diff --git a/synapse/rest/media/v1/preview_html.py b/synapse/rest/media/v1/preview_html.py
index 13ec7ab533..ed8f21a483 100644
--- a/synapse/rest/media/v1/preview_html.py
+++ b/synapse/rest/media/v1/preview_html.py
@@ -30,6 +30,9 @@ _xml_encoding_match = re.compile(
)
_content_type_match = re.compile(r'.*; *charset="?(.*?)"?(;|$)', flags=re.I)
+# Certain elements aren't meant for display.
+ARIA_ROLES_TO_IGNORE = {"directory", "menu", "menubar", "toolbar"}
+
def _normalise_encoding(encoding: str) -> Optional[str]:
"""Use the Python codec's name as the normalised entry."""
@@ -174,13 +177,15 @@ def parse_html_to_open_graph(tree: "etree.Element") -> Dict[str, Optional[str]]:
# "og:video:secure_url": "https://www.youtube.com/v/LXDBoHyjmtw?version=3",
og: Dict[str, Optional[str]] = {}
- for tag in tree.xpath("//*/meta[starts-with(@property, 'og:')]"):
- if "content" in tag.attrib:
- # if we've got more than 50 tags, someone is taking the piss
- if len(og) >= 50:
- logger.warning("Skipping OG for page with too many 'og:' tags")
- return {}
- og[tag.attrib["property"]] = tag.attrib["content"]
+ for tag in tree.xpath(
+ "//*/meta[starts-with(@property, 'og:')][@content][not(@content='')]"
+ ):
+ # if we've got more than 50 tags, someone is taking the piss
+ if len(og) >= 50:
+ logger.warning("Skipping OG for page with too many 'og:' tags")
+ return {}
+
+ og[tag.attrib["property"]] = tag.attrib["content"]
# TODO: grab article: meta tags too, e.g.:
@@ -192,21 +197,23 @@ def parse_html_to_open_graph(tree: "etree.Element") -> Dict[str, Optional[str]]:
# "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]")
- if title and title[0].text is not None:
- og["og:title"] = title[0].text.strip()
+ # Attempt to find a title from the title tag, or the biggest header on the page.
+ title = tree.xpath("((//title)[1] | (//h1)[1] | (//h2)[1] | (//h3)[1])/text()")
+ if title:
+ og["og:title"] = title[0].strip()
else:
og["og:title"] = 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"
+ "//*/meta[translate(@itemprop, 'IMAGE', 'image')='image'][not(@content='')]/@content[1]"
)
+ # If a meta image is found, use it.
if meta_image:
og["og:image"] = meta_image[0]
else:
+ # Try to find images which are larger than 10px by 10px.
+ #
# TODO: consider inlined CSS styles as well as width & height attribs
images = tree.xpath("//img[@src][number(@width)>10][number(@height)>10]")
images = sorted(
@@ -215,17 +222,24 @@ def parse_html_to_open_graph(tree: "etree.Element") -> Dict[str, Optional[str]]:
-1 * float(i.attrib["width"]) * float(i.attrib["height"])
),
)
+ # If no images were found, try to find *any* images.
if not images:
- images = tree.xpath("//img[@src]")
+ images = tree.xpath("//img[@src][1]")
if images:
og["og:image"] = images[0].attrib["src"]
+ # Finally, fallback to the favicon if nothing else.
+ else:
+ favicons = tree.xpath("//link[@href][contains(@rel, 'icon')]/@href[1]")
+ if favicons:
+ og["og:image"] = favicons[0]
+
if "og:description" not in og:
+ # Check the first meta description tag for content.
meta_description = tree.xpath(
- "//*/meta"
- "[translate(@name, 'DESCRIPTION', 'description')='description']"
- "/@content"
+ "//*/meta[translate(@name, 'DESCRIPTION', 'description')='description'][not(@content='')]/@content[1]"
)
+ # If a meta description is found with content, use it.
if meta_description:
og["og:description"] = meta_description[0]
else:
@@ -306,6 +320,10 @@ def _iterate_over_text(
if isinstance(el, str):
yield el
elif el.tag not in tags_to_ignore:
+ # If the element isn't meant for display, ignore it.
+ if el.get("role") in ARIA_ROLES_TO_IGNORE:
+ continue
+
# el.text is the text before the first child, so we can immediately
# return it if the text exists.
if el.text:
|
