Add a Howto for ODH Virtual Knowledge Graph access with R

[stefanodavid]

Since ODH data can now be accessed using the R framework, we need an howto with an example of data access.

https://docs.opendatahub.bz.it/en/latest/howto/generic/r-howto.html

[stefanodavid]

I'm currently stuck, due to examples not working, so I need to postpone this.

[Piiit]

Which examples are not working?

[stefanodavid]

@Piiit I tried to set up an R query to our sparql endpoint but it fails with some error that I can not understand.

[Piiit]

@stefanodavid OK, now I understand. It was not obvious that you were talking about sparql, I thought you were refering to the bzar library. Do you want to write to Ontopic about this issue?

[Piiit]

Changed the title to be clearer... maybe you need to rephrase it again... sounds strange now ;-)

[stefanodavid]

I forwarded you an email with code & errors, FYI. I probably contact Peter next week if I don't find the issue (which is the most probably case, I have very limited R knowledge)

[stefanodavid]

Changed the title to be clearer... maybe you need to rephrase it again... sounds strange now ;-)

FTFY :-)

[Piiit]

I forwarded you an email with code & errors, FYI. I probably contact Peter next week if I don't find the issue (which is the most probably case, I have very limited R knowledge)

Strange, I do not have any emails regarding that topic... let me check my quarantine

[stefanodavid]

It's the "usual" problem... It should have been sent right now Apr 9 17:07:59 mail postfix/smtp[25338]: 60E505E214A: [ cut ] delay=593, delays=592/0.04/0.34/1.1, dsn=2.6.0, status=sent (250 2.6.0 [ cut] 12676 bytes in 0.139, 88.661 KB/sec Queued mail for delivery)

[Piiit]

@stefanodavid Got it now, have you resend it?

[stefanodavid]

No, my emails are now all deferred at the first trial and sent at the second attempt. :-(

[Piiit]

Hope it will get better with those email issues :-/

I will have a look at R/sparql if I find the time, but not so soon I fear... maybe it is faster to talk to Peter first.

[mrabans]

offtopic about the mail issue: This is called greylisting and it's a widely used anti-spam mechanism (https://tools.ietf.org/html/rfc6647). So it cannot get better per definition regarding the first vs. second attempt of mail delivery.

[stefanodavid]

Yes, they evolved from rejecting TLS connections to greylisting, in a coouple of months perhaps they'll accept my emails at the first attempt :P

[stefanodavid]

@mrabans @Piiit I received an answer from Peter, the R script works, it was a stupid mistake on my side. I will complete this howto at latest on Monday morning.

[Piiit]

@stefanodavid Great, good to know

[stefanodavid]

In this issue I am adding a generic R tutorial which uses R's SPARQL package. In the future, I can consider to add an example using bzar (I think this is not a priotity ATM).