/// <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;
}
}