What one gets back when resolving a DOI depends on content negotiation. I was looking at https://citation.crosscite.org/docs.html#sec-3 and I see different services offer different Content Types.
For a particular URL I want to know all the content types it can give me. Some of them might be more useful than any that I am aware of (i.e. i don't want to write a list of preferences in advance).
For example:
https://doi.org/10.5061/dryad.1r170
I thought maybe OPTIONS was the way to do it
but that gave back nothing interesting, only about allowed request methods.
shell> curl -v -X OPTIONS http://doi.org/10.5061/dryad.1r170
* Hostname was NOT found in DNS cache
* Trying 2600:1f14:6cf:c01::d...
* Trying 54.191.229.235...
* Connected to doi.org (2600:1f14:6cf:c01::d) port 80 (#0)
> OPTIONS /10.5061/dryad.1r170 HTTP/1.1
> User-Agent: curl/7.38.0
> Host: doi.org
> Accept: */*
>
< HTTP/1.1 200 OK
* Server Apache-Coyote/1.1 is not blacklisted
< Server: Apache-Coyote/1.1
< Allow: GET, HEAD, POST, TRACE, OPTIONS
< Content-Length: 0
< Date: Mon, 29 Jan 2018 07:01:14 GMT
<
* Connection #0 to host doi.org left intact