SWHID as a Package-URL type?

[zvr]

Do want to work towards defining an encoding of SWHID as a package-url ?

The specification is at https://github.com/package-url/purl-spec/blob/master/PURL-SPECIFICATION.rst

One can see how different other types are handled in https://github.com/package-url/purl-spec/blob/master/PURL-TYPES.rst

I assume the majority of work would be to see what encoding/decoding has to be specified in the representation.

[zvr]

OK, this might not be so hard, after all.

Carefully reading the spec, we have to follow the structure scheme:type/namespace/name@version?qualifiers#subpath.

Simple SWHIDs are pretty easily mappable:

swh:1:cnt:94a9ed024d3859793618152ea559a168bbcbb5e2

pkg:swh-1/cnt/94a9ed024d3859793618152ea559a168bbcbb5e2

Identifiers with qualifiers have to be transformed like URL query strings, so:

swh:1:cnt:4d99d2d18326621ccdd70f5ea66c2e2ac236ad8b;
  origin=https://gitorious.org/ocamlp3l/ocamlp3l_cvs.git;
  visit=swh:1:snp:d7f1b9eb7ccb596c2622c4780febaa02549830f9;
  anchor=swh:1:rev:2db189928c94d62a3b4757b3eec68f0a4d4113f0;
  path=/Examples/SimpleFarm/simplefarm.ml;
  lines=9-15

pkg:swh-1/cnt/4d99d2d18326621ccdd70f5ea66c2e2ac236ad8b?
  origin=https%3A%2F%2Fgitorious.org%2Focamlp3l%2Focamlp3l_cvs.git&
  visit=swh%3A1%3Asnp%3Ad7f1b9eb7ccb596c2622c4780febaa02549830f9&
  anchor=swh%3A1%3Arev%3A2db189928c94d62a3b4757b3eec68f0a4d4113f0&
  path=%2FExamples%2FSimpleFarm%2Fsimplefarm.ml&
  lines=9-15

I created and used type of swh-1 since it's not easy to encode the version otherwise. Not ideal (or pretty), but it makes the job done.

[rdicosmo]

Thanks for raising this!
Looking at the intent of purls, which is to identify "packages" I get the impression that we should probably only translate directory, release or revision SWHIDs.

On a side note, it would be great if we could have SWHIDs used in other package managers, instead of naked hashes as we see in the purl examples, but that's for another day I suppose :-)