Ignoring JSONPath references with whitespace in keys

[webhart]

I try to map the following data:

{
	"key 1":{
		"key 2":{
			"key 3":"value 3"
		}
	}
}

using the following mapping:

@prefix rml: <http://semweb.mmlab.be/ns/rml#> .
@prefix rr: <http://www.w3.org/ns/r2rml#> .
@prefix ql: <http://semweb.mmlab.be/ns/ql#> .
@prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
@prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> .
@prefix ex: <https://example.org/> .
@prefix xsd: <http://www.w3.org/2001/XMLSchema#> .


ex:my_Map a rr:TriplesMap ;
  rml:logicalSource [
    rml:source "test_data.json";
    rml:referenceFormulation ql:JSONPath;
    rml:iterator "$[*]"
  ] ; 
  rr:subjectMap [ rr:termType rr:BlankNode ] ;
  rr:predicateObjectMap [
    rr:predicate ex:prop;
    rr:objectMap [ 
	  rml:reference "[\"key 2\"][\"key 3\"]" ; 
	  rr:datatype xsd:string 
	]
  ] .

As soon as the keys in the rml:reference contain whitespaces, the value is not picked up anymore. Any help on how to circumvent this is appreciated.

[DylanVanAssche]

Maybe try using the brackets formatting?

https://stackoverflow.com/questions/59837470/unable-to-get-value-of-key-with-spaces-using-jsonpath-library

I'm afraid this is depending on how JSONPath operates and is defined.

[webhart]

Maybe try using the brackets formatting?

https://stackoverflow.com/questions/59837470/unable-to-get-value-of-key-with-spaces-using-jsonpath-library

I'm afraid this is depending on how JSONPath operates and is defined.

Unfortunately this doesn't do the trick. As soon as the rml:reference contains a single or double quote or a square bracket, the construction/concatenation of the JSONPath produces a second root element ($) in the path expression:

java.lang.IllegalArgumentException: JSONPath '$.key 1$.['['key 2']['key 3']']': Property must be separated by comma or Property must be terminated close square bracket at index 5

The updated mapping for this purpose looks like this:

ex:my_Map a rr:TriplesMap ;
  rml:logicalSource [
    rml:source "testdata.json";
    rml:referenceFormulation ql:JSONPath;
    rml:iterator "$['key 1']"
  ] ; 
  rr:subjectMap [ rr:termType rr:BlankNode ] ;
  rr:predicateObjectMap [
    rr:predicate ex:prop;
    rr:objectMap [ 
	  rml:reference "['key 2']['key 3']" ; 
	  rr:datatype xsd:string 
	]
  ] .

[DylanVanAssche]

I discussed this internally and this appears to be a bug in DataIO, the data input/output library used in RMLMapper. We will look into this.