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Re: [dotNetRDF-Develop] connecting to a BrighstarDB store from dotnetRDF
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From: Iván P. <iva...@gm...> - 2015-02-20 11:17:25
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Hi again. it's been a while but I got back to work on this and despite
trying to follow your suggestion on disabling the http debugging, I found
no way to do this effectively.
I tried in visual studio, tools->options->debugging->just-in-time, and
UNselecting all options, based on what I read on msdn pages, but still when
I run my solution this exception arises.
As a reminder, since I firstly asked this long time ago, here is my code:
----------
using System;
using VDS.RDF;
using VDS.RDF.Query;
using VDS.RDF.Storage;
namespace ConsoleApplication3
{
class ReadFromBrightstarDB
{
static void Main(string[] args)
{
Options.HttpDebugging = true;
Options.HttpFullDebugging = true;
//Create a connection to BrightstarDB SPARQL Query endpoint
SparqlConnector connect = new SparqlConnector(new Uri("http://
<IP_ADDRESS>:8090/brightstar/cobacoreDV2/sparql"));
PersistentTripleStore store = new
PersistentTripleStore(connect);
//IEnumerable<Uri> graphs = connect.ListGraphs();
//foreach (Uri uri in graphs)
//{
// Console.WriteLine(uri.ToString());
//}
Object results = store.ExecuteQuery("SELECT * WHERE {?s ?p
?o}");
if (results is SparqlResultSet)
{
//Print out the results
SparqlResultSet rset = (SparqlResultSet)results;
//Create/open a file to write output into it
System.IO.StreamWriter file = new
System.IO.StreamWriter("c:\\output.txt");
foreach (SparqlResult result in rset)
{
file.WriteLine(result.ToString());
//Console.WriteLine(result.ToString());
}
file.Close();
}
}
}
}
----------
when the exception arises, the line with the sparql query is highlighted in
yellow in the IDE, and before that the whole data in the triplestore I
access is shown in console, even though now I don't print in console, but
rather try to do it on a text file (although I don't even know whether the
write to file is even executed at all).
any further guide on this would be very appreciated,
Iván
2014-12-02 14:48 GMT+00:00 Rob Vesse <rv...@do...>:
> Ivan
>
> As the error message says you have Full HTTP Debugging enabled and this
> prevents the calling code from using the HTTP response normally, disable
> HTTP debugging and this error will go away
>
> Rob
>
> From: Iván Palomares <iva...@gm...>
> Reply-To: dotNetRDF Developer Discussion and Feature Request <
> dot...@li...>
> Date: Tuesday, 2 December 2014 14:45
>
> To: dotNetRDF Developer Discussion and Feature Request <
> dot...@li...>
> Subject: Re: [dotNetRDF-Develop] connecting to a BrighstarDB store from
> dotnetRDF
>
> Many thanks for this! it seems that was the main source of the problem.
> It has been partially solved, there is still a minor issue but I can
> figure out the reason. Now a lot of the triplestore data is shown in
> console but after having finished printing in console, the following
> exception arises:
>
> An unhandled exception of type 'VDS.RDF.RdfException' occurred in
> dotNetRDF.dll
>
> Additional information: Full HTTP Debugging is enabled and the HTTP
> response stream has been consumed and written to the standard error stream,
> the stream is no longer available for calling code to consume
>
> I'm not pretty if what I have to do to prevent this from appearing is
> doing something like try-catch statements in Java. Seemingly the code
> executed completely and did what I wanted, except for this "distubring"
> exception, am I wrong?
>
> many thanks,
> Iván
>
> 2014-12-02 11:24 GMT+00:00 Rob Vesse <rv...@do...>:
>
>> Ivan
>>
>> Kal appears to have confirmed what I said in my email, Brightstar is
>> responding with unexpected data because you are using the incorrect
>> endpoint URI
>>
>> Note that ListGraphs() is internally just a query to the remote database
>> so as you suggested and Kal has confirmed the problem is in your connection
>> settings.
>>
>> Correcting the endpoint URL should hopefully resolve your issue
>>
>> Rob
>>
>> From: Kal Ahmed <ka...@ne...>
>> Reply-To: dotNetRDF Developer Discussion and Feature Request <
>> dot...@li...>
>> Date: Tuesday, 2 December 2014 08:18
>> To: dotNetRDF Developer Discussion and Feature Request <
>> dot...@li...>
>> Subject: Re: [dotNetRDF-Develop] connecting to a BrighstarDB store from
>> dotnetRDF
>>
>> Hi,
>>
>> I believe this is a problem with the URL you are using for the SPARQL
>> endpoint. The correct SPARQL endpoint for your store is
>> http://<IP>:8090/brightstar/<STORE>/sparql as described here:
>> http://brightstardb.readthedocs.org/en/latest/SPARQL_Endpoint/
>>
>> Cheers
>>
>> Kal
>>
>> On Mon, Dec 1, 2014 at 4:28 PM, Iván Palomares <iva...@gm...>
>> wrote:
>>
>>> Hi,
>>> Thanks to all who are trying to help with this question. In order to try
>>> to find out the source of the problem, I replaced the code where the SparQL
>>> query is executed and shown, by something simple in which I attempt to
>>> obtain the graphs in the triplestore ans show its URIs.
>>>
>>> * //Create a connection to BrightstarDB SPARQL Query endpoint*
>>> * SparqlConnector connect = new SparqlConnector(new
>>> Uri("http://<IP>:8090/brightstar/<STORE>"));*
>>> * PersistentTripleStore store = new
>>> PersistentTripleStore(connect);*
>>>
>>>
>>> * IEnumerable<Uri> graphs = connect.ListGraphs();*
>>> * foreach (Uri uri in graphs)*
>>> * {*
>>> * Console.WriteLine(uri.ToString());*
>>> * }*
>>>
>>> Now I obtain a new exception in the ListGraphs() line, a
>>> RdfStorageException being unhandled:
>>>
>>> An unhandled exception of type 'VDS.RDF.Storage.RdfStorageException'
>>> occurred in dotNetRDF.dll
>>>
>>> Additional information: An unexpected error occurred while listing
>>> Graphs from the Store. See inner exception for further details
>>>
>>> This makes me thing that perhaps the source of the problem is not in the
>>> previous query itself, but rather somewhere before, in the connection
>>> settings? Maybe the classes SaprqlConnector and the PersistentTripleStore
>>> as a wrapper, are not the appropriate choice to connect to a BrightstarDB
>>> triplestore?
>>>
>>> Also, to give you more info, my triplestore has been directly imported
>>> into BrightstarDB from a .owl file that was previously generated from an
>>> ontology in Protegé. The importation process in BrightstarDB was done with
>>> a management tool called Polaris it seemingly was all done correctly,
>>> according to the output I received when I imported it.
>>>
>>> Kind regards,
>>> Iván
>>>
>>> 2014-12-01 12:02 GMT+00:00 Iván Palomares <iva...@gm...>:
>>>
>>>> Hi,
>>>> I'm currently trying to make a first connection from a .NET project
>>>> with dotnetRDF, to a BrightstarDB remote endpoint in which I have a
>>>> triplestore.
>>>> The code I use is quite simple, just try to connect and execute a
>>>> "trival" SPARQL query, as follows (<IP>, <PORT> and <STORE_NAME> stand for
>>>> the existing address
>>>> and triplestore name I want to access):
>>>>
>>>> namespace ConsoleApplication3
>>>> {
>>>>
>>>> class ReadFromBrightstarDB
>>>> {
>>>> static void Main(string[] args)
>>>> {
>>>> //Create a connection to BrightstarDB SPARQL Query endpoint
>>>> SparqlConnector connect = new SparqlConnector(new Uri("http://<IP>:<PORT>/brightstar/<STORE_NAME>"));
>>>> PersistentTripleStore store = new PersistentTripleStore(connect);
>>>>
>>>> Object results = store.ExecuteQuery("SELECT * WHERE {?s ?p ?o}");
>>>> if(results is SparqlResultSet)
>>>> {
>>>> //Print out the results
>>>> SparqlResultSet rset = (SparqlResultSet)results;
>>>> foreach (SparqlResult result in rset)
>>>> {
>>>> Console.WriteLine(result.ToString());
>>>> }
>>>> }
>>>>
>>>> }
>>>> }
>>>>
>>>> }When executing, I obtain an exception entitled "RDFParseException was
>>>> unhandled", with the following description:
>>>>
>>>> An unhandled exception of type 'VDS.RDF.Parsing.RdfParseException'
>>>> occurred in dotNetRDF.dll
>>>> Additional information: Unable to Parse a SPARQL Result Set from the
>>>> provided XML since the Document Element is not a <sparql> element!
>>>>
>>>> Any help would be appreciate, I'm quite new to .NET in general and
>>>> BrightStarDB as well as to SparQL, so maybe there is a very silly issue
>>>> here but I couldn't find it yet.
>>>> Thanks!
>>>> Iván
>>>>
>>>
>>>
>>>
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>>>
>>
>>
>> --
>> Kal Ahmed
>> Director, Networked Planet Limited
>> e: kal...@ne...
>> w: www.networkedplanet.com
>> ------------------------------------------------------------------------------
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>>
>>
>>
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>>
>>
> ------------------------------------------------------------------------------
> Download BIRT iHub F-Type - The Free Enterprise-Grade BIRT Server from
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> dotNetRDF-develop mailing list dot...@li...
> https://lists.sourceforge.net/lists/listinfo/dotnetrdf-develop
>
>
>
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