Clarify that the list media API only shows media from unencrypted events.

Some hopefully-useful notes on setting up a turnserver.

This also expands type-hints to the SSO and registration code.

Refactors the CAS code to more closely match OIDC/SAML.

Synctl did not check if a worker thread was already running when using
`synctl start` and would naively start a fresh copy. This would
sometimes lead to cases where many duplicate copies of a single worker
would run.

This fix adds a pid check when starting worker threads and synctl will
now refuse to start individual workers if they're already running.

When using `add_header` nginx will literally add a header. If a
`content-type` header is already configured (for example through a
server wide default), this means we end up with 2 content-type headers,
like so:

```
content-type: text/html
content-type: application/json
access-control-allow-origin: *
```

That doesn't make sense. Instead, we want the content type of that
block to only be `application/json` which we can achieve using
`default_type` instead.

Signed-off-by: Daniele Sluijters <daenney@users.noreply.github.com>

Checks that the localpart returned by mapping providers for SAML and
OIDC are valid before registering new users.

Extends the OIDC tests for existing users and invalid data.

If the SAML metadata includes multiple IdPs it is necessary to
specify which IdP to redirect users to for authentication.

* Consistently use room_id from federation request body

Some federation APIs have a redundant `room_id` path param (see
https://github.com/matrix-org/matrix-doc/issues/2330). We should make sure we
consistently use either the path param or the body param, and the body param is
easier.

* Kill off some references to "context"

Once upon a time, "rooms" were known as "contexts". I think this kills of the
last references to "contexts".

Improve appservice handler to send only the most recent read receipts when no stream_id is stored. (#8744)

* Make this line debug (it's noisy)

* Don't include from_key for presence if we are at 0

* Limit read receipts for all rooms to 100

* changelog.d/8744.bugfix

* Allow from_key to be None

* Update 8744.bugfix

* The from_key is superflous

* Update comment

This was broken due to #8617 and #8761.

Updates the sample configuration with the pysaml2 configuration for
accepting clock skew/drift between the homeserver and IdP.

Short-term fix for https://github.com/matrix-org/synapse/issues/8766.

Make `make_request` actually render the request

De-duplicates code between the SAML and OIDC implementations.

Signed-off-by: Chagai Friedlander <chagai95@gmail.com>

remove the stubbing out of `request.process`, so that `requestReceived` also renders the request via the appropriate resource.

Replace render() with a stub for now.

the preview resource is mointed at preview_url, not url_preview

Pass a Site into `make_request`

FakeChannel has everything we need, and this more accurately models the real
flow.

`_locally_reject_invite` generates an out-of-band membership event which can be passed to clients, but not other homeservers.

This is used when we fail to reject an invite over federation. If this happens, we instead just generate a leave event locally and send it down /sync, allowing clients to reject invites even if we can't reach the remote homeserver.

A similar flow needs to be put in place for rescinding knocks. If we're unable to contact any remote server from the room we've tried to knock on, we'd still like to generate and store the leave event locally. Hence the need to reuse, and thus generalise, this method.

Separated from #6739.

The root resource isn't necessarily a JsonResource, so rename this method
accordingly, and update a couple of test classes to use the method rather than
directly manipulating self.resource.

Some tests want to set some custom HTTP request headers, so provide a way to do
that before calling requestReceived().

Where we want to render a request against a specific Resource, call the global
make_request() function rather than the one in HomeserverTestCase, allowing us
to pass in an appropriate `Site`.