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[dotNetRDF-Develop] Issue CORE-290 has been added to a project you are monitoring.
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From: <tr...@do...> - 2012-12-01 11:31:42
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<p>The following issue has been added to a project that you are monitoring.</p>
<table border="0">
<tr>
<td width="90px" valign="top"><b>Title:</b></td>
<td>Querying dates from Virtuoso</td>
</tr>
<tr>
<td><b>Project:</b></td>
<td>Core Library (dotNetRDF.dll)</td>
</tr>
<tr>
<td><b>Created By:</b></td>
<td>Dimitri</td>
</tr>
<tr>
<td><b>Milestone:</b></td>
<td>none</td>
</tr>
<tr>
<td><b>Category:</b></td>
<td>Parsing</td>
</tr>
<tr>
<td><b>Priority:</b></td>
<td>Normal</td>
</tr>
<tr>
<td><b>Type:</b></td>
<td>Bug</td>
</tr>
<tr>
<td><b>Description:</b></td>
</tr>
<tr>
<td colspan="2"><p>
Hi everyone,</p>
<p>
I have had some trouble querying dates using VDS.RDF.Query.SparqlRemoteEndpoint and connecting to a Virtuoso server.</p>
<p>
The following code</p>
<p>
</p>
<div>
<em>var endp = new VDS.RDF.Query.SparqlRemoteEndpoint(new Uri("http://localhost:8890/sparql"));</em></div>
<div>
</div>
<div>
<em> var dateResult = endp.QueryWithResultSet(@"</em></div>
<div>
<em> prefix res: <http://localhost/rdf/resource/></em></div>
<div>
<em> prefix onto: <http://localhost/rdf/ontology#></em></div>
<div>
<em> select str(?date) as ?date1 where {res:AvoidTheBugListed onto:hasDate ?date}</em></div>
<div>
<em> ");</em></div>
<div>
</div>
<div>
<em> var datefound = DateTime.Parse(dateResult[0][0].ToString());</em></div>
<div>
</div>
<div>
causes the following error:</div>
<div>
</div>
<div>
<div>
<em>VDS.RDF.Parsing.RdfParseException : [Line 4 Column 73] Date</em></div>
<div>
<em>Unexpected Token 'Date' encountered, expected a Property Value describing one of the properties of an Variable Binding</em></div>
<div>
<em> at VDS.RDF.Parsing.SparqlJsonParser.Error(SparqlJsonParserContext context, String message) in SparqlJsonParser.cs: line 754</em></div>
<div>
<em> at VDS.RDF.Parsing.SparqlJsonParser.ParseBoundVariable(SparqlJsonParserContext context, String var, SparqlResult r) in SparqlJsonParser.cs: line 589</em></div>
<div>
<em> at VDS.RDF.Parsing.SparqlJsonParser.ParseBinding(SparqlJsonParserContext context) in SparqlJsonParser.cs: line 531</em></div>
<div>
<em> at VDS.RDF.Parsing.SparqlJsonParser.ParseBindings(SparqlJsonParserContext context) in SparqlJsonParser.cs: line 498</em></div>
<div>
<em> at VDS.RDF.Parsing.SparqlJsonParser.ParseResults(SparqlJsonParserContext context) in SparqlJsonParser.cs: line 456</em></div>
<div>
<em> at VDS.RDF.Parsing.SparqlJsonParser.ParseBody(SparqlJsonParserContext context) in SparqlJsonParser.cs: line 381</em></div>
<div>
<em> at VDS.RDF.Parsing.SparqlJsonParser.ParseResultSetObject(SparqlJsonParserContext context) in SparqlJsonParser.cs: line 195</em></div>
<div>
<em> at VDS.RDF.Parsing.SparqlJsonParser.Parse(TextReader input, ISparqlResultsHandler handler) in SparqlJsonParser.cs: line 146</em></div>
<div>
<em> at VDS.RDF.Parsing.SparqlJsonParser.Load(ISparqlResultsHandler handler, TextReader input) in SparqlJsonParser.cs: line 116</em></div>
<div>
<em> at VDS.RDF.Parsing.SparqlJsonParser.Load(ISparqlResultsHandler handler, StreamReader input) in SparqlJsonParser.cs: line 125</em></div>
<div>
<em> at VDS.RDF.Query.SparqlRemoteEndpoint.QueryWithResultSet(ISparqlResultsHandler handler, String sparqlQuery) in SparqlRemoteEndpoint.cs: line 337</em></div>
<div>
<em> at VDS.RDF.Query.SparqlRemoteEndpoint.QueryWithResultSet(String sparqlQuery) in SparqlRemoteEndpoint.cs: line 293</em></div>
<div>
<em> at DotNetRdfDatesVirtuoso.DateTests.SelectDate() in DateTests.cs: line 18</em></div>
</div>
<p>
</p>
<p>
</p>
<p>
On my local installation, I have managed to circumvent this by changing the dotNetRDF library source code.</p>
<p>
In the file dotNetRdf/Parsing/SparqlJsonParser.cs, line 587 I have changed the following code:</p>
<p>
</p>
<div>
<em>if (context.Input.TokenType != JsonToken.String)</em></div>
<div>
<em>{</em></div>
<div>
<em> throw Error(context, "Unexpected Token '" + context.Input.TokenType.ToString() + "' encountered, expected a Property Value describing one of the properties of an Variable Binding");</em></div>
<div>
<em>}</em></div>
<div>
</div>
<div>
to this</div>
<div>
</div>
<div>
<div>
<em>if (context.Input.TokenType != JsonToken.String && context.Input.TokenType != JsonToken.Date)</em></div>
<div>
<em>{</em></div>
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<em> throw Error(context, "Unexpected Token '" + context.Input.TokenType.ToString() + "' encountered, expected a Property Value describing one of the properties of an Variable Binding");</em></div>
<div>
<em>}</em></div>
<div>
</div>
<div>
and everything seems to work fine.</div>
<div>
</div>
<div>
The version of the dotNetRdf library I have performed the change on is 0.7.2</div>
<div>
</div>
<div>
I have made the same test on 0.8.2 and the same problem arises, so the fix should work there to.</div>
<div>
</div>
<div>
The Virtuoso version I am using is 06.01.3127</div>
<div>
</div>
<div>
If it would be best for the project, I could perform this sort of improvements in a branch in the future and ask for your approval but I am not sure if my fix is even correct at this point (it just works for me) :)</div>
<div>
</div>
<div>
Best regards,</div>
<div>
</div>
<div>
Dimitri</div>
<div>
</div>
</div>
<p>
</p>
<p>
</p>
<p>
</p></td>
</tr>
</table>
<p>
More information on this issue can be found at
<a href="http://www.dotnetrdf.org/tracker/Issues/IssueDetail.aspx?id=290" target="_blank">http://www.dotnetrdf.org/tracker/Issues/IssueDetail.aspx?id=290</a></p>
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