t was doing a sequential scan on `destination_rooms`, which took
minutes.

The idea here is that we will have an instance of OidcProvider for each
configured IdP, with OidcHandler just doing the marshalling of them.

For now it's still hardcoded with a single provider.

A reactor was being passed instead of a whitelist for the BlacklistingAgentWrapper
used by the WellyKnownResolver. This coulld cause exceptions when attempting to
connect to IP addresses that are blacklisted, but in reality this did not have any
observable affect since this code is not used for IP literals.

* Add complete test for UI-Auth-via-SSO.

* review comments

Removes a bare `except Exception` clause and replaces it with
catching a specific exception around the portion that might throw.

This checks that the domain given to `DomainSpecificString.is_valid` (e.g.
`UserID`, `RoomAlias`, etc.) is of a valid form. Previously some validation
was done on the localpart (e.g. the sigil), but not the domain portion.

Some light refactoring of OidcHandler, in preparation for bigger things:

  * remove inheritance from deprecated BaseHandler
  * add an object to hold the things that go into a session cookie
  * factor out a separate class for manipulating said cookies

This only applies if the user's data is to be erased.

If we have integrations with multiple identity providers, when the user does a UI Auth, we need to redirect them to the right one.

There are a few steps to this. First of all we actually need to store the userid of the user we are trying to validate in the UIA session, since the /auth/sso/fallback/web request is unauthenticated.

Then, once we get the /auth/sso/fallback/web request, we can fish the user id out of the session, and use it to look up the external id mappings, and hence pick an SSO provider for them.

It is expected that the proxy would be on a private IP address so the
configured proxy should be connected to regardless of the IP range
blacklist.

Homeserver.get_ip_from_request() used to be a bit more complicated, but now it is totally redundant. Let's get rid of it.

SynapseRequest is in danger of becoming a bit of a dumping-ground for "useful stuff relating to Requests",
which isn't really its intention (its purpose is to override render, finished and connectionLost to set up the 
LoggingContext and write the right entries to the request log).

Putting utility functions inside SynapseRequest means that lots of our code ends up requiring a
SynapseRequest when there is nothing synapse-specific about the Request at all, and any old
twisted.web.iweb.IRequest will do. This increases code coupling and makes testing more difficult.

In short: move get_user_agent out to a utility function.

For remote users, only the rooms which the server knows about are returned.
Local users have all of their joined rooms returned.

Factor out the exception handling in the startup code to a utility function,
and fix the some logging and exit code stuff.

These tables are unused, and can be dropped now the schema version has been bumped.

Co-authored-by: Patrick Cloke <clokep@users.noreply.github.com>

* Dropped last_used column from access_tokens

Signed-off-by: Jerin J Titus <72017981+jerinjtitus@users.noreply.github.com>

This PR adds the missing user_mapping_provider section in oidc.md

Signed-off-by: Christopher Rücker <chris-ruecker@protonmail.com>

You can't continue using a transaction once an exception has been
raised, so catching and dropping the error here is pointless and just
causes more errors.

I'm not even sure what this was supposed to do, but the fact it has python2isms
and nobody has noticed suggests it's not terribly important.

It doesn't seem to have been used since ff23e5ba.

We were running some linters on some files and some on others. Extract a common
setting and use it everywhere.

This is in preparation for moving `SendToDeviceServlet` off master

Currently `DeviceMessageHandler` only ever exists on master, but that is about to change.

Signed-off-by: Emelie <em@nao.sh>

This allows for efficiently finding which users ignore a particular
user.

Co-authored-by: Erik Johnston <erik@matrix.org>