1 Commits (f0e02f5df2bc3ae779ac8c18578deebdfecc7e97)

Author	SHA1	Message	Date
Michael[tm] Smith	27c06a6e06	Drop Origin & Accept from Access-Control-Allow-Headers value (#10114) ... * 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>	3 years ago