Hi Henrik,
Requests to Fuseki are HTTP requests.
You could simply copy the HTTP response body stream into a file if you
can get the body as a stream of bytes from the local HTTP client library.
Whether it streams or whether the HTTP client library in your
application collects the whole response then passes it to the
application is purely a client-side issue - Fuseki (or any other
webserver) has no control over that.
By chunks do you mean HTTP chunk-encoding?
Fuseki does provide chunk-encoding on responses for CONSTRUCT
(Jetty does it because there isn't a Content-Length). Try it with "wget
-S" or "curl -v" --> Transfer-Encoding: chunked)
Being a Transfer-Encoding intermediates servers may change this.
Or the response comes back in (sync|async) callbacks (c.f. HTTP/2)? That
is a matter for client-side HTTP code.
I can't tell from the doc you point to whether it is referring to HTTP
chunk encoding (which requires the sever to cooperator and the HTTP
header used aren't shown) or locally collecting bytes together to return
in blocks.
Andy
On 24/09/2021 09:12, Dibowski Henrik (CR/ADT3) wrote:
Dear Jena team,
in our current project we are exploring a way how to extract triples from a Jena Fuseki
dataset via SPARQL Construct queries. We want to write (i.e. stream) the returned statements
directly on-the-fly into a file on our server, without the need of loading all the statements
into main memory first, as this is the bottleneck especially for large amounts of data. Our
TypeScript backend application uses Node.js and will connect directly via http (REST), using
the SPARQL protocol API, with Fuseki. Our question: Does Fuseki support streams, i.e. the
sending of the result in chunks? We are considering to use Node Fetch for enabling &
using this on our application side. See also https://www.npmjs.com/package/node-fetch#streams
Is that supported by Fuseki? Or is there some other way how to "stream" large
results into files?
Best regards
Henrik
