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https://git.anonymousland.org/anonymousland/synapse.git
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68f47d6744
* Fix parsing of Content-Disposition headers TIL: filenames in content-dispostion headers can contain semicolons, and aren't %-encoded. * fix python2 incompatibility * Fix docstrings
324 lines
10 KiB
Python
324 lines
10 KiB
Python
# -*- coding: utf-8 -*-
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# Copyright 2014-2016 OpenMarket Ltd
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# Copyright 2019 New Vector Ltd.
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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import logging
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import os
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from six import PY3
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from six.moves import urllib
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from twisted.internet import defer
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from twisted.protocols.basic import FileSender
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from synapse.api.errors import Codes, SynapseError, cs_error
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from synapse.http.server import finish_request, respond_with_json
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from synapse.util import logcontext
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from synapse.util.stringutils import is_ascii
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logger = logging.getLogger(__name__)
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def parse_media_id(request):
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try:
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# This allows users to append e.g. /test.png to the URL. Useful for
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# clients that parse the URL to see content type.
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server_name, media_id = request.postpath[:2]
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if isinstance(server_name, bytes):
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server_name = server_name.decode('utf-8')
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media_id = media_id.decode('utf8')
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file_name = None
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if len(request.postpath) > 2:
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try:
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file_name = urllib.parse.unquote(request.postpath[-1].decode("utf-8"))
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except UnicodeDecodeError:
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pass
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return server_name, media_id, file_name
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except Exception:
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raise SynapseError(
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404, "Invalid media id token %r" % (request.postpath,), Codes.UNKNOWN
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)
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def respond_404(request):
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respond_with_json(
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request,
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404,
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cs_error("Not found %r" % (request.postpath,), code=Codes.NOT_FOUND),
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send_cors=True,
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)
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@defer.inlineCallbacks
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def respond_with_file(request, media_type, file_path, file_size=None, upload_name=None):
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logger.debug("Responding with %r", file_path)
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if os.path.isfile(file_path):
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if file_size is None:
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stat = os.stat(file_path)
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file_size = stat.st_size
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add_file_headers(request, media_type, file_size, upload_name)
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with open(file_path, "rb") as f:
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yield logcontext.make_deferred_yieldable(
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FileSender().beginFileTransfer(f, request)
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)
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finish_request(request)
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else:
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respond_404(request)
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def add_file_headers(request, media_type, file_size, upload_name):
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"""Adds the correct response headers in preparation for responding with the
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media.
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Args:
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request (twisted.web.http.Request)
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media_type (str): The media/content type.
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file_size (int): Size in bytes of the media, if known.
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upload_name (str): The name of the requested file, if any.
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"""
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def _quote(x):
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return urllib.parse.quote(x.encode("utf-8"))
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request.setHeader(b"Content-Type", media_type.encode("UTF-8"))
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if upload_name:
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if is_ascii(upload_name):
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disposition = "inline; filename=%s" % (_quote(upload_name),)
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else:
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disposition = "inline; filename*=utf-8''%s" % (_quote(upload_name),)
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request.setHeader(b"Content-Disposition", disposition.encode('ascii'))
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# cache for at least a day.
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# XXX: we might want to turn this off for data we don't want to
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# recommend caching as it's sensitive or private - or at least
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# select private. don't bother setting Expires as all our
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# clients are smart enough to be happy with Cache-Control
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request.setHeader(b"Cache-Control", b"public,max-age=86400,s-maxage=86400")
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request.setHeader(b"Content-Length", b"%d" % (file_size,))
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@defer.inlineCallbacks
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def respond_with_responder(request, responder, media_type, file_size, upload_name=None):
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"""Responds to the request with given responder. If responder is None then
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returns 404.
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Args:
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request (twisted.web.http.Request)
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responder (Responder|None)
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media_type (str): The media/content type.
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file_size (int|None): Size in bytes of the media. If not known it should be None
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upload_name (str|None): The name of the requested file, if any.
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"""
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if not responder:
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respond_404(request)
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return
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logger.debug("Responding to media request with responder %s")
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add_file_headers(request, media_type, file_size, upload_name)
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try:
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with responder:
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yield responder.write_to_consumer(request)
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except Exception as e:
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# The majority of the time this will be due to the client having gone
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# away. Unfortunately, Twisted simply throws a generic exception at us
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# in that case.
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logger.warning("Failed to write to consumer: %s %s", type(e), e)
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finish_request(request)
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class Responder(object):
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"""Represents a response that can be streamed to the requester.
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Responder is a context manager which *must* be used, so that any resources
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held can be cleaned up.
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"""
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def write_to_consumer(self, consumer):
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"""Stream response into consumer
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Args:
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consumer (IConsumer)
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Returns:
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Deferred: Resolves once the response has finished being written
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"""
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pass
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def __enter__(self):
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pass
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def __exit__(self, exc_type, exc_val, exc_tb):
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pass
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class FileInfo(object):
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"""Details about a requested/uploaded file.
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Attributes:
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server_name (str): The server name where the media originated from,
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or None if local.
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file_id (str): The local ID of the file. For local files this is the
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same as the media_id
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url_cache (bool): If the file is for the url preview cache
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thumbnail (bool): Whether the file is a thumbnail or not.
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thumbnail_width (int)
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thumbnail_height (int)
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thumbnail_method (str)
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thumbnail_type (str): Content type of thumbnail, e.g. image/png
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"""
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def __init__(
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self,
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server_name,
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file_id,
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url_cache=False,
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thumbnail=False,
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thumbnail_width=None,
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thumbnail_height=None,
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thumbnail_method=None,
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thumbnail_type=None,
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):
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self.server_name = server_name
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self.file_id = file_id
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self.url_cache = url_cache
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self.thumbnail = thumbnail
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self.thumbnail_width = thumbnail_width
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self.thumbnail_height = thumbnail_height
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self.thumbnail_method = thumbnail_method
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self.thumbnail_type = thumbnail_type
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def get_filename_from_headers(headers):
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"""
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Get the filename of the downloaded file by inspecting the
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Content-Disposition HTTP header.
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Args:
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headers (dict[bytes, list[bytes]]): The HTTP request headers.
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Returns:
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A Unicode string of the filename, or None.
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"""
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content_disposition = headers.get(b"Content-Disposition", [b''])
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# No header, bail out.
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if not content_disposition[0]:
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return
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_, params = _parse_header(content_disposition[0])
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upload_name = None
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# First check if there is a valid UTF-8 filename
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upload_name_utf8 = params.get(b"filename*", None)
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if upload_name_utf8:
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if upload_name_utf8.lower().startswith(b"utf-8''"):
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upload_name_utf8 = upload_name_utf8[7:]
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# We have a filename*= section. This MUST be ASCII, and any UTF-8
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# bytes are %-quoted.
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if PY3:
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try:
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# Once it is decoded, we can then unquote the %-encoded
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# parts strictly into a unicode string.
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upload_name = urllib.parse.unquote(
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upload_name_utf8.decode('ascii'), errors="strict"
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)
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except UnicodeDecodeError:
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# Incorrect UTF-8.
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pass
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else:
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# On Python 2, we first unquote the %-encoded parts and then
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# decode it strictly using UTF-8.
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try:
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upload_name = urllib.parse.unquote(upload_name_utf8).decode('utf8')
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except UnicodeDecodeError:
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pass
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# If there isn't check for an ascii name.
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if not upload_name:
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upload_name_ascii = params.get(b"filename", None)
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if upload_name_ascii and is_ascii(upload_name_ascii):
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upload_name = upload_name_ascii.decode('ascii')
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# This may be None here, indicating we did not find a matching name.
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return upload_name
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def _parse_header(line):
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"""Parse a Content-type like header.
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Cargo-culted from `cgi`, but works on bytes rather than strings.
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Args:
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line (bytes): header to be parsed
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Returns:
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Tuple[bytes, dict[bytes, bytes]]:
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the main content-type, followed by the parameter dictionary
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"""
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parts = _parseparam(b';' + line)
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key = next(parts)
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pdict = {}
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for p in parts:
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i = p.find(b'=')
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if i >= 0:
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name = p[:i].strip().lower()
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value = p[i + 1:].strip()
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# strip double-quotes
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if len(value) >= 2 and value[0:1] == value[-1:] == b'"':
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value = value[1:-1]
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value = value.replace(b'\\\\', b'\\').replace(b'\\"', b'"')
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pdict[name] = value
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return key, pdict
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def _parseparam(s):
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"""Generator which splits the input on ;, respecting double-quoted sequences
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Cargo-culted from `cgi`, but works on bytes rather than strings.
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Args:
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s (bytes): header to be parsed
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Returns:
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Iterable[bytes]: the split input
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"""
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while s[:1] == b';':
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s = s[1:]
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# look for the next ;
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end = s.find(b';')
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# if there is an odd number of " marks between here and the next ;, skip to the
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# next ; instead
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while end > 0 and (s.count(b'"', 0, end) - s.count(b'\\"', 0, end)) % 2:
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end = s.find(b';', end + 1)
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if end < 0:
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end = len(s)
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f = s[:end]
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yield f.strip()
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s = s[end:]
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