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Availability is false for vocab.getty.edu #42

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VladimirAlexiev opened this issue Jul 22, 2015 · 5 comments
Open

Availability is false for vocab.getty.edu #42

VladimirAlexiev opened this issue Jul 22, 2015 · 5 comments

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@VladimirAlexiev
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http://sparqles.ai.wu.ac.at/availability shows
http://vocab.getty.edu/sparql (2) 0% 0%
I know for a fact this endpoint is up all the time.

Can you provide more info when it was last checked and what was the result?
@VladimirAlexiev VladimirAlexiev mentioned this issue Aug 3, 2015
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@lmatteis
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We've started debugging this issue. Our logs seem to be throwing an error for the http://vocab.getty.edu/sparql endpoint:

12-09-15 14:24:38 ATask:114 WARN - failed SELECT query for http://vocab.getty.edu/sparql, EXC@0#349> QueryException HTTP msg:null cause:null

Obviously there's something wrong on our end because of the "null" messages. We'll keep you updated once this is fixed.

@VladimirAlexiev VladimirAlexiev mentioned this issue Sep 13, 2015
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@lmatteis
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lmatteis commented Oct 5, 2015

Hi @VladimirAlexiev. Sorry for the delay but it seems like your endpoint isn't read correctly by standard SPARQL tools:

$ java -cp "lib/*" arq.rsparql --service "http://dbpedia.org/sparql" 'SELECT ?s WHERE {?s ?p ?o} LIMIT 1'
----------------------------------------------------------------
| s                                                            |
================================================================
| <http://www.openlinksw.com/virtrdf-data-formats#default-iid> |
----------------------------------------------------------------
$ java -cp "lib/*" arq.rsparql --service "http://vocab.getty.edu/sparql" 'SELECT ?s WHERE {?s ?p ?o} LIMIT 1'
HTTP Exeception
HttpException: 404
    at org.apache.jena.sparql.engine.http.HttpQuery.execGet(HttpQuery.java:346)
    at org.apache.jena.sparql.engine.http.HttpQuery.exec(HttpQuery.java:292)
    at org.apache.jena.sparql.engine.http.QueryEngineHTTP.execResultSetInner(QueryEngineHTTP.java:345)
    at org.apache.jena.sparql.engine.http.QueryEngineHTTP.execSelect(QueryEngineHTTP.java:337)
    at org.apache.jena.sparql.util.QueryExecUtils.doSelectQuery(QueryExecUtils.java:196)
    at org.apache.jena.sparql.util.QueryExecUtils.executeQuery(QueryExecUtils.java:78)
    at arq.rsparql.exec(rsparql.java:76)
    at jena.cmd.CmdMain.mainMethod(CmdMain.java:93)
    at jena.cmd.CmdMain.mainRun(CmdMain.java:58)
    at jena.cmd.CmdMain.mainRun(CmdMain.java:45)
    at arq.rsparql.main(rsparql.java:44)

As you can see, in the first example we run a test query against DBpedia. Running the same query against your endpoint leads to an error. Let us know if you can debug.

@VladimirAlexiev
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Thanks for the report!
I think that arq.rsparql doesn't send an Accept header. Without an Accept header, we return HTML and maybe rsparql fails on that. This returns results in XML:
curl -Haccept:application/sparql-results+xml "http://vocab.getty.edu/sparql?query=SELECT+%3Fs+WHERE+%7B%3Fs+%3Fp+%3Fo%7D+LIMIT+1"

In contrast, http://dbpedia.org/sparql has a drop-down "Results Format" with default value HTML. But if you send the query without an Accept header, it returns application/sparql-results+xml.

However, I tried this and it still fails with a similar exception:
rsparql --results xml --service "http://vocab.getty.edu/sparql" "SELECT ?s WHERE {?s ?p ?o} LIMIT 1"
We'll look into it.

@VladimirAlexiev
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Re the last command: I'm on Windows, so the syntax is slightly different.
A rsparql cheat sheet is at http://richard.cyganiak.de/blog/wp-content/uploads/2013/09/jena-sparql-cli-v1.pdf, that's where I got the --results xml param

@VladimirAlexiev
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Now rsparql obtains 1 result as expected:

<?xml version="1.0"?>
<sparql xmlns="http://www.w3.org/2005/sparql-results#">
  <head>
    <variable name="s"/>
  </head>
  <results>
    <result>
      <binding name="s">
        <uri>http://www.w3.org/1999/02/22-rdf-syntax-ns#type</uri>
      </binding>
    </result>
  </results>
</sparql>

The Availabiliy shows 100%, but the query reports are still failing. Should we close this?

@VladimirAlexiev VladimirAlexiev mentioned this issue Feb 19, 2016
Open
@berezovskyi berezovskyi mentioned this issue Jan 5, 2022
Open
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@lmatteis @VladimirAlexiev