W3C

– DRAFT –
WoT Thing Description

15 October 2025

Attendees

Present
Daniel_Peintner, Ege_Korkan, Klaus_Hartke, Kunihiko_Toumura, Luca_Barbato, Mahda_Noura, Tomoaki_Mizushima
Regrets
-
Chair
Ege_Korkan
Scribe
dape

Meeting minutes

Minutes

https://www.w3.org/2025/10/08-wot-td-minutes.html

EK: Minutes from Wednesday are approved

Quick Schedule

URI vs IRI

<Ege> w3c/wot-thing-description#2156

EK: Issue come out of an OPC-UA discussion

<Ege> https://github.com/eclipse-thingweb/node-wot/tree/master/packages/binding-opcua#getting-started

EK: the URI schema for OPC-UA contains s= meaning a string
… protocol allows any string which is UTF8 encoded
… technically possible
… can contain German Umlaut or Japanese characters
… we noticed discrepancy
… we reference RFC3986
… anyURI is IRI
… both are in normative tables and we have some conflict

KH: in href we say IRU and not URI

EK: Correct
… I think W3C review asked us to use IRI
… but correct, there is a discrepancy
… IRI parsing not common in code basis
… I found https://www.w3.org/International/wiki/IRIStatus

EK: We can restrict it per protocol to URIs

LB: Would it be enough to point IRI RFC
… saying non ASCII characters are allowed
… most parsing libraries do work with unicode
… main problem is weird escaping
… DNS had problems with IRI
… we could restrict strings to UTF8

EK: IRI handling in specific parts only?

LB: yes, but sounds more profile worthy
… we should review the RFCs
… and pick the one that fits our target
… TD should give freedom
… profile can restrict

KH: We want address resources on the Web
… we should use Web standards
… we can choose URL, IRI etc
… no matter of taste
… it is about protocol
… protocol driver (HTTP, CoAP) needs to know
… so far URI standard is used
… value in href field (or base field) use URI

<luca_barbato> Related specifications: https://url.spec.whatwg.org https://www.rfc-editor.org/rfc/rfc3987

KH: w.r.t. to OPC-UA I need to see the ABNF grammar

EK: Document is open to members
… not sure if it contains ABNF

KH: There should be something
… saying URI or IRI
… you cannot say URI standard and put unicode characters in query string

LB: We can make it extra flexible
… field is UTF8 string and offload it to protocol

KH: This cannot work
… because of base

EK: True
… unless we indicate in a different way the protocol

KH: We could get rid of base and href ...
… and come upo with a combined string per protocol
… but it creates major problems

MN: hypermedia concept claim does no longer make sense also

LB: Easiest thing is to pick the right definittion of href
… additional field for anything we cannot support

KH: I would go with URI
… no huge problem, I think we need a pragmatic solution
… for base is correct
… for href it should be used URI also (currently not the case)

LB: Uniform to URI

KH: Yes, it should be always been URI
… there are options to support unicode in URI
… we need to better understand the OPC-UA requirements

EK: IRI to URI is in RFC?

KH: Yes, there is a conversion algorithm
… UTF8 bytes to percentage encoding

DP: the OPCUA binding requires percentage encoding

EK: Not sure

KH: We need to check we (or OPCUA) violate the standard

EK: Let's look at the OPC spec

KH: Next week Wed I cannot join, I can join Thursday

EK: Thanks!

<egekorkan> w3c/wot-thing-description#2154

Common definitions

w3c/wot-thing-description#2154

EK: I started the exercise to extend the examples

<egekorkan> https://github.com/w3c/wot-thing-description/blob/ege-common-definitions-examples/proposals/common-definitions/tooling/tds.js

EK: examples at line 454
… recommendedTDs
… e.g., change from default contentType JSON to cbor etc
… or Modbus with all parameters
… multi IP addresses
… local vs public security

EK: Do you see more useful examples?
… to test this new method
… will show it tomorrow in more details
… please provide feedback in PR
… in PR I summarized also some of my findings

Bindings

<egekorkan> github.com/w3c/wot-binding-templates/pull/446

<egekorkan> w3c/wot-binding-templates#446

EK: realized some mistakes
… no proper rendering for Modbus
… the same stupid error appeared more often
… I also updated the authors
… same change everywhere expect Modbus with more changes
… I will wait a bit for feedback

KH: Wonder why S has been removed in general

EK: We started off with S and changed later on
… due to W3C feedback

KH: I see

KH: IANA uses plural and W3C seems to use singular

[adjourned]

Minutes manually created (not a transcript), formatted by scribe.perl version 246 (Wed Oct 1 15:02:24 2025 UTC).

Diagnostics

Succeeded: s/EK: IANA/KH: IANA

Maybe present: DP, EK, KH, LB, MN

All speakers: DP, EK, KH, LB, MN

Active on IRC: dape, Ege, egekorkan, luca_barbato, Mahda, MIzushima