1039 lines
36 KiB
Python
1039 lines
36 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: (c) 2013 by the Werkzeug Team, see AUTHORS for more details.
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:license: BSD, see LICENSE for more details.
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"""
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import re
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import os
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import sys
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import posixpath
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import mimetypes
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from itertools import chain
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from zlib import adler32
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from time import time, mktime
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from datetime import datetime
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from functools import partial, update_wrapper
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from werkzeug._compat import iteritems, text_type, string_types, \
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implements_iterator, make_literal_wrapper, to_unicode, to_bytes, \
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wsgi_get_bytes, try_coerce_native, PY2
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from werkzeug._internal import _empty_stream, _encode_idna
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from werkzeug.http import is_resource_modified, http_date
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from werkzeug.urls import uri_to_iri, url_quote, url_parse, url_join
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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(environ, root_only=False, strip_querystring=False,
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host_only=False, trusted_hosts=None):
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"""A handy helper function that recreates the full URL for the current
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request or parts of it. Here 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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: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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hostname = _normalize(hostname)
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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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ref = _normalize(ref)
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if ref == hostname:
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return True
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if suffix_match and hostname.endswith('.' + 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 real host for the given WSGI environment. This takes care
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of the `X-Forwarded-Host` header. Optionally it verifies that the host
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is in a list of trusted hosts. If the host is not in there it will raise
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a :exc:`~werkzeug.exceptions.SecurityError`.
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:param environ: the WSGI environment to get the host of.
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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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if 'HTTP_X_FORWARDED_HOST' in environ:
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rv = environ['HTTP_X_FORWARDED_HOST'].split(',')[0].strip()
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elif 'HTTP_HOST' in environ:
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rv = environ['HTTP_HOST']
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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 \
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in (('https', '443'), ('http', '80')):
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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 werkzeug.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 `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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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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.. versionadded:: 0.9
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:param environ: the WSGI environ to fetch the stream from.
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:param safe: indicates weather the function should use an empty
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stream as safe fallback or just return the original
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WSGI input stream if it can't wrap it safely. The
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default is to return an empty string in those cases.
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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 savely
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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 we don't have a content length we fall back to an empty stream
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# in case of a safe fallback, otherwise we return the stream unchanged.
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# The non-safe fallback is not recommended but might be useful in
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# some situations.
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if content_length is None:
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return safe_fallback and _empty_stream or 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(wsgi_get_bytes(segments[0]),
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charset, errors, allow_none_charset=True)
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def extract_path_info(environ_or_baseurl, path_or_url, charset='utf-8',
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errors='replace', collapse_http_schemes=True):
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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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.. versionadded:: 0.6
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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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"""
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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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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,
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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, = \
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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 \
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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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class SharedDataMiddleware(object):
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"""A WSGI middleware that provides static content for development
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environments or simple server setups. Usage is quite simple::
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import os
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from werkzeug.wsgi import SharedDataMiddleware
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app = SharedDataMiddleware(app, {
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'/shared': os.path.join(os.path.dirname(__file__), 'shared')
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})
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The contents of the folder ``./shared`` will now be available on
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``http://example.com/shared/``. This is pretty useful during development
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because a standalone media server is not required. One can also mount
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files on the root folder and still continue to use the application because
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the shared data middleware forwards all unhandled requests to the
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application, even if the requests are below one of the shared folders.
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If `pkg_resources` is available you can also tell the middleware to serve
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files from package data::
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app = SharedDataMiddleware(app, {
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'/shared': ('myapplication', 'shared_files')
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})
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This will then serve the ``shared_files`` folder in the `myapplication`
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Python package.
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The optional `disallow` parameter can be a list of :func:`~fnmatch.fnmatch`
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rules for files that are not accessible from the web. If `cache` is set to
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`False` no caching headers are sent.
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Currently the middleware does not support non ASCII filenames. If the
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encoding on the file system happens to be the encoding of the URI it may
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work but this could also be by accident. We strongly suggest using ASCII
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only file names for static files.
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The middleware will guess the mimetype using the Python `mimetype`
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module. If it's unable to figure out the charset it will fall back
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to `fallback_mimetype`.
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.. versionchanged:: 0.5
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The cache timeout is configurable now.
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.. versionadded:: 0.6
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The `fallback_mimetype` parameter was added.
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:param app: the application to wrap. If you don't want to wrap an
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application you can pass it :exc:`NotFound`.
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:param exports: a dict of exported files and folders.
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:param disallow: a list of :func:`~fnmatch.fnmatch` rules.
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:param fallback_mimetype: the fallback mimetype for unknown files.
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:param cache: enable or disable caching headers.
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:Param cache_timeout: the cache timeout in seconds for the headers.
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"""
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def __init__(self, app, exports, disallow=None, cache=True,
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cache_timeout=60 * 60 * 12, fallback_mimetype='text/plain'):
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self.app = app
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self.exports = {}
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self.cache = cache
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self.cache_timeout = cache_timeout
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for key, value in iteritems(exports):
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if isinstance(value, tuple):
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loader = self.get_package_loader(*value)
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elif isinstance(value, string_types):
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if os.path.isfile(value):
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loader = self.get_file_loader(value)
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else:
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loader = self.get_directory_loader(value)
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else:
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raise TypeError('unknown def %r' % value)
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self.exports[key] = loader
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if disallow is not None:
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from fnmatch import fnmatch
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self.is_allowed = lambda x: not fnmatch(x, disallow)
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self.fallback_mimetype = fallback_mimetype
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def is_allowed(self, filename):
|
|
"""Subclasses can override this method to disallow the access to
|
|
certain files. However by providing `disallow` in the constructor
|
|
this method is overwritten.
|
|
"""
|
|
return True
|
|
|
|
def _opener(self, filename):
|
|
return lambda: (
|
|
open(filename, 'rb'),
|
|
datetime.utcfromtimestamp(os.path.getmtime(filename)),
|
|
int(os.path.getsize(filename))
|
|
)
|
|
|
|
def get_file_loader(self, filename):
|
|
return lambda x: (os.path.basename(filename), self._opener(filename))
|
|
|
|
def get_package_loader(self, package, package_path):
|
|
from pkg_resources import DefaultProvider, ResourceManager, \
|
|
get_provider
|
|
loadtime = datetime.utcnow()
|
|
provider = get_provider(package)
|
|
manager = ResourceManager()
|
|
filesystem_bound = isinstance(provider, DefaultProvider)
|
|
def loader(path):
|
|
if path is None:
|
|
return None, None
|
|
path = posixpath.join(package_path, path)
|
|
if not provider.has_resource(path):
|
|
return None, None
|
|
basename = posixpath.basename(path)
|
|
if filesystem_bound:
|
|
return basename, self._opener(
|
|
provider.get_resource_filename(manager, path))
|
|
return basename, lambda: (
|
|
provider.get_resource_stream(manager, path),
|
|
loadtime,
|
|
0
|
|
)
|
|
return loader
|
|
|
|
def get_directory_loader(self, directory):
|
|
def loader(path):
|
|
if path is not None:
|
|
path = os.path.join(directory, path)
|
|
else:
|
|
path = directory
|
|
if os.path.isfile(path):
|
|
return os.path.basename(path), self._opener(path)
|
|
return None, None
|
|
return loader
|
|
|
|
def generate_etag(self, mtime, file_size, real_filename):
|
|
if not isinstance(real_filename, bytes):
|
|
real_filename = real_filename.encode(sys.getfilesystemencoding())
|
|
return 'wzsdm-%d-%s-%s' % (
|
|
mktime(mtime.timetuple()),
|
|
file_size,
|
|
adler32(real_filename) & 0xffffffff
|
|
)
|
|
|
|
def __call__(self, environ, start_response):
|
|
cleaned_path = get_path_info(environ)
|
|
if PY2:
|
|
cleaned_path = cleaned_path.encode(sys.getfilesystemencoding())
|
|
# sanitize the path for non unix systems
|
|
cleaned_path = cleaned_path.strip('/')
|
|
for sep in os.sep, os.altsep:
|
|
if sep and sep != '/':
|
|
cleaned_path = cleaned_path.replace(sep, '/')
|
|
path = '/'.join([''] + [x for x in cleaned_path.split('/')
|
|
if x and x != '..'])
|
|
file_loader = None
|
|
for search_path, loader in iteritems(self.exports):
|
|
if search_path == path:
|
|
real_filename, file_loader = loader(None)
|
|
if file_loader is not None:
|
|
break
|
|
if not search_path.endswith('/'):
|
|
search_path += '/'
|
|
if path.startswith(search_path):
|
|
real_filename, file_loader = loader(path[len(search_path):])
|
|
if file_loader is not None:
|
|
break
|
|
if file_loader is None or not self.is_allowed(real_filename):
|
|
return self.app(environ, start_response)
|
|
|
|
guessed_type = mimetypes.guess_type(real_filename)
|
|
mime_type = guessed_type[0] or self.fallback_mimetype
|
|
f, mtime, file_size = file_loader()
|
|
|
|
headers = [('Date', http_date())]
|
|
if self.cache:
|
|
timeout = self.cache_timeout
|
|
etag = self.generate_etag(mtime, file_size, real_filename)
|
|
headers += [
|
|
('Etag', '"%s"' % etag),
|
|
('Cache-Control', 'max-age=%d, public' % timeout)
|
|
]
|
|
if not is_resource_modified(environ, etag, last_modified=mtime):
|
|
f.close()
|
|
start_response('304 Not Modified', headers)
|
|
return []
|
|
headers.append(('Expires', http_date(time() + timeout)))
|
|
else:
|
|
headers.append(('Cache-Control', 'public'))
|
|
|
|
headers.extend((
|
|
('Content-Type', mime_type),
|
|
('Content-Length', str(file_size)),
|
|
('Last-Modified', http_date(mtime))
|
|
))
|
|
start_response('200 OK', headers)
|
|
return wrap_file(environ, f)
|
|
|
|
|
|
class DispatcherMiddleware(object):
|
|
"""Allows one to mount middlewares or applications in a WSGI application.
|
|
This is useful if you want to combine multiple WSGI applications::
|
|
|
|
app = DispatcherMiddleware(app, {
|
|
'/app2': app2,
|
|
'/app3': app3
|
|
})
|
|
"""
|
|
|
|
def __init__(self, app, mounts=None):
|
|
self.app = app
|
|
self.mounts = mounts or {}
|
|
|
|
def __call__(self, environ, start_response):
|
|
script = environ.get('PATH_INFO', '')
|
|
path_info = ''
|
|
while '/' in script:
|
|
if script in self.mounts:
|
|
app = self.mounts[script]
|
|
break
|
|
items = script.split('/')
|
|
script = '/'.join(items[:-1])
|
|
path_info = '/%s%s' % (items[-1], path_info)
|
|
else:
|
|
app = self.mounts.get(script, self.app)
|
|
original_script_name = environ.get('SCRIPT_NAME', '')
|
|
environ['SCRIPT_NAME'] = original_script_name + script
|
|
environ['PATH_INFO'] = path_info
|
|
return app(environ, start_response)
|
|
|
|
|
|
@implements_iterator
|
|
class ClosingIterator(object):
|
|
"""The WSGI specification requires that all middlewares and gateways
|
|
respect the `close` callback of an iterator. Because it is useful to add
|
|
another close action to a returned iterator and adding a custom iterator
|
|
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, callbacks=None):
|
|
iterator = iter(iterable)
|
|
self._next = partial(next, iterator)
|
|
if callbacks is None:
|
|
callbacks = []
|
|
elif callable(callbacks):
|
|
callbacks = [callbacks]
|
|
else:
|
|
callbacks = list(callbacks)
|
|
iterable_close = getattr(iterator, 'close', None)
|
|
if iterable_close:
|
|
callbacks.insert(0, iterable_close)
|
|
self._callbacks = callbacks
|
|
|
|
def __iter__(self):
|
|
return self
|
|
|
|
def __next__(self):
|
|
return self._next()
|
|
|
|
def close(self):
|
|
for callback in self._callbacks:
|
|
callback()
|
|
|
|
|
|
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 __iter__(self):
|
|
return self
|
|
|
|
def __next__(self):
|
|
data = self.file.read(self.buffer_size)
|
|
if data:
|
|
return data
|
|
raise StopIteration()
|
|
|
|
|
|
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):
|
|
"""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.
|
|
|
|
: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.
|
|
"""
|
|
_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 = []
|
|
for item in chain(buffer, new_data.splitlines(True)):
|
|
new_buf.append(item)
|
|
if item and item[-1:] in crlf:
|
|
yield _join(new_buf)
|
|
new_buf = []
|
|
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):
|
|
"""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.
|
|
|
|
: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.
|
|
"""
|
|
_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 = []
|
|
for item in chain(buffer, chunks):
|
|
if item == separator:
|
|
yield _join(new_buf)
|
|
new_buf = []
|
|
else:
|
|
new_buf.append(item)
|
|
buffer = new_buf
|
|
if buffer:
|
|
yield _join(buffer)
|
|
|
|
|
|
@implements_iterator
|
|
class LimitedStream(object):
|
|
"""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 werkzeug.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
|