MatrixSynapse/synapse/rest/media/v1/preview_url_resource.py

165 lines
6.1 KiB
Python

# Copyright 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.
from twisted.web.resource import Resource
from lxml import html
from synapse.http.client import SimpleHttpClient
from synapse.http.server import respond_with_json_bytes
from simplejson import json
import logging
logger = logging.getLogger(__name__)
class PreviewUrlResource(Resource):
isLeaf = True
def __init__(self, hs, filepaths):
Resource.__init__(self)
self.client = SimpleHttpClient(hs)
self.filepaths = filepaths
self.max_spider_size = hs.config.max_spider_size
self.server_name = hs.hostname
self.clock = hs.get_clock()
def render_GET(self, request):
self._async_render_GET(request)
return NOT_DONE_YET
@request_handler
@defer.inlineCallbacks
def _async_render_GET(self, request):
url = request.args.get("url")
try:
# TODO: keep track of whether there's an ongoing request for this preview
# and block and return their details if there is one.
media_info = self._download_url(url)
except:
os.remove(fname)
raise
if self._is_media(media_type):
dims = yield self._generate_local_thumbnails(
media_info.filesystem_id, media_info
)
og = {
"og:description" : media_info.download_name,
"og:image" : "mxc://%s/%s" % (self.server_name, media_info.filesystem_id),
"og:image:type" : media_info.media_type,
"og:image:width" : dims.width,
"og:image:height" : dims.height,
}
# define our OG response for this media
elif self._is_html(media_type):
tree = html.parse(media_info.filename)
# suck it up into lxml and define our OG response.
# if we see any URLs in the OG response, then spider them
# (although the client could choose to do this by asking for previews of those URLs to avoid DoSing the server)
# "og:type" : "article"
# "og:url" : "https://twitter.com/matrixdotorg/status/684074366691356672"
# "og:title" : "Matrix on Twitter"
# "og:image" : "https://pbs.twimg.com/profile_images/500400952029888512/yI0qtFi7_400x400.png"
# "og:description" : "“Synapse 0.12 is out! Lots of polishing, performance & bugfixes: /sync API, /r0 prefix, fulltext search, 3PID invites https://t.co/5alhXLLEGP”"
# "og:site_name" : "Twitter"
og = {}
for tag in tree.xpath("//*/meta[starts-with(@property, 'og:')]"):
og[tag.attrib['property']] = tag.attrib['content']
# TODO: store our OG details in a cache (and expire them when stale)
# TODO: delete the content to stop diskfilling, as we only ever cared about its OG
respond_with_json_bytes(request, 200, json.dumps(og), send_cors=True)
def _download_url(url):
requester = yield self.auth.get_user_by_req(request)
# XXX: horrible duplication with base_resource's _download_remote_file()
file_id = random_string(24)
fname = self.filepaths.local_media_filepath(file_id)
self._makedirs(fname)
try:
with open(fname, "wb") as f:
length, headers = yield self.client.get_file(
url, output_stream=f, max_size=self.max_spider_size,
)
media_type = headers["Content-Type"][0]
time_now_ms = self.clock.time_msec()
content_disposition = headers.get("Content-Disposition", None)
if content_disposition:
_, params = cgi.parse_header(content_disposition[0],)
download_name = None
# First check if there is a valid UTF-8 filename
download_name_utf8 = params.get("filename*", None)
if download_name_utf8:
if download_name_utf8.lower().startswith("utf-8''"):
download_name = download_name_utf8[7:]
# If there isn't check for an ascii name.
if not download_name:
download_name_ascii = params.get("filename", None)
if download_name_ascii and is_ascii(download_name_ascii):
download_name = download_name_ascii
if download_name:
download_name = urlparse.unquote(download_name)
try:
download_name = download_name.decode("utf-8")
except UnicodeDecodeError:
download_name = None
else:
download_name = None
yield self.store.store_local_media(
media_id=fname,
media_type=media_type,
time_now_ms=self.clock.time_msec(),
upload_name=download_name,
media_length=length,
user_id=requester.user,
)
except:
os.remove(fname)
raise
return {
"media_type": media_type,
"media_length": length,
"download_name": download_name,
"created_ts": time_now_ms,
"filesystem_id": file_id,
"filename": fname,
}
def _is_media(content_type):
if content_type.lower().startswith("image/"):
return True
def _is_html(content_type):
content_type = content_type.lower()
if content_type == "text/html" or
content_type.startswith("application/xhtml"):
return True