I have a test application running at test.rsscloud.io on ports 80 and 9876.
The following code works:
curl --location --request POST 'https://brokenriverbooks.com/?rsscloud=notify' \
--header 'Content-Type: application/x-www-form-urlencoded' \
--data-urlencode 'domain=test.rsscloud.io' \
--data-urlencode 'port=80' \
--data-urlencode 'path=/feedupdated-s8759' \
--data-urlencode 'registerProcedure=' \
--data-urlencode 'protocol=http-post' \
--data-urlencode 'url1=https://brokenriverbooks.com/feed/'
However if you change the port to 9876 it fails. For some reason the rssCloud plugin seems unable to hit ports that are not 80.
👋 Hi!
On the port front, I'm not inclined to change it. WordPress and the RSSCloud plugin have been working this way for more than 7 years.
The scheme issue seems to be new, or at least something that may have changed in the last 7 years. I'll unwind that code path more and see what falls out. The already suggested idea of defaulting to HTTP when no scheme is provided sounds like a reasonable way forward.
Separately, it looks like there are couple of spots in the plugin that need updating to run under PHP 8. I'll look into that closer and get an update out if needed.