Hi Andy, Thanks for the reply. I'll try again tomorrow with the clarification regarding ?graph= which is in the doc but not the examples and I didn't read the doc above the examples closely.
Chris > On May 10, 2020, at 14:53, Andy Seaborne <[email protected]> wrote: > > > >> On 08/05/2020 21:34, Chris Tomlinson wrote: >> Hello, >> I’ve enabled a shacl endpoint as described in Apache Jena Shacl >> <https://jena.apache.org/documentation/shacl/> and have some questions. >> Our objective in using the endpoint is to be able to validate a given >> resource graph in the tdb:unionDefaultGraph against a given shapes graph. >> 1) I added: >> fuseki:endpoint [ fuseki:operation fuseki:shacl ; fuseki:name "shacl" ] >> ; >> to the Fuseki assembler file for a dataset and restarted, and it is >> reachable. >> One observation is that using the above “new style” endpoint declaration >> apparently can be replaced by: >> fuseki:serviceShacl "shacl" ; >> I’m not sure about this but the comment in the doc: >>> This is not installed into a dataset setup by default; a configuration file >>> using fuseki:serviceShacl is necessary >> seems to suggest it sort of. > > That wasn't intended - I'll fix the documentation. > > The limitation is that fuseki:serviceQuery etc require fixed names to known > to the configuration engine which is in fuseki-core. > > Extension operations (new operations can be added to Fuseki) use the new > style where the predicate is fuseki:operation. In fact, for SHACL, it can be > added quite simply because it comes from Jena itself but the code seems to > say that the old-style isn't enabled. > > >> 2) In any event, when I call the endpoint like: >> curl -s GET http://ldspdi-dev.bdrc.io/shapes/core/PersonShapes | curl -XPOST >> --data-binary @- --header 'Content-type: text/turtle' >> 'http://ahost:aport/fuseki/newcorerw/shacl?http://purl.bdrc.io/graph/P707' > > Maybe it's email corruption but that isn't the invocation syntax. > > That should have ?graph= > > Otherwise it defaults to "?graph=default" which seems consistent with the > report. > > "?http://purl.bdrc.io/graph/P707"; is going to be ignored and for you that's > the union default graph. > > >> I see a result like: >> [ a sh:ValidationReport ; >> sh:conforms false ; >> sh:result [ a sh:ValidationResult ; >> sh:focusNode bdr:UNKNOWN_Person ; >> sh:resultMessage "minCount[1]: Invalid >> cardinality: expected min 1: Got count = 0" ; >> sh:resultPath bdo:personName ; >> sh:resultSeverity sh:Violation ; >> sh:sourceConstraintComponent >> sh:MinCountConstraintComponent ; >> sh:sourceShape bds:PersonShape-personName >> ] >> ] . >> which is surprising given that there’s no reference in the graph >> http://purl.bdrc.io/graph/P707 <http://purl.bdrc.io/graph/P707> that refers >> eventually to bdr:UNKNOWN_Person. The P707 graph is a Person graph. I’ve >> also tried using an encoded url, http%3a%2f%2fpurl.bdrc.io%2fgraph%2fP707, >> but that makes no difference. >> In fact, using a non-Person graph like http://purl.bdrc.io/graph/W12827 >> <http://purl.bdrc.io/graph/W12827> produces the same result. As does, >> submitting a non-existent graph URL like http://no.such.org/flip/flop >> <http://no.such.org/flip/flop>. > > See above. > >> This all leads me to conclude that SHACL-Validation#L61 >> <https://github.com/apache/jena/blob/ab7882a73445c7a75e811eb58d06211c410891b0/jena-fuseki2/jena-fuseki-core/src/main/java/org/apache/jena/fuseki/servlets/SHACL_Validation.java#L61> >> isn’t getting in a way that I understand. >> I haven’t found any logging that gives any helpful entries and so I’m asking >> questions rather than diving deeper for now. >> If I use another shape graph like >> http://ldspdi-dev.bdrc.io/shapes/core/WorkShapes >> <http://ldspdi-dev.bdrc.io/shapes/core/WorkShapes>, then I get a result like: >> [ a sh:ValidationReport ; >> sh:conforms true >> ] . >> again regardless of the graph argument. >> I don’t understand the results. >> 3) This result leads to a related question. It seems that a result of: >> sh:conforms true >> means that the data graph conforms to the shapes graph in all respects where >> the shapes graph picks out features in the data graph, even if the shapes >> graph picks out nothing at all in the data graph. > > Yes - that a SHACL-ism. > > An empty graph or graph with no targets is "conforms true". > >> Is there any way to tell whether the shapes graph in some sense doesn’t >> apply to the data graph? This seems like an important distinction. > > You can add a constraint that is always triggered. > > [] sh:targetNode ex:myNode > > is always triggered; it does not require ex:myNode to be in the data. > > From there, a SPARQL constraint could do any validations for "right graph", > "empty graph" etc. > >> I appreciate any help on these questions, >> Chris > > Andy
