# These Are All Just Persistent URLs, No?

I am beginning to walk through each question of the FAIR Implementation Profile (FIP) Ontology. My goal is to construct and share a populated model of people’s articulations – aka declarations – of choices they’ve made or with challenges they face with regard to addressing each question, as well as the considerations they associate with any such choice or challenge.

The first question for which I’m seeking declarations is F1-D:

What globally unique, persistent, resolvable identifiers do you use for datasets?

I’ve gotten some great responses so far, mostly about people choosing to use the Handle (incl. DOI) or ARK systems.

I got a great question from my former group-mate Shyam Dwaraknath:

In the end these are all just persistent URLs no?

For all intents and purposes, yes. Practically, if you don’t give someone a resolving1 HTTP(S) URL, such that they can Locate and retrieve the Resource given a Uniform Identifier (i.e., URI$$\implies$$URL), they should be able to straightforwardly construct one.

Handles and ARKs use their compact forms to communicate

1. an intention of persistence, and (related to this)

2. a URL-construction protocol in case they are

(a) not communicated as URLs, or

(b) they are, but the URLs don’t resolve.

If you see e.g. 10.1038/sdata.2016.18 somewhere, the hope is you will grok that the \d+[\.\d+]+/.+ pattern (period-delimited numbers, then a /, then stuff) is likely a Handle, so you will try putting https://doi.org/ or https://hdl.handle.net/ before it. There either need to be well-known public Handle HTTP Proxy servers, or you search around for “Handle proxy server”. You’ll also see doi:10.1038/sdata.2016.18 sometimes. Same principle. The hope is you know how to URLify it trivially.

The form of an ARK is similar in intent. The hope is that if you see e.g. ark:57802/dw0/agu/6045 somewhere (for ARKs, the ark: prefix is part of the ID form, even in URL paths), you’ll think “this ID is intended to be persistent – an archival resource key” and “I hope some name mapping authority (NMA) is publicly resolving ark:57802 IDs”. The well-known public ARK HTTP Proxy is https://n2t.net, and e.g. https://n2t.net/ark:57802/dw0/agu/6045 passes through to https://ns.polyneme.xyz/ark:57802/dw0/agu/6045 because https://ns.polyneme.xyz is registered there as the NMA for the name assigning authority (NAA) ark:57802.

Other persistent ID systems that imply/offer HTTP URLs have tighter coupling to the DNS domain responsible for resolving the IDs. Some of these systems are intended for general use, such as https://purl.org/ and https://w3id.org/.

In these systems, prefixes are not allocated like with Handles or ARKs, and there is no emphasis on prefixes being semantically opaque so as to increase the likelihood of continued commitment to persistence if/when stewarding organizations change names. Rather, prefixes are claimed, like http://purl.org/dc (serving e.g. http://purl.org/dc/terms) and https://purl.org/dw (serving e.g. https://purl.org/dw/squirrel), or https://w3id.org/nmdc (where currently, all path extensions, e.g. https://w3id.org/nmdc/nmdc-schema, resolve to the same page).

Other DNS-coupled systems are socially positioned as providing specific types of persistent identifiers. Such systems include the World Wide Web Consortium (W3C) https://w3.org/ namespace for standards (e.g. https://w3.org/ns/dcat), the Open Researcher and Contributor ID (ORCID) https://orcid.org/ (e.g. https://orcid.org/0000-0002-8424-0604), the International Generic Sample Number (IGSN) https://igsn.org (e.g. https://igsn.org/IEWFS0001), and the Research Organization Registry (ROR) https://ror.org/ (e.g. https://ror.org/02jbv0t02).

If/when any such special-purpose, domain-name-tied system cannot fulfill persistence, it is hoped that there will be (a) an adopter organization and (b) sufficient signage (e.g. minimal maintenance of the old domain as a static notice) to enable programmatic workarounds, like the case of the Global Researcher Identifier Database (GRID) https://grid.ac/ being passed to ROR for stewardship.

1. Any HTTP URL is technically resolvable. Whether it actually resolves in response to an HTTP request is a matter of service. ↩︎