Implement HEAD

[ktk]

There is currently no support for HTTP HEAD. I think that would be nice to add, as it screwed myself several times when I did a curl for head and didn't get the result I expected.

[ktk]

Quick fix: Return HTTP code 405

[ktk]

When I did this issue I was talking about checking if a resource exists, for example:

curl -I https://ld.admin.ch/canton/1

This currently returns a 404 even though it works just fine with a GET.

It should probably provide a result for all other resources as well with hard-configured routing, like /query in case SPARQL is available.

[ludovicm67]

Done here: https://github.com/zazuko/trifid-handler-sparql/commit/249be98cbe0b7a2e7408c2447fc9dba7a2e60a30

[ludovicm67]

Example when calling an existing resource:

> curl -I https://lindas.zazukoians.org/canton/23

HTTP/2 200
date: Mon, 19 Dec 2022 17:16:49 GMT
content-type: text/plain; charset=utf-8
etag: W/"2-nOO9QiTIwXgNtWtBJezz8kv3SLc"
strict-transport-security: max-age=15724800

Example when calling a non-existing resource:

> curl -I https://lindas.zazukoians.org/canton/424242

HTTP/2 404
date: Mon, 19 Dec 2022 17:16:55 GMT
content-type: text/html; charset=utf-8
etag: W/"a-DBXRJ1WgvoTmQDRFxCcjHCdJGcY"
strict-transport-security: max-age=15724800

This should be the expected behavior now.

[ktk]

Looks good, I tested CORS as well:

 curl --include \
     --request GET \
     --header 'Origin: http://example.com' \
      https://lindas.zazukoians.org/canton/23

Returned headers look good:

HTTP/2 200
date: Wed, 04 Jan 2023 13:41:35 GMT
content-type: text/turtle
access-control-allow-origin: *
access-control-expose-headers: SD-Query-Id
cache-control: public, max-age=120
sd-query-id: 10007
set-cookie: i18n=en; Max-Age=2592000; Path=/; Expires=Fri, 03 Feb 2023 13:41:35 GMT
strict-transport-security: max-age=15724800
vary: Accept, Accept-Encoding