I've recently updated a TYPO3 instance from 7 to 8 (now 8.7.22, PHP 7.2) (it was before the release of 9.5, obviously) and I run into an issue with the previously working self set og: and twitter: meta tags.
The customer needs these for SEO optimization and twitter improved twitter sharing behaviour.
We built this:
page.meta {
description.data = levelfield:-1, description, slide
keywords.data = levelfield:-1, keywords, slide
bitly-verification =
og:site_name =
og:description.data = levelfield:-1, description, slide
og:description.attribute = property
og:type = website
og:type.attribute = property
og:locale.attribute = property
og:site_name.attribute = property
X-UA-Compatible = IE=edge
twitter:card.data = levelfield:-1, tx_metadata_twitter_card, slide
twitter:card.attribute = property
twitter:site.data = levelfield:-1, tx_metadata_twitter_site, slide
twitter:site.attribute = property
twitter:creator.data = levelfield:-1, tx_metadata_twitter_creator, slide
twitter:creator.attribute = property
twitter:account_id.data = levelfield:-1, tx_metadata_twitter_account_id, slide
twitter:account_id.attribute = property
fb:admins.data = levelfield:-1, tx_metadata_facebook_admin, slide
fb:admins.attribute = property
viewport = width=device-width, initial-scale=1.0, minimum-scale=1.0, maximum-scale=1.0, user-scalable=no
author >
}
And added the fields to $TYPO3_CONF_VARS['FE']['addRootlineFields'] (which according to the configuration module still works perfectly).
The issue is, that only the og:description, og:site_name as well as og:type meta information seem to work, but the twitter: and fb: ones don't work at all.
The data is available in the database.
I was wondering if someething could screw up my typoscript but the parsed typoscript displays completely in the Typoscript Object Browser.
I suspect that something is wrong in the parsing when evaluating the twitter: and fb: keys but I could not pinpoint where this evaluation is made in the code. The documentation does not give much either.
[EDIT]: I forgot to mention that the meta data is not rendered in the order it is in the typoscript but is somehow scrambled, so I also suspected an extension to screw this up.
[UPDATE]: In a local development environment with docker (same setup as the production webserver) the tags do work normally.
[UPDATE 2]: It appears that the culprit is somewhere in EXT:frontend/Classes/Page/PageGenerator.php:PageGenerator::generateMetaTagHtml when resolving the values from Typoscript using stdWrap. I'll continue digging there.
So, it turns out, TYPO3 is really good in caching rootline information, but not in clearing the data...
Truncating all cf_* tables solved the issue. Appearently, even when clearing the whole cache in the install tool, this cache is not properly flushed.