kaslo/synapse
1
0
Fork 0
Code Packages Releases 124 Wiki Activity

Update URL Preview code to work with lxml 6.0.0 (#18622)

Browse Source
This commit is contained in:
Andrew Morgan
2025-07-15 15:04:29 +01:00
committed by GitHub
parent e6dbbbb315
commit 5f027adb33
2 changed files with 27 additions and 4 deletions
Download Patch File Download Diff File Expand all files Collapse all files

1
changelog.d/18622.misc Normal file
View File

@@ -0,0 +1 @@
Update URL Preview code to work with `lxml` 6.0.0+.

30
synapse/media/preview_html.py
View File

@@ -133,7 +133,7 @@ def decode_body(
content_type: The Content-Type header.
Returns:
The parsed HTML body, or None if an error occurred during processed.
The parsed HTML body, or None if an error occurred during processing.
"""
# If there's no body, nothing useful is going to be found.
if not body:
@@ -158,9 +158,31 @@ def decode_body(
# Create an HTML parser.
parser = etree.HTMLParser(recover=True, encoding=encoding)
# Attempt to parse the body. Returns None if the body was successfully
# parsed, but no tree was found.
return etree.fromstring(body, parser)
# Attempt to parse the body. With `lxml` 6.0.0+, this will be an empty HTML
# tree if the body was successfully parsed, but no tree was found. In
# previous `lxml` versions, `etree.fromstring` would return `None` in that
# case.
html_tree = etree.fromstring(body, parser)
# Account for the above referenced case where `html_tree` is an HTML tree
# with an empty body. If so, return None.
if html_tree is not None and html_tree.tag == "html":
# If the tree has only a single <body> element and it's empty, then
# return None.
body_el = html_tree.find("body")
if body_el is not None and len(html_tree) == 1:
# Extract the content of the body tag as text.
body_text = "".join(cast(Iterable[str], body_el.itertext()))
# Strip any undecodable Unicode characters and whitespace.
body_text = body_text.strip("\ufffd").strip()
# If there's no text left, and there were no child tags,
# then we consider the <body> tag empty.
if not body_text and len(body_el) == 0:
return None
return html_tree
def _get_meta_tags(