Currently we use `JsonEncoder.iterencode` to write JSON responses, which ensures that we don't block the main reactor thread when encoding huge objects. The downside to this is that `iterencode` falls back to using a pure Python encoder that is *much* less efficient and can easily burn a lot of CPU for huge responses. To fix this, while still ensuring we don't block the reactor loop, we encode the JSON on a threadpool using the standard `JsonEncoder.encode` functions, which is backed by a C library.
Doing so, however, requires `respond_with_json` to have access to the reactor, which it previously didn't. There are two ways of doing this:
1. threading through the reactor object, which is a bit fiddly as e.g. `DirectServeJsonResource` doesn't currently take a reactor, but is exposed to modules and so is a PITA to change; or
2. expose the reactor in `SynapseRequest`, which requires updating a bunch of servlet types.
I went with the latter as that is just a mechanical change, and I think makes sense as a request already has a reactor associated with it (via its http channel).
In `MatrixFederationHttpClient._send_request()`, we make a HTTP request
using an `Agent`, wrap that request in a timeout and await the resulting
`Deferred`. On its own, the `Agent` performing the HTTP request
correctly stashes and restores the logging context while waiting.
The addition of the timeout introduces a path where the logging context
is not restored when execution resumes.
To address this, we wrap the timeout `Deferred` in a
`make_deferred_yieldable()` to stash the logging context and restore it
on completion of the `await`. However this is not sufficient, since by
the time we construct the timeout `Deferred`, the `Agent` has already
stashed and cleared the logging context when using
`make_deferred_yieldable()` to produce its `Deferred` for the request.
Hence, we wrap the `Agent` request in a `run_in_background()` to "fork"
and preserve the logging context so that we can stash and restore it
when `await`ing the timeout `Deferred`.
This approach is similar to the one used with `defer.gatherResults`.
Note that the code is still not fully correct. When a timeout occurs,
the request remains running in the background (existing behavior which
is nothing to do with the new call to `run_in_background`) and may
re-start the logging context after it has finished.
Mostly this involves decorating a few Deferred declarations with extra type hints. We wrap the types in quotes to avoid runtime errors when running against older versions of Twisted that don't have generics on Deferred.
* switch from `types.CoroutineType` to `typing.Coroutine`
these should be identical semantically, and since `defer.ensureDeferred` is
defined to take a `typing.Coroutine`, will keep mypy happy
* Fix some annotations on inlineCallbacks functions
* changelog
Improves type hints for:
* parse_{boolean,integer}
* parse_{boolean,integer}_from_args
* parse_json_{value,object}_from_request
And fixes any incorrect calls that resulted from unknown types.
* Drop Origin & Accept from Access-Control-Allow-Headers value
This change drops the Origin and Accept header names from the value of the
Access-Control-Allow-Headers response header sent by Synapse. Per the CORS
protocol, it’s not necessary or useful to include those header names.
Details:
Per-spec at https://fetch.spec.whatwg.org/#forbidden-header-name, Origin
is a “forbidden header name” set by the browser and that frontend
JavaScript code is never allowed to set.
So the value of Access-Control-Allow-Headers isn’t relevant to Origin or
in general to other headers set by the browser itself — the browser
never ever consults the Access-Control-Allow-Headers value to confirm
that it’s OK for the request to include an Origin header.
And per-spec at https://fetch.spec.whatwg.org/#cors-safelisted-request-header,
Accept is a “CORS-safelisted request-header”, which means that browsers
allow requests to contain the Accept header regardless of whether the
Access-Control-Allow-Headers value contains "Accept".
So it’s unnecessary for the Access-Control-Allow-Headers to explicitly
include Accept. Browsers will not perform a CORS preflight for requests
containing an Accept request header.
Related: https://github.com/matrix-org/matrix-doc/pull/3225
Signed-off-by: Michael[tm] Smith <mike@w3.org>
Add 'federation_ip_range_whitelist'. This allows backwards-compatibility, If 'federation_ip_range_blacklist' is set. Otherwise 'ip_range_whitelist' will be used for federation servers.
Signed-off-by: Michael Kutzner 1mikure@gmail.com
Instead of parsing the full response to `/send_join` into Python objects (which can be huge for large rooms) and *then* parsing that into events, we instead use ijson to stream parse the response directly into `EventBase` objects.
