"*!/!*" is not a valid MIME type-CodePudding

Since upgrading to Rails 6 I began getting this error: ActionDispatch::Http::MimeNegotiation::InvalidType ("!/!" is not a valid MIME type).

In backtrace I have

/GEM_ROOT/gems/actionpack-6.1.4.4/lib/action_dispatch/http/mime_negotiation.rb:55 → rescue in block in accepts
/GEM_ROOT/gems/actionpack-6.1.4.4/lib/action_dispatch/http/mime_negotiation.rb:46 → block in accepts
/GEM_ROOT/gems/rack-2.2.3/lib/rack/request.rb:69 → fetch
/GEM_ROOT/gems/rack-2.2.3/lib/rack/request.rb:69 → fetch_header
/GEM_ROOT/gems/actionpack-6.1.4.4/lib/action_dispatch/http/mime_negotiation.rb:45 → accepts
/GEM_ROOT/gems/actionpack-6.1.4.4/lib/action_dispatch/http/mime_negotiation.rb:74 → block in formats
/GEM_ROOT/gems/rack-2.2.3/lib/rack/request.rb:69 → fetch
/GEM_ROOT/gems/rack-2.2.3/lib/rack/request.rb:69 → fetch_header
/GEM_ROOT/gems/actionpack-6.1.4.4/lib/action_dispatch/http/mime_negotiation.rb:70 → formats
/GEM_ROOT/gems/actionpack-6.1.4.4/lib/action_dispatch/http/mime_negotiation.rb:66 → format
/GEM_ROOT/gems/actionpack-6.1.4.4/lib/action_controller/metal/instrumentation.rb:26 → process_action
/GEM_ROOT/gems/actionpack-6.1.4.4/lib/action_controller/metal/params_wrapper.rb:249 → process_action
/GEM_ROOT/gems/activerecord-6.1.4.4/lib/active_record/railties/controller_runtime.rb:27 → process_action
/GEM_ROOT/gems/actionpack-6.1.4.4/lib/abstract_controller/base.rb:165 → process

What does this mime type means? And how to fix this error?

CodePudding user response：

It helped me to add defaults: { format: 'js' } in routes.rb:

get 'user/card', to: 'user#card', defaults: { format: 'js' }

I have in this action only js format for view. I think that it helps in similar cases.