Can't import ontologies from the web

[Simon Cox]

I'm trying to load the SEAS ontologies from 

https://w3id.org/seas/ or https://w3id.org/seas/seas-1.0 or

HTTP GET appears to work (tested using PostMan), but TBC is consistently throwing an error while trying to import

" ERROR [ModalContext] (ErrorHandlerFactory.java:84) - [line: 1, col: 50] White spaces are required between publicId and systemId."

Any clue what the issue is?

Simon

[Richard Cyganiak]

You might want to try the Turtle version:

https://w3id.org/seas/seas-1.0.ttl

Hope that helps,

Richard

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[Andy Seaborne]

If this is the latest version of TBC, then the conneg with redirections and extension-less files triggers a problem in Apache Jena

https://issues.apache.org/jira/browse/JENA-1378

As Richard suggests, you can use https://w3id.org/seas/seas-1.0.ttl and maybe https://w3id.org/seas/seas-1.0.rdf

    Andy

[Simon Cox]

Running TBC 5.2.1

No improvement even if trying to import the .ttl version - looks like an XML error, so maybe something is going wrong in the redirects. 

And then even if I grab a copy and put it local, then the same error is triggered by all the imports (which is essentially all this top graph does). 

[Andy Seaborne]

This seems to be a bit of a moving target. The site seems to be changing because things happen different to a few days ago. I got the same XML parse error because XML processing instruction was bad, now I get the RDF, or a "500 Internal Server Error" for bad conneg.

TBC 5.2.1 used Apache Jena 3.1.0 and, for me, at the moment, Jena (3.1.0 or current development or anything but 3.4.0) fetches and parses the top level https://w3id.org/seas/

There are then a lot of imports, each of which is a redirection. Are you behind any sort of cache? Maybe an old version of an import is cached.

Downloading https://w3id.org/seas/seas-1.0.ttl gets the Turtle ... but following the imports will get RDF/XML.

    Andy

[Irene Polikoff]

Simon,

Even if one downloads the top level file as TTL, the import statements then refer to the RDF/XML files that have problems - as you have discovered. With this, the only approach I could think of is to download all the TTL files and then fix their base URIs so that the imports work.

This would be busy work. You may want to contact owners of the site and see if they could fix the problems or provide zips with the files for download.

Sent from my iPhone

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[Maxime Lefrançois]

Dear Simon, all,

I'm the developer of the SEAS ontology and want to report this issue is solved --> one can now load the entire SEAS ontology with all of its modules in TBC 

There was two issues actually:

1. There was a HTTPS -> HTTP redirection that was known to be problematic for some clients (the body of the redirection caused the bad XML processing instruction Andy was referring to)

2. The SEAS website parses the Accept header to choose the most appropriate representation. And for some reason I was receiving Accept headers such as the following:

Accept: text/html, image/gif, image/jpeg, *; q=.2, */*; q=.2

Where '*; q=.2'  will make my call of javax.ws.rs.core.MediaType.valueOf() trigger an error. This was causing the "500 Internal Server Error" Andy was referring to.

Best,

Maxime Lefrançois

http://maxime-lefrancois.info/

@INPROCEEDINGS {seassisiot,
    author    = "Lefran\c{c}ois, Maxime",
    title     = "{Planned ETSI SAREF Extensions based on the W3C\\&OGC SOSA/SSN-compatible SEAS Ontology Patterns}",
    booktitle = "Proceedings of Workshop on Semantic Interoperability and Standardization in the IoT, SIS-IoT,",
    year      = "2017",
    month     = "July",
    city      = "Amsterdam, Netherlands"
}

[Maxime Lefrançois]

Dear Simon, all,

I'm the developer of the SEAS ontology and want to report this issue is solved --> one can now load the entire SEAS ontology with all of its modules in TBC 

There was two issues actually:

1. There was a HTTPS -> HTTP redirection that was known to be problematic for some clients (the body of the redirection caused the bad XML processing instruction Andy was referring to)

2. The SEAS website parses the Accept header to choose the most appropriate representation. And for some reason I was receiving Accept headers such as the following:

Accept: text/html, image/gif, image/jpeg, *; q=.2, */*; q=.2

Where '*; q=.2'  will make my call of javax.ws.rs.core.MediaType.valueOf() trigger an error. This was causing the "500 Internal Server Error" Andy was referring to.

Best,

Maxime Lefrançois

http://maxime-lefrancois.info/

@INPROCEEDINGS {seassisiot,
    author    = "Lefran\c{c}ois, Maxime",
    title     = "{Planned ETSI SAREF Extensions based on the W3C\\&OGC SOSA/SSN-compatible SEAS Ontology Patterns}",
    booktitle = "Proceedings of Workshop on Semantic Interoperability and Standardization in the IoT, SIS-IoT,",
    year      = "2017",
    month     = "July",
    city      = "Amsterdam, Netherlands"
}

[Simon Cox]

Thanks Maxime - 

I know that you take seriously the publishing of ontologies so was confident you would 
(a) like to know if something was failing

(b) would fix it promptly if necessary

You did it. 

Simon