middleware: expose function to retrieve locale.

[fernandojbf]

Is your feature request related to a problem? Please describe.

I want to have a way to pass a header to my applications with the locale.

To make this possible, i need to make sure I have the request.header set before building the response via handleI18nRouting.

Would be nice to have the same function that handleI18nRouting to retrieve the locale. this will make sure that handleI18nRouting and the locale predefined before would be target as the same value.

Adding this as discussion. Would this make sense?

Describe the solution you'd like

Maybe:

const locale = getResolveLocale(config, request)
const request.headers.set('x..', locale);
const response = handleI18nRouting(request);

Describe alternatives you've considered

Can be other api. the idea is to have a way of getting the locale before we generate the response

[fernandojbf]

It seems that the middleware already sets the locale via HEADER_LOCALE_NAME.

I do not require the feature anymore since is already injected in the headers.

Thanks