When we proxy a media request to a remote server, add a query-param, which will
tell the remote server to 404 if it doesn't recognise the server_name.
This should fix a routing loop where the server keeps forwarding back to
itself.
Also improves the error handling on remote media fetches, so that we don't
always return a rather obscure 502.
We might as well treat all refresh_tokens as invalid. Just return a 403 from
/tokenrefresh, so that we don't have a load of dead, untestable code hanging
around.
Still TODO: removing the table from the schema.
The 'time' caveat on the access tokens was something of a lie, since we weren't
enforcing it; more pertinently its presence stops us ever adding useful time
caveats.
Let's move in the right direction by not lying in our caveats.
This is currently very conservative in that it only does this if there is no
`since` token. This limits the risk to clients likely to be doing one-off
syncs (like bridges), but does mean that normal human clients won't benefit
from the time savings here. If the savings are large enough, I would consider
generalising this to just check the filter.
When a server sends a third party invite another server may be the one
that the inviting user registers with. In this case it is that remote
server that will issue an actual invitation, and wants to do it "in the
name of" the original invitee. However, the new proper invite will not
be signed by the original server, and thus other servers would reject
the invite if it was seen as coming from the original user.
To fix this, a special case has been added to the auth rules whereby
another server can send an invite "in the name of" another server's
user, so long as that user had previously issued a third party invite
that is now being accepted.
Clients can continue to supply access tokens as query parameters
or can supply the token as a header:
Authorization: Bearer <access_token_goes_here>
This matches the ouath2 format of
https://tools.ietf.org/html/rfc6750#section-2.1
Rather than reimplementing the token parsing in the various places.
This will make it easier to change the token parsing to allow access_tokens
in HTTP headers.
