diff options
Diffstat (limited to 'synapse/rest/media/v1')
| -rw-r--r-- | synapse/rest/media/v1/preview_url_resource.py | 353 |
1 files changed, 196 insertions, 157 deletions
diff --git a/synapse/rest/media/v1/preview_url_resource.py b/synapse/rest/media/v1/preview_url_resource.py index bdd0e60c5b..beafc8e736 100644 --- a/synapse/rest/media/v1/preview_url_resource.py +++ b/synapse/rest/media/v1/preview_url_resource.py @@ -163,7 +163,7 @@ class PreviewUrlResource(Resource): logger.debug("got media_info of '%s'" % media_info) - if self._is_media(media_info['media_type']): + if _is_media(media_info['media_type']): dims = yield self.media_repo._generate_local_thumbnails( media_info['filesystem_id'], media_info ) @@ -184,11 +184,9 @@ class PreviewUrlResource(Resource): logger.warn("Couldn't get dims for %s" % url) # define our OG response for this media - elif self._is_html(media_info['media_type']): + elif _is_html(media_info['media_type']): # TODO: somehow stop a big HTML tree from exploding synapse's RAM - from lxml import etree - file = open(media_info['filename']) body = file.read() file.close() @@ -199,17 +197,35 @@ class PreviewUrlResource(Resource): match = re.match(r'.*; *charset=(.*?)(;|$)', media_info['media_type'], re.I) encoding = match.group(1) if match else "utf-8" - try: - parser = etree.HTMLParser(recover=True, encoding=encoding) - tree = etree.fromstring(body, parser) - og = yield self._calc_og(tree, media_info, requester) - except UnicodeDecodeError: - # blindly try decoding the body as utf-8, which seems to fix - # the charset mismatches on https://google.com - parser = etree.HTMLParser(recover=True, encoding=encoding) - tree = etree.fromstring(body.decode('utf-8', 'ignore'), parser) - og = yield self._calc_og(tree, media_info, requester) + og = decode_and_calc_og(body, media_info['uri'], encoding) + # 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( + _rebase_url(og['og:image'], media_info['uri']), requester.user + ) + + if _is_media(image_info['media_type']): + # TODO: make sure we don't choke on white-on-transparent images + dims = yield self.media_repo._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"] else: logger.warn("Failed to find any OG data in %s", url) og = {} @@ -233,139 +249,6 @@ class PreviewUrlResource(Resource): 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:')]"): - if 'content' in tag.attrib: - 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 * float(i.attrib['width']) * float(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.media_repo._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. - - # We don't just use XPATH here as that is slow on some machines. - - # We clone `tree` as we modify it. - cloned_tree = deepcopy(tree.find("body")) - - TAGS_TO_REMOVE = ("header", "nav", "aside", "footer", "script", "style",) - for el in cloned_tree.iter(TAGS_TO_REMOVE): - el.getparent().remove(el) - - # Split all the text nodes into paragraphs (by splitting on new - # lines) - text_nodes = ( - re.sub(r'\s+', '\n', el.text).strip() - for el in cloned_tree.iter() - if el.text and isinstance(el.tag, basestring) # Removes comments - ) - og['og:description'] = summarize_paragraphs(text_nodes) - - # 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.urlparse(base)) - url = list(urlparse.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 urlparse.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 @@ -445,17 +328,173 @@ class PreviewUrlResource(Resource): "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 +def decode_and_calc_og(body, media_uri, request_encoding=None): + from lxml import etree + + try: + parser = etree.HTMLParser(recover=True, encoding=request_encoding) + tree = etree.fromstring(body, parser) + og = _calc_og(tree, media_uri) + except UnicodeDecodeError: + # blindly try decoding the body as utf-8, which seems to fix + # the charset mismatches on https://google.com + parser = etree.HTMLParser(recover=True, encoding=request_encoding) + tree = etree.fromstring(body.decode('utf-8', 'ignore'), parser) + og = _calc_og(tree, media_uri) + + return og + + +def _calc_og(tree, media_uri): + # 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:')]"): + if 'content' in tag.attrib: + 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'] = _rebase_url(meta_image[0], media_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 * float(i.attrib['width']) * float(i.attrib['height']) + )) + if not images: + images = tree.xpath("//img[@src]") + if images: + og['og:image'] = images[0].attrib['src'] + + 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. + + # We don't just use XPATH here as that is slow on some machines. + + from lxml import etree + + TAGS_TO_REMOVE = ( + "header", "nav", "aside", "footer", "script", "style", etree.Comment + ) + + # Split all the text nodes into paragraphs (by splitting on new + # lines) + text_nodes = ( + re.sub(r'\s+', '\n', el).strip() + for el in _iterate_over_text(tree.find("body"), *TAGS_TO_REMOVE) + ) + og['og:description'] = summarize_paragraphs(text_nodes) + + # TODO: delete the url downloads to stop diskfilling, + # as we only ever cared about its OG + return og + + +def _iterate_over_text(tree, *tags_to_ignore): + """Iterate over the tree returning text nodes in a depth first fashion, + skipping text nodes inside certain tags. + """ + import itertools + + # This is basically a stack that we extend using itertools.chain. + # This will either consist of an element to iterate over *or* a string + # to be returned. + elements = iter([tree]) + while True: + el = elements.next() + if isinstance(el, basestring): + yield el + elif el.tag not in tags_to_ignore: + # el.text is the text before the first child, so we can immediately + # return it if the text exists. + if el.text: + yield el.text + + # We add to the stack all the elements children, interspersed with + # each child's tail text (if it exists). The tail text of a node + # is text that comes *after* the node, so we always include it even + # if we ignore the child node. + elements = itertools.chain( + itertools.chain.from_iterable( # Basically a flatmap + [child, child.tail] if child.tail else [child] + for child in el.iterchildren() + ), + elements + ) + + +def _rebase_url(url, base): + base = list(urlparse.urlparse(base)) + url = list(urlparse.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 urlparse.urlunparse(url) + + +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.startswith("text/html") or + content_type.startswith("application/xhtml") + ): + return True def summarize_paragraphs(text_nodes, min_size=200, max_size=500): |