diff --git a/synapse/rest/media/v1/preview_url_resource.py b/synapse/rest/media/v1/preview_url_resource.py
index a7ffe593b1..1273472dab 100644
--- a/synapse/rest/media/v1/preview_url_resource.py
+++ b/synapse/rest/media/v1/preview_url_resource.py
@@ -20,6 +20,7 @@ from twisted.internet import defer
from lxml import html
from urlparse import urlparse, urlunparse
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, respond_with_json_bytes
@@ -36,6 +37,12 @@ class PreviewUrlResource(BaseMediaResource):
def __init__(self, hs, filepaths):
BaseMediaResource.__init__(self, hs, filepaths)
self.client = SpiderHttpClient(hs)
+ self.cache = ExpiringCache(
+ cache_name = "url_previews",
+ clock = self.clock,
+ expiry_ms = 60*60*1000, # don't spider URLs more often than once an hour
+ )
+ self.cache.start()
def render_GET(self, request):
self._async_render_GET(request)
@@ -50,6 +57,11 @@ class PreviewUrlResource(BaseMediaResource):
requester = yield self.auth.get_user_by_req(request)
url = request.args.get("url")[0]
+ if self.cache:
+ og = self.cache.get(url)
+ respond_with_json_bytes(request, 200, json.dumps(og), send_cors=True)
+ return
+
# TODO: keep track of whether there's an ongoing request for this preview
# and block and return their details if there is one.
@@ -74,98 +86,25 @@ class PreviewUrlResource(BaseMediaResource):
elif self._is_html(media_info['media_type']):
# TODO: somehow stop a big HTML tree from exploding synapse's RAM
- def _calc_og():
- # 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"
-
- # or:
-
- # "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" : " ",
- # "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&autohide=1",
-
- og = {}
- for tag in tree.xpath("//*/meta[starts-with(@property, 'og:')]"):
- og[tag.attrib['property']] = tag.attrib['content']
-
- 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 if title else None
-
-
- if 'og:image' not in og:
- meta_image = tree.xpath("//*/meta[@itemprop='image']/@content");
- if meta_image:
- og['og:image'] = self._rebase_url(meta_image[0], media_info['uri'])
- else:
- images = [ i for i in tree.xpath("//img") if 'src' in i.attrib ]
- big_images = [ i for i in images if (
- 'width' in i.attrib and 'height' in i.attrib and
- i.attrib['width'] > 64 and i.attrib['height'] > 64
- )]
- big_images = big_images.sort(key=lambda i: (-1 * int(i.attrib['width']) * int(i.attrib['height'])))
- images = big_images if big_images else images
-
- if images:
- og['og:image'] = self._rebase_url(images[0].attrib['src'], media_info['uri'])
-
- if 'og:description' not in og:
- meta_description = tree.xpath("//*/meta[@name='description']/@content");
- if meta_description:
- og['og:description'] = meta_description[0]
- else:
- text_nodes = tree.xpath("//h1/text() | //h2/text() | //h3/text() | //p/text() | //div/text() | //span/text() | //a/text()")
- # text_nodes = tree.xpath("//h1/text() | //h2/text() | //h3/text() | //p/text() | //div/text()")
- 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: extract a favicon?
- # TODO: turn any OG media URLs into mxc URLs to capture and thumbnail them too
- # 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
- return og
-
try:
tree = html.parse(media_info['filename'])
- og = _calc_og()
+ og = yield self._calc_og(tree, media_info, requester)
except UnicodeDecodeError:
# XXX: evil evil bodge
file = open(media_info['filename'])
body = file.read()
file.close()
tree = html.fromstring(body.decode('utf-8','ignore'))
- og = _calc_og()
+ og = yield self._calc_og(tree, media_info, requester)
else:
logger.warn("Failed to find any OG data in %s", url)
og = {}
- logger.warn(og)
+ if self.cache:
+ self.cache[url] = og
+
+ logger.warn(og);
respond_with_json_bytes(request, 200, json.dumps(og), send_cors=True)
except:
@@ -182,11 +121,112 @@ class PreviewUrlResource(BaseMediaResource):
)
raise
+ @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" : "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"
+
+ # or:
+
+ # "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" : " ",
+ # "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&autohide=1",
+
+ 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.:
+
+ #
+ #
+ #
+ #
+ #
+ #
+
+ 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[@itemprop='image']/@content");
+ if meta_image:
+ og['og:image'] = self._rebase_url(meta_image[0], media_info['uri'])
+ else:
+ 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'] = self._rebase_url(images[0].attrib['src'], media_info['uri'])
+
+ # pre-cache the image for posterity
+ if 'og:image' in og and og['og:image']:
+ image_info = yield self._download_url(og['og:image'], 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
+ )
+ og["og:image"] = "mxc://%s/%s" % (self.server_name, image_info['filesystem_id'])
+ og["og:image:type"] = image_info['media_type']
+ og["og:image:width"] = dims['width']
+ og["og:image:height"] = dims['height']
+ else:
+ del og["og:image"]
+
+ if 'og:description' not in og:
+ meta_description = tree.xpath("//*/meta[@name='description']/@content");
+ if meta_description:
+ og['og:description'] = meta_description[0]
+ else:
+ # text_nodes = tree.xpath("//h1/text() | //h2/text() | //h3/text() | //p/text() | //div/text() | //span/text() | //a/text()")
+ 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: persist a cache mapping { url, etag } -> { og, mxc of url (if we bother keeping it around), age }
+ # 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] and not url[1]:
- url[0] = base[0]
+ if not url[0]:
+ url[0] = base[0] or "http"
+ if not url[1]:
url[1] = base[1]
if not url[2].startswith('/'):
url[2] = re.sub(r'/[^/]+$', '/', base[2]) + url[2]