/// <summary>
/// Processes a HEAD operation
/// </summary>
/// <param name="context">HTTP Context</param>
public override void ProcessHead(IHttpContext context)
{
//Work out the Graph URI we want to get
Uri graphUri = this.ResolveGraphUri(context);
try
{
bool exists = this.HasGraph(graphUri);
if (exists)
{
//Send the Content Type we'd select based on the Accept header to the user
String ctype;
IRdfWriter writer = MimeTypesHelper.GetWriter(HandlerHelper.GetAcceptTypes(context), out ctype);
context.Response.ContentType = ctype;
}
else
{
context.Response.StatusCode = (int)HttpStatusCode.NotFound;
}
}
catch (RdfQueryException)
{
//If the GetGraph() method errors this implies that the Store does not contain the Graph
//In such a case we should return a 404
context.Response.StatusCode = (int)HttpStatusCode.NotFound;
return;
}
}
/// <summary>
/// Sends the given Graph to the Client via the HTTP Response
/// </summary>
/// <param name="context">HTTP Context</param>
/// <param name="g">Graph to send</param>
protected void SendResultsToClient(HttpContext context, IGraph g)
{
IRdfWriter writer;
String ctype;
//Look up the MIME Type Definition - if none use GetWriter instead
MimeTypeDefinition definition = MimeTypesHelper.GetDefinitions(HandlerHelper.GetAcceptTypes(context)).FirstOrDefault(d => d.CanWriteRdf);
if (definition != null)
{
writer = definition.GetRdfWriter();
ctype = definition.CanonicalMimeType;
}
else
{
writer = MimeTypesHelper.GetWriter(HandlerHelper.GetAcceptTypes(context), out ctype);
}
//Set up the Writer
if (writer is ICompressingWriter)
{
((ICompressingWriter)writer).CompressionLevel = Options.DefaultCompressionLevel;
}
//Send Content to Client
context.Response.ContentType = ctype;
if (definition != null)
{
context.Response.ContentEncoding = definition.Encoding;
writer.Save(g, new StreamWriter(context.Response.OutputStream, definition.Encoding));
}
else
{
writer.Save(g, new StreamWriter(context.Response.OutputStream));
}
}