Re: [spdx-tech] A proposal for SPDX Private License Identifiers. Example:

Alexios Zavras

Since these will be "private" (which I understand to simply mean "not in the official list"), why don't we simplify our lives and use URLs for naming as well?

SPDX-License-Identifier: <>

The enclosure in "<"/">" takes care of not being an approved SPDX short identifier, and marks it "private"; the ownership of the domain URL takes care of namespace collisions -- and we have a single line so that our grep-like tools continue working.

I agree with Gary's remark that ideally the URL should point to an XML format that can provide some more info than the bare text (e.g., some matching alternatives).

-- zvr -

-----Original Message-----
From: Spdx-tech@... <Spdx-tech@...> On Behalf Of Gary O'Neall
Sent: Sunday, 27 January, 2019 19:50
To: atwoodm@...; spdx-tech@...; spdx-legal@...
Subject: Re: [spdx-tech] A proposal for SPDX Private License Identifiers. Example:

HI Mark,

I like the idea of a DNS naming approach to the private license identifiers.
It neatly solves the namespace issue.

Rather than having a URL pointing to the canonical license text, I wonder if we could have a URL pointing to metadata about the entire license which would include the license text and reference URL's for the source. We could use the same license XML format we use for the license list. This would be more work for the creators of the private license identifier but would enable better machine matching algorithms.

There is a use case we've been discussing where we could have an identifier for a license which has been submitted to the license list but not yet approved. Perhaps we solve this using a similar approach.


-----Original Message-----
From: Spdx-legal@... <Spdx-legal@...> On Behalf
Atwood via Lists.Spdx.Org
Sent: Thursday, January 24, 2019 10:31 AM
To: spdx-tech@...; spdx-legal@...
Cc: Spdx-legal@...
Subject: A proposal for SPDX Private License Identifiers. Example:

I would like to propose a syntax for SPDX "Private License Identifiers".

SPDX short identifiers and SPDX-License-Identifier declarations in source
code and in compliance documents have proven to be useful. This proposal
extends SPDX license tags to licenses created and used by
organizations, that are unlikely to be applied to content by anyone
other than the

And when I see an expanding namespace with worries about collisions
and an overworked central naming authority, I always think "why not use the DNS?"

Examples (these URLs are not correct):




Private License Identifiers are indicated by a leading dot, followed
reversed DNS name of the organization who created or authored the
license, followed by a dot dash dot and then a short name of the same
general form
a SPDX license short identifier.

The leading dot is sufficient to separate this namespace from the
SPDX short identifiers, and is inspired by the fact that DNS names have an
implied trailing dot. The dot dash dot is to prevent someone from
reversing the entire identifier string into a DNS name and trying to
dereference it, because a bare dash is not a valid DNS name part.
. DNS names be IDN (Internationalized Domain Name) and thus can
contain non-ASCII characters. IDN components can be encoded in IDN
Punycode, or in UTF-8, or in the Unicode encoding appropriate to the document.

In a SPDX-License-identifier declaration, a Private License Identifier
can optionally be followed by a URI pointing to the canonical license text.
This URI should be under the control of the entity that controls the
DNS namespace of the Private License Identifier.


Mark Atwood <atwoodm@...>
Principal, Open Source

Intel Deutschland GmbH
Registered Address: Am Campeon 10-12, 85579 Neubiberg, Germany
Tel: +49 89 99 8853-0,
Managing Directors: Christin Eisenschmid
Chairperson of the Supervisory Board: Nicole Lau
Registered Office: Munich
Commercial Register: Amtsgericht Muenchen HRB 186928

Join { to automatically receive all group messages.