Based on information found here on the chromium blog
I found that options requests that render with head :ok
are blocked by CORB because the resposne
has headers of Content-Type: text/plain
and X-Content-Type-Options: nosniff
. The text/plain
content type is a "trigger"
for CORB checking and when Rails sets the contet type options to nosniff
for this response CORB cannot inspect the response
to see if it is safe.
TL;DR add response.headers.delete('X-Content-Type-Options')
in your OPTIONS
preflight handler