/// <summary>
/// Generates a SPARQL Service Description Graph for the given Update Handler Configuration or uses the configuration supplied Description Graph
/// </summary>
/// <param name="context">HTTP Context</param>
/// <param name="config">Update Handler Configuration</param>
/// <param name="descripUri">Base URI of the Description</param>
/// <returns></returns>
public static IGraph GetServiceDescription(HttpContext context, BaseUpdateHandlerConfiguration config, Uri descripUri)
{
//Use user specified Service Description if present
if (config.ServiceDescription != null)
{
return(config.ServiceDescription);
}
IGraph g = SparqlServiceDescriber.GetNewGraph();
//Add the Top Level Node representing the Service
IUriNode descrip = g.CreateUriNode(descripUri);
IUriNode rdfType = g.CreateUriNode(new Uri(RdfSpecsHelper.RdfType));
IUriNode service = g.CreateUriNode("sd:" + ClassService);
g.Assert(descrip, rdfType, service);
//Add its sd:url
IUriNode url = g.CreateUriNode("sd:" + PropertyUrl);
g.Assert(descrip, url, descrip);
//Add the sd:supportedLanguage
IUriNode supportedLang = g.CreateUriNode("sd:" + PropertySupportedLanguage);
g.Assert(descrip, supportedLang, g.CreateUriNode("sd:" + InstanceSparql11Update));
//Add Features and Dataset Description
//First add descriptions for Global Expression Factories
IUriNode extensionFunction = g.CreateUriNode("sd:" + PropertyExtensionFunction);
IUriNode extensionAggregate = g.CreateUriNode("sd:" + PropertyExtensionAggregate);
foreach (ISparqlCustomExpressionFactory factory in SparqlExpressionFactory.Factories)
{
foreach (Uri u in factory.AvailableExtensionFunctions)
{
g.Assert(descrip, extensionFunction, g.CreateUriNode(u));
}
foreach (Uri u in factory.AvailableExtensionAggregates)
{
g.Assert(descrip, extensionAggregate, g.CreateUriNode(u));
}
}
//Then get the Configuration Object to add any other Feature Descriptions it wishes to
config.AddFeatureDescription(g, descrip);
return(g);
}
/// <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>
/// 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 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);
}
}
