1014 lines
34 KiB
Python
1014 lines
34 KiB
Python
# -*- coding: utf-8 -*-
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"""
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werkzeug.wsgi
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~~~~~~~~~~~~~
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This module implements WSGI related helpers.
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:copyright: 2007 Pallets
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:license: BSD-3-Clause
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"""
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import io
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import re
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from functools import partial
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from functools import update_wrapper
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from itertools import chain
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from ._compat import BytesIO
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from ._compat import implements_iterator
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from ._compat import make_literal_wrapper
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from ._compat import string_types
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from ._compat import text_type
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from ._compat import to_bytes
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from ._compat import to_unicode
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from ._compat import try_coerce_native
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from ._compat import wsgi_get_bytes
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from ._internal import _encode_idna
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from .urls import uri_to_iri
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from .urls import url_join
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from .urls import url_parse
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from .urls import url_quote
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def responder(f):
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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,
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root_only=False,
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strip_querystring=False,
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host_only=False,
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trusted_hosts=None,
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):
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"""A handy helper function that recreates the full URL as IRI for the
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current request or parts of it. Here's an example:
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>>> from werkzeug.test import create_environ
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>>> env = create_environ("/?param=foo", "http://localhost/script")
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>>> get_current_url(env)
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'http://localhost/script/?param=foo'
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>>> get_current_url(env, root_only=True)
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'http://localhost/script/'
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>>> get_current_url(env, host_only=True)
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'http://localhost/'
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>>> get_current_url(env, strip_querystring=True)
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'http://localhost/script/'
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This optionally it verifies that the host is in a list of trusted hosts.
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If the host is not in there it will raise a
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:exc:`~werkzeug.exceptions.SecurityError`.
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Note that the string returned might contain unicode characters as the
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representation is an IRI not an URI. If you need an ASCII only
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representation you can use the :func:`~werkzeug.urls.iri_to_uri`
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function:
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>>> from werkzeug.urls import iri_to_uri
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>>> iri_to_uri(get_current_url(env))
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'http://localhost/script/?param=foo'
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:param environ: the WSGI environment to get the current URL from.
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:param root_only: set `True` if you only want the root URL.
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:param strip_querystring: set to `True` if you don't want the querystring.
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:param host_only: set to `True` if the host URL should be returned.
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:param trusted_hosts: a list of trusted hosts, see :func:`host_is_trusted`
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for more information.
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"""
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tmp = [environ["wsgi.url_scheme"], "://", get_host(environ, trusted_hosts)]
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cat = tmp.append
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if host_only:
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return uri_to_iri("".join(tmp) + "/")
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cat(url_quote(wsgi_get_bytes(environ.get("SCRIPT_NAME", ""))).rstrip("/"))
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cat("/")
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if not root_only:
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cat(url_quote(wsgi_get_bytes(environ.get("PATH_INFO", "")).lstrip(b"/")))
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if not strip_querystring:
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qs = get_query_string(environ)
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if qs:
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cat("?" + qs)
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return uri_to_iri("".join(tmp))
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def host_is_trusted(hostname, trusted_list):
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"""Checks if a host is trusted against a list. This also takes care
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of port normalization.
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.. versionadded:: 0.9
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:param hostname: the hostname to check
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:param trusted_list: a list of hostnames to check against. If a
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hostname starts with a dot it will match against
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all subdomains as well.
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"""
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if not hostname:
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return False
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if isinstance(trusted_list, string_types):
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trusted_list = [trusted_list]
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def _normalize(hostname):
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if ":" in hostname:
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hostname = hostname.rsplit(":", 1)[0]
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return _encode_idna(hostname)
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try:
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hostname = _normalize(hostname)
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except UnicodeError:
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return False
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for ref in trusted_list:
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if ref.startswith("."):
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ref = ref[1:]
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suffix_match = True
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else:
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suffix_match = False
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try:
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ref = _normalize(ref)
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except UnicodeError:
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return False
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if ref == hostname:
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return True
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if suffix_match and hostname.endswith(b"." + ref):
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return True
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return False
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def get_host(environ, trusted_hosts=None):
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"""Return the host for the given WSGI environment. This first checks
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the ``Host`` header. If it's not present, then ``SERVER_NAME`` and
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``SERVER_PORT`` are used. The host will only contain the port if it
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is different 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: The WSGI environment to get the host from.
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:param trusted_hosts: A list of trusted hosts.
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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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if "HTTP_HOST" in environ:
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rv = environ["HTTP_HOST"]
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if environ["wsgi.url_scheme"] == "http" and rv.endswith(":80"):
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rv = rv[:-3]
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elif environ["wsgi.url_scheme"] == "https" and rv.endswith(":443"):
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rv = rv[:-4]
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else:
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rv = environ["SERVER_NAME"]
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if (environ["wsgi.url_scheme"], environ["SERVER_PORT"]) not in (
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("https", "443"),
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("http", "80"),
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):
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rv += ":" + environ["SERVER_PORT"]
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if trusted_hosts is not None:
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if not host_is_trusted(rv, trusted_hosts):
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from .exceptions import SecurityError
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raise SecurityError('Host "%s" is not trusted' % rv)
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return rv
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def get_content_length(environ):
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"""Returns the content length from the WSGI environment as
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integer. If it's not available or chunked transfer encoding is used,
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``None`` is returned.
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.. versionadded:: 0.9
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:param environ: the WSGI environ to fetch the content length from.
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"""
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if environ.get("HTTP_TRANSFER_ENCODING", "") == "chunked":
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return None
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content_length = environ.get("CONTENT_LENGTH")
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if content_length is not None:
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try:
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return max(0, int(content_length))
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except (ValueError, TypeError):
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pass
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def get_input_stream(environ, safe_fallback=True):
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"""Returns the input stream from the WSGI environment and wraps it
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in the most sensible way possible. The stream returned is not the
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raw WSGI stream in most cases but one that is safe to read from
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without taking into account the content length.
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If content length is not set, the stream will be empty for safety reasons.
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If the WSGI server supports chunked or infinite streams, it should set
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the ``wsgi.input_terminated`` value in the WSGI environ to indicate that.
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.. versionadded:: 0.9
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:param environ: the WSGI environ to fetch the stream from.
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:param safe_fallback: use an empty stream as a safe fallback when the
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content length is not set. Disabling this allows infinite streams,
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which can be a denial-of-service risk.
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"""
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stream = environ["wsgi.input"]
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content_length = get_content_length(environ)
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# A wsgi extension that tells us if the input is terminated. In
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# that case we return the stream unchanged as we know we can safely
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# read it until the end.
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if environ.get("wsgi.input_terminated"):
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return stream
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# If the request doesn't specify a content length, returning the stream is
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# potentially dangerous because it could be infinite, malicious or not. If
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# safe_fallback is true, return an empty stream instead for safety.
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if content_length is None:
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return BytesIO() if safe_fallback else stream
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# Otherwise limit the stream to the content length
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return LimitedStream(stream, content_length)
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def get_query_string(environ):
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"""Returns the `QUERY_STRING` from the WSGI environment. This also takes
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care about the WSGI decoding dance on Python 3 environments as a
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native string. The string returned will be restricted to ASCII
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characters.
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.. versionadded:: 0.9
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:param environ: the WSGI environment object to get the query string from.
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"""
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qs = wsgi_get_bytes(environ.get("QUERY_STRING", ""))
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# QUERY_STRING really should be ascii safe but some browsers
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# will send us some unicode stuff (I am looking at you IE).
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# In that case we want to urllib quote it badly.
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return try_coerce_native(url_quote(qs, safe=":&%=+$!*'(),"))
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def get_path_info(environ, charset="utf-8", errors="replace"):
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"""Returns the `PATH_INFO` from the WSGI environment and properly
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decodes it. This also takes care about the WSGI decoding dance
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on Python 3 environments. if the `charset` is set to `None` a
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bytestring is returned.
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.. versionadded:: 0.9
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:param environ: the WSGI environment object to get the path from.
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:param charset: the charset for the path info, or `None` if no
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decoding should be performed.
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:param errors: the decoding error handling.
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"""
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path = wsgi_get_bytes(environ.get("PATH_INFO", ""))
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return to_unicode(path, charset, errors, allow_none_charset=True)
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def get_script_name(environ, charset="utf-8", errors="replace"):
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"""Returns the `SCRIPT_NAME` from the WSGI environment and properly
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decodes it. This also takes care about the WSGI decoding dance
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on Python 3 environments. if the `charset` is set to `None` a
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bytestring is returned.
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.. versionadded:: 0.9
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:param environ: the WSGI environment object to get the path from.
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:param charset: the charset for the path, or `None` if no
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decoding should be performed.
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:param errors: the decoding error handling.
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"""
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path = wsgi_get_bytes(environ.get("SCRIPT_NAME", ""))
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return to_unicode(path, charset, errors, allow_none_charset=True)
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def pop_path_info(environ, charset="utf-8", errors="replace"):
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"""Removes and returns the next segment of `PATH_INFO`, pushing it onto
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`SCRIPT_NAME`. Returns `None` if there is nothing left on `PATH_INFO`.
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If the `charset` is set to `None` a bytestring is returned.
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If there are empty segments (``'/foo//bar``) these are ignored but
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properly pushed to the `SCRIPT_NAME`:
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>>> env = {'SCRIPT_NAME': '/foo', 'PATH_INFO': '/a/b'}
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>>> pop_path_info(env)
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'a'
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>>> env['SCRIPT_NAME']
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'/foo/a'
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>>> pop_path_info(env)
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'b'
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>>> env['SCRIPT_NAME']
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'/foo/a/b'
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.. versionadded:: 0.5
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.. versionchanged:: 0.9
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The path is now decoded and a charset and encoding
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parameter can be provided.
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:param environ: the WSGI environment that is modified.
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"""
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path = environ.get("PATH_INFO")
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if not path:
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return None
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script_name = environ.get("SCRIPT_NAME", "")
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# shift multiple leading slashes over
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old_path = path
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path = path.lstrip("/")
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if path != old_path:
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script_name += "/" * (len(old_path) - len(path))
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if "/" not in path:
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environ["PATH_INFO"] = ""
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environ["SCRIPT_NAME"] = script_name + path
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rv = wsgi_get_bytes(path)
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else:
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segment, path = path.split("/", 1)
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environ["PATH_INFO"] = "/" + path
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environ["SCRIPT_NAME"] = script_name + segment
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rv = wsgi_get_bytes(segment)
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return to_unicode(rv, charset, errors, allow_none_charset=True)
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def peek_path_info(environ, charset="utf-8", errors="replace"):
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"""Returns the next segment on the `PATH_INFO` or `None` if there
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is none. Works like :func:`pop_path_info` without modifying the
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environment:
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>>> env = {'SCRIPT_NAME': '/foo', 'PATH_INFO': '/a/b'}
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>>> peek_path_info(env)
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'a'
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>>> peek_path_info(env)
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'a'
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If the `charset` is set to `None` a bytestring is returned.
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.. versionadded:: 0.5
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.. versionchanged:: 0.9
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The path is now decoded and a charset and encoding
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parameter can be provided.
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:param environ: the WSGI environment that is checked.
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"""
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segments = environ.get("PATH_INFO", "").lstrip("/").split("/", 1)
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if segments:
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return to_unicode(
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wsgi_get_bytes(segments[0]), charset, errors, allow_none_charset=True
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)
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def extract_path_info(
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environ_or_baseurl,
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path_or_url,
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charset="utf-8",
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errors="werkzeug.url_quote",
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collapse_http_schemes=True,
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):
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"""Extracts the path info from the given URL (or WSGI environment) and
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path. The path info returned is a unicode string, not a bytestring
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suitable for a WSGI environment. The URLs might also be IRIs.
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If the path info could not be determined, `None` is returned.
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Some examples:
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>>> extract_path_info('http://example.com/app', '/app/hello')
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u'/hello'
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>>> extract_path_info('http://example.com/app',
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... 'https://example.com/app/hello')
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u'/hello'
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>>> extract_path_info('http://example.com/app',
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... 'https://example.com/app/hello',
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... collapse_http_schemes=False) is None
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True
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Instead of providing a base URL you can also pass a WSGI environment.
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:param environ_or_baseurl: a WSGI environment dict, a base URL or
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base IRI. This is the root of the
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application.
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:param path_or_url: an absolute path from the server root, a
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relative path (in which case it's the path info)
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or a full URL. Also accepts IRIs and unicode
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parameters.
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:param charset: the charset for byte data in URLs
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:param errors: the error handling on decode
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:param collapse_http_schemes: if set to `False` the algorithm does
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not assume that http and https on the
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same server point to the same
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resource.
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.. versionchanged:: 0.15
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The ``errors`` parameter defaults to leaving invalid bytes
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quoted instead of replacing them.
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.. versionadded:: 0.6
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"""
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def _normalize_netloc(scheme, netloc):
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parts = netloc.split(u"@", 1)[-1].split(u":", 1)
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if len(parts) == 2:
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netloc, port = parts
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if (scheme == u"http" and port == u"80") or (
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scheme == u"https" and port == u"443"
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):
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port = None
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else:
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netloc = parts[0]
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port = None
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if port is not None:
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netloc += u":" + port
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return netloc
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# make sure whatever we are working on is a IRI and parse it
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path = uri_to_iri(path_or_url, charset, errors)
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if isinstance(environ_or_baseurl, dict):
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environ_or_baseurl = get_current_url(environ_or_baseurl, root_only=True)
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base_iri = uri_to_iri(environ_or_baseurl, charset, errors)
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base_scheme, base_netloc, base_path = url_parse(base_iri)[:3]
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cur_scheme, cur_netloc, cur_path, = url_parse(url_join(base_iri, path))[:3]
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# normalize the network location
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base_netloc = _normalize_netloc(base_scheme, base_netloc)
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cur_netloc = _normalize_netloc(cur_scheme, cur_netloc)
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# is that IRI even on a known HTTP scheme?
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if collapse_http_schemes:
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for scheme in base_scheme, cur_scheme:
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if scheme not in (u"http", u"https"):
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return None
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else:
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if not (base_scheme in (u"http", u"https") and base_scheme == cur_scheme):
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return None
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# are the netlocs compatible?
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if base_netloc != cur_netloc:
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return None
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# are we below the application path?
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base_path = base_path.rstrip(u"/")
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if not cur_path.startswith(base_path):
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return None
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return u"/" + cur_path[len(base_path) :].lstrip(u"/")
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|
|
|
|
@implements_iterator
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class ClosingIterator(object):
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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__(self, iterable, callbacks=None):
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iterator = iter(iterable)
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self._next = 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):
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return self
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def __next__(self):
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return self._next()
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def close(self):
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for callback in self._callbacks:
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callback()
|
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|
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def wrap_file(environ, file, buffer_size=8192):
|
|
"""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:`~BaseResponse.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)(file, buffer_size)
|
|
|
|
|
|
@implements_iterator
|
|
class FileWrapper(object):
|
|
"""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:`BaseResponse` 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, buffer_size=8192):
|
|
self.file = file
|
|
self.buffer_size = buffer_size
|
|
|
|
def close(self):
|
|
if hasattr(self.file, "close"):
|
|
self.file.close()
|
|
|
|
def seekable(self):
|
|
if hasattr(self.file, "seekable"):
|
|
return self.file.seekable()
|
|
if hasattr(self.file, "seek"):
|
|
return True
|
|
return False
|
|
|
|
def seek(self, *args):
|
|
if hasattr(self.file, "seek"):
|
|
self.file.seek(*args)
|
|
|
|
def tell(self):
|
|
if hasattr(self.file, "tell"):
|
|
return self.file.tell()
|
|
return None
|
|
|
|
def __iter__(self):
|
|
return self
|
|
|
|
def __next__(self):
|
|
data = self.file.read(self.buffer_size)
|
|
if data:
|
|
return data
|
|
raise StopIteration()
|
|
|
|
|
|
@implements_iterator
|
|
class _RangeWrapper(object):
|
|
# 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:`BaseResponse` 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, start_byte=0, byte_range=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 = self.start_byte + self.byte_range
|
|
self.read_length = 0
|
|
self.seekable = hasattr(iterable, "seekable") and iterable.seekable()
|
|
self.end_reached = False
|
|
|
|
def __iter__(self):
|
|
return self
|
|
|
|
def _next_chunk(self):
|
|
try:
|
|
chunk = next(self.iterable)
|
|
self.read_length += len(chunk)
|
|
return chunk
|
|
except StopIteration:
|
|
self.end_reached = True
|
|
raise
|
|
|
|
def _first_iteration(self):
|
|
chunk = None
|
|
if self.seekable:
|
|
self.iterable.seek(self.start_byte)
|
|
self.read_length = self.iterable.tell()
|
|
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):
|
|
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):
|
|
chunk = self._next()
|
|
if chunk:
|
|
return chunk
|
|
self.end_reached = True
|
|
raise StopIteration()
|
|
|
|
def close(self):
|
|
if hasattr(self.iterable, "close"):
|
|
self.iterable.close()
|
|
|
|
|
|
def _make_chunk_iter(stream, limit, buffer_size):
|
|
"""Helper for the line and chunk iter functions."""
|
|
if isinstance(stream, (bytes, bytearray, text_type)):
|
|
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
|
|
if not isinstance(stream, LimitedStream) and limit is not None:
|
|
stream = LimitedStream(stream, limit)
|
|
_read = stream.read
|
|
while 1:
|
|
item = _read(buffer_size)
|
|
if not item:
|
|
break
|
|
yield item
|
|
|
|
|
|
def make_line_iter(stream, limit=None, buffer_size=10 * 1024, cap_at_buffer=False):
|
|
"""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_literal_wrapper(first_item)
|
|
empty = s("")
|
|
cr = s("\r")
|
|
lf = s("\n")
|
|
crlf = s("\r\n")
|
|
|
|
_iter = chain((first_item,), _iter)
|
|
|
|
def _iter_basic_lines():
|
|
_join = empty.join
|
|
buffer = []
|
|
while 1:
|
|
new_data = next(_iter, "")
|
|
if not new_data:
|
|
break
|
|
new_buf = []
|
|
buf_size = 0
|
|
for item in 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, separator, limit=None, buffer_size=10 * 1024, cap_at_buffer=False
|
|
):
|
|
"""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, "")
|
|
if not first_item:
|
|
return
|
|
|
|
_iter = chain((first_item,), _iter)
|
|
if isinstance(first_item, text_type):
|
|
separator = to_unicode(separator)
|
|
_split = re.compile(r"(%s)" % re.escape(separator)).split
|
|
_join = u"".join
|
|
else:
|
|
separator = to_bytes(separator)
|
|
_split = re.compile(b"(" + re.escape(separator) + b")").split
|
|
_join = b"".join
|
|
|
|
buffer = []
|
|
while 1:
|
|
new_data = next(_iter, "")
|
|
if not new_data:
|
|
break
|
|
chunks = _split(new_data)
|
|
new_buf = []
|
|
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)
|
|
|
|
|
|
@implements_iterator
|
|
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, limit):
|
|
self._read = stream.read
|
|
self._readline = stream.readline
|
|
self._pos = 0
|
|
self.limit = limit
|
|
|
|
def __iter__(self):
|
|
return self
|
|
|
|
@property
|
|
def is_exhausted(self):
|
|
"""If the stream is exhausted this attribute is `True`."""
|
|
return self._pos >= self.limit
|
|
|
|
def on_exhausted(self):
|
|
"""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):
|
|
"""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=1024 * 64):
|
|
"""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=None):
|
|
"""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 (IOError, 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=None):
|
|
"""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, IOError):
|
|
return self.on_disconnect()
|
|
if size and not line:
|
|
return self.on_disconnect()
|
|
self._pos += len(line)
|
|
return line
|
|
|
|
def readlines(self, size=None):
|
|
"""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 underlaying 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 1:
|
|
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):
|
|
"""Returns the position of the stream.
|
|
|
|
.. versionadded:: 0.9
|
|
"""
|
|
return self._pos
|
|
|
|
def __next__(self):
|
|
line = self.readline()
|
|
if not line:
|
|
raise StopIteration()
|
|
return line
|
|
|
|
def readable(self):
|
|
return True
|
|
|
|
|
|
from werkzeug import _DeprecatedImportModule
|
|
|
|
_DeprecatedImportModule(
|
|
__name__,
|
|
{
|
|
".middleware.dispatcher": ["DispatcherMiddleware"],
|
|
".middleware.http_proxy": ["ProxyMiddleware"],
|
|
".middleware.shared_data": ["SharedDataMiddleware"],
|
|
},
|
|
"Werkzeug 1.0",
|
|
)
|