DS-4466 REST API should obtain language settings from Client

[ddinuzzo]

References

• DS-4466
• Approved REST Contract

Description

This PR add the general infrastructure needed to deal with the accept-language header from the client and test specific to proof that the submission definition are managed properly in a multi-lang environment. The implementation of the multilanguage support in the authority control is left outside as a major rework of this aspects is undergoing.

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[tdonohue]

👍 Overall, the code here looks great @ddinuzzo ! The tests look good as well & do a good job of providing this works as expected for language-specific submission configurations (which is one of the main use cases). That said, I do have one minor request for JavaDocs inline below. Please update those JavaDocs before we can merge this.

[abollini]

@tdonohue this should be ready to go now

[benbosman]

@ddinuzzo It seems there's no IT yet for the use case of multiple languages in header

Can you add an IT with default locale English and the language header to fr;q=1, it;q=0.9
This should try French (but not find it), and go for the second option Italian (and not go to the default English)

[benbosman]

Thanks @ddinuzzo
This looks good to me, I only found one use case that's not supported
If I set webui.supported.locales = en, de, nl and I have submission forms in nl but not in de, and I use Accept-Language: de;q=0.9,nl;q=0.8,en;q=0.7, this returns the English form (the default)
This is because it's assumed that all webui.supported.locales are available for each submission form, and I18nUtil.isSupportedLocale(current) doesn't take into account whether there's a submission form for this language.

I don't see this as a blocking issue, but I would prefer a github issue would be created for this

[tdonohue]

This is at +2, merging