# -*- coding: utf-8 -*-
# Copyright 2014-2016 OpenMarket Ltd
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
import logging
import os
from six import PY3
from six.moves import urllib
from twisted.internet import defer
from twisted.protocols.basic import FileSender
from synapse.api.errors import Codes, SynapseError, cs_error
from synapse.http.server import finish_request, respond_with_json
from synapse.util import logcontext
from synapse.util.stringutils import is_ascii
logger = logging.getLogger(__name__)
def parse_media_id(request):
try:
# This allows users to append e.g. /test.png to the URL. Useful for
# clients that parse the URL to see content type.
server_name, media_id = request.postpath[:2]
if isinstance(server_name, bytes):
server_name = server_name.decode('utf-8')
media_id = media_id.decode('utf8')
file_name = None
if len(request.postpath) > 2:
try:
file_name = urllib.parse.unquote(request.postpath[-1].decode("utf-8"))
except UnicodeDecodeError:
pass
return server_name, media_id, file_name
except Exception:
raise SynapseError(
404, "Invalid media id token %r" % (request.postpath,), Codes.UNKNOWN
)
def respond_404(request):
respond_with_json(
request,
404,
cs_error("Not found %r" % (request.postpath,), code=Codes.NOT_FOUND),
send_cors=True,
)
@defer.inlineCallbacks
def respond_with_file(request, media_type, file_path, file_size=None, upload_name=None):
logger.debug("Responding with %r", file_path)
if os.path.isfile(file_path):
if file_size is None:
stat = os.stat(file_path)
file_size = stat.st_size
add_file_headers(request, media_type, file_size, upload_name)
with open(file_path, "rb") as f:
yield logcontext.make_deferred_yieldable(
FileSender().beginFileTransfer(f, request)
)
finish_request(request)
else:
respond_404(request)
def add_file_headers(request, media_type, file_size, upload_name):
"""Adds the correct response headers in preparation for responding with the
media.
Args:
request (twisted.web.http.Request)
media_type (str): The media/content type.
file_size (int): Size in bytes of the media, if known.
upload_name (str): The name of the requested file, if any.
"""
def _quote(x):
return urllib.parse.quote(x.encode("utf-8"))
request.setHeader(b"Content-Type", media_type.encode("UTF-8"))
if upload_name:
if is_ascii(upload_name):
disposition = "inline; filename=%s" % (_quote(upload_name),)
else:
disposition = "inline; filename*=utf-8''%s" % (_quote(upload_name),)
request.setHeader(b"Content-Disposition", disposition.encode('ascii'))
# cache for at least a day.
# XXX: we might want to turn this off for data we don't want to
# recommend caching as it's sensitive or private - or at least
# select private. don't bother setting Expires as all our
# clients are smart enough to be happy with Cache-Control
request.setHeader(b"Cache-Control", b"public,max-age=86400,s-maxage=86400")
request.setHeader(b"Content-Length", b"%d" % (file_size,))
@defer.inlineCallbacks
def respond_with_responder(request, responder, media_type, file_size, upload_name=None):
"""Responds to the request with given responder. If responder is None then
returns 404.
Args:
request (twisted.web.http.Request)
responder (Responder|None)
media_type (str): The media/content type.
file_size (int|None): Size in bytes of the media. If not known it should be None
upload_name (str|None): The name of the requested file, if any.
"""
if not responder:
respond_404(request)
return
logger.debug("Responding to media request with responder %s")
add_file_headers(request, media_type, file_size, upload_name)
with responder:
yield responder.write_to_consumer(request)
finish_request(request)
class Responder(object):
"""Represents a response that can be streamed to the requester.
Responder is a context manager which *must* be used, so that any resources
held can be cleaned up.
"""
def write_to_consumer(self, consumer):
"""Stream response into consumer
Args:
consumer (IConsumer)
Returns:
Deferred: Resolves once the response has finished being written
"""
pass
def __enter__(self):
pass
def __exit__(self, exc_type, exc_val, exc_tb):
pass
class FileInfo(object):
"""Details about a requested/uploaded file.
Attributes:
server_name (str): The server name where the media originated from,
or None if local.
file_id (str): The local ID of the file. For local files this is the
same as the media_id
url_cache (bool): If the file is for the url preview cache
thumbnail (bool): Whether the file is a thumbnail or not.
thumbnail_width (int)
thumbnail_height (int)
thumbnail_method (str)
thumbnail_type (str): Content type of thumbnail, e.g. image/png
"""
def __init__(
self,
server_name,
file_id,
url_cache=False,
thumbnail=False,
thumbnail_width=None,
thumbnail_height=None,
thumbnail_method=None,
thumbnail_type=None,
):
self.server_name = server_name
self.file_id = file_id
self.url_cache = url_cache
self.thumbnail = thumbnail
self.thumbnail_width = thumbnail_width
self.thumbnail_height = thumbnail_height
self.thumbnail_method = thumbnail_method
self.thumbnail_type = thumbnail_type
def get_filename_from_headers(headers):
"""
Get the filename of the downloaded file by inspecting the
Content-Disposition HTTP header.
Args:
headers (twisted.web.http_headers.Headers): The HTTP
request headers.
Returns:
A Unicode string of the filename, or None.
"""
content_disposition = headers.get(b"Content-Disposition", [b''])
# No header, bail out.
if not content_disposition[0]:
return
# dict of unicode: bytes, corresponding to the key value sections of the
# Content-Disposition header.
params = {}
parts = content_disposition[0].split(b";")
for i in parts:
# Split into key-value pairs, if able
# We don't care about things like `inline`, so throw it out
if b"=" not in i:
continue
key, value = i.strip().split(b"=")
params[key.decode('ascii')] = value
upload_name = None
# First check if there is a valid UTF-8 filename
upload_name_utf8 = params.get("filename*", None)
if upload_name_utf8:
if upload_name_utf8.lower().startswith(b"utf-8''"):
upload_name_utf8 = upload_name_utf8[7:]
# We have a filename*= section. This MUST be ASCII, and any UTF-8
# bytes are %-quoted.
if PY3:
try:
# Once it is decoded, we can then unquote the %-encoded
# parts strictly into a unicode string.
upload_name = urllib.parse.unquote(
upload_name_utf8.decode('ascii'), errors="strict"
)
except UnicodeDecodeError:
# Incorrect UTF-8.
pass
else:
# On Python 2, we first unquote the %-encoded parts and then
# decode it strictly using UTF-8.
try:
upload_name = urllib.parse.unquote(upload_name_utf8).decode('utf8')
except UnicodeDecodeError:
pass
# If there isn't check for an ascii name.
if not upload_name:
upload_name_ascii = params.get("filename", None)
if upload_name_ascii and is_ascii(upload_name_ascii):
# Make sure there's no %-quoted bytes. If there is, reject it as
# non-valid ASCII.
if b"%" not in upload_name_ascii:
upload_name = upload_name_ascii.decode('ascii')
# This may be None here, indicating we did not find a matching name.
return upload_name