So it look like in order to set the content type I have to set (config) it beforehand (since hapi server being created) by passing it as views.contentType and no mechanism to override.
IMO you guys have weird approach for doing things.
my Content-Type got overrode without my consent (also the solution is to override it to something else) and this approach make me unable to use same file extension for templates file (with same template engine) that have different MIME-Type.
Anyway I'm totally new to hapi. I might be wrong. If someone have something to add please do so. Probably you have proper solution to set Content-Type per request rather than using different file extension on template files.