Synergy - Project SOLID and SAFEnetwork

[happybeing]

Thanks for the feedback and support Josh, I’m glad you’re interested in this and it would be great to have as much input from you as you want to / can give

You ask important questions and ideas which are food for thought. Some answers & comment…

The library is one file just for convenience atm but the code is structured so it can be split up easily, new services added, implementable replaced etc, even by non coders. So yes, that’s to be done.

I’ve also just fleshed my thoughts on how to standardise this for SAFE, by using RESTful file based services as you may have seen:

Proposals for RESTful service handling

SAFE Network Services Currently SAFE services are created by inserting an entry into the services MD of a public name. For example, for the public name ‘thing’ the entries in the corresponding services MD might be: Key Explanation blog@www There’s a website at safe://blog.thing www There’s a different website website at safe://www.thing which you can also reach at safe://thing mail@email You can send email to an inbox at mail.thing I propose a modification to this convention for…

The LDP and Solid standards use a file / document metaphor, which are resources in RDF terminology. So this is how the storage is implemented, and the transactions boil down to CRUD operations on containers and files, but using RDF (usually Turtle for any payload and response body). Turtle is essentially a text format for Subject/Predicate/Object triples (e.g. Josh/works for/Maidsafe etc - BTW that’s not Turtle, just a hint about what a triple is ).

Linked Data is generally implemented in a Solid or LDP server as directories of files where each file represents an RDF resource that can be addressed with its own URI. Responses are therfore often parsed into a graph which is then queried and manipulated.

SPARQL queries return the triples which might be a subset of one resource or drawn from multiple resources, even spread across different servers.

So my implementation stores each RDF resource as a file (using SAFE NFS). Content negotiation (not yet implemented) allows the requester to receive results in different forms, depending on the representation that is stored (Turtle, N3, JSON-LD etc) and whatever conversions the server supports from each stored representation. In addition, rdflib.js Fetcher has several conversions built in too - so client side.

Note that a resource can be in any format, not just RDF, so plain text, .png, .mp3 etc, but using RDF leverages the semantic Web, SPARQL etc and if you upload a Word document to Tim’s Solid server, a kitten dies.

I’ll be showing the RESTful LDP interface at work, and the Turtle it returns for container listings, and that is used store blog posts in my demo. So if you want to see some really simple LD maybe take a look at that - it’s all there in the console output if you visit plumetest atm).

@joshuef

I wonder how LD triples lend themselves to site indexing (although probably there’d be a need for more detailed info than RDF triples provides?)

I don’t think there’s any limit to what triples can represent, though what is the best implementation is a different matter. Some use file system back ends, some graph databases etc.

For leveraging the existing semantic Web (the data out there, applications, tools, libraries and skills), and to create an ecosystem where SAFE apps can share, reuse and reach across a sea of data, it’s the protocols Solid, LDP and the standards RDF/LinkedData, WebID etc that we should support. And things like the RESTful principles and the [Architecture of the World Wide Web] (Architecture of the World Wide Web, Volume One). Sitting in on the chats between Tim and his colleagues has taught me a lot about these things, and the value of building with them.

@joshuef

What would be the expected / potential structures of LD for a website or a user profile? (is that standardised anywhere?)

HTML has various ways of integrating with LinkedData and there is a standard way for users to publish a profile as part of a Web identity (a WebID URI), which is something a user owns and controls.

@joshuef

Could we query the network directly for triples? Is that even possible? Is that even desirable?

Now you’re thinking! Lots of ways to pay with this and I haven’t really got the basics yet. Step by step I plod. I look forward to working with folks to figure things like this out.