We know that Wikipedia generally don't use any third party CDN service. However, it is quite common for other wiki site (e.g. we the Moegirlpedia) to use commercial CDN service (Akamai/Cloudflare etc...). By far, there is no third party cache/proxy purge support available in Mediaiwki. Not even a hook allow extensions to get the page purge request.
When new content is uploaded to a MediaWiki, the wiki software will request that each cache server (as configured in $wgSquidServers) discard the outdated version of the page or image. This notification is not sent to third-party web proxies (such as those listed in Extension:TrustedXFF) and appears to be hard-coded in SquidPurgeClient.php in core MediaWiki code with no hooks to allow an extension to change this behavior.
We wish Mediawiki to add a new hook, which allows extension developer to catch the purge request url, then send the request to commercial CDN service via their API system.
There was a similar hook available, however it was removed completely in Mediawiki version 1.17.0.
To be more specific,
We know that $wgSquidServers setting is able to send standard Squid/Varnish purge request format PURGE http://wiki.example.org/Page. However, most commercial CDN service have their own purge request API system, and refuse to honor the standard format purge request.
Therefore, to create a extension, which implement third party commercial CDN purge function. The extension need to acquire all the URL of pages need purge, then convert the request to specific API format, then send to CDN servers.
We are developing Mediawiki extension that send purge request to Cloudflare. But there is no internal ways to get url of purge request from Mediawiki.
Therefore, a Mediawiki hook, which can pass all the purge request url to extensions, is needed.