Return 303 status code for unsupported application/vnd.crossref.unixref+xml content type

[codycooperross]

We don't actively support content negotiation requests for Crossref XML, i.e. application/vnd.crossref.unixref+xml, but previously returned a blank response when using this header. This blank response was rendered by bolognese: https://github.com/datacite/bolognese/blob/64b18d1439801216c7ce59e5a76a7c383d171161/lib/bolognese/writers/crossref_writer.rb#L3-L11 This change removes internal support for application/vnd.crossref.unixref+xml and instead treats it as an unsupported content type.

closes: datacite/datacite#2448

[richardhallett]

Why would it return 303? Shouldn't it return 406 (looking at code)

[codycooperross]

I was basing this on the other tests here:

content-negotiation/spec/api/api_spec.rb

Lines 278 to 292 in ab7a875

	context "unknown accept header" do
	it "header" do
	get "/#{doi}", nil, { "HTTP_ACCEPT" => "application/xml" }
	expect(last_response.status).to eq(303)
	expect(last_response.headers["Location"]).to eq("https://blog.datacite.org/announcing-schema-4-2/")
	end
	it "link" do
	get "/application/xml/#{doi}"
	expect(last_response.status).to eq(404)
	expect(last_response.body).to eq("The resource you are looking for doesn't exist.")
	end
	end

But good point. I can take a look.

[richardhallett]

It's entirely possible that it does return a 303, I don't see where, but I'm not overly familiar with this codebase. I wouldn't worry too much as long as it's logically consistent.

[codycooperross]

Currently, we return 303s when a content type is not recognized. Try this:

curl --location 'https://doi.org/10.48322/553p-pm90' \
--header 'Accept: application/not-real-content-type'

That aligns with my understanding of how content negotiation is intended to work. If the content type is supported, then the formatted content is returned; if the content type is not supported, then the landing page is returned.

[richardhallett]

I guess the 303 is because it throws it off to the end DOI url to be processed. Alright fair enough