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.
The abort() method calls loseConnection() which tries to shutdown the
TLS connection cleanly. We now call abortConnection() directly which
should promptly close both the TLS connection and the underlying TCP
connection.
I also added some TODO markers to consider cancelling the old previous
timeout rather than checking time.time(). But given how urgently we want
to get this code released I'd rather leave the existing code with the
duplicate timeouts and the time.time() check.
Add a timeout parameter for controlling how long synapse will wait
for responses from remote servers. For servers that fail include how
they failed to make it easier to debug.
Fetch keys from different servers in parallel rather than in series.
Set the default timeout to 10s.
Always set the config key with an empty list, even if a list isn't specified.
This means that the codepaths are the same for both the empty list and
for a missing key. Since the behaviour is the same for both cases this
makes the code somewhat easier to reason about.
Add url_preview_ip_range_blacklist to let admins specify internal IP ranges that must not be spidered.
Add url_preview_url_blacklist to let admins specify URL patterns that must not be spidered.
Implement a custom SpiderEndpoint and associated support classes to implement url_preview_ip_range_blacklist
Add commentary and generally address PR feedback
pycharm supports them so there is no need to use the other format.
Might as well convert the existing strings to reduce the risk of
people accidentally cargo culting the wrong doc string format.
