public static object ToRdfWriter(RdfFormat rdfFormat)
{
switch (rdfFormat.GetJenaName())
{
case "RDF/XML":
return(new PrettyRdfXmlWriter());
case "JSON-LD":
return(new JsonLdWriter());
case "TURTLE":
return(new CompressingTurtleWriter());
case "N-QUADS":
return(new NQuadsWriter());
default:
throw new RdfParseException("Unknown rdf format");
}
}
public static object ToRdfReader(RdfFormat rdfFormat)
{
switch (rdfFormat.GetJenaName())
{
case "RDF/XML":
return(new RdfXmlParser());
case "JSON-LD":
return(new JsonLdParser());
case "TURTLE":
return(new TurtleParser());
case "N-QUADS":
return(new NQuadsParser());
case "N-TRIPLE":
return(new NTriplesParser());
default:
throw new RdfParseException("Unknown rdf format");
}
}
/// <summary>
/// Converts rdf string to dotNetRdf graph.
/// </summary>
/// <param name="baseUri"></param>
/// <param name="serializedModel">Literal string read from file.</param>
/// <param name="rdfFormat"></param>
/// <returns></returns>
public IGraph DeserializeGraph(string baseUri, string serializedModel, RdfFormat rdfFormat)
{
// TODO: Handle 'Optional' properly
var reader = RdfFormatsMapper.ToRdfReader(rdfFormat);
try
{
if (reader is IRdfReader)
{
var g = new Graph();
if (!String.IsNullOrEmpty(baseUri))
{
g.BaseUri = new Uri(baseUri);
}
g.LoadFromString(serializedModel, (IRdfReader)reader);
return(g);
}
if (reader is IStoreReader)
{
var ts = new TripleStore();
ts.LoadFromString(serializedModel, (IStoreReader)reader);
var g = ts.Graphs[null];
if (!String.IsNullOrEmpty(baseUri))
{
g.BaseUri = new Uri(baseUri);
}
return(g);
}
return(null);
}
catch (IOException ex)
{
string msg = String.Format("Unable to parse serialized RDF from '%s' format.", rdfFormat.GetJenaName());
throw new RdfSerializationException(msg, ex);
}
}
public Block CreateBlock(string dataGraphIri, string rawRdf, RdfFormat rdfFormat)
{
_logger.LogDebug("Creating block with graphIri '{0}' and rdfFormat '{1}'...", dataGraphIri, rdfFormat.GetJenaName());
try
{
HashSet <Triple> triples = GetTriplesFromSerializedModel(rawRdf, rdfFormat);
long newIndex = GenerateNewIndex();
string newBlockIri = GenerateNewBlockIri(newIndex);
LastBlockInfo lastBlockInfo = _repositoryManager.GetLastBlockInfo();
string previousBlock = lastBlockInfo.BlockIri;
string previousHash = lastBlockInfo.BlockHash;
string timestamp = TimestampCreator.CreateTimestampString();
string dataHash = _hashingService.CalculateHash(triples);
string stringToCalculateHash = (newIndex + previousBlock + previousHash + timestamp + dataGraphIri + dataHash).Trim();
string hash = _hashCalculator.CalculateHash(stringToCalculateHash).ToLower();
BlockHeader blockHeader = new BlockHeader(
dataGraphIri,
dataHash,
hash,
newIndex.ToString(),
previousBlock,
previousHash,
timestamp);
BlockContent blockContent = new BlockContent(dataGraphIri, triples);
Block blockToStore = new Block(newBlockIri, blockHeader, blockContent);
_repositoryManager.PersistBlock(blockToStore, true);
// MAYBE: Maybe this should be obtained from Triple Store in order to avoid some kind of inconsistency.
_lastIndex++;
return(GetBlock(newIndex.ToString()));
}
catch (ReadingBlockException ex)
{
string msg = "Exception was thrown while getting information about the last block.";
throw new CreatingBlockException(msg, ex);
}
catch (RdfSerializationException ex)
{
string msg = String.Format("Exception was thrown while deserializing RDF model from '{0}' format.", rdfFormat);
throw new CreatingBlockException(msg, ex);
}
catch (CalculatingHashException ex)
{
throw new CreatingBlockException("Exception was thrown while calculating hash.", ex);
}
}