/// <summary>
/// Processes a PATCH operation
/// </summary>
/// <param name="context">HTTP Context</param>
public override void ProcessPatch(HttpContext context)
{
//Work out the Graph URI we want to patch
Uri graphUri = this.ResolveGraphUri(context);
//If the Request has the SPARQL Update MIME Type then we can process it
if (context.Request.ContentLength > 0)
{
if (context.Request.ContentType.Equals("application/sparql-update"))
{
//Try and parse the SPARQL Update
//No error handling here as we assume the calling IHttpHandler does that
String patchData;
using (StreamReader reader = new StreamReader(context.Request.InputStream))
{
patchData = reader.ReadToEnd();
reader.Close();
}
SparqlUpdateParser parser = new SparqlUpdateParser();
SparqlUpdateCommandSet cmds = parser.ParseFromString(patchData);
//Assuming that we've got here i.e. the SPARQL Updates are parseable then
//we need to check that they actually affect the relevant Graph
if (cmds.Commands.All(c => c.AffectsSingleGraph && c.AffectsGraph(graphUri)))
{
GenericUpdateProcessor processor = new GenericUpdateProcessor(this._manager);
processor.ProcessCommandSet(cmds);
processor.Flush();
}
else
{
//One/More commands either do no affect a Single Graph or don't affect the Graph
//implied by the HTTP Request so give a 422 response
context.Response.StatusCode = 422;
return;
}
}
else
{
//Don't understand other forms of PATCH requests
context.Response.StatusCode = (int)HttpStatusCode.UnsupportedMediaType;
return;
}
}
else
{
//Empty Request is a Bad Request
context.Response.StatusCode = (int)HttpStatusCode.BadRequest;
return;
}
}
