A Facebook Canvas URL‘s source has been updated with Open Graph protocol meta elements and linted (no problems). Here’s what happens once the changes are published:
- Accessing the canvas URL directly: Open Graph changes ARE reflected in the source, as expected.
- Posting the apps.facebook.com “Canvas Page” URL (which points to the remote Canvas URL) on one’s wall: The Open Graph changes ARE NOT reflected. That is, no image, title, description, et. al.
- If the Canvas Page URL is slightly modified (e.g., appended with “index.html” or “#”) before posting to one’s wall, the changes ARE reflected. Just not with the base URL.
- Using http-equiv “no-cache” meta in the source page has no effect.
Q: Is there some way to force something along the lines of a cache clear on the apps.facebook.com side, for the base Canvas URL?
Other thoughts:
- No FBML/XFBML is in use.
- Editing the app settings in various ways does not appear to help.
- Can’t rename the Canvas page at this point, as the app is now in production.
- Can’t append the Canvas URL with anything, as it must remain a directory.
- Renaming the Canvas page URL to use another path doesn’t help either.
UPDATE: I see I’m not the only one. Hmm … plundering the FB Bugzilla vaults. http://forum.developers.facebook.net/viewtopic.php?pid=329599#p329599
Filed with Facebook Bugzilla. Later confirmed as a share scraper bug and fixed.