/// <summary>
/// Processes SPARQL Update requests
/// </summary>
/// <param name="context">HTTP Context</param>
public void ProcessRequest(HttpContext context)
{
this._config = this.LoadConfig(context);
//Add our Standard Headers
HandlerHelper.AddStandardHeaders(context, this._config);
if (context.Request.HttpMethod.Equals("OPTIONS"))
{
//OPTIONS requests always result in the Service Description document
IGraph svcDescrip = SparqlServiceDescriber.GetServiceDescription(context, this._config, new Uri(context.Request.Url.AbsoluteUri));
HandlerHelper.SendToClient(context, svcDescrip, this._config);
return;
}
//See if there has been an update submitted
String updateText = context.Request.QueryString["update"];
if (updateText == null || updateText.Equals(String.Empty))
{
updateText = context.Request.Form["update"];
}
//If no Update sent either show Update Form or give a HTTP 400 response
if (updateText == null || updateText.Equals(String.Empty))
{
//If there is no Update we may return the SPARQL Service Description where appropriate
try
{
//If we might show the Update Form only show the Description if the selected writer is
//not a HTML writer
MimeTypeDefinition definition = MimeTypesHelper.GetDefinitions(HandlerHelper.GetAcceptTypes(context)).FirstOrDefault(d => d.CanWriteRdf);
if (definition != null)
{
IRdfWriter writer = definition.GetRdfWriter();
if (!this._config.ShowUpdateForm || !(writer is IHtmlWriter))
{
//If not a HTML Writer selected OR not showing Update Form then show the Service Description Graph
//unless an error occurs creating it
IGraph serviceDescrip = SparqlServiceDescriber.GetServiceDescription(context, this._config, new Uri(context.Request.Url.AbsoluteUri));
context.Response.ContentType = definition.CanonicalMimeType;
context.Response.ContentEncoding = definition.Encoding;
writer.Save(serviceDescrip, new StreamWriter(context.Response.OutputStream, definition.Encoding));
return;
}
}
}
catch
{
//Ignore Exceptions - we'll just show the Query Form or return a 400 Bad Request instead
}
//If a Writer can't be selected then we'll either show the Update Form or return a 400 Bad Request
if (this._config.ShowUpdateForm)
{
this.ShowUpdateForm(context);
}
else
{
context.Response.StatusCode = (int)HttpStatusCode.BadRequest;
}
return;
}
try
{
//Now we're going to parse the Updates
SparqlUpdateParser parser = new SparqlUpdateParser();
parser.ExpressionFactories = this._config.ExpressionFactories;
SparqlUpdateCommandSet commands = parser.ParseFromString(updateText);
//Check whether we need to use authentication
//If there are no user groups then no authentication is in use so we default to authenticated with no per-action authentication needed
bool isAuth = true, requireActionAuth = false;
if (this._config.UserGroups.Any())
{
//If we have user
isAuth = HandlerHelper.IsAuthenticated(context, this._config.UserGroups);
requireActionAuth = true;
}
if (!isAuth)
{
return;
}
//First check actions to see whether they are all permissible
foreach (SparqlUpdateCommand cmd in commands.Commands)
{
//Authenticate each action
bool actionAuth = true;
if (requireActionAuth)
{
actionAuth = HandlerHelper.IsAuthenticated(context, this._config.UserGroups, this.GetPermissionAction(cmd));
}
if (!actionAuth)
{
throw new SparqlUpdateException("You are not authorised to perform the " + this.GetPermissionAction(cmd) + " action");
}
}
//Then assuming we got here this means all our actions are permitted so now we can process the updates
this.ProcessUpdates(commands);
//Flush outstanding changes
this._config.Processor.Flush();
//Update the Cache as the request may have changed the endpoint
this.UpdateConfig(context);
}
catch (RdfParseException parseEx)
{
HandleErrors(context, "Parsing Error", updateText, parseEx);
}
catch (SparqlUpdateException updateEx)
{
HandleErrors(context, "Update Error", updateText, updateEx);
}
catch (RdfException rdfEx)
{
HandleErrors(context, "RDF Error", updateText, rdfEx);
}
catch (Exception ex)
{
HandleErrors(context, "Error", updateText, ex);
}
}
/// <summary>
/// Processes the request by loading the Configuration in order to obtain the Graph to be served and then serving it to the client
/// </summary>
/// <param name="context">HTTP Context</param>
public void ProcessRequest(HttpContext context)
{
this._config = this.LoadConfig(context);
//Add our Standard Headers
HandlerHelper.AddStandardHeaders(context, this._config);
//Check whether we need to use authentication
//If there are no user groups then no authentication is in use so we default to authenticated with no per-action authentication needed
bool isAuth = true;
if (this._config.UserGroups.Any())
{
//If we have user
isAuth = HandlerHelper.IsAuthenticated(context, this._config.UserGroups);
}
if (!isAuth)
{
return;
}
//Check whether we can just send a 304 Not Modified
if (HandlerHelper.CheckCachingHeaders(context, this._config.ETag, null))
{
context.Response.StatusCode = (int)HttpStatusCode.NotModified;
HandlerHelper.AddCachingHeaders(context, this._config.ETag, null);
return;
}
try
{
String[] acceptTypes = HandlerHelper.GetAcceptTypes(context);
//Retrieve an appropriate MIME Type Definition which can be used to get a Writer
MimeTypeDefinition definition = MimeTypesHelper.GetDefinitions(acceptTypes).FirstOrDefault(d => d.CanWriteRdf);
if (definition == null)
{
throw new RdfWriterSelectionException("No MIME Type Definitions have a registered RDF Writer for the MIME Types specified in the HTTP Accept Header");
}
IRdfWriter writer = this.SelectWriter(definition);
HandlerHelper.ApplyWriterOptions(writer, this._config);
IGraph g = this.ProcessGraph(this._config.Graph);
if (this._config.ETag == null)
{
this._config.ETag = this.ComputeETag(g);
}
//Serve the Graph to the User
context.Response.ContentType = definition.CanonicalMimeType;
HandlerHelper.AddCachingHeaders(context, this._config.ETag, null);
if (writer is IHtmlWriter)
{
if (!this._config.Stylesheet.Equals(String.Empty))
{
((IHtmlWriter)writer).Stylesheet = this._config.Stylesheet;
}
}
context.Response.ContentEncoding = definition.Encoding;
HandlerHelper.ApplyWriterOptions(writer, this._config);
writer.Save(g, new StreamWriter(context.Response.OutputStream, definition.Encoding));
this.UpdateConfig(context);
}
catch (RdfWriterSelectionException)
{
context.Response.StatusCode = (int)HttpStatusCode.NotAcceptable;
}
catch
{
context.Response.StatusCode = (int)HttpStatusCode.InternalServerError;
}
}
/// <summary>
/// Helper function which returns the Results (Graph/Triple Store/SPARQL Results) back to the Client in one of their accepted formats
/// </summary>
/// <param name="context">Context of the HTTP Request</param>
/// <param name="result">Results of the Sparql Query</param>
/// <param name="config">Handler Configuration</param>
public static void SendToClient(HttpContext context, Object result, BaseHandlerConfiguration config)
{
MimeTypeDefinition definition = null;
String ctype = "text/plain";
String[] acceptTypes = HandlerHelper.GetAcceptTypes(context);
//Return the Results
if (result is SparqlResultSet)
{
ISparqlResultsWriter sparqlWriter = null;
//Try and get a MIME Type Definition using the HTTP Requests Accept Header
if (acceptTypes != null)
{
definition = MimeTypesHelper.GetDefinitions(acceptTypes).FirstOrDefault(d => d.CanWriteSparqlResults);
}
//Try and get the registered Definition for SPARQL Results XML
if (definition == null)
{
definition = MimeTypesHelper.GetDefinitions(MimeTypesHelper.SparqlXml[0]).FirstOrDefault();
}
//If Definition is still null create a temporary definition
if (definition == null)
{
definition = new MimeTypeDefinition("SPARQL Results XML", MimeTypesHelper.SparqlXml, Enumerable.Empty <String>());
definition.SparqlResultsWriterType = typeof(VDS.RDF.Writing.SparqlXmlWriter);
}
//Set up the Writer appropriately
sparqlWriter = definition.GetSparqlResultsWriter();
context.Response.ContentType = definition.CanonicalMimeType;
HandlerHelper.ApplyWriterOptions(sparqlWriter, config);
//Clear any existing Response
context.Response.Clear();
//Send Result Set to Client
context.Response.ContentEncoding = definition.Encoding;
sparqlWriter.Save((SparqlResultSet)result, new StreamWriter(context.Response.OutputStream, definition.Encoding));
}
else if (result is IGraph)
{
IRdfWriter rdfWriter = null;
//Try and get a MIME Type Definition using the HTTP Requests Accept Header
if (acceptTypes != null)
{
definition = MimeTypesHelper.GetDefinitions(acceptTypes).FirstOrDefault(d => d.CanWriteRdf);
}
if (definition == null)
{
//If no appropriate definition then use the GetWriter method instead
rdfWriter = MimeTypesHelper.GetWriter(acceptTypes, out ctype);
}
else
{
rdfWriter = definition.GetRdfWriter();
}
//Setup the writer
if (definition != null)
{
ctype = definition.CanonicalMimeType;
}
context.Response.ContentType = ctype;
HandlerHelper.ApplyWriterOptions(rdfWriter, config);
//Clear any existing Response
context.Response.Clear();
//Send Graph to Client
if (definition != null)
{
context.Response.ContentEncoding = definition.Encoding;
rdfWriter.Save((IGraph)result, new StreamWriter(context.Response.OutputStream, definition.Encoding));
}
else
{
rdfWriter.Save((IGraph)result, new StreamWriter(context.Response.OutputStream));
}
}
else if (result is ITripleStore)
{
IStoreWriter storeWriter = null;
//Try and get a MIME Type Definition using the HTTP Requests Accept Header
if (acceptTypes != null)
{
definition = MimeTypesHelper.GetDefinitions(acceptTypes).FirstOrDefault(d => d.CanWriteRdfDatasets);
}
if (definition == null)
{
//If no appropriate definition then use the GetStoreWriter method instead
storeWriter = MimeTypesHelper.GetStoreWriter(acceptTypes, out ctype);
}
else
{
storeWriter = definition.GetRdfDatasetWriter();
}
//Setup the writer
if (definition != null)
{
ctype = definition.CanonicalMimeType;
}
context.Response.ContentType = ctype;
HandlerHelper.ApplyWriterOptions(storeWriter, config);
//Clear any existing Response
context.Response.Clear();
//Send Triple Store to Client
if (definition != null)
{
context.Response.ContentEncoding = definition.Encoding;
storeWriter.Save((ITripleStore)result, new VDS.RDF.Storage.Params.StreamParams(context.Response.OutputStream, definition.Encoding));
}
else
{
storeWriter.Save((ITripleStore)result, new VDS.RDF.Storage.Params.StreamParams(context.Response.OutputStream));
}
}
else if (result is ISparqlDataset)
{
//Wrap in a Triple Store and then call self so the Triple Store writing branch of this if gets called instead
TripleStore store = new TripleStore(new DatasetGraphCollection((ISparqlDataset)result));
HandlerHelper.SendToClient(context, store, config);
}
else
{
throw new RdfOutputException("Unexpected Result Object of Type '" + result.GetType().ToString() + "' returned - unable to write Objects of this Type to the HTTP Response");
}
}
/// <summary>
/// Processes SPARQL Update requests
/// </summary>
/// <param name="context">HTTP Context</param>
public void ProcessRequest(HttpContext context)
{
this._config = this.LoadConfig(context);
//Add our Standard Headers
HandlerHelper.AddStandardHeaders(context, this._config);
if (context.Request.HttpMethod.Equals("OPTIONS"))
{
//OPTIONS requests always result in the Service Description document
IGraph svcDescrip = SparqlServiceDescriber.GetServiceDescription(context, this._config, UriFactory.Create(context.Request.Url.AbsoluteUri));
HandlerHelper.SendToClient(context, svcDescrip, this._config);
return;
}
//See if there has been an update submitted
String updateText = null;
if (context.Request.ContentType != null)
{
if (context.Request.ContentType.Equals(MimeTypesHelper.WWWFormURLEncoded))
{
updateText = context.Request.Form["update"];
}
else if (context.Request.ContentType.Equals(MimeTypesHelper.SparqlUpdate))
{
updateText = new StreamReader(context.Request.InputStream).ReadToEnd();
}
}
else
{
updateText = context.Request.Form["update"];
}
//If no Update sent either show Update Form or give a HTTP 400 response
if (updateText == null || updateText.Equals(String.Empty))
{
//If there is no Update we may return the SPARQL Service Description where appropriate
try
{
//If we might show the Update Form only show the Description if the selected writer is
//not a HTML writer
MimeTypeDefinition definition = MimeTypesHelper.GetDefinitions(HandlerHelper.GetAcceptTypes(context)).FirstOrDefault(d => d.CanWriteRdf);
if (definition != null)
{
IRdfWriter writer = definition.GetRdfWriter();
if (!this._config.ShowUpdateForm || !(writer is IHtmlWriter))
{
//If not a HTML Writer selected OR not showing Update Form then show the Service Description Graph
//unless an error occurs creating it
IGraph serviceDescrip = SparqlServiceDescriber.GetServiceDescription(context, this._config, UriFactory.Create(context.Request.Url.AbsoluteUri));
context.Response.ContentType = definition.CanonicalMimeType;
context.Response.ContentEncoding = definition.Encoding;
writer.Save(serviceDescrip, new StreamWriter(context.Response.OutputStream, definition.Encoding));
return;
}
}
}
catch
{
//Ignore Exceptions - we'll just show the Query Form or return a 400 Bad Request instead
}
//If a Writer can't be selected then we'll either show the Update Form or return a 400 Bad Request
if (this._config.ShowUpdateForm)
{
this.ShowUpdateForm(context);
}
else
{
context.Response.StatusCode = (int)HttpStatusCode.BadRequest;
}
return;
}
//Get Other options associated with this update
List <String> userDefaultGraphs = new List <String>();
List <String> userNamedGraphs = new List <String>();
//Get the USING URIs (if any)
if (context.Request.QueryString["using-graph-uri"] != null)
{
userDefaultGraphs.AddRange(context.Request.QueryString.GetValues("using-graph-uri"));
}
else if (context.Request.Form["using-graph-uri"] != null)
{
userDefaultGraphs.AddRange(context.Request.Form.GetValues("using-graph-uri"));
}
//Get the USING NAMED URIs (if any)
if (context.Request.QueryString["using-named-graph-uri"] != null)
{
userNamedGraphs.AddRange(context.Request.QueryString.GetValues("using-named-graph-uri"));
}
else if (context.Request.Form["using-named-graph-uri"] != null)
{
userNamedGraphs.AddRange(context.Request.Form.GetValues("using-named-graph-uri"));
}
try
{
//Now we're going to parse the Updates
SparqlUpdateParser parser = new SparqlUpdateParser();
parser.ExpressionFactories = this._config.ExpressionFactories;
SparqlUpdateCommandSet commands = parser.ParseFromString(updateText);
//Check whether we need to use authentication
//If there are no user groups then no authentication is in use so we default to authenticated with no per-action authentication needed
bool isAuth = true, requireActionAuth = false;
if (this._config.UserGroups.Any())
{
//If we have user
isAuth = HandlerHelper.IsAuthenticated(context, this._config.UserGroups);
requireActionAuth = true;
}
if (!isAuth)
{
return;
}
//First check actions to see whether they are all permissible and apply USING/USING NAMED parameters
foreach (SparqlUpdateCommand cmd in commands.Commands)
{
//Authenticate each action
bool actionAuth = true;
if (requireActionAuth)
{
actionAuth = HandlerHelper.IsAuthenticated(context, this._config.UserGroups, this.GetPermissionAction(cmd));
}
if (!actionAuth)
{
throw new SparqlUpdatePermissionException("You are not authorised to perform the " + this.GetPermissionAction(cmd) + " action");
}
//Check whether we need to (and are permitted to) apply USING/USING NAMED parameters
if (userDefaultGraphs.Count > 0 || userNamedGraphs.Count > 0)
{
BaseModificationCommand modify = cmd as BaseModificationCommand;
if (modify != null)
{
if (modify.GraphUri != null || modify.UsingUris.Any() || modify.UsingNamedUris.Any())
{
//Invalid if a command already has a WITH/USING/USING NAMED
throw new SparqlUpdateMalformedException("A command in your update request contains a WITH/USING/USING NAMED clause but you have also specified one/both of the using-graph-uri or using-named-graph-uri parameters which is not permitted by the SPARQL Protocol");
}
else
{
//Otherwise go ahead and apply
userDefaultGraphs.ForEach(u => modify.AddUsingUri(UriFactory.Create(u)));
userNamedGraphs.ForEach(u => modify.AddUsingNamedUri(UriFactory.Create(u)));
}
}
}
}
//Then assuming we got here this means all our actions are permitted so now we can process the updates
this.ProcessUpdates(commands);
//Flush outstanding changes
this._config.Processor.Flush();
//Update the Cache as the request may have changed the endpoint
this.UpdateConfig(context);
}
catch (RdfParseException parseEx)
{
HandleErrors(context, "Parsing Error", updateText, parseEx, (int)HttpStatusCode.BadRequest);
}
catch (SparqlUpdatePermissionException permEx)
{
HandleErrors(context, "Permissions Error", updateText, permEx, (int)HttpStatusCode.Forbidden);
}
catch (SparqlUpdateMalformedException malEx)
{
HandleErrors(context, "Malformed Update Error", updateText, malEx, (int)HttpStatusCode.BadRequest);
}
catch (SparqlUpdateException updateEx)
{
HandleErrors(context, "Update Error", updateText, updateEx);
}
catch (RdfException rdfEx)
{
HandleErrors(context, "RDF Error", updateText, rdfEx);
}
catch (Exception ex)
{
HandleErrors(context, "Error", updateText, ex);
}
}
/// <summary>
/// Processes a SPARQL Query Request
/// </summary>
/// <param name="context">HTTP Context</param>
public void ProcessRequest(HttpContext context)
{
this._config = this.LoadConfig(context);
//Add our Standard Headers
HandlerHelper.AddStandardHeaders(context, this._config);
if (context.Request.HttpMethod.Equals("OPTIONS"))
{
//OPTIONS requests always result in the Service Description document
IGraph svcDescrip = SparqlServiceDescriber.GetServiceDescription(context, this._config, new Uri(context.Request.Url.AbsoluteUri));
HandlerHelper.SendToClient(context, svcDescrip, this._config);
return;
}
//See if there has been an query submitted
String queryText = context.Request.QueryString["query"];
if (queryText == null || queryText.Equals(String.Empty))
{
queryText = context.Request.Form["query"];
}
//If no Query sent either show Query Form or give a HTTP 400 response
if (queryText == null || queryText.Equals(String.Empty))
{
//If there is no Query we may return the SPARQL Service Description where appropriate
try
{
//If we might show the Query Form only show the Description if the selected writer is
//not a HTML writer
MimeTypeDefinition definition = MimeTypesHelper.GetDefinitions(HandlerHelper.GetAcceptTypes(context)).FirstOrDefault(d => d.CanWriteRdf);
if (definition != null)
{
IRdfWriter writer = definition.GetRdfWriter();
if (!this._config.ShowQueryForm || !(writer is IHtmlWriter))
{
//If not a HTML Writer selected OR not showing Query Form then show the Service Description Graph
//unless an error occurs creating it
IGraph serviceDescrip = SparqlServiceDescriber.GetServiceDescription(context, this._config, new Uri(context.Request.Url.AbsoluteUri));
context.Response.ContentType = definition.CanonicalMimeType;
context.Response.ContentEncoding = definition.Encoding;
writer.Save(serviceDescrip, new StreamWriter(context.Response.OutputStream, definition.Encoding));
return;
}
}
}
catch
{
//Ignore Exceptions - we'll just show the Query Form or return a 400 Bad Request instead
}
//If a Writer can't be selected then we'll either show the Query Form or return a 400 Bad Request
if (this._config.ShowQueryForm)
{
this.ShowQueryForm(context);
}
else
{
context.Response.StatusCode = (int)HttpStatusCode.BadRequest;
}
return;
}
//Get Other options associated with this query
List <String> userDefaultGraphs = new List <String>();
List <String> userNamedGraphs = new List <String>();
long timeout = 0;
bool partialResults = this._config.DefaultPartialResults;
//Get the Default Graph URIs (if any)
if (context.Request.QueryString["default-graph-uri"] != null)
{
userDefaultGraphs.AddRange(context.Request.QueryString.GetValues("default-graph-uri"));
}
else if (context.Request.Form["default-graph-uri"] != null)
{
userDefaultGraphs.AddRange(context.Request.Form.GetValues("default-graph-uri"));
}
//Get the Named Graph URIs (if any)
if (context.Request.QueryString["named-graph-uri"] != null)
{
userNamedGraphs.AddRange(context.Request.QueryString.GetValues("named-graph-uri"));
}
else if (context.Request.Form["named-graph-uri"] != null)
{
userNamedGraphs.AddRange(context.Request.Form.GetValues("named-graph-uri"));
}
//Get Timeout setting (if any)
if (context.Request.QueryString["timeout"] != null)
{
if (!Int64.TryParse(context.Request.QueryString["timeout"], out timeout))
{
timeout = this._config.DefaultTimeout;
}
}
else if (context.Request.Form["timeout"] != null)
{
if (!Int64.TryParse(context.Request.Form["timeout"], out timeout))
{
timeout = this._config.DefaultTimeout;
}
}
//Get Partial Results Setting (if any);
if (context.Request.QueryString["partialResults"] != null)
{
if (!Boolean.TryParse(context.Request.QueryString["partialResults"], out partialResults))
{
partialResults = this._config.DefaultPartialResults;
}
}
else if (context.Request.Form["partialResults"] != null)
{
if (!Boolean.TryParse(context.Request.Form["partialResults"], out partialResults))
{
partialResults = this._config.DefaultPartialResults;
}
}
try
{
//Now we're going to parse the Query
SparqlQueryParser parser = new SparqlQueryParser(this._config.Syntax);
parser.ExpressionFactories = this._config.ExpressionFactories;
parser.QueryOptimiser = this._config.QueryOptimiser;
SparqlQuery query = parser.ParseFromString(queryText);
query.AlgebraOptimisers = this._config.AlgebraOptimisers;
//Check whether we need to use authentication
//If there are no user groups then no authentication is in use so we default to authenticated with no per-action authentication needed
bool isAuth = true, requireActionAuth = false;
if (this._config.UserGroups.Any())
{
//If we have user
isAuth = HandlerHelper.IsAuthenticated(context, this._config.UserGroups);
requireActionAuth = true;
}
if (!isAuth)
{
return;
}
//Is this user allowed to make this kind of query?
if (requireActionAuth)
{
HandlerHelper.IsAuthenticated(context, this._config.UserGroups, this.GetPermissionAction(query));
}
//Set the Default Graph URIs (if any)
if (userDefaultGraphs.Count > 0)
{
//Default Graph Uri specified by default-graph-uri parameter or Web.config settings
foreach (String userDefaultGraph in userDefaultGraphs)
{
if (!userDefaultGraph.Equals(String.Empty))
{
query.AddDefaultGraph(new Uri(userDefaultGraph));
}
}
}
else if (!this._config.DefaultGraphURI.Equals(String.Empty))
{
//Only applies if the Query doesn't specify any Default Graph
if (!query.DefaultGraphs.Any())
{
query.AddDefaultGraph(new Uri(this._config.DefaultGraphURI));
}
}
//Set the Named Graph URIs (if any)
if (userNamedGraphs.Count > 0)
{
foreach (String userNamedGraph in userNamedGraphs)
{
if (!userNamedGraph.Equals(String.Empty))
{
query.AddNamedGraph(new Uri(userNamedGraph));
}
}
}
//Set Timeout setting
if (timeout > 0)
{
query.Timeout = timeout;
}
else
{
query.Timeout = this._config.DefaultTimeout;
}
//Set Partial Results Setting
query.PartialResultsOnTimeout = partialResults;
//Set Describe Algorithm
query.Describer = this._config.DescribeAlgorithm;
//Now we can finally make the query and return the results
Object result = this.ProcessQuery(query);
this.ProcessResults(context, result);
//Update the Cache as the request may have changed the endpoint
this.UpdateConfig(context);
}
catch (RdfParseException parseEx)
{
HandleErrors(context, "Parsing Error", queryText, parseEx, (int)HttpStatusCode.BadRequest);
}
catch (RdfQueryTimeoutException timeoutEx)
{
HandleErrors(context, "Query Timeout Error", queryText, timeoutEx);
}
catch (RdfQueryException queryEx)
{
HandleErrors(context, "Update Error", queryText, queryEx);
}
catch (RdfWriterSelectionException writerSelEx)
{
HandleErrors(context, "Output Selection Error", queryText, writerSelEx, (int)HttpStatusCode.NotAcceptable);
}
catch (RdfException rdfEx)
{
HandleErrors(context, "RDF Error", queryText, rdfEx);
}
catch (Exception ex)
{
HandleErrors(context, "Error", queryText, ex);
}
}
/// <summary>
/// Processes a SPARQL Query Request
/// </summary>
/// <param name="context">HTTP Context</param>
public void ProcessRequest(HttpContext context)
{
this._config = this.LoadConfig(context);
WebContext webContext = new WebContext(context);
//Add our Standard Headers
HandlerHelper.AddStandardHeaders(webContext, this._config);
//Options we need to determine based on the HTTP Method used
String[] queries;
String queryText = null;
List <String> userDefaultGraphs = new List <String>();
List <String> userNamedGraphs = new List <String>();
try
{
//Decide what to do based on the HTTP Method
switch (context.Request.HttpMethod.ToUpper())
{
case "OPTIONS":
//OPTIONS requests always result in the Service Description document
IGraph svcDescrip = SparqlServiceDescriber.GetServiceDescription(this._config, UriFactory.Create(context.Request.Url.AbsoluteUri));
HandlerHelper.SendToClient(webContext, svcDescrip, this._config);
return;
case "HEAD":
//Just return from a HEAD request
return;
case "GET":
//GET expects a query parameter in the querystring
queries = context.Request.QueryString.GetValues("query");
if (queries != null)
{
if (queries.Length > 1)
{
throw new ArgumentException("The query parameter was specified multiple times in the querystring");
}
queryText = queries.Length == 1 ? queries[0] : null;
}
//If no Query sent either show Query Form or give a HTTP 400 response
if (String.IsNullOrEmpty(queryText))
{
//If there is no Query we may return the SPARQL Service Description where appropriate
try
{
//If we might show the Query Form only show the Description if the selected writer is
//not a HTML writer
MimeTypeDefinition definition = MimeTypesHelper.GetDefinitions(HandlerHelper.GetAcceptTypes(webContext)).FirstOrDefault(d => d.CanWriteRdf);
if (definition != null)
{
IRdfWriter writer = definition.GetRdfWriter();
if (!this._config.ShowQueryForm || !(writer is IHtmlWriter))
{
//If not a HTML Writer selected OR not showing Query Form then show the Service Description Graph
//unless an error occurs creating it
IGraph serviceDescrip = SparqlServiceDescriber.GetServiceDescription(this._config, UriFactory.Create(context.Request.Url.AbsoluteUri));
context.Response.ContentType = definition.CanonicalMimeType;
context.Response.ContentEncoding = definition.Encoding;
writer.Save(serviceDescrip, new StreamWriter(context.Response.OutputStream, definition.Encoding));
return;
}
}
}
catch
{
//Ignore Exceptions - we'll just show the Query Form or return a 400 Bad Request instead
}
//Otherwise we'll either show the Query Form or return a 400 Bad Request
if (this._config.ShowQueryForm)
{
this.ShowQueryForm(context);
}
else
{
throw new ArgumentException("Missing required query parameter");
}
return;
}
//Get the Default Graph URIs (if any)
if (context.Request.QueryString["default-graph-uri"] != null)
{
userDefaultGraphs.AddRange(context.Request.QueryString.GetValues("default-graph-uri"));
}
//Get the Named Graph URIs (if any)
if (context.Request.QueryString["named-graph-uri"] != null)
{
userNamedGraphs.AddRange(context.Request.QueryString.GetValues("named-graph-uri"));
}
break;
case "POST":
//POST requires a valid content type
if (context.Request.ContentType != null)
{
MimeTypeSelector contentType = MimeTypeSelector.Create(context.Request.ContentType, 0);
if (contentType.Type.Equals(MimeTypesHelper.WWWFormURLEncoded))
{
//Form URL Encoded was declared type so expect a query parameter in the Form parameters
queries = context.Request.Form.GetValues("query");
if (queries == null)
{
throw new ArgumentException("Required query parameter in POST body was missing");
}
if (queries.Length == 0)
{
throw new ArgumentException("Required query parameter in POST body was missing");
}
if (queries.Length > 1)
{
throw new ArgumentException("The query parameter was specified multiple times in the POST body");
}
queryText = queries[0];
//For Form URL Encoded the Default/Named Graphs may be specified by Form parameters
//Get the Default Graph URIs (if any)
if (context.Request.Form["default-graph-uri"] != null)
{
userDefaultGraphs.AddRange(context.Request.Form.GetValues("default-graph-uri"));
}
//Get the Named Graph URIs (if any)
if (context.Request.Form["named-graph-uri"] != null)
{
userNamedGraphs.AddRange(context.Request.Form.GetValues("named-graph-uri"));
}
break;
}
else if (contentType.Type.Equals(MimeTypesHelper.SparqlQuery))
{
//application/sparql-query was declared type so expect utf-8 charset (if present)
if (contentType.Charset != null && !contentType.Charset.ToLower().Equals(MimeTypesHelper.CharsetUtf8))
{
throw new ArgumentException("HTTP POST request was received with a " + MimeTypesHelper.SparqlQuery + " Content-Type but a non UTF-8 charset parameter");
}
//Read the query from the request body
using (StreamReader reader = new StreamReader(context.Request.InputStream))
{
queryText = reader.ReadToEnd();
reader.Close();
}
//For application/sparql-query the Default/Named Graphs may be specified by querystring parameters
//Get the Default Graph URIs (if any)
if (context.Request.QueryString["default-graph-uri"] != null)
{
userDefaultGraphs.AddRange(context.Request.QueryString.GetValues("default-graph-uri"));
}
//Get the Named Graph URIs (if any)
if (context.Request.QueryString["named-graph-uri"] != null)
{
userNamedGraphs.AddRange(context.Request.QueryString.GetValues("named-graph-uri"));
}
break;
}
else
{
throw new ArgumentException("HTTP POST made to SPARQL query endpoint had an invalid Content-Type header, only " + MimeTypesHelper.WWWFormURLEncoded + " and " + MimeTypesHelper.SparqlQuery + " are acceptable");
}
}
throw new ArgumentException("HTTP POST made to SPARQL Query endpoint was missing the required Content-Type header");
default:
throw new NotSupportedException("HTTP " + context.Request.HttpMethod.ToUpper() + " is not supported by a SPARQL Query endpoint");
}
//Get non-standard options associated with the query
long timeout = 0;
bool partialResults = this._config.DefaultPartialResults;
//Get Timeout setting (if any)
if (context.Request.QueryString["timeout"] != null)
{
if (!Int64.TryParse(context.Request.QueryString["timeout"], out timeout))
{
timeout = this._config.DefaultTimeout;
}
}
else if (context.Request.Form["timeout"] != null)
{
if (!Int64.TryParse(context.Request.Form["timeout"], out timeout))
{
timeout = this._config.DefaultTimeout;
}
}
//Get Partial Results Setting (if any);
if (context.Request.QueryString["partialResults"] != null)
{
if (!Boolean.TryParse(context.Request.QueryString["partialResults"], out partialResults))
{
partialResults = this._config.DefaultPartialResults;
}
}
else if (context.Request.Form["partialResults"] != null)
{
if (!Boolean.TryParse(context.Request.Form["partialResults"], out partialResults))
{
partialResults = this._config.DefaultPartialResults;
}
}
//Now we're going to parse the Query
SparqlQueryParser parser = new SparqlQueryParser(this._config.Syntax);
parser.DefaultBaseUri = context.Request.Url;
parser.ExpressionFactories = this._config.ExpressionFactories;
parser.QueryOptimiser = this._config.QueryOptimiser;
SparqlQuery query = parser.ParseFromString(queryText);
query.AlgebraOptimisers = this._config.AlgebraOptimisers;
query.PropertyFunctionFactories = this._config.PropertyFunctionFactories;
//Check whether we need to use authentication
//If there are no user groups then no authentication is in use so we default to authenticated with no per-action authentication needed
bool isAuth = true, requireActionAuth = false;
if (this._config.UserGroups.Any())
{
//If we have user
isAuth = HandlerHelper.IsAuthenticated(webContext, this._config.UserGroups);
requireActionAuth = true;
}
if (!isAuth)
{
return;
}
//Is this user allowed to make this kind of query?
if (requireActionAuth)
{
HandlerHelper.IsAuthenticated(webContext, this._config.UserGroups, this.GetPermissionAction(query));
}
//Clear query dataset if there is a protocol defined one
userDefaultGraphs.RemoveAll(g => String.IsNullOrEmpty(g));
userNamedGraphs.RemoveAll(g => String.IsNullOrEmpty(g));
bool isProtocolDataset = false;
if (userDefaultGraphs.Count > 0 || userNamedGraphs.Count > 0)
{
query.ClearDefaultGraphs();
query.ClearNamedGraphs();
isProtocolDataset = true;
}
//Set the Default Graph URIs (if any)
if (isProtocolDataset)
{
foreach (String userDefaultGraph in userDefaultGraphs)
{
query.AddDefaultGraph(UriFactory.Create(userDefaultGraph));
}
}
else if (!this._config.DefaultGraphURI.Equals(String.Empty))
{
//Only applies if the Query doesn't specify any Default Graph and there wasn't a protocol defined
//dataset present
if (!query.DefaultGraphs.Any())
{
query.AddDefaultGraph(UriFactory.Create(this._config.DefaultGraphURI));
}
}
//Set the Named Graph URIs (if any)
if (isProtocolDataset)
{
query.ClearNamedGraphs();
foreach (String userNamedGraph in userNamedGraphs)
{
query.AddNamedGraph(UriFactory.Create(userNamedGraph));
}
}
//Set Timeout setting
if (timeout > 0)
{
query.Timeout = timeout;
}
else
{
query.Timeout = this._config.DefaultTimeout;
}
//Set Partial Results Setting
query.PartialResultsOnTimeout = partialResults;
//Set Describe Algorithm
query.Describer = this._config.DescribeAlgorithm;
//Now we can finally make the query and return the results
Object result = this.ProcessQuery(query);
this.ProcessResults(context, result);
//Update the Cache as the request may have changed the endpoint
this.UpdateConfig(context);
}
catch (RdfParseException parseEx)
{
HandleErrors(context, "Parsing Error", queryText, parseEx, (int)HttpStatusCode.BadRequest);
}
catch (RdfQueryTimeoutException timeoutEx)
{
HandleErrors(context, "Query Timeout Error", queryText, timeoutEx);
}
catch (RdfQueryException queryEx)
{
HandleErrors(context, "Update Error", queryText, queryEx);
}
catch (RdfWriterSelectionException writerSelEx)
{
HandleErrors(context, "Output Selection Error", queryText, writerSelEx, (int)HttpStatusCode.NotAcceptable);
}
catch (RdfException rdfEx)
{
HandleErrors(context, "RDF Error", queryText, rdfEx);
}
catch (NotSupportedException notSupEx)
{
HandleErrors(context, "HTTP Request Error", null, notSupEx, (int)HttpStatusCode.MethodNotAllowed);
}
catch (ArgumentException argEx)
{
HandleErrors(context, "HTTP Request Error", null, argEx, (int)HttpStatusCode.BadRequest);
}
catch (Exception ex)
{
HandleErrors(context, "Error", queryText, ex);
}
}
/// <summary>
/// Processes SPARQL Update requests
/// </summary>
/// <param name="context">HTTP Context</param>
public void ProcessRequest(HttpContext context)
{
this._config = this.LoadConfig(context);
WebContext webContext = new WebContext(context);
//Add our Standard Headers
HandlerHelper.AddStandardHeaders(webContext, this._config);
//Options we need to determine based on the HTTP Method used
String[] updates;
String updateText = null;
List <String> userDefaultGraphs = new List <String>();
List <String> userNamedGraphs = new List <String>();
try
{
//Decide what to do based on the HTTP Method
switch (context.Request.HttpMethod.ToUpper())
{
case "OPTIONS":
//OPTIONS requests always result in the Service Description document
IGraph svcDescrip = SparqlServiceDescriber.GetServiceDescription(this._config, UriFactory.Create(context.Request.Url.AbsoluteUri));
HandlerHelper.SendToClient(webContext, svcDescrip, this._config);
return;
case "HEAD":
//Just return from a HEAD request
return;
case "GET":
//A GET with an update parameter is a Bad Request
updates = context.Request.QueryString.GetValues("update");
if (updates != null && updates.Length > 0)
{
throw new ArgumentException("Updates cannot be submitted as GET requests");
}
//Otherwise GET either results in the Service Description if appropriately conneg'd or
//the update form if enabled
try
{
//If we might show the Update Form only show the Description if the selected writer is
//not a HTML writer
MimeTypeDefinition definition = MimeTypesHelper.GetDefinitions(HandlerHelper.GetAcceptTypes(webContext)).FirstOrDefault(d => d.CanWriteRdf);
if (definition != null)
{
IRdfWriter writer = definition.GetRdfWriter();
if (!(writer is IHtmlWriter))
{
//If not a HTML Writer selected then show the Service Description Graph
//unless an error occurs creating it
IGraph serviceDescrip = SparqlServiceDescriber.GetServiceDescription(this._config, UriFactory.Create(context.Request.Url.AbsoluteUri));
context.Response.ContentType = definition.CanonicalMimeType;
context.Response.ContentEncoding = definition.Encoding;
writer.Save(serviceDescrip, new StreamWriter(context.Response.OutputStream, definition.Encoding));
return;
}
}
}
catch
{
//Ignore Exceptions - we'll just show the Query Form or return a 400 Bad Request instead
}
//If a Writer can't be selected then we'll either show the Update Form or return a 400 Bad Request
if (this._config.ShowUpdateForm)
{
this.ShowUpdateForm(context);
}
else
{
throw new ArgumentException("Updates cannot be submitted as GET requests");
}
return;
case "POST":
if (context.Request.ContentType != null)
{
MimeTypeSelector contentType = MimeTypeSelector.Create(context.Request.ContentType, 0);
if (contentType.Type.Equals(MimeTypesHelper.WWWFormURLEncoded))
{
//Form URL Encoded was declared type so expect an update parameter in the Form parameters
updates = context.Request.Form.GetValues("update");
if (updates == null)
{
throw new ArgumentException("Required update parameter in POST body was missing");
}
if (updates.Length == 0)
{
throw new ArgumentException("Required update parameter in POST body was missing");
}
if (updates.Length > 1)
{
throw new ArgumentException("The update parameter was specified multiple times in the POST body");
}
updateText = updates[0];
//For Form URL Encoded the Using/Using Named Graphs may be specified by Form parameters
//Get the USING URIs (if any)
if (context.Request.Form["using-graph-uri"] != null)
{
userDefaultGraphs.AddRange(context.Request.Form.GetValues("using-graph-uri"));
}
//Get the USING NAMED URIs (if any)
if (context.Request.Form["using-named-graph-uri"] != null)
{
userNamedGraphs.AddRange(context.Request.Form.GetValues("using-named-graph-uri"));
}
break;
}
else if (contentType.Type.Equals(MimeTypesHelper.SparqlUpdate))
{
//application/sparql-update was declared type so expect utf-8 charset (if present)
if (contentType.Charset != null && !contentType.Charset.ToLower().Equals(MimeTypesHelper.CharsetUtf8))
{
throw new ArgumentException("HTTP POST request was received with a " + MimeTypesHelper.SparqlUpdate + " Content-Type but a non UTF-8 charset parameter");
}
using (StreamReader reader = new StreamReader(context.Request.InputStream))
{
updateText = reader.ReadToEnd();
reader.Close();
}
//For application/sparql-update the Using/Using Named Graphs may be specified by querystring parameters
//Get the USING URIs (if any)
if (context.Request.QueryString["using-graph-uri"] != null)
{
userDefaultGraphs.AddRange(context.Request.QueryString.GetValues("using-graph-uri"));
}
//Get the USING NAMED URIs (if any)
if (context.Request.QueryString["using-named-graph-uri"] != null)
{
userNamedGraphs.AddRange(context.Request.QueryString.GetValues("using-named-graph-uri"));
}
break;
}
else
{
throw new ArgumentException("HTTP POST made to SPARQL update endpoint had an invalid Content-Type header, only " + MimeTypesHelper.WWWFormURLEncoded + " and " + MimeTypesHelper.SparqlUpdate + " are acceptable");
}
}
throw new ArgumentException("HTTP POST made to SPARQL Query endpoint was missing the required Content-Type header");
default:
throw new NotSupportedException("HTTP " + context.Request.HttpMethod.ToUpper() + " is not supported by a SPARQL Update endpoint");
}
//Clean up protocol provided dataset
userDefaultGraphs.RemoveAll(g => String.IsNullOrEmpty(g));
userNamedGraphs.RemoveAll(g => String.IsNullOrEmpty(g));
//Now we're going to parse the Updates
SparqlUpdateParser parser = new SparqlUpdateParser();
parser.DefaultBaseUri = context.Request.Url;
parser.ExpressionFactories = this._config.ExpressionFactories;
SparqlUpdateCommandSet commands = parser.ParseFromString(updateText);
//Check whether we need to use authentication
//If there are no user groups then no authentication is in use so we default to authenticated with no per-action authentication needed
bool isAuth = true, requireActionAuth = false;
if (this._config.UserGroups.Any())
{
//If we have user
isAuth = HandlerHelper.IsAuthenticated(webContext, this._config.UserGroups);
requireActionAuth = true;
}
if (!isAuth)
{
return;
}
//First check actions to see whether they are all permissible and apply USING/USING NAMED parameters
foreach (SparqlUpdateCommand cmd in commands.Commands)
{
//Authenticate each action
bool actionAuth = true;
if (requireActionAuth)
{
actionAuth = HandlerHelper.IsAuthenticated(webContext, this._config.UserGroups, this.GetPermissionAction(cmd));
}
if (!actionAuth)
{
throw new SparqlUpdatePermissionException("You are not authorised to perform the " + this.GetPermissionAction(cmd) + " action");
}
//Check whether we need to (and are permitted to) apply USING/USING NAMED parameters
if (userDefaultGraphs.Count > 0 || userNamedGraphs.Count > 0)
{
BaseModificationCommand modify = cmd as BaseModificationCommand;
if (modify != null)
{
if (modify.GraphUri != null || modify.UsingUris.Any() || modify.UsingNamedUris.Any())
{
//Invalid if a command already has a WITH/USING/USING NAMED
throw new SparqlUpdateMalformedException("A command in your update request contains a WITH/USING/USING NAMED clause but you have also specified one/both of the using-graph-uri or using-named-graph-uri parameters which is not permitted by the SPARQL Protocol");
}
else
{
//Otherwise go ahead and apply
userDefaultGraphs.ForEach(u => modify.AddUsingUri(UriFactory.Create(u)));
userNamedGraphs.ForEach(u => modify.AddUsingNamedUri(UriFactory.Create(u)));
}
}
}
}
//Then assuming we got here this means all our actions are permitted so now we can process the updates
this.ProcessUpdates(commands);
//Flush outstanding changes
this._config.Processor.Flush();
//Update the Cache as the request may have changed the endpoint
this.UpdateConfig(context);
}
catch (RdfParseException parseEx)
{
HandleErrors(context, "Parsing Error", updateText, parseEx, (int)HttpStatusCode.BadRequest);
}
catch (SparqlUpdatePermissionException permEx)
{
HandleErrors(context, "Permissions Error", updateText, permEx, (int)HttpStatusCode.Forbidden);
}
catch (SparqlUpdateMalformedException malEx)
{
HandleErrors(context, "Malformed Update Error", updateText, malEx, (int)HttpStatusCode.BadRequest);
}
catch (SparqlUpdateException updateEx)
{
HandleErrors(context, "Update Error", updateText, updateEx);
}
catch (RdfException rdfEx)
{
HandleErrors(context, "RDF Error", updateText, rdfEx);
}
catch (NotSupportedException notSupEx)
{
HandleErrors(context, "HTTP Request Error", null, notSupEx, (int)HttpStatusCode.MethodNotAllowed);
}
catch (ArgumentException argEx)
{
HandleErrors(context, "HTTP Request Error", null, argEx, (int)HttpStatusCode.BadRequest);
}
catch (Exception ex)
{
HandleErrors(context, "Error", updateText, ex);
}
}