public static List<RDFFormat> filterAvailableWriters(List<RDFFormat> rdfFormats) {
final List<RDFFormat> result = new ArrayList<>();
final RDFWriterRegistry writerRegistry = RDFWriterRegistry.getInstance();
for (RDFFormat f : rdfFormats) {
if (writerRegistry.has(f)) {
result.add(f);
}
}
return result;
}
@Override
protected void doGet(HttpAction action) {
// Assume success - do the set up before grabbing the lock.
// Sets content type.
MediaType mediaType = ActionLib.contentNegotationRDF(action);
ServletOutputStream output;
try {
output = action.response.getOutputStream();
} catch (IOException ex) {
ServletOps.errorOccurred(ex);
output = null;
}
TypedOutputStream out = new TypedOutputStream(output, mediaType);
Lang lang = RDFLanguages.contentTypeToLang(mediaType.getContentType());
if (action.verbose)
action.log.info(
format(
"[%d] Get: Content-Type=%s, Charset=%s => %s",
action.id, mediaType.getContentType(), mediaType.getCharset(), lang.getName()));
action.beginRead();
setCommonHeaders(action.response);
try {
Target target = determineTarget(action);
if (action.log.isDebugEnabled()) action.log.debug("GET->" + target);
boolean exists = target.exists();
if (!exists) ServletOps.errorNotFound("No such graph: <" + target.name + ">");
// If we want to set the Content-Length, we need to buffer.
// response.setContentLength(??) ;
String ct = lang.getContentType().toHeaderString();
action.response.setContentType(ct);
Graph g = target.graph();
// Special case RDF/XML to be the plain (faster, less readable) form
RDFFormat fmt =
(lang == Lang.RDFXML)
? RDFFormat.RDFXML_PLAIN
: RDFWriterRegistry.defaultSerialization(lang);
try {
RDFDataMgr.write(out, g, fmt);
} catch (JenaException ex) {
// Some RDF/XML data is unwritable. All we can do is pretend it's a bad
// request (inappropriate content type).
// Good news - this happens before any output for RDF/XML-ABBREV.
if (fmt.getLang().equals(Lang.RDFXML))
ServletOps.errorBadRequest("Failed to write output in RDF/XML: " + ex.getMessage());
else ServletOps.errorOccurred("Failed to write output: " + ex.getMessage(), ex);
}
ServletOps.success(action);
} finally {
action.endRead();
}
}
