/// <summary>
/// Processes Service Description requests
/// </summary>
/// <param name="context">HTTP Context</param>
public void ProcessDescriptionRequest(HttpContext context)
{
try
{
//Get the Service Description Graph
IGraph serviceDescrip = SparqlServiceDescriber.GetServiceDescription(context, this._config, new Uri(context.Request.Url.AbsoluteUri), ServiceDescriptionType.All);
HandlerHelper.SendToClient(context, serviceDescrip, this._config);
}
catch
{
//If any errors occur then return a 500 Internal Server Error
context.Response.StatusCode = (int)HttpStatusCode.InternalServerError;
}
}
/// <summary>
/// Serves the Dataset to the Client
/// </summary>
/// <param name="context">HTTP Context</param>
/// <param name="dataset">Dataset to serve</param>
/// <remarks>
/// <para>
/// Implementations should override this if they wish to override the default behaviour of outputting the entire dataset using the <see cref="HandlerHelper.SendToClient">HandlerHelper.SendToClient()</see> method e.g. to use a custom writer or server only portions of the dataset
/// </para>
/// </remarks>
public virtual void SendDatasetToClient(HttpContext context, ISparqlDataset dataset)
{
try
{
HandlerHelper.SendToClient(context, dataset, this._config);
}
catch (RdfWriterSelectionException)
{
context.Response.StatusCode = (int)HttpStatusCode.NotAcceptable;
}
catch
{
context.Response.StatusCode = (int)HttpStatusCode.InternalServerError;
}
}
/// <summary>
/// Processes requests
/// </summary>
/// <param name="context">HTTP Context</param>
public void ProcessRequest(HttpContext context)
{
this._config = this.LoadConfig(context, out this._basePath);
//Add our Standard Headers
HandlerHelper.AddStandardHeaders(context, this._config);
String path = context.Request.Path;
if (path.StartsWith(this._basePath))
{
path = path.Substring(this._basePath.Length);
}
//OPTIONS requests always result in the Service Description document
if (context.Request.HttpMethod.Equals("OPTIONS"))
{
IGraph svcDescrip = SparqlServiceDescriber.GetServiceDescription(context, this._config, new Uri(new Uri(context.Request.Url.AbsoluteUri), this._basePath + "description"), ServiceDescriptionType.All);
HandlerHelper.SendToClient(context, svcDescrip, this._config);
}
else
{
//Otherwise determine the type of request based on the Path
switch (path)
{
case "query":
this.ProcessQueryRequest(context);
break;
case "update":
this.ProcessUpdateRequest(context);
break;
case "description":
this.ProcessDescriptionRequest(context);
break;
default:
this.ProcessProtocolRequest(context);
break;
}
}
}
/// <summary>
/// Checks whether a User is authenticated (or guests are permitted)
/// </summary>
/// <param name="context">HTTP Context</param>
/// <param name="groups">User Groups to test against</param>
/// <returns></returns>
public static bool IsAuthenticated(HttpContext context, IEnumerable <UserGroup> groups)
{
String user = HandlerHelper.GetUsername(context);
if (groups.Any())
{
if (user != null && groups.Any(g => g.HasMember(user)))
{
//A Group has the given Member so is authenticated
return(true);
}
else if (!groups.Any(g => g.AllowGuests))
{
//No Groups allow guests so we require authentication
context.Response.StatusCode = (int)HttpStatusCode.Unauthorized;
return(false);
}
}
return(true);
}
/// <summary>
/// Handles errors in processing SPARQL Update Requests
/// </summary>
/// <param name="context">Context of the HTTP Request</param>
/// <param name="title">Error title</param>
/// <param name="update">SPARQL Update</param>
/// <param name="ex">Error</param>
protected virtual void HandleUpdateErrors(HttpContext context, String title, String update, Exception ex)
{
HandlerHelper.HandleUpdateErrors(context, this._config, title, update, ex);
}
/// <summary>
/// Handles errors in processing SPARQL Query Requests
/// </summary>
/// <param name="context">Context of the HTTP Request</param>
/// <param name="title">Error title</param>
/// <param name="query">Sparql Query</param>
/// <param name="ex">Error</param>
/// <param name="statusCode">HTTP Status Code to return</param>
protected virtual void HandleQueryErrors(HttpContext context, String title, String query, Exception ex, int statusCode)
{
HandlerHelper.HandleQueryErrors(context, this._config, title, query, ex, statusCode);
}
/// <summary>
/// Internal Helper function which returns the 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>
/// <remarks>
/// <para>
/// Implementations should override this if they want to control how results are sent to the client rather than using the default behaviour provided by <see cref="HandlerHelper.ProcessResults">HandlerHelper.ProcessResults()</see>
/// </para>
/// </remarks>
protected virtual void ProcessQueryResults(HttpContext context, Object result)
{
HandlerHelper.SendToClient(context, result, this._config);
}
/// <summary>
/// Handles errors in processing SPARQL Query Requests
/// </summary>
/// <param name="context">Context of the HTTP Request</param>
/// <param name="title">Error title</param>
/// <param name="query">Sparql Query</param>
/// <param name="ex">Error</param>
protected virtual void HandleErrors(HttpContext context, String title, String query, Exception ex)
{
HandlerHelper.HandleQueryErrors(context, this._config, title, query, ex, (int)HttpStatusCode.InternalServerError);
}
/// <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(webContext.GetAcceptTypes()).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);
}
}
/// <summary>
/// Handles errors in processing SPARQL Update Requests
/// </summary>
/// <param name="context">Context of the HTTP Request</param>
/// <param name="title">Error title</param>
/// <param name="update">SPARQL Update</param>
/// <param name="ex">Error</param>
protected virtual void HandleErrors(HttpContext context, String title, String update, Exception ex)
{
HandlerHelper.HandleUpdateErrors(new WebContext(context), this._config, title, update, ex, (int)HttpStatusCode.InternalServerError);
}
/// <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>
/// 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>
/// 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>
public static void SendToClient(HttpContext context, Object result)
{
HandlerHelper.SendToClient(context, result, null);
}
/// <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 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>
/// Processes Query requests
/// </summary>
/// <param name="context">HTTP Context</param>
public void ProcessQueryRequest(HttpContext context)
{
if (this._config.QueryProcessor == null)
{
context.Response.StatusCode = (int)HttpStatusCode.NotImplemented;
return;
}
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), ServiceDescriptionType.Query);
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 (this._config.ShowQueryForm)
{
this.ShowQueryForm(context);
return;
}
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.QuerySyntax);
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.GetQueryPermissionAction(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.ProcessQueryResults(context, result);
//Update the Cache as the request may have changed the endpoint
this.UpdateConfig(context);
}
catch (RdfParseException parseEx)
{
HandleQueryErrors(context, "Parsing Error", queryText, parseEx, (int)HttpStatusCode.BadRequest);
}
catch (RdfQueryTimeoutException timeoutEx)
{
HandleQueryErrors(context, "Query Timeout Error", queryText, timeoutEx);
}
catch (RdfQueryException queryEx)
{
HandleQueryErrors(context, "Query Error", queryText, queryEx);
}
catch (RdfWriterSelectionException writerSelEx)
{
HandleQueryErrors(context, "Output Selection Error", queryText, writerSelEx, (int)HttpStatusCode.NotAcceptable);
}
catch (RdfException rdfEx)
{
HandleQueryErrors(context, "RDF Error", queryText, rdfEx);
}
catch (Exception ex)
{
HandleQueryErrors(context, "Error", queryText, ex);
}
}
/// <summary>
/// Handles errors in processing SPARQL Update Requests
/// </summary>
/// <param name="context">Context of the HTTP Request</param>
/// <param name="title">Error title</param>
/// <param name="update">SPARQL Update</param>
/// <param name="ex">Error</param>
/// <param name="statusCode">HTTP Status Code</param>
protected virtual void HandleErrors(HttpContext context, String title, String update, Exception ex, int statusCode)
{
HandlerHelper.HandleUpdateErrors(new WebContext(context), this._config, title, update, ex, statusCode);
}
/// <summary>
/// Processes Update requests
/// </summary>
/// <param name="context">HTTP Context</param>
public void ProcessUpdateRequest(HttpContext context)
{
if (this._config.UpdateProcessor == null)
{
context.Response.StatusCode = (int)HttpStatusCode.NotImplemented;
return;
}
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), ServiceDescriptionType.Update);
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 (this._config.ShowUpdateForm)
{
this.ShowUpdateForm(context);
return;
}
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.GetUpdatePermissionAction(cmd));
}
if (!actionAuth)
{
throw new SparqlUpdateException("You are not authorised to perform the " + this.GetUpdatePermissionAction(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.UpdateProcessor.Flush();
//Update the Cache as the request may have changed the endpoint
this.UpdateConfig(context);
}
catch (RdfParseException parseEx)
{
HandleUpdateErrors(context, "Parsing Error", updateText, parseEx);
}
catch (SparqlUpdateException updateEx)
{
HandleUpdateErrors(context, "Update Error", updateText, updateEx);
}
catch (RdfException rdfEx)
{
HandleUpdateErrors(context, "RDF Error", updateText, rdfEx);
}
catch (Exception ex)
{
HandleUpdateErrors(context, "Error", updateText, ex);
}
}
/// <summary>
/// Processes requests made to the Graph Store HTTP Protocol endpoint and invokes the appropriate methods on the Protocol Processor that is in use
/// </summary>
/// <param name="context">HTTP Context</param>
/// <remarks>
/// <para>
/// Implementations may override this if necessary - if the implementation is only providing additional logic such as authentication, ACLs etc. then it is recommended that the override applies its logic and then calls the base method since this base method will handle much of the error handling and sending of appropriate HTTP Response Codes.
/// </para>
/// </remarks>
public virtual void ProcessRequest(HttpContext context)
{
this._config = this.LoadConfig(context, out this._basePath);
WebContext webContext = new WebContext(context);
// Add our Standard Headers
HandlerHelper.AddStandardHeaders(webContext, this._config);
if (context.Request.HttpMethod.Equals("OPTIONS"))
{
// OPTIONS requests always result in the Service Description document
IGraph svcDescrip = SparqlServiceDescriber.GetServiceDescription(this._config, new Uri(UriFactory.Create(context.Request.Url.AbsoluteUri), this._basePath));
HandlerHelper.SendToClient(webContext, svcDescrip, this._config);
return;
}
// Check whether we need to use authentication
if (!HandlerHelper.IsAuthenticated(webContext, this._config.UserGroups, context.Request.HttpMethod))
{
return;
}
try
{
// Invoke the appropriate method on our protocol processor
switch (context.Request.HttpMethod)
{
case "GET":
this._config.Processor.ProcessGet(webContext);
break;
case "PUT":
this._config.Processor.ProcessPut(webContext);
break;
case "POST":
Uri serviceUri = new Uri(UriFactory.Create(context.Request.Url.AbsoluteUri), this._basePath);
if (context.Request.Url.AbsoluteUri.Equals(serviceUri.AbsoluteUri))
{
// If there is a ?graph parameter or ?default parameter then this is a normal Post
// Otherwise it is a PostCreate
if (context.Request.QueryString["graph"] != null)
{
this._config.Processor.ProcessPost(webContext);
}
else if (context.Request.QueryString.AllKeys.Contains("default") || Regex.IsMatch(context.Request.QueryString.ToString(), BaseProtocolProcessor.DefaultParameterPattern))
{
this._config.Processor.ProcessPost(webContext);
}
else
{
this._config.Processor.ProcessPostCreate(webContext);
}
}
else
{
this._config.Processor.ProcessPost(webContext);
}
break;
case "DELETE":
this._config.Processor.ProcessDelete(webContext);
break;
case "HEAD":
this._config.Processor.ProcessHead(webContext);
break;
case "PATCH":
this._config.Processor.ProcessPatch(webContext);
break;
default:
// For any other HTTP Verb we send a 405 Method Not Allowed
context.Response.StatusCode = (int)HttpStatusCode.MethodNotAllowed;
break;
}
// Update the Cache as the request may have changed the endpoint
this.UpdateConfig(context);
}
catch (SparqlHttpProtocolUriResolutionException)
{
// If URI Resolution fails we send a 400 Bad Request
context.Response.StatusCode = (int)HttpStatusCode.BadRequest;
}
catch (SparqlHttpProtocolUriInvalidException)
{
// If URI is invalid we send a 400 Bad Request
context.Response.StatusCode = (int)HttpStatusCode.BadRequest;
}
catch (NotSupportedException)
{
// If Not Supported we send a 405 Method Not Allowed
context.Response.StatusCode = (int)HttpStatusCode.MethodNotAllowed;
}
catch (NotImplementedException)
{
// If Not Implemented we send a 501 Not Implemented
context.Response.StatusCode = (int)HttpStatusCode.NotImplemented;
}
catch (RdfWriterSelectionException)
{
// If we can't select a valid Writer when returning content we send a 406 Not Acceptable
context.Response.StatusCode = (int)HttpStatusCode.NotAcceptable;
}
catch (RdfParserSelectionException)
{
// If we can't select a valid Parser when receiving content we send a 415 Unsupported Media Type
context.Response.StatusCode = (int)HttpStatusCode.UnsupportedMediaType;
}
catch (RdfParseException)
{
// If we can't parse the received content successfully we send a 400 Bad Request
context.Response.StatusCode = (int)HttpStatusCode.BadRequest;
}
catch (Exception)
{
// For any other error we'll send a 500 Internal Server Error
context.Response.StatusCode = (int)HttpStatusCode.InternalServerError;
}
}
/// <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);
}
}
