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https://issues.apache.org/jira/browse/JENA-2302?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17502517#comment-17502517
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Andy Seaborne commented on JENA-2302:
-------------------------------------
It's quite unlikely to have repeated headers but on the web, "things happen".
As the application may not have control of the data coming in, robustness is
"header after the body" - if the sender assembles some JSON (i.e. complete
result set, correct order) and then serialses it, it is at the mercy of the
JSON serializer used.
The Jena JSON parser is streaming. The streaming part isn't accessible in the
release. (Why our own parser? When it was written the state of parsers was
different that it is today. All we want is a parser, not an ORM which leads to
security problems.)
We also have use of jakarta.json in the code base.
And jackson but that is (IIRC) just for jsonld-java which may get replaced as
JSON 1.1 becomes dominant in the wild.
{quote}Would that be of interest?
{quote}
Yes.
{quote}when XML was the default result set format
{quote}
Content negotiation is settable!
> RowSetReaderJSON is not streaming
> ---------------------------------
>
> Key: JENA-2302
> URL: https://issues.apache.org/jira/browse/JENA-2302
> Project: Apache Jena
> Issue Type: Bug
> Components: ARQ
> Affects Versions: Jena 4.5.0
> Reporter: Claus Stadler
> Priority: Major
>
> Retrieving all data from our TDB2 endpoint with jena 4.5.0-SNAPSHOT is no
> longer streaming for the JSON format. I tracked the issue to RowSetReaderJson
> which reads everything into in memory (and then checks whether it is a SPARQL
> ASK result)
> {code:java}
> public class RowSetReaderJson {
> private void parse(InputStream in) {
> JsonObject obj = JSON.parse(in); // !!! Loads everything !!!
> // Boolean?
> if ( obj.hasKey(kBoolean) ) { ... }
> }
> }
> {code}
> Streaming works when switching the to RS_XML in the example below:
> {code:java}
> public class Main {
> public static void main(String[] args) {
> System.out.println("Test Started");
> try (QueryExecution qe = QueryExecutionHTTP.create()
>
> .acceptHeader(ResultSetLang.RS_JSON.getContentType().getContentTypeStr())
> .endpoint("http://moin.aksw.org/sparql";).queryString("SELECT
> * { ?s ?p ?o }").build()) {
> qe.execSelect().forEachRemaining(System.out::println);
> }
> System.out.println("Done");
> }
> }
> {code}
> For completeness, I can rule out any problem with TDB2 because streaming of
> JSON works just fine with:
> {code:bash}
> curl --data-urlencode "query=select * { ?s ?p ?o }"
> "http://moin.aksw.org/sparql";
> {code}
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