Re: the necessity of describing responses in-band

Hi Markus,

> Nice post! One question I have is why you blanked the URL bar in the second
> screenshot? Even if the resource itself isn't self-describing, the client
> would still know how it retrieved it, no?

I blanked it out because IRIs should be opaque, i.e., no information should be deduced from them. In this particular case, the URL would still “tell” human users they're on Amazon and that the page shows search results for “Peppa Pig”. That would be an unfair advantage compared to machines, who cannot (and should not) parse this URL for information. (As an alternative, I could have mangled the URL.)

The reason for hiding it here was to highlight: the response doesn't allow you to deduce you're on Amazon looking at Peppa Pig results. That point would have been less obvious if the URL was still there. Even if it contains information, it is still in the URL, not in the response.

> I have to say though, that I'm not a big fan of exchanging named graphs as
> they have undefined semantics...

Which is a major problem in the RDF 1.1 spec.
I can't imagine why anybody wants to label a graph with an IRI
but then not be able to use that IRI to refer to the graph.

That said, we can be explicit about it if needed.

<#about> {
  <> ex:graphNameRefersToGraph true.
}
or
<#about> {
  <#about> sd:name "http://example.org/toys/peppa#about".
}

> It is the graph's name but it's semantics are not clear. It is undefined
> whether the name denotes the graph or not. The reasons for that are because
> the RDF WG at the time couldn't find consensus.

:'( of course, that's always what happens

> Graph names have
> historically used for different purposes (timestamp graphs, record
> provenance, slice data by subject, ...) and it wasn't clear which to elect
> to the "winner" and what would break by doing so. 

…and as a result, we can't reference to our graphs now.
Sigh.

Anyways, I choose to deliberately ignore that.
Named graphs just don't make sense if we can't refer to them by name.
Or just do
    <#about> sd:name "http://example.org/toys/peppa#about".
then.

> With the current state of affairs I think using datasets on the public Web
> is basically made impossible.

It's so sad this was not specced.
But it's not impossible, we can still use an explicit approach.

Best,

Ruben

Received on Friday, 9 October 2015 08:49:05 UTC