P::M::SCF triggers the following warning:
Use of uninitialized value in pattern match (m//) at [MY PATH]/local-lib/lib/perl5/Plack/Middleware/SimpleContentFilter.pm line 18.
This is being caused because our request object is simply:
'stuff to redirect to'
So there is no Content-Type header to introspect.
#376 - SimpleContentFilter throws warning when no content-type is pre…
Content-Type is a required header in PSGI response per spec.
What is the appropriate content-type header for an HTTP 301?
You should be just able to use text/html for 301.