diff --git a/README.rst b/README.rst
index 6136e0c1fe..02e7c61d1e 100644
--- a/README.rst
+++ b/README.rst
@@ -104,7 +104,7 @@ Installing prerequisites on Ubuntu or Debian::
sudo apt-get install build-essential python2.7-dev libffi-dev \
python-pip python-setuptools sqlite3 \
- libssl-dev python-virtualenv libjpeg-dev
+ libssl-dev python-virtualenv libjpeg-dev libxslt1-dev
Installing prerequisites on ArchLinux::
@@ -557,6 +557,23 @@ as the primary means of identity and E2E encryption is not complete. As such,
we are running a single identity server (https://matrix.org) at the current
time.
+
+URL Previews
+============
+
+Synapse 0.15.0 introduces an experimental new API for previewing URLs at
+/_matrix/media/r0/preview_url. This is disabled by default. To turn it on
+you must enable the `url_preview_enabled: True` config parameter and explicitly
+specify the IP ranges that Synapse is not allowed to spider for previewing in
+the `url_preview_ip_range_blacklist` configuration parameter. This is critical
+from a security perspective to stop arbitrary Matrix users spidering 'internal'
+URLs on your network. At the very least we recommend that your loopback and
+RFC1918 IP addresses are blacklisted.
+
+This also requires the optional lxml and netaddr python dependencies to be
+installed.
+
+
Password reset
==============
diff --git a/UPGRADE.rst b/UPGRADE.rst
index 4f08cbb96a..699f04c2c2 100644
--- a/UPGRADE.rst
+++ b/UPGRADE.rst
@@ -30,6 +30,14 @@ running:
python synapse/python_dependencies.py | xargs -n1 pip install
+Upgrading to v0.15.0
+====================
+
+If you want to use the new URL previewing API (/_matrix/media/r0/preview_url)
+then you have to explicitly enable it in the config and update your dependencies
+dependencies. See README.rst for details.
+
+
Upgrading to v0.11.0
====================
diff --git a/docs/url_previews.rst b/docs/url_previews.rst
new file mode 100644
index 0000000000..634d9d907f
--- /dev/null
+++ b/docs/url_previews.rst
@@ -0,0 +1,74 @@
+URL Previews
+============
+
+Design notes on a URL previewing service for Matrix:
+
+Options are:
+
+ 1. Have an AS which listens for URLs, downloads them, and inserts an event that describes their metadata.
+ * Pros:
+ * Decouples the implementation entirely from Synapse.
+ * Uses existing Matrix events & content repo to store the metadata.
+ * Cons:
+ * Which AS should provide this service for a room, and why should you trust it?
+ * Doesn't work well with E2E; you'd have to cut the AS into every room
+ * the AS would end up subscribing to every room anyway.
+
+ 2. Have a generic preview API (nothing to do with Matrix) that provides a previewing service:
+ * Pros:
+ * Simple and flexible; can be used by any clients at any point
+ * Cons:
+ * If each HS provides one of these independently, all the HSes in a room may needlessly DoS the target URI
+ * We need somewhere to store the URL metadata rather than just using Matrix itself
+ * We can't piggyback on matrix to distribute the metadata between HSes.
+
+ 3. Make the synapse of the sending user responsible for spidering the URL and inserting an event asynchronously which describes the metadata.
+ * Pros:
+ * Works transparently for all clients
+ * Piggy-backs nicely on using Matrix for distributing the metadata.
+ * No confusion as to which AS
+ * Cons:
+ * Doesn't work with E2E
+ * We might want to decouple the implementation of the spider from the HS, given spider behaviour can be quite complicated and evolve much more rapidly than the HS. It's more like a bot than a core part of the server.
+
+ 4. Make the sending client use the preview API and insert the event itself when successful.
+ * Pros:
+ * Works well with E2E
+ * No custom server functionality
+ * Lets the client customise the preview that they send (like on FB)
+ * Cons:
+ * Entirely specific to the sending client, whereas it'd be nice if /any/ URL was correctly previewed if clients support it.
+
+ 5. Have the option of specifying a shared (centralised) previewing service used by a room, to avoid all the different HSes in the room DoSing the target.
+
+Best solution is probably a combination of both 2 and 4.
+ * Sending clients do their best to create and send a preview at the point of sending the message, perhaps delaying the message until the preview is computed? (This also lets the user validate the preview before sending)
+ * Receiving clients have the option of going and creating their own preview if one doesn't arrive soon enough (or if the original sender didn't create one)
+
+This is a bit magical though in that the preview could come from two entirely different sources - the sending HS or your local one. However, this can always be exposed to users: "Generate your own URL previews if none are available?"
+
+This is tantamount also to senders calculating their own thumbnails for sending in advance of the main content - we are trusting the sender not to lie about the content in the thumbnail. Whereas currently thumbnails are calculated by the receiving homeserver to avoid this attack.
+
+However, this kind of phishing attack does exist whether we let senders pick their thumbnails or not, in that a malicious sender can send normal text messages around the attachment claiming it to be legitimate. We could rely on (future) reputation/abuse management to punish users who phish (be it with bogus metadata or bogus descriptions). Bogus metadata is particularly bad though, especially if it's avoidable.
+
+As a first cut, let's do #2 and have the receiver hit the API to calculate its own previews (as it does currently for image thumbnails). We can then extend/optimise this to option 4 as a special extra if needed.
+
+API
+---
+
+GET /_matrix/media/r0/preview_url?url=http://wherever.com
+200 OK
+{
+ "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"
+}
+
+* Downloads the URL
+ * If HTML, just stores it in RAM and parses it for OG meta tags
+ * Download any media OG meta tags to the media repo, and refer to them in the OG via mxc:// URIs.
+ * If a media filetype we know we can thumbnail: store it on disk, and hand it to the thumbnailer. Generate OG meta tags from the thumbnailer contents.
+ * Otherwise, don't bother downloading further.
diff --git a/synapse/config/repository.py b/synapse/config/repository.py
index 2e96c09013..49922c6d03 100644
--- a/synapse/config/repository.py
+++ b/synapse/config/repository.py
@@ -16,6 +16,8 @@
from ._base import Config
from collections import namedtuple
+import sys
+
ThumbnailRequirement = namedtuple(
"ThumbnailRequirement", ["width", "height", "method", "media_type"]
)
@@ -23,7 +25,7 @@ ThumbnailRequirement = namedtuple(
def parse_thumbnail_requirements(thumbnail_sizes):
""" Takes a list of dictionaries with "width", "height", and "method" keys
- and creates a map from image media types to the thumbnail size, thumnailing
+ and creates a map from image media types to the thumbnail size, thumbnailing
method, and thumbnail media type to precalculate
Args:
@@ -53,12 +55,25 @@ class ContentRepositoryConfig(Config):
def read_config(self, config):
self.max_upload_size = self.parse_size(config["max_upload_size"])
self.max_image_pixels = self.parse_size(config["max_image_pixels"])
+ self.max_spider_size = self.parse_size(config["max_spider_size"])
self.media_store_path = self.ensure_directory(config["media_store_path"])
self.uploads_path = self.ensure_directory(config["uploads_path"])
self.dynamic_thumbnails = config["dynamic_thumbnails"]
self.thumbnail_requirements = parse_thumbnail_requirements(
config["thumbnail_sizes"]
)
+ self.url_preview_enabled = config["url_preview_enabled"]
+ if self.url_preview_enabled:
+ try:
+ from netaddr import IPSet
+ if "url_preview_ip_range_blacklist" in config:
+ self.url_preview_ip_range_blacklist = IPSet(
+ config["url_preview_ip_range_blacklist"]
+ )
+ if "url_preview_url_blacklist" in config:
+ self.url_preview_url_blacklist = config["url_preview_url_blacklist"]
+ except ImportError:
+ sys.stderr.write("\nmissing netaddr dep - disabling preview_url API\n")
def default_config(self, **kwargs):
media_store = self.default_path("media_store")
@@ -80,7 +95,7 @@ class ContentRepositoryConfig(Config):
# the resolution requested by the client. If true then whenever
# a new resolution is requested by the client the server will
# generate a new thumbnail. If false the server will pick a thumbnail
- # from a precalcualted list.
+ # from a precalculated list.
dynamic_thumbnails: false
# List of thumbnail to precalculate when an image is uploaded.
@@ -100,4 +115,62 @@ class ContentRepositoryConfig(Config):
- width: 800
height: 600
method: scale
+
+ # Is the preview URL API enabled? If enabled, you *must* specify
+ # an explicit url_preview_ip_range_blacklist of IPs that the spider is
+ # denied from accessing.
+ url_preview_enabled: False
+
+ # List of IP address CIDR ranges that the URL preview spider is denied
+ # from accessing. There are no defaults: you must explicitly
+ # specify a list for URL previewing to work. You should specify any
+ # internal services in your network that you do not want synapse to try
+ # to connect to, otherwise anyone in any Matrix room could cause your
+ # synapse to issue arbitrary GET requests to your internal services,
+ # causing serious security issues.
+ #
+ # url_preview_ip_range_blacklist:
+ # - '127.0.0.0/8'
+ # - '10.0.0.0/8'
+ # - '172.16.0.0/12'
+ # - '192.168.0.0/16'
+
+ # Optional list of URL matches that the URL preview spider is
+ # denied from accessing. You should use url_preview_ip_range_blacklist
+ # in preference to this, otherwise someone could define a public DNS
+ # entry that points to a private IP address and circumvent the blacklist.
+ # This is more useful if you know there is an entire shape of URL that
+ # you know that will never want synapse to try to spider.
+ #
+ # Each list entry is a dictionary of url component attributes as returned
+ # by urlparse.urlsplit as applied to the absolute form of the URL. See
+ # https://docs.python.org/2/library/urlparse.html#urlparse.urlsplit
+ # The values of the dictionary are treated as an filename match pattern
+ # applied to that component of URLs, unless they start with a ^ in which
+ # case they are treated as a regular expression match. If all the
+ # specified component matches for a given list item succeed, the URL is
+ # blacklisted.
+ #
+ # url_preview_url_blacklist:
+ # # blacklist any URL with a username in its URI
+ # - username: '*'
+ #
+ # # blacklist all *.google.com URLs
+ # - netloc: 'google.com'
+ # - netloc: '*.google.com'
+ #
+ # # blacklist all plain HTTP URLs
+ # - scheme: 'http'
+ #
+ # # blacklist http(s)://www.acme.com/foo
+ # - netloc: 'www.acme.com'
+ # path: '/foo'
+ #
+ # # blacklist any URL with a literal IPv4 address
+ # - netloc: '^[0-9]+\.[0-9]+\.[0-9]+\.[0-9]+$'
+
+ # The largest allowed URL preview spidering size in bytes
+ max_spider_size: "10M"
+
+
""" % locals()
diff --git a/synapse/http/client.py b/synapse/http/client.py
index cbd45b2bbe..6c89b20984 100644
--- a/synapse/http/client.py
+++ b/synapse/http/client.py
@@ -15,17 +15,24 @@
from OpenSSL import SSL
from OpenSSL.SSL import VERIFY_NONE
-from synapse.api.errors import CodeMessageException
+from synapse.api.errors import (
+ CodeMessageException, SynapseError, Codes,
+)
from synapse.util.logcontext import preserve_context_over_fn
import synapse.metrics
+from synapse.http.endpoint import SpiderEndpoint
from canonicaljson import encode_canonical_json
-from twisted.internet import defer, reactor, ssl
+from twisted.internet import defer, reactor, ssl, protocol
+from twisted.internet.endpoints import SSL4ClientEndpoint, TCP4ClientEndpoint
from twisted.web.client import (
- Agent, readBody, FileBodyProducer, PartialDownloadError,
+ BrowserLikeRedirectAgent, ContentDecoderAgent, GzipDecoder, Agent,
+ readBody, FileBodyProducer, PartialDownloadError,
)
+from twisted.web.http import PotentialDataLoss
from twisted.web.http_headers import Headers
+from twisted.web._newclient import ResponseDone
from StringIO import StringIO
@@ -238,6 +245,107 @@ class SimpleHttpClient(object):
else:
raise CodeMessageException(response.code, body)
+ # XXX: FIXME: This is horribly copy-pasted from matrixfederationclient.
+ # The two should be factored out.
+
+ @defer.inlineCallbacks
+ def get_file(self, url, output_stream, max_size=None):
+ """GETs a file from a given URL
+ Args:
+ url (str): The URL to GET
+ output_stream (file): File to write the response body to.
+ Returns:
+ A (int,dict,string,int) tuple of the file length, dict of the response
+ headers, absolute URI of the response and HTTP response code.
+ """
+
+ response = yield self.request(
+ "GET",
+ url.encode("ascii"),
+ headers=Headers({
+ b"User-Agent": [self.user_agent],
+ })
+ )
+
+ headers = dict(response.headers.getAllRawHeaders())
+
+ if 'Content-Length' in headers and headers['Content-Length'] > max_size:
+ logger.warn("Requested URL is too large > %r bytes" % (self.max_size,))
+ raise SynapseError(
+ 502,
+ "Requested file is too large > %r bytes" % (self.max_size,),
+ Codes.TOO_LARGE,
+ )
+
+ if response.code > 299:
+ logger.warn("Got %d when downloading %s" % (response.code, url))
+ raise SynapseError(
+ 502,
+ "Got error %d" % (response.code,),
+ Codes.UNKNOWN,
+ )
+
+ # TODO: if our Content-Type is HTML or something, just read the first
+ # N bytes into RAM rather than saving it all to disk only to read it
+ # straight back in again
+
+ try:
+ length = yield preserve_context_over_fn(
+ _readBodyToFile,
+ response, output_stream, max_size
+ )
+ except Exception as e:
+ logger.exception("Failed to download body")
+ raise SynapseError(
+ 502,
+ ("Failed to download remote body: %s" % e),
+ Codes.UNKNOWN,
+ )
+
+ defer.returnValue((length, headers, response.request.absoluteURI, response.code))
+
+
+# XXX: FIXME: This is horribly copy-pasted from matrixfederationclient.
+# The two should be factored out.
+
+class _ReadBodyToFileProtocol(protocol.Protocol):
+ def __init__(self, stream, deferred, max_size):
+ self.stream = stream
+ self.deferred = deferred
+ self.length = 0
+ self.max_size = max_size
+
+ def dataReceived(self, data):
+ self.stream.write(data)
+ self.length += len(data)
+ if self.max_size is not None and self.length >= self.max_size:
+ self.deferred.errback(SynapseError(
+ 502,
+ "Requested file is too large > %r bytes" % (self.max_size,),
+ Codes.TOO_LARGE,
+ ))
+ self.deferred = defer.Deferred()
+ self.transport.loseConnection()
+
+ def connectionLost(self, reason):
+ if reason.check(ResponseDone):
+ self.deferred.callback(self.length)
+ elif reason.check(PotentialDataLoss):
+ # stolen from https://github.com/twisted/treq/pull/49/files
+ # http://twistedmatrix.com/trac/ticket/4840
+ self.deferred.callback(self.length)
+ else:
+ self.deferred.errback(reason)
+
+
+# XXX: FIXME: This is horribly copy-pasted from matrixfederationclient.
+# The two should be factored out.
+
+def _readBodyToFile(response, stream, max_size):
+ d = defer.Deferred()
+ response.deliverBody(_ReadBodyToFileProtocol(stream, d, max_size))
+ return d
+
class CaptchaServerHttpClient(SimpleHttpClient):
"""
@@ -269,6 +377,59 @@ class CaptchaServerHttpClient(SimpleHttpClient):
defer.returnValue(e.response)
+class SpiderEndpointFactory(object):
+ def __init__(self, hs):
+ self.blacklist = hs.config.url_preview_ip_range_blacklist
+ self.policyForHTTPS = hs.get_http_client_context_factory()
+
+ def endpointForURI(self, uri):
+ logger.info("Getting endpoint for %s", uri.toBytes())
+ if uri.scheme == "http":
+ return SpiderEndpoint(
+ reactor, uri.host, uri.port, self.blacklist,
+ endpoint=TCP4ClientEndpoint,
+ endpoint_kw_args={
+ 'timeout': 15
+ },
+ )
+ elif uri.scheme == "https":
+ tlsPolicy = self.policyForHTTPS.creatorForNetloc(uri.host, uri.port)
+ return SpiderEndpoint(
+ reactor, uri.host, uri.port, self.blacklist,
+ endpoint=SSL4ClientEndpoint,
+ endpoint_kw_args={
+ 'sslContextFactory': tlsPolicy,
+ 'timeout': 15
+ },
+ )
+ else:
+ logger.warn("Can't get endpoint for unrecognised scheme %s", uri.scheme)
+
+
+class SpiderHttpClient(SimpleHttpClient):
+ """
+ Separate HTTP client for spidering arbitrary URLs.
+ Special in that it follows retries and has a UA that looks
+ like a browser.
+
+ used by the preview_url endpoint in the content repo.
+ """
+ def __init__(self, hs):
+ SimpleHttpClient.__init__(self, hs)
+ # clobber the base class's agent and UA:
+ self.agent = ContentDecoderAgent(
+ BrowserLikeRedirectAgent(
+ Agent.usingEndpointFactory(
+ reactor,
+ SpiderEndpointFactory(hs)
+ )
+ ), [('gzip', GzipDecoder)]
+ )
+ # We could look like Chrome:
+ # self.user_agent = ("Mozilla/5.0 (%s) (KHTML, like Gecko)
+ # Chrome Safari" % hs.version_string)
+
+
def encode_urlencode_args(args):
return {k: encode_urlencode_arg(v) for k, v in args.items()}
diff --git a/synapse/http/endpoint.py b/synapse/http/endpoint.py
index bc28a2959a..a456dc19da 100644
--- a/synapse/http/endpoint.py
+++ b/synapse/http/endpoint.py
@@ -75,6 +75,37 @@ def matrix_federation_endpoint(reactor, destination, ssl_context_factory=None,
return transport_endpoint(reactor, domain, port, **endpoint_kw_args)
+class SpiderEndpoint(object):
+ """An endpoint which refuses to connect to blacklisted IP addresses
+ Implements twisted.internet.interfaces.IStreamClientEndpoint.
+ """
+ def __init__(self, reactor, host, port, blacklist,
+ endpoint=TCP4ClientEndpoint, endpoint_kw_args={}):
+ self.reactor = reactor
+ self.host = host
+ self.port = port
+ self.blacklist = blacklist
+ self.endpoint = endpoint
+ self.endpoint_kw_args = endpoint_kw_args
+
+ @defer.inlineCallbacks
+ def connect(self, protocolFactory):
+ address = yield self.reactor.resolve(self.host)
+
+ from netaddr import IPAddress
+ if IPAddress(address) in self.blacklist:
+ raise ConnectError(
+ "Refusing to spider blacklisted IP address %s" % address
+ )
+
+ logger.info("Connecting to %s:%s", address, self.port)
+ endpoint = self.endpoint(
+ self.reactor, address, self.port, **self.endpoint_kw_args
+ )
+ connection = yield endpoint.connect(protocolFactory)
+ defer.returnValue(connection)
+
+
class SRVClientEndpoint(object):
"""An endpoint which looks up SRV records for a service.
Cycles through the list of servers starting with each call to connect
@@ -120,7 +151,7 @@ class SRVClientEndpoint(object):
return self.default_server
else:
raise ConnectError(
- "Not server available for %s", self.service_name
+ "Not server available for %s" % self.service_name
)
min_priority = self.servers[0].priority
@@ -174,7 +205,7 @@ def resolve_service(service_name, dns_client=client, cache=SERVER_CACHE, clock=t
and answers[0].type == dns.SRV
and answers[0].payload
and answers[0].payload.target == dns.Name('.')):
- raise ConnectError("Service %s unavailable", service_name)
+ raise ConnectError("Service %s unavailable" % service_name)
for answer in answers:
if answer.type != dns.SRV or not answer.payload:
diff --git a/synapse/python_dependencies.py b/synapse/python_dependencies.py
index cf1414b4db..1adbdd9421 100644
--- a/synapse/python_dependencies.py
+++ b/synapse/python_dependencies.py
@@ -41,7 +41,11 @@ REQUIREMENTS = {
CONDITIONAL_REQUIREMENTS = {
"web_client": {
"matrix_angular_sdk>=0.6.8": ["syweb>=0.6.8"],
- }
+ },
+ "preview_url": {
+ "lxml>=3.6.0": ["lxml"],
+ "netaddr>=0.7.18": ["netaddr"],
+ },
}
diff --git a/synapse/rest/media/v1/base_resource.py b/synapse/rest/media/v1/base_resource.py
index 58ef91c0b8..2b1938dc8e 100644
--- a/synapse/rest/media/v1/base_resource.py
+++ b/synapse/rest/media/v1/base_resource.py
@@ -72,6 +72,7 @@ class BaseMediaResource(Resource):
self.store = hs.get_datastore()
self.max_upload_size = hs.config.max_upload_size
self.max_image_pixels = hs.config.max_image_pixels
+ self.max_spider_size = hs.config.max_spider_size
self.filepaths = filepaths
self.version_string = hs.version_string
self.downloads = {}
diff --git a/synapse/rest/media/v1/media_repository.py b/synapse/rest/media/v1/media_repository.py
index 7dfb027dd1..97b7e84af9 100644
--- a/synapse/rest/media/v1/media_repository.py
+++ b/synapse/rest/media/v1/media_repository.py
@@ -17,6 +17,7 @@ from .upload_resource import UploadResource
from .download_resource import DownloadResource
from .thumbnail_resource import ThumbnailResource
from .identicon_resource import IdenticonResource
+from .preview_url_resource import PreviewUrlResource
from .filepath import MediaFilePaths
from twisted.web.resource import Resource
@@ -78,3 +79,9 @@ class MediaRepositoryResource(Resource):
self.putChild("download", DownloadResource(hs, filepaths))
self.putChild("thumbnail", ThumbnailResource(hs, filepaths))
self.putChild("identicon", IdenticonResource())
+ if hs.config.url_preview_enabled:
+ try:
+ self.putChild("preview_url", PreviewUrlResource(hs, filepaths))
+ except Exception as e:
+ logger.warn("Failed to mount preview_url")
+ logger.exception(e)
diff --git a/synapse/rest/media/v1/preview_url_resource.py b/synapse/rest/media/v1/preview_url_resource.py
new file mode 100644
index 0000000000..8464fc0176
--- /dev/null
+++ b/synapse/rest/media/v1/preview_url_resource.py
@@ -0,0 +1,462 @@
+# -*- coding: utf-8 -*-
+# 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 .base_resource import BaseMediaResource
+
+from twisted.web.server import NOT_DONE_YET
+from twisted.internet import defer
+from urlparse import urlparse, urlsplit, urlunparse
+
+from synapse.api.errors import (
+ SynapseError, Codes,
+)
+from synapse.util.stringutils import random_string
+from synapse.util.caches.expiringcache import ExpiringCache
+from synapse.http.client import SpiderHttpClient
+from synapse.http.server import (
+ request_handler, respond_with_json_bytes
+)
+from synapse.util.async import ObservableDeferred
+from synapse.util.stringutils import is_ascii
+
+import os
+import re
+import fnmatch
+import cgi
+import ujson as json
+
+import logging
+logger = logging.getLogger(__name__)
+
+try:
+ from lxml import html
+except ImportError:
+ pass
+
+
+class PreviewUrlResource(BaseMediaResource):
+ isLeaf = True
+
+ def __init__(self, hs, filepaths):
+ try:
+ if html:
+ pass
+ except:
+ raise RuntimeError("Disabling PreviewUrlResource as lxml not available")
+
+ if not hasattr(hs.config, "url_preview_ip_range_blacklist"):
+ logger.warn(
+ "For security, you must specify an explicit target IP address "
+ "blacklist in url_preview_ip_range_blacklist for url previewing "
+ "to work"
+ )
+ raise RuntimeError(
+ "Disabling PreviewUrlResource as "
+ "url_preview_ip_range_blacklist not specified"
+ )
+
+ BaseMediaResource.__init__(self, hs, filepaths)
+ self.client = SpiderHttpClient(hs)
+ if hasattr(hs.config, "url_preview_url_blacklist"):
+ self.url_preview_url_blacklist = hs.config.url_preview_url_blacklist
+
+ # simple memory cache mapping urls to OG metadata
+ self.cache = ExpiringCache(
+ cache_name="url_previews",
+ clock=self.clock,
+ # don't spider URLs more often than once an hour
+ expiry_ms=60 * 60 * 1000,
+ )
+ self.cache.start()
+
+ self.downloads = {}
+
+ def render_GET(self, request):
+ self._async_render_GET(request)
+ return NOT_DONE_YET
+
+ @request_handler
+ @defer.inlineCallbacks
+ def _async_render_GET(self, request):
+
+ # XXX: if get_user_by_req fails, what should we do in an async render?
+ requester = yield self.auth.get_user_by_req(request)
+ url = request.args.get("url")[0]
+ if "ts" in request.args:
+ ts = int(request.args.get("ts")[0])
+ else:
+ ts = self.clock.time_msec()
+
+ # impose the URL pattern blacklist
+ if hasattr(self, "url_preview_url_blacklist"):
+ url_tuple = urlsplit(url)
+ for entry in self.url_preview_url_blacklist:
+ match = True
+ for attrib in entry:
+ pattern = entry[attrib]
+ value = getattr(url_tuple, attrib)
+ logger.debug((
+ "Matching attrib '%s' with value '%s' against"
+ " pattern '%s'"
+ ) % (attrib, value, pattern))
+
+ if value is None:
+ match = False
+ continue
+
+ if pattern.startswith('^'):
+ if not re.match(pattern, getattr(url_tuple, attrib)):
+ match = False
+ continue
+ else:
+ if not fnmatch.fnmatch(getattr(url_tuple, attrib), pattern):
+ match = False
+ continue
+ if match:
+ logger.warn(
+ "URL %s blocked by url_blacklist entry %s", url, entry
+ )
+ raise SynapseError(
+ 403, "URL blocked by url pattern blacklist entry",
+ Codes.UNKNOWN
+ )
+
+ # first check the memory cache - good to handle all the clients on this
+ # HS thundering away to preview the same URL at the same time.
+ og = self.cache.get(url)
+ if og:
+ respond_with_json_bytes(request, 200, json.dumps(og), send_cors=True)
+ return
+
+ # then check the URL cache in the DB (which will also provide us with
+ # historical previews, if we have any)
+ cache_result = yield self.store.get_url_cache(url, ts)
+ if (
+ cache_result and
+ cache_result["download_ts"] + cache_result["expires"] > ts and
+ cache_result["response_code"] / 100 == 2
+ ):
+ respond_with_json_bytes(
+ request, 200, cache_result["og"].encode('utf-8'),
+ send_cors=True
+ )
+ return
+
+ # Ensure only one download for a given URL is active at a time
+ download = self.downloads.get(url)
+ if download is None:
+ download = self._download_url(url, requester.user)
+ download = ObservableDeferred(
+ download,
+ consumeErrors=True
+ )
+ self.downloads[url] = download
+
+ @download.addBoth
+ def callback(media_info):
+ del self.downloads[url]
+ return media_info
+ media_info = yield download.observe()
+
+ # FIXME: we should probably update our cache now anyway, so that
+ # even if the OG calculation raises, we don't keep hammering on the
+ # remote server. For now, leave it uncached to aid debugging OG
+ # calculation problems
+
+ logger.debug("got media_info of '%s'" % media_info)
+
+ if self._is_media(media_info['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'],
+ "matrix:image:size": media_info['media_length'],
+ }
+
+ if dims:
+ og["og:image:width"] = dims['width']
+ og["og:image:height"] = dims['height']
+ else:
+ logger.warn("Couldn't get dims for %s" % url)
+
+ # define our OG response for this media
+ elif self._is_html(media_info['media_type']):
+ # TODO: somehow stop a big HTML tree from exploding synapse's RAM
+
+ try:
+ tree = html.parse(media_info['filename'])
+ og = yield self._calc_og(tree, media_info, requester)
+ except UnicodeDecodeError:
+ # XXX: evil evil bodge
+ # Empirically, sites like google.com mix Latin-1 and utf-8
+ # encodings in the same page. The rogue Latin-1 characters
+ # cause lxml to choke with a UnicodeDecodeError, so if we
+ # see this we go and do a manual decode of the HTML before
+ # handing it to lxml as utf-8 encoding, counter-intuitively,
+ # which seems to make it happier...
+ file = open(media_info['filename'])
+ body = file.read()
+ file.close()
+ tree = html.fromstring(body.decode('utf-8', 'ignore'))
+ og = yield self._calc_og(tree, media_info, requester)
+
+ else:
+ logger.warn("Failed to find any OG data in %s", url)
+ og = {}
+
+ logger.debug("Calculated OG for %s as %s" % (url, og))
+
+ # store OG in ephemeral in-memory cache
+ self.cache[url] = og
+
+ # store OG in history-aware DB cache
+ yield self.store.store_url_cache(
+ url,
+ media_info["response_code"],
+ media_info["etag"],
+ media_info["expires"],
+ json.dumps(og),
+ media_info["filesystem_id"],
+ media_info["created_ts"],
+ )
+
+ respond_with_json_bytes(request, 200, json.dumps(og), send_cors=True)
+
+
+ @defer.inlineCallbacks
+ def _calc_og(self, tree, media_info, requester):
+ # suck our tree into lxml and define our OG response.
+
+ # if we see any image 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" : "video",
+ # "og:url" : "https://www.youtube.com/watch?v=LXDBoHyjmtw",
+ # "og:site_name" : "YouTube",
+ # "og:video:type" : "application/x-shockwave-flash",
+ # "og:description" : "Fun stuff happening here",
+ # "og:title" : "RemoteJam - Matrix team hack for Disrupt Europe Hackathon",
+ # "og:image" : "https://i.ytimg.com/vi/LXDBoHyjmtw/maxresdefault.jpg",
+ # "og:video:url" : "http://www.youtube.com/v/LXDBoHyjmtw?version=3&autohide=1",
+ # "og:video:width" : "1280"
+ # "og:video:height" : "720",
+ # "og:video:secure_url": "https://www.youtube.com/v/LXDBoHyjmtw?version=3",
+
+ og = {}
+ for tag in tree.xpath("//*/meta[starts-with(@property, 'og:')]"):
+ og[tag.attrib['property']] = tag.attrib['content']
+
+ # TODO: grab article: meta tags too, e.g.:
+
+ # "article:publisher" : "https://www.facebook.com/thethudonline" />
+ # "article:author" content="https://www.facebook.com/thethudonline" />
+ # "article:tag" content="baby" />
+ # "article:section" content="Breaking News" />
+ # "article:published_time" content="2016-03-31T19:58:24+00:00" />
+ # "article:modified_time" content="2016-04-01T18:31:53+00:00" />
+
+ if 'og:title' not in og:
+ # do some basic spidering of the HTML
+ title = tree.xpath("(//title)[1] | (//h1)[1] | (//h2)[1] | (//h3)[1]")
+ og['og:title'] = title[0].text.strip() if title else None
+
+ if 'og:image' not in og:
+ # TODO: extract a favicon failing all else
+ meta_image = tree.xpath(
+ "//*/meta[translate(@itemprop, 'IMAGE', 'image')='image']/@content"
+ )
+ if meta_image:
+ og['og:image'] = self._rebase_url(meta_image[0], media_info['uri'])
+ else:
+ # TODO: consider inlined CSS styles as well as width & height attribs
+ images = tree.xpath("//img[@src][number(@width)>10][number(@height)>10]")
+ images = sorted(images, key=lambda i: (
+ -1 * int(i.attrib['width']) * int(i.attrib['height'])
+ ))
+ if not images:
+ images = tree.xpath("//img[@src]")
+ if images:
+ og['og:image'] = images[0].attrib['src']
+
+ # pre-cache the image for posterity
+ # FIXME: it might be cleaner to use the same flow as the main /preview_url request
+ # itself and benefit from the same caching etc. But for now we just rely on the
+ # caching on the master request to speed things up.
+ if 'og:image' in og and og['og:image']:
+ image_info = yield self._download_url(
+ self._rebase_url(og['og:image'], media_info['uri']), requester.user
+ )
+
+ if self._is_media(image_info['media_type']):
+ # TODO: make sure we don't choke on white-on-transparent images
+ dims = yield self._generate_local_thumbnails(
+ image_info['filesystem_id'], image_info
+ )
+ if dims:
+ og["og:image:width"] = dims['width']
+ og["og:image:height"] = dims['height']
+ else:
+ logger.warn("Couldn't get dims for %s" % og["og:image"])
+
+ og["og:image"] = "mxc://%s/%s" % (
+ self.server_name, image_info['filesystem_id']
+ )
+ og["og:image:type"] = image_info['media_type']
+ og["matrix:image:size"] = image_info['media_length']
+ else:
+ del og["og:image"]
+
+ if 'og:description' not in og:
+ meta_description = tree.xpath(
+ "//*/meta"
+ "[translate(@name, 'DESCRIPTION', 'description')='description']"
+ "/@content")
+ if meta_description:
+ og['og:description'] = meta_description[0]
+ else:
+ # grab any text nodes which are inside the <body/> tag...
+ # unless they are within an HTML5 semantic markup tag...
+ # <header/>, <nav/>, <aside/>, <footer/>
+ # ...or if they are within a <script/> or <style/> tag.
+ # This is a very very very coarse approximation to a plain text
+ # render of the page.
+ text_nodes = tree.xpath("//text()[not(ancestor::header | ancestor::nav | "
+ "ancestor::aside | ancestor::footer | "
+ "ancestor::script | ancestor::style)]" +
+ "[ancestor::body]")
+ text = ''
+ for text_node in text_nodes:
+ if len(text) < 500:
+ text += text_node + ' '
+ else:
+ break
+ text = re.sub(r'[\t ]+', ' ', text)
+ text = re.sub(r'[\t \r\n]*[\r\n]+', '\n', text)
+ text = text.strip()[:500]
+ og['og:description'] = text if text else None
+
+ # TODO: delete the url downloads to stop diskfilling,
+ # as we only ever cared about its OG
+ defer.returnValue(og)
+
+ def _rebase_url(self, url, base):
+ base = list(urlparse(base))
+ url = list(urlparse(url))
+ if not url[0]: # fix up schema
+ url[0] = base[0] or "http"
+ if not url[1]: # fix up hostname
+ url[1] = base[1]
+ if not url[2].startswith('/'):
+ url[2] = re.sub(r'/[^/]+$', '/', base[2]) + url[2]
+ return urlunparse(url)
+
+ @defer.inlineCallbacks
+ def _download_url(self, url, user):
+ # TODO: we should probably honour robots.txt... except in practice
+ # we're most likely being explicitly triggered by a human rather than a
+ # bot, so are we really a robot?
+
+ # 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:
+ logger.debug("Trying to get url '%s'" % url)
+ length, headers, uri, code = yield self.client.get_file(
+ url, output_stream=f, max_size=self.max_spider_size,
+ )
+ # FIXME: pass through 404s and other error messages nicely
+
+ 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=file_id,
+ media_type=media_type,
+ time_now_ms=self.clock.time_msec(),
+ upload_name=download_name,
+ media_length=length,
+ user_id=user,
+ )
+
+ except Exception as e:
+ os.remove(fname)
+ raise SynapseError(
+ 500, ("Failed to download content: %s" % e),
+ Codes.UNKNOWN
+ )
+
+ defer.returnValue({
+ "media_type": media_type,
+ "media_length": length,
+ "download_name": download_name,
+ "created_ts": time_now_ms,
+ "filesystem_id": file_id,
+ "filename": fname,
+ "uri": uri,
+ "response_code": code,
+ # FIXME: we should calculate a proper expiration based on the
+ # Cache-Control and Expire headers. But for now, assume 1 hour.
+ "expires": 60 * 60 * 1000,
+ "etag": headers["ETag"][0] if "ETag" in headers else None,
+ })
+
+ def _is_media(self, content_type):
+ if content_type.lower().startswith("image/"):
+ return True
+
+ def _is_html(self, content_type):
+ content_type = content_type.lower()
+ if (
+ content_type.startswith("text/html") or
+ content_type.startswith("application/xhtml")
+ ):
+ return True
diff --git a/synapse/rest/media/v1/thumbnail_resource.py b/synapse/rest/media/v1/thumbnail_resource.py
index ab52499785..513b445688 100644
--- a/synapse/rest/media/v1/thumbnail_resource.py
+++ b/synapse/rest/media/v1/thumbnail_resource.py
@@ -72,6 +72,11 @@ class ThumbnailResource(BaseMediaResource):
self._respond_404(request)
return
+ if media_info["media_type"] == "image/svg+xml":
+ file_path = self.filepaths.local_media_filepath(media_id)
+ yield self._respond_with_file(request, media_info["media_type"], file_path)
+ return
+
thumbnail_infos = yield self.store.get_local_media_thumbnails(media_id)
if thumbnail_infos:
@@ -103,6 +108,11 @@ class ThumbnailResource(BaseMediaResource):
self._respond_404(request)
return
+ if media_info["media_type"] == "image/svg+xml":
+ file_path = self.filepaths.local_media_filepath(media_id)
+ yield self._respond_with_file(request, media_info["media_type"], file_path)
+ return
+
thumbnail_infos = yield self.store.get_local_media_thumbnails(media_id)
for info in thumbnail_infos:
t_w = info["thumbnail_width"] == desired_width
@@ -138,6 +148,11 @@ class ThumbnailResource(BaseMediaResource):
desired_method, desired_type):
media_info = yield self._get_remote_media(server_name, media_id)
+ if media_info["media_type"] == "image/svg+xml":
+ file_path = self.filepaths.remote_media_filepath(server_name, media_id)
+ yield self._respond_with_file(request, media_info["media_type"], file_path)
+ return
+
thumbnail_infos = yield self.store.get_remote_media_thumbnails(
server_name, media_id,
)
@@ -181,6 +196,11 @@ class ThumbnailResource(BaseMediaResource):
# We should proxy the thumbnail from the remote server instead.
media_info = yield self._get_remote_media(server_name, media_id)
+ if media_info["media_type"] == "image/svg+xml":
+ file_path = self.filepaths.remote_media_filepath(server_name, media_id)
+ yield self._respond_with_file(request, media_info["media_type"], file_path)
+ return
+
thumbnail_infos = yield self.store.get_remote_media_thumbnails(
server_name, media_id,
)
@@ -208,6 +228,8 @@ class ThumbnailResource(BaseMediaResource):
@defer.inlineCallbacks
def _respond_default_thumbnail(self, request, media_info, width, height,
method, m_type):
+ # XXX: how is this meant to work? store.get_default_thumbnails
+ # appears to always return [] so won't this always 404?
media_type = media_info["media_type"]
top_level_type = media_type.split("/")[0]
sub_type = media_type.split("/")[-1].split(";")[0]
diff --git a/synapse/storage/media_repository.py b/synapse/storage/media_repository.py
index 9d3ba32478..a820fcf07f 100644
--- a/synapse/storage/media_repository.py
+++ b/synapse/storage/media_repository.py
@@ -25,7 +25,7 @@ class MediaRepositoryStore(SQLBaseStore):
def get_local_media(self, media_id):
"""Get the metadata for a local piece of media
Returns:
- None if the meia_id doesn't exist.
+ None if the media_id doesn't exist.
"""
return self._simple_select_one(
"local_media_repository",
@@ -50,6 +50,61 @@ class MediaRepositoryStore(SQLBaseStore):
desc="store_local_media",
)
+ def get_url_cache(self, url, ts):
+ """Get the media_id and ts for a cached URL as of the given timestamp
+ Returns:
+ None if the URL isn't cached.
+ """
+ def get_url_cache_txn(txn):
+ # get the most recently cached result (relative to the given ts)
+ sql = (
+ "SELECT response_code, etag, expires, og, media_id, download_ts"
+ " FROM local_media_repository_url_cache"
+ " WHERE url = ? AND download_ts <= ?"
+ " ORDER BY download_ts DESC LIMIT 1"
+ )
+ txn.execute(sql, (url, ts))
+ row = txn.fetchone()
+
+ if not row:
+ # ...or if we've requested a timestamp older than the oldest
+ # copy in the cache, return the oldest copy (if any)
+ sql = (
+ "SELECT response_code, etag, expires, og, media_id, download_ts"
+ " FROM local_media_repository_url_cache"
+ " WHERE url = ? AND download_ts > ?"
+ " ORDER BY download_ts ASC LIMIT 1"
+ )
+ txn.execute(sql, (url, ts))
+ row = txn.fetchone()
+
+ if not row:
+ return None
+
+ return dict(zip((
+ 'response_code', 'etag', 'expires', 'og', 'media_id', 'download_ts'
+ ), row))
+
+ return self.runInteraction(
+ "get_url_cache", get_url_cache_txn
+ )
+
+ def store_url_cache(self, url, response_code, etag, expires, og, media_id,
+ download_ts):
+ return self._simple_insert(
+ "local_media_repository_url_cache",
+ {
+ "url": url,
+ "response_code": response_code,
+ "etag": etag,
+ "expires": expires,
+ "og": og,
+ "media_id": media_id,
+ "download_ts": download_ts,
+ },
+ desc="store_url_cache",
+ )
+
def get_local_media_thumbnails(self, media_id):
return self._simple_select_list(
"local_media_repository_thumbnails",
diff --git a/synapse/storage/schema/delta/31/local_media_repository_url_cache.sql b/synapse/storage/schema/delta/31/local_media_repository_url_cache.sql
new file mode 100644
index 0000000000..9efb4280eb
--- /dev/null
+++ b/synapse/storage/schema/delta/31/local_media_repository_url_cache.sql
@@ -0,0 +1,27 @@
+/* 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.
+ */
+
+CREATE TABLE local_media_repository_url_cache(
+ url TEXT, -- the URL being cached
+ response_code INTEGER, -- the HTTP response code of this download attempt
+ etag TEXT, -- the etag header of this response
+ expires INTEGER, -- the number of ms this response was valid for
+ og TEXT, -- cache of the OG metadata of this URL as JSON
+ media_id TEXT, -- the media_id, if any, of the URL's content in the repo
+ download_ts BIGINT -- the timestamp of this download attempt
+);
+
+CREATE INDEX local_media_repository_url_cache_by_url_download_ts
+ ON local_media_repository_url_cache(url, download_ts);
|
