refactor calc_og; spider image URLs; fix xpath; add a (broken) expiringcache; loads of other fixes
Matthew Hodgson
parent
c60b751694
commit
5fd07da764
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@ -20,6 +20,7 @@ from twisted.internet import defer
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from lxml import html
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from urlparse import urlparse, urlunparse
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from synapse.util.stringutils import random_string
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from synapse.util.caches.expiringcache import ExpiringCache
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from synapse.http.client import SpiderHttpClient
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from synapse.http.server import request_handler, respond_with_json, respond_with_json_bytes
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@ -36,6 +37,12 @@ class PreviewUrlResource(BaseMediaResource):
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def __init__(self, hs, filepaths):
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BaseMediaResource.__init__(self, hs, filepaths)
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self.client = SpiderHttpClient(hs)
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self.cache = ExpiringCache(
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cache_name = "url_previews",
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clock = self.clock,
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expiry_ms = 60*60*1000, # don't spider URLs more often than once an hour
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)
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self.cache.start()
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def render_GET(self, request):
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self._async_render_GET(request)
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@ -50,6 +57,11 @@ class PreviewUrlResource(BaseMediaResource):
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requester = yield self.auth.get_user_by_req(request)
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url = request.args.get("url")[0]
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if self.cache:
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og = self.cache.get(url)
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respond_with_json_bytes(request, 200, json.dumps(og), send_cors=True)
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return
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# TODO: keep track of whether there's an ongoing request for this preview
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# and block and return their details if there is one.
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@ -74,98 +86,25 @@ class PreviewUrlResource(BaseMediaResource):
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elif self._is_html(media_info['media_type']):
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# TODO: somehow stop a big HTML tree from exploding synapse's RAM
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def _calc_og():
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# suck it up into lxml and define our OG response.
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# if we see any URLs in the OG response, then spider them
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# (although the client could choose to do this by asking for previews of those URLs to avoid DoSing the server)
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# "og:type" : "article"
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# "og:url" : "https://twitter.com/matrixdotorg/status/684074366691356672"
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# "og:title" : "Matrix on Twitter"
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# "og:image" : "https://pbs.twimg.com/profile_images/500400952029888512/yI0qtFi7_400x400.png"
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# "og:description" : "Synapse 0.12 is out! Lots of polishing, performance & bugfixes: /sync API, /r0 prefix, fulltext search, 3PID invites https://t.co/5alhXLLEGP"
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# "og:site_name" : "Twitter"
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# or:
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# "og:type" : "video",
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# "og:url" : "https://www.youtube.com/watch?v=LXDBoHyjmtw",
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# "og:site_name" : "YouTube",
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# "og:video:type" : "application/x-shockwave-flash",
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# "og:description" : " ",
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# "og:title" : "RemoteJam - Matrix team hack for Disrupt Europe Hackathon",
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# "og:image" : "https://i.ytimg.com/vi/LXDBoHyjmtw/maxresdefault.jpg",
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# "og:video:url" : "http://www.youtube.com/v/LXDBoHyjmtw?version=3&autohide=1",
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# "og:video:width" : "1280"
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# "og:video:height" : "720",
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# "og:video:secure_url": "https://www.youtube.com/v/LXDBoHyjmtw?version=3&autohide=1",
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og = {}
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for tag in tree.xpath("//*/meta[starts-with(@property, 'og:')]"):
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og[tag.attrib['property']] = tag.attrib['content']
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if 'og:title' not in og:
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# do some basic spidering of the HTML
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title = tree.xpath("(//title)[1] | (//h1)[1] | (//h2)[1] | (//h3)[1]")
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og['og:title'] = title[0].text if title else None
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if 'og:image' not in og:
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meta_image = tree.xpath("//*/meta[@itemprop='image']/@content");
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if meta_image:
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og['og:image'] = self._rebase_url(meta_image[0], media_info['uri'])
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else:
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images = [ i for i in tree.xpath("//img") if 'src' in i.attrib ]
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big_images = [ i for i in images if (
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'width' in i.attrib and 'height' in i.attrib and
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i.attrib['width'] > 64 and i.attrib['height'] > 64
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)]
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big_images = big_images.sort(key=lambda i: (-1 * int(i.attrib['width']) * int(i.attrib['height'])))
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images = big_images if big_images else images
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if images:
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og['og:image'] = self._rebase_url(images[0].attrib['src'], media_info['uri'])
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if 'og:description' not in og:
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meta_description = tree.xpath("//*/meta[@name='description']/@content");
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if meta_description:
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og['og:description'] = meta_description[0]
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else:
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text_nodes = tree.xpath("//h1/text() | //h2/text() | //h3/text() | //p/text() | //div/text() | //span/text() | //a/text()")
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# text_nodes = tree.xpath("//h1/text() | //h2/text() | //h3/text() | //p/text() | //div/text()")
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text = ''
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for text_node in text_nodes:
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if len(text) < 500:
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text += text_node + ' '
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else:
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break
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text = re.sub(r'[\t ]+', ' ', text)
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text = re.sub(r'[\t \r\n]*[\r\n]+', '\n', text)
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text = text.strip()[:500]
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og['og:description'] = text if text else None
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# TODO: extract a favicon?
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# TODO: turn any OG media URLs into mxc URLs to capture and thumbnail them too
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# TODO: store our OG details in a cache (and expire them when stale)
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# TODO: delete the content to stop diskfilling, as we only ever cared about its OG
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return og
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try:
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tree = html.parse(media_info['filename'])
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og = _calc_og()
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og = yield self._calc_og(tree, media_info, requester)
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except UnicodeDecodeError:
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# XXX: evil evil bodge
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file = open(media_info['filename'])
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body = file.read()
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file.close()
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tree = html.fromstring(body.decode('utf-8','ignore'))
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og = _calc_og()
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og = yield self._calc_og(tree, media_info, requester)
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else:
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logger.warn("Failed to find any OG data in %s", url)
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og = {}
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logger.warn(og)
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if self.cache:
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self.cache[url] = og
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logger.warn(og);
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respond_with_json_bytes(request, 200, json.dumps(og), send_cors=True)
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except:
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@ -182,11 +121,112 @@ class PreviewUrlResource(BaseMediaResource):
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)
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raise
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@defer.inlineCallbacks
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def _calc_og(self, tree, media_info, requester):
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# suck our tree into lxml and define our OG response.
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# if we see any image URLs in the OG response, then spider them
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# (although the client could choose to do this by asking for previews of those URLs to avoid DoSing the server)
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# "og:type" : "article"
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# "og:url" : "https://twitter.com/matrixdotorg/status/684074366691356672"
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# "og:title" : "Matrix on Twitter"
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# "og:image" : "https://pbs.twimg.com/profile_images/500400952029888512/yI0qtFi7_400x400.png"
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# "og:description" : "Synapse 0.12 is out! Lots of polishing, performance &amp; bugfixes: /sync API, /r0 prefix, fulltext search, 3PID invites https://t.co/5alhXLLEGP"
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# "og:site_name" : "Twitter"
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# or:
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# "og:type" : "video",
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# "og:url" : "https://www.youtube.com/watch?v=LXDBoHyjmtw",
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# "og:site_name" : "YouTube",
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# "og:video:type" : "application/x-shockwave-flash",
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# "og:description" : " ",
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# "og:title" : "RemoteJam - Matrix team hack for Disrupt Europe Hackathon",
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# "og:image" : "https://i.ytimg.com/vi/LXDBoHyjmtw/maxresdefault.jpg",
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# "og:video:url" : "http://www.youtube.com/v/LXDBoHyjmtw?version=3&autohide=1",
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# "og:video:width" : "1280"
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# "og:video:height" : "720",
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# "og:video:secure_url": "https://www.youtube.com/v/LXDBoHyjmtw?version=3&autohide=1",
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og = {}
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for tag in tree.xpath("//*/meta[starts-with(@property, 'og:')]"):
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og[tag.attrib['property']] = tag.attrib['content']
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# TODO: grab article: meta tags too, e.g.:
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# <meta property="article:publisher" content="https://www.facebook.com/thethudonline" />
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# <meta property="article:author" content="https://www.facebook.com/thethudonline" />
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# <meta property="article:tag" content="baby" />
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# <meta property="article:section" content="Breaking News" />
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# <meta property="article:published_time" content="2016-03-31T19:58:24+00:00" />
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# <meta property="article:modified_time" content="2016-04-01T18:31:53+00:00" />
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if 'og:title' not in og:
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# do some basic spidering of the HTML
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title = tree.xpath("(//title)[1] | (//h1)[1] | (//h2)[1] | (//h3)[1]")
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og['og:title'] = title[0].text.strip() if title else None
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if 'og:image' not in og:
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# TODO: extract a favicon failing all else
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meta_image = tree.xpath("//*/meta[@itemprop='image']/@content");
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if meta_image:
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og['og:image'] = self._rebase_url(meta_image[0], media_info['uri'])
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else:
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images = tree.xpath("//img[@src][number(@width)>10][number(@height)>10]")
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images = sorted(images, key=lambda i: (-1 * int(i.attrib['width']) * int(i.attrib['height'])))
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if not images:
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images = tree.xpath("//img[@src]")
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if images:
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og['og:image'] = self._rebase_url(images[0].attrib['src'], media_info['uri'])
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# pre-cache the image for posterity
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if 'og:image' in og and og['og:image']:
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image_info = yield self._download_url(og['og:image'], requester.user)
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if self._is_media(image_info['media_type']):
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# TODO: make sure we don't choke on white-on-transparent images
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dims = yield self._generate_local_thumbnails(
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image_info['filesystem_id'], image_info
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)
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og["og:image"] = "mxc://%s/%s" % (self.server_name, image_info['filesystem_id'])
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og["og:image:type"] = image_info['media_type']
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og["og:image:width"] = dims['width']
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og["og:image:height"] = dims['height']
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else:
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del og["og:image"]
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if 'og:description' not in og:
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meta_description = tree.xpath("//*/meta[@name='description']/@content");
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if meta_description:
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og['og:description'] = meta_description[0]
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else:
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# text_nodes = tree.xpath("//h1/text() | //h2/text() | //h3/text() | //p/text() | //div/text() | //span/text() | //a/text()")
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text_nodes = tree.xpath("//text()[not(ancestor::header | ancestor::nav | ancestor::aside | " +
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"ancestor::footer | ancestor::script | ancestor::style)]" +
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"[ancestor::body]")
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text = ''
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for text_node in text_nodes:
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if len(text) < 500:
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text += text_node + ' '
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else:
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break
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text = re.sub(r'[\t ]+', ' ', text)
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text = re.sub(r'[\t \r\n]*[\r\n]+', '\n', text)
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text = text.strip()[:500]
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og['og:description'] = text if text else None
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# TODO: persist a cache mapping { url, etag } -> { og, mxc of url (if we bother keeping it around), age }
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# TODO: delete the url downloads to stop diskfilling, as we only ever cared about its OG
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defer.returnValue(og);
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def _rebase_url(self, url, base):
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base = list(urlparse(base))
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url = list(urlparse(url))
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if not url[0] and not url[1]:
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url[0] = base[0]
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if not url[0]:
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url[0] = base[0] or "http"
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if not url[1]:
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url[1] = base[1]
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if not url[2].startswith('/'):
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url[2] = re.sub(r'/[^/]+$', '/', base[2]) + url[2]
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