Use Facebook user agent for openGraph queries

We found that some websites return opengraph information based on the user agent. Since Facebook is the creator of opengraph, using the Facebook user agent when requesting the opengraph metadata should work in the widest variety of situations. https://developers.facebook.com/docs/sharing/webmasters/#user-agent Signed-off-by: Andrew Ryan <[email protected]>
matrix-org · Feb 13, 2022 · 04ee6a1 · 04ee6a1
1 parent 55113dd
commit 04ee6a1
Show file tree

Hide file tree

Showing 2 changed files with 5 additions and 1 deletion.
diff --git a/changelog.d/11985.misc b/changelog.d/11985.misc
@@ -0,0 +1 @@
+Use Facebook user agent for openGraph queries.
diff --git a/synapse/rest/media/v1/preview_url_resource.py b/synapse/rest/media/v1/preview_url_resource.py
@@ -402,7 +402,10 @@ async def _download_url(self, url: str, output_stream: BinaryIO) -> DownloadResu
                 url,
                 output_stream=output_stream,
                 max_size=self.max_spider_size,
-                headers={"Accept-Language": self.url_preview_accept_language},
+                headers={
+                    "Accept-Language": self.url_preview_accept_language,
+                    "User-Agent": "facebookexternalhit/1.1 (+http://www.facebook.com/externalhit_uatext.php)",
+                },
                 is_allowed_content_type=_is_previewable,
             )
         except SynapseError: