable[bytes], t.IO[bytes]],
separator: bytes,
limit: t.Optional[int] = None,
buffer_size: int = 10 * 1024,
cap_at_buffer: bool = False,
) -> t.Iterator[bytes]:
"""Works like :func:`make_line_iter` but accepts a separator
which divides chunks. If you want newline based processing
you should use :func:`make_line_iter` instead as it
supports arbitrary newline markers.
.. versionadded:: 0.8
.. versionadded:: 0.9
added support for iterators as input stream.
.. versionadded:: 0.11.10
added support for the `cap_at_buffer` parameter.
:param stream: the stream or iterate to iterate over.
:param separator: the separator that divides chunks.
:param limit: the limit in bytes for the stream. (Usually
content length. Not necessary if the `stream`
is otherwise already limited).
:param buffer_size: The optional buffer size.
:param cap_at_buffer: if this is set chunks are split if they are longer
than the buffer size. Internally this is implemented
that the buffer size might be exhausted by a factor
of two however.
"""
_iter = _make_chunk_iter(stream, limit, buffer_size)
first_item = next(_iter, b"")
if not first_item:
return
_iter = t.cast(t.Iterator[bytes], chain((first_item,), _iter))
if isinstance(first_item, str):
separator = _to_str(separator)
_split = re.compile(f"({re.escape(separator)})").split
_join = "".join
else:
separator = _to_bytes(separator)
_split = re.compile(b"(" + re.escape(separator) + b")").split
_join = b"".join
buffer: t.List[bytes] = []
while True:
new_data = next(_iter, b"")
if not new_data:
break
chunks = _split(new_data)
new_buf: t.List[bytes] = []
buf_size = 0
for item in chain(buffer, chunks):
if item == separator:
yield _join(new_buf)
new_buf = []
buf_size = 0
else:
buf_size += len(item)
new_buf.append(item)
if cap_at_buffer and buf_size >= buffer_size:
rv = _join(new_buf)
while len(rv) >= buffer_size:
yield rv[:buffer_size]
rv = rv[buffer_size:]
new_buf = [rv]
buf_size = len(rv)
buffer = new_buf
if buffer:
yield _join(buffer)
class LimitedStream(io.IOBase):
"""Wraps a stream so that it doesn't read more than n bytes. If the
stream is exhausted and the caller tries to get more bytes from it
:func:`on_exhausted` is called which by default returns an empty
string. The return value of that function is forwarded
to the reader function. So if it returns an empty string
:meth:`read` will return an empty string as well.
The limit however must never be higher than what the stream can
output. Otherwise :meth:`readlines` will try to read past the
limit.
.. admonition:: Note on WSGI compliance
calls to :meth:`readline` and :meth:`readlines` are not
WSGI compliant because it passes a size argument to the
readline methods. Unfortunately the WSGI PEP is not safely
implementable without a size argument to :meth:`readline`
because there is no EOF marker in the stream. As a result
of that the use of :meth:`readline` is discouraged.
For the same reason iterating over the :class:`LimitedStream`
is not portable. It internally calls :meth:`readline`.
We strongly suggest using :meth:`read` only or using the
:func:`make_line_iter` which safely iterates line-based
over a WSGI input stream.
:param stream: the stream to wrap.
:param limit: the limit for the stream, must not be longer than
what the string can provide if the stream does not
end with `EOF` (like `wsgi.input`)
"""
def __init__(self, stream: t.IO[bytes], limit: int) -> None:
self._read = stream.read
self._readline = stream.readline
self._pos = 0
self.limit = limit
def __iter__(self) -> "LimitedStream":
return self
@property
def is_exhausted(self) -> bool:
"""If the stream is exhausted this attribute is `True`."""
return self._pos >= self.limit
def on_exhausted(self) -> bytes:
"""This is called when the stream tries to read past the limit.
The return value of this function is returned from the reading
function.
"""
# Read null bytes from the stream so that we get the
# correct end of stream marker.
return self._read(0)
def on_disconnect(self) -> bytes:
"""What should happen if a disconnect is detected? The return
value of this function is returned from read functions in case
the client went away. By default a
:exc:`~werkzeug.exceptions.ClientDisconnected` exception is raised.
"""
from .exceptions import ClientDisconnected
raise ClientDisconnected()
def exhaust(self, chunk_size: int = 1024 * 64) -> None:
"""Exhaust the stream. This consumes all the data left until the
limit is reached.
:param chunk_size: the size for a chunk. It will read the chunk
until the stream is exhausted and throw away
the results.
"""
to_read = self.limit - self._pos
chunk = chunk_size
while to_read > 0:
chunk = min(to_read, chunk)
self.read(chunk)
to_read -= chunk
def read(self, size: t.Optional[int] = None) -> bytes:
"""Read `size` bytes or if size is not provided everything is read.
:param size: the number of bytes read.
"""
if self._pos >= self.limit:
return self.on_exhausted()
if size is None or size == -1: # -1 is for consistence with file
size = self.limit
to_read = min(self.limit - self._pos, size)
try:
read = self._read(to_read)
except (OSError, ValueError):
return self.on_disconnect()
if to_read and len(read) != to_read:
return self.on_disconnect()
self._pos += len(read)
return read
def readline(self, size: t.Optional[int] = None) -> bytes:
"""Reads one line from the stream."""
if self._pos >= self.limit:
return self.on_exhausted()
if size is None:
size = self.limit - self._pos
else:
size = min(size, self.limit - self._pos)
try:
line = self._readline(size)
except (ValueError, OSError):
return self.on_disconnect()
if size and not line:
return self.on_disconnect()
self._pos += len(line)
return line
def readlines(self, size: t.Optional[int] = None) -> t.List[bytes]:
"""Reads a file into a list of strings. It calls :meth:`readline`
until the file is read to the end. It does support the optional
`size` argument if the underlying stream supports it for
`readline`.
"""
last_pos = self._pos
result = []
if size is not None:
end = min(self.limit, last_pos + size)
else:
end = self.limit
while True:
if size is not None:
size -= last_pos - self._pos
if self._pos >= end:
break
result.append(self.readline(size))
if size is not None:
last_pos = self._pos
return result
def tell(self) -> int:
"""Returns the position of the stream.
.. versionadded:: 0.9
"""
return self._pos
def __next__(self) -> bytes:
line = self.readline()
if not line:
raise StopIteration()
return line
def readable(self) -> bool:
return True
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