Hydra W3C Community Group Telecon

Minutes for 2018-02-05

Thomas Bergwinkl is scribing.

Topic: Current state of the specification and vocabulary

Karol Szczepański: some stuff needed to be implemented, which was not in the spec
Karol Szczepański: e.g. collection property
elf Pavlik: it was discussed in one of the last calls if this will be added to the namespace
Karol Szczepański: it should be started by added the missing properties of vocab in github
Markus Lanthaler: there should be issues for the missing properties with the label solved, but not closed yet
Markus Lanthaler: besides these issues the vocab should be up to date
ACTION: Karol to send a pull request to update the vocabulary to include everything we decided so far

Topic: Actions with explicit target (Use cases / PR-154)

elf Pavlik: referencing once from the action and once from the operation could be to messy
Markus Lanthaler: not so happy with any of the solutions. maybe the meaning of operation could be changed.
Markus Lanthaler: would be helpful if elf-pavlik could make some examples
ACTION: Pavlik to write down a few proposals for PR-154 and send a notice to the mailing list announcing the potential breaking change
elf Pavlik: would break linked data fragments, so other changes should be made the same time.
Thomas Bergwinkl: I've made a new issue https://github.com/HydraCG/Specifications/issues/156 [scribe assist by elf Pavlik]
... not related to this issue we just discussed
Markus Lanthaler: we can discuss it now [scribe assist by elf Pavlik]

Topic: Operation linked to class and property (PR-156)

Thomas Bergwinkl: the use case was a datacube [scribe assist by elf Pavlik]
... i wanted to make slices using hydra
... i encountered a problem that they expect different input for each dataset
... i noticed that current structure in hydra property has IRI of the property and only allows to define supported properties 'globally'
... to have a different operation with different input i have to define different property, but then client has difficulty to understand it
Thomas Bergwinkl: is it by design that property has globally supported operation or is possible to have supported operations for specific class? [scribe assist by elf Pavlik]
Markus Lanthaler: i don't know if should be like that, but currently we have global properties [scribe assist by elf Pavlik]
... no matter which type of resource uses it
elf Pavlik: in RDF, properties are global [scribe assist by Markus Lanthaler]
... I don't think we should change this to what is typically done in OOP languages
Markus Lanthaler: I don't yet fully understand this use case, that's why i need to poke it around to get better idea [scribe assist by elf Pavlik]
elf Pavlik: Why do you have an expects on a GET operation? [scribe assist by Markus Lanthaler]
Thomas Bergwinkl: not sure.. I basically wanted to express something like a search interface with a SPARQL payload [scribe assist by Markus Lanthaler]
elf Pavlik: could you please try to come up with a simpler example... I'm not familiar with the DataCube vocab [scribe assist by Markus Lanthaler]
Karol Szczepański: I'm bac
Karol Szczepański: back

Topic: Implementation of the use case 8.filtering-events (Heracles/PR-29)

Markus Lanthaler: we can hear you
Karol Szczepański: but I cant :(
Karol Szczepański: something's weird hapenning
Markus Lanthaler: did you change your audio output?
Karol Szczepański: yes
Markus Lanthaler: client in your implementation would not understand exactly that it does filter [scribe assist by elf Pavlik]
Karol Szczepański: it seems that I introduced a bespoke filtering approach instead of using hydra search [scribe assist by elf Pavlik]
Markus Lanthaler: I would just continue with you PR and just change description [scribe assist by elf Pavlik]
Markus Lanthaler: the work Pavlik does now may render hydra:search not needed [scribe assist by elf Pavlik]
Karol Szczepański: I think actions change semantics and make operations work different [scribe assist by elf Pavlik]
Markus Lanthaler: I'll try to tell you what we discuss on that topic while you were offline [scribe assist by elf Pavlik]
Markus Lanthaler: action describes semantics, operation the http request
Markus Lanthaler: elf-pavlik is working on an issue which should make it much easier to understand
Markus Lanthaler: elf-pavliks proposal will remove the search and replace it with an action
elf Pavlik: q?
elf Pavlik: what was the intention
Karol Szczepański: the use case should cover a custom property
Karol Szczepański: we should wait for the actions PR

Topic: Follow-up on action items on Tomasz to come up with a rough structure of how the documentation should look like (hydra-cg.com/12)

Karol Szczepański: will contact tomasz
Karol Szczepański: what effect will the action proposal have?
Karol Szczepański: looks like it will be a breaking change
Markus Lanthaler: doesn't need to be a breaking change, can be an additional property
elf Pavlik: from now on the client should search for action, which is pointing to an operation