I am currently developing a service that connects a Youtube account with a Facebook account.
More specifically, it will check firstly if the Facebook user has a Youtube account too, and vice versa and then it will create some visualizations.
The problem is that the application will need the user’s email to check in either of these SNS’ because the username will not probably be the same.
The question in hand is how to get the Youtube user’s email account form his channel, in order to search if he has a Facebook account too.
That would not solve your problem either. I could be using a different email for youtube and facebook. Check for some APIs for youtube and facebook that lets the current user do things.
Edit: Here are some links, if we assume that you want to help users upload videos they’ve uploaded to Facebook to their YouTube accuont.
You can access all the videos uploaded by this URL https://graph.facebook.com/me/videos/uploaded?access_token=YOUR_TOKEN
which will give you a list of
Videos(found this information at the facebook API reference)
Then you can use the YouTube API to upload those videos to YouTube: https://developers.google.com/youtube/2.0/developers_guide_protocol_uploading_videos