/// <summary>
/// Queries the store asynchronously
/// </summary>
/// <param name="sparqlQuery">SPARQL Query</param>
/// <param name="rdfHandler">RDF Handler</param>
/// <param name="resultsHandler">Results Handler</param>
/// <param name="callback">Callback</param>
/// <param name="state">State to pass to the callback</param>
public void Query(IRdfHandler rdfHandler, ISparqlResultsHandler resultsHandler, string sparqlQuery, AsyncStorageCallback callback, object state)
{
try
{
// First off parse the Query to see what kind of query it is
SparqlQuery q;
try
{
q = _parser.ParseFromString(sparqlQuery);
}
catch (RdfParseException parseEx)
{
callback(this, new AsyncStorageCallbackArgs(AsyncStorageOperation.SparqlQueryWithHandler, parseEx), state);
return;
}
catch (Exception ex)
{
callback(this, new AsyncStorageCallbackArgs(AsyncStorageOperation.SparqlQueryWithHandler, new RdfStorageException("An unexpected error occurred while trying to parse the SPARQL Query prior to sending it to the Store, see inner exception for details", ex)), state);
return;
}
// Now select the Accept Header based on the query type
String accept = (SparqlSpecsHelper.IsSelectQuery(q.QueryType) || q.QueryType == SparqlQueryType.Ask) ? MimeTypesHelper.HttpSparqlAcceptHeader : MimeTypesHelper.HttpAcceptHeader;
// Create the Request, for simplicity async requests are always POST
HttpWebRequest request = (HttpWebRequest)WebRequest.Create(_endpoint.Uri);
request.Accept = accept;
request.Method = "POST";
request.ContentType = MimeTypesHelper.Utf8WWWFormURLEncoded;
request = ApplyRequestOptions(request);
Tools.HttpDebugRequest(request);
request.BeginGetRequestStream(r =>
{
try
{
Stream stream = request.EndGetRequestStream(r);
using (StreamWriter writer = new StreamWriter(stream, new UTF8Encoding(Options.UseBomForUtf8)))
{
writer.Write("query=");
writer.Write(HttpUtility.UrlEncode(sparqlQuery));
writer.Close();
}
request.BeginGetResponse(r2 =>
{
// Get the Response and process based on the Content Type
try
{
HttpWebResponse response = (HttpWebResponse)request.EndGetResponse(r2);
Tools.HttpDebugResponse(response);
StreamReader data = new StreamReader(response.GetResponseStream());
String ctype = response.ContentType;
if (SparqlSpecsHelper.IsSelectQuery(q.QueryType) || q.QueryType == SparqlQueryType.Ask)
{
// ASK/SELECT should return SPARQL Results
ISparqlResultsReader resreader = MimeTypesHelper.GetSparqlParser(ctype, q.QueryType == SparqlQueryType.Ask);
resreader.Load(resultsHandler, data);
response.Close();
}
else
{
// CONSTRUCT/DESCRIBE should return a Graph
IRdfReader rdfreader = MimeTypesHelper.GetParser(ctype);
rdfreader.Load(rdfHandler, data);
response.Close();
}
callback(this, new AsyncStorageCallbackArgs(AsyncStorageOperation.SparqlQueryWithHandler, sparqlQuery, rdfHandler, resultsHandler), state);
}
catch (WebException webEx)
{
callback(this, new AsyncStorageCallbackArgs(AsyncStorageOperation.SparqlQueryWithHandler, StorageHelper.HandleHttpQueryError(webEx)), state);
}
catch (Exception ex)
{
callback(this, new AsyncStorageCallbackArgs(AsyncStorageOperation.SparqlQueryWithHandler, StorageHelper.HandleQueryError(ex)), state);
}
}, state);
}
catch (WebException webEx)
{
callback(this, new AsyncStorageCallbackArgs(AsyncStorageOperation.SparqlQueryWithHandler, StorageHelper.HandleHttpQueryError(webEx)), state);
}
catch (Exception ex)
{
callback(this, new AsyncStorageCallbackArgs(AsyncStorageOperation.SparqlQueryWithHandler, StorageHelper.HandleQueryError(ex)), state);
}
}, state);
}
catch (WebException webEx)
{
callback(this, new AsyncStorageCallbackArgs(AsyncStorageOperation.SparqlQueryWithHandler, StorageHelper.HandleHttpQueryError(webEx)), state);
}
catch (Exception ex)
{
callback(this, new AsyncStorageCallbackArgs(AsyncStorageOperation.SparqlQueryWithHandler, StorageHelper.HandleQueryError(ex)), state);
}
}
/// <summary>
/// Executes a SPARQL Query on the Fuseki store processing the results using an appropriate handler from those provided
/// </summary>
/// <param name="rdfHandler">RDF Handler</param>
/// <param name="resultsHandler">Results Handler</param>
/// <param name="sparqlQuery">SPARQL Query</param>
/// <param name="callback">Callback</param>
/// <param name="state">State to pass to the callback</param>
/// <returns></returns>
public void Query(IRdfHandler rdfHandler, ISparqlResultsHandler resultsHandler, String sparqlQuery, AsyncStorageCallback callback, Object state)
{
try
{
HttpWebRequest request;
// Create the Request, always use POST for async for simplicity
String queryUri = this._queryUri;
request = (HttpWebRequest)WebRequest.Create(queryUri);
request.Method = "POST";
request.Accept = MimeTypesHelper.HttpRdfOrSparqlAcceptHeader;
request = base.ApplyRequestOptions(request);
// Build the Post Data and add to the Request Body
request.ContentType = MimeTypesHelper.Utf8WWWFormURLEncoded;
StringBuilder postData = new StringBuilder();
postData.Append("query=");
postData.Append(HttpUtility.UrlEncode(sparqlQuery));
request.BeginGetRequestStream(r =>
{
try
{
Stream stream = request.EndGetRequestStream(r);
using (StreamWriter writer = new StreamWriter(stream, new UTF8Encoding(Options.UseBomForUtf8)))
{
writer.Write(postData);
writer.Close();
}
Tools.HttpDebugRequest(request);
// Get the Response and process based on the Content Type
request.BeginGetResponse(r2 =>
{
try
{
HttpWebResponse response = (HttpWebResponse)request.EndGetResponse(r2);
Tools.HttpDebugResponse(response);
StreamReader data = new StreamReader(response.GetResponseStream());
String ctype = response.ContentType;
try
{
// Is the Content Type referring to a Sparql Result Set format?
ISparqlResultsReader resreader = MimeTypesHelper.GetSparqlParser(ctype, true);
resreader.Load(resultsHandler, data);
response.Close();
}
catch (RdfParserSelectionException)
{
// If we get a Parse exception then the Content Type isn't valid for a Sparql Result Set
// Is the Content Type referring to a RDF format?
IRdfReader rdfreader = MimeTypesHelper.GetParser(ctype);
rdfreader.Load(rdfHandler, data);
response.Close();
}
callback(this, new AsyncStorageCallbackArgs(AsyncStorageOperation.SparqlQueryWithHandler, sparqlQuery, rdfHandler, resultsHandler), state);
}
catch (WebException webEx)
{
callback(this, new AsyncStorageCallbackArgs(AsyncStorageOperation.SparqlQueryWithHandler, StorageHelper.HandleHttpQueryError(webEx)), state);
}
catch (Exception ex)
{
callback(this, new AsyncStorageCallbackArgs(AsyncStorageOperation.SparqlQueryWithHandler, StorageHelper.HandleQueryError(ex)), state);
}
}, state);
}
catch (WebException webEx)
{
callback(this, new AsyncStorageCallbackArgs(AsyncStorageOperation.SparqlQueryWithHandler, StorageHelper.HandleHttpQueryError(webEx)), state);
}
catch (Exception ex)
{
callback(this, new AsyncStorageCallbackArgs(AsyncStorageOperation.SparqlQueryWithHandler, StorageHelper.HandleQueryError(ex)), state);
}
}, state);
}
catch (WebException webEx)
{
callback(this, new AsyncStorageCallbackArgs(AsyncStorageOperation.SparqlQueryWithHandler, StorageHelper.HandleHttpQueryError(webEx)), state);
}
catch (Exception ex)
{
callback(this, new AsyncStorageCallbackArgs(AsyncStorageOperation.SparqlQueryWithHandler, StorageHelper.HandleQueryError(ex)), state);
}
}
