Re: Build websites and Web APIs on top of KGs with Walder

Hi Harshvardhan,

Thanks for your questions. I added my comments below. :)

Kind regards
Pieter Heyvaert
Ghent University, IDLab - imec
@HeyPieter <https://twitter.com/HeyPieter>

On 01.09.20 13:36, Harshvardhan J. Pandit wrote:
> Hello.
> @ Pieter and the team at IDLAB - this is a cool piece of tech and 
> practically useful.
Thanks!
>
> I have a few questions:
>
> 1) Is Walder a Node-js framework?
> I'm not familiar with Node-js, and the GitHub page does not say 
> anything about this either other than Walder being a javascript library.
It is not a framework, but a JavaScript library, which can be used by 
Node, and it is also accessible via the command line. Internally it uses 
different Node.js frameworks to offer the different features. For 
example, Express is used, which is a web application framework, to build 
the routes that are defined in the config file.
>
> 2) Is Walder entirely server-side? Or is there a possibility to also 
> run it from within a browser (e.g. consolidate data from different 
> sources similar to SPARQL with different SERVICE queries) ?
Yes, Walder is entirely server-side. But you have 100% control of what 
runs on the client-side because you choose what HTML/CSS/JS is sent over 
to the client. So theoretically speaking you can also do querying on the 
client-side.
>
> 3) Is there a source for the knows.idlab.ugent.be website? I would 
> like to look at the code and output to see how it works. (e.g. Jekyll 
> content files + website allow me to see what I have to write and how 
> it translates to HTML)
At the moment the source is not available, but that is something we 
might look into. There are examples in the repo, which display the 
features that Walder offers. Did you check those? Are things missing 
that you would like to see there?
>
> 4) What are other similar or related technologies/frameworks? The 
> listing of teams page on the website reminds me of Semantic MediaWiki 
> regarding automatic generation of 'index' or 'listings'. (e.g. the API 
> is more configurable, also templates?)
Most related technologies/frameworks do not take into account Semantic 
Web technologies. For example site generators (when looking at the 
website use case) such as Gatsby do not offer the use of SPARQL 
endpoints, TPF interfaces, and so on out of the box. There are options 
sometimes to plug in custom data sources, but in that case the semantics 
gets lost once the data enters the framework. As a consequence, it's 
hard to do for example content negotiation for Turtle, JSON-LD, and so 
on because the framework only considers the "raw data" and not its 
semantics.
>
> *) I think the example on GitHub's readme has a minor error: in the 
> multiple config files section the filepath refers to musicians but the 
> code refers to actors
Could you create an issue for that on Github? Thanks! :)
>
> Thanks, and keep up the good work.
> Cheers,
> Harsh
>
>
>
> On 01/09/2020 12:08, Pieter Heyvaert wrote:
>> Hello everybody,
>>
>> We are happy to let you know that we have released Walder [1]! Walder 
>> offers an easy way to set up a website or Web API on top of 
>> decentralized knowledge graphs, which can be hosted via Solid PODs, 
>> SPARQL endpoints, Triple Pattern Fragments interfaces, RDF files, and 
>> so on. Using content negotiation, Walder makes the data in these 
>> knowledge graphs available to clients via HTML, RDF, and JSON-LD. You 
>> define in a configuration file which data Walder uses and how it 
>> processes this data.
>>
>> Our own website [2] uses Walder. Especially, our team page [3] shows 
>> the power of decentralized knowledge graphs as it queries different 
>> Solid PODs, websites with JSON-LD and plain RDF files to collect the 
>> content that is displayed.
>>
>> Wanna try it out? Check out the examples in the repository or follow 
>> our tutorial that guides you through the creation of your first 
>> website using Walder [4].
>>
>> [1] https://github.com/KNowledgeOnWebScale/walder
>> [2] https://knows.idlab.ugent.be/
>> [3] https://knows.idlab.ugent.be/team
>> [4] 
>> https://pieterheyvaert.com/blog/2020/08/31/getting-started-with-walder/
>>
>> -- 
>> Kind regards
>> Pieter Heyvaert
>> Ghent University, IDLab - imec
>> @HeyPieter <https://twitter.com/HeyPieter>
>>
>