Youtube PubSubHubBub Integration

Question

Been stuck on this integration problem for hours now. I am trying to subscribe to a youtube channel updates using https://pubsubhubbub.appspot.com/subscribe.

And my server is setup to respond with:

But when I press DO IT, I always get back the error saying Challenge mismatch.

I am unsure which parameter I am missing to set.

Answer 1

The intended response is not a static value as hub_challenge. It should return back the hub.challenge value which is received in query parameters when GET request is sent to the callback url.

More Information

The request will be something like /notifications?hub.topic=https://www.youtube.com/xml/feeds/videos.xml%3Fchannel_id%3DUCn0QU5ZOaVnEf7LkdyPF9kQ&hub.challenge=216582865281647747&hub.mode=subscribe&hub.lease_seconds=432000"

The response of should be the value hub.challenge (216582865281647747)