Cross-site authenticated RSS

Or: How we can make it so that people can read friends-only entries on other sites from their DW reading page.

I dump in an email I wrote in order to kick off the conversation:

Syndicated feeds are treated like any other account -- each item in the feed
is given its own entryID in the syndicated account, and that behaves just like
any other entry (in terms of building the friends page, etc). Now, there's a
mechanism in RSS to authenticate to the server providing the feed, and LJ
treats that authenticated RSS like they would if you were logged in; if you'd
see the entry on someone else's journal, you'll see it in their RSS feed while
you're using RSS authentication.

The easy-but-evil solution would be for us to use someone's authentication
credits to pull down the RSS feed of a journal, store all the FO entries
locally, and then every time someone who had that feed friended reloaded their
FP, check against the feedowner's friends list on LJ to see if the local
viewer was permitted to see that entry. That's the evil way to do it. We
aren't going to do that.

Now, the idea that I'm currently fronting to solve the problem is instead to
create a new type of account -- call it an aggregation account or whatever.
Users can then give us the list of people who have them friended on LJ (or
wherever, assume that I mean any LJ-based site when I say LJ, it's easier) and
also give us their login credentials for LJ, or give us their LJ OpenID or
whatever, any way that we can get the authentication done, I'm not a coder,
blah blah. The aggregation account would then poll those RSS feeds at a MUCH
slower rate than for the regular RSS feed (to prevent LJ from banning us for
hitting them too often -- because with a regular syndication account for just
the public entries, you only have to check once; to check for FO entries, you
have to check with every single person's separate credentials to see if they
have entries they can see) and see if there are any FO entries that they can
see.

If there is a new entry, and it's FO/filtered, and the person whose login
credentials are being supplied can see it, we insert an item into the
aggregation account that says "your friend $friendname posted a friends-locked
entry that you can see. Its URL is: $url".

The aggregation account will then insert that item into the actual reading
list, so that notification will appear on your DW readlist -- not the
*content* of the entry, but the fact that someone *posted* it, along with a
link. Sure, there's a chance the poster will have re-filtered the entry by the
time the person gets to it, especially since we'd *have* to make the
polling-for-FO-entries a very slow thing (probably only once every 12 or 24
hours), but we could still introduce the fact that there *was* an entry into
your reading list. You could then go click the link and open up the entry in
another tab, another window, etc.

--Rahaeli 10:27, 30 January 2009 (UTC)