No the content types aren't wrong you're just using them for the wrong things.
Per application/json several people have already commented that there is no serialization directly linked to application/json. There are specific MIME types for specific variants of JSON e.g. application/ld+json for JSON-LD And for application/n-quads that is a dataset serialization not a graph serialization If you ask for a content type that isn't supported by the server you are talking to then the server can choose to do one of two things. NB - this is standard HTTP spec stuff, nothing specific to Fuseki. 1. Reject the request and send back a 406 Not Acceptable i.e. give you an error 2. Fall back to its preferred default serialization So in both cases since you are asking for content types that have no associated graph serialization Fuseki falls back to using it's default Rob On 31/01/2019, 13:34, "vincent ventresque" <[email protected]> wrote: Sorry, let me sum up the previous messages : 1) I wanted to export a named graph from tdb to ntriples 2) Andy advised to modify s-get, which I did 3) when modifying s-get, I noticed there were 2 wrong content-types : application/json & application/n-quads ; both give rdf-xml output 4) Andy suggested it came from s-get settings 5) I showed that commenting the settings in s-get have no effect AND that the problem is the same with curl. 6) my purpose is also to understand how all this stuff works! Le 31/01/2019 à 14:22, Martynas Jusevičius a écrit : > Vincent, > > can you start by explaining what you are trying to do and why, rather > describing how you're doing it? > > On Thu, Jan 31, 2019 at 2:20 PM vincent ventresque > <[email protected]> wrote: >> Sorry, I should have explained more clearly : the previous messages >> where about default settings in s-get, and when creating a new function >> to handle --output option, I noticed there was a wrong content-type in >> s-get for plain json (see my s-get file here : >> https://sourceforge.net/projects/ffl-misc/files/fuseki_scripts_custom-ruby/s-get/download). >> >> >> My purpose was to demonstrate that the problem isn't linked to s-get, >> since it's the same with curl. Besides, I noticed the same problem with >> n-quads. >> >> curl --header 'Accept: application/n-quads' >> 'http://localhost:3030/test_tdb2?graph=http://test' >> <rdf:RDF >> xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"; >> xmlns:j.0="http://example.org/"; > >> <rdf:Description rdf:about="http://example.org/titi";> >> <j.0:tata>coucou</j.0:tata> >> </rdf:Description> >> </rdf:RDF> >> >> >> >> Le 31/01/2019 à 14:12, ajs6f a écrit : >>> I'm not sure what you expect to get back from Fuseki with an "application/json" mimetype? There is no W3C-spec plain-JSON RDF serialization that I know of. I suppose there's the old Tallis idea: >>> >>> https://jena.apache.org/documentation/io/rdf-json.html >>> >>> but I can't imagine that's what you're looking for. >>> >>> ajs6f >>> >>>> On Jan 31, 2019, at 8:09 AM, vincent ventresque <[email protected]> wrote: >>>> >>>> It seems that the problem is completely independent from s-get (see these results with curl below). So I think there's a default setting somewhere in Fuseki itself. >>>> >>>> >>>> #~~~~~~~ --header 'Accept: application/json' ~~~~~~~~~~~~~~~~~~~~~ >>>> >>>> :~/Documents/fuseki/bin$ curl --header 'Accept: application/json' 'http://localhost:3030/test_tdb2?graph=http://test' >>>> <rdf:RDF >>>> xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"; >>>> xmlns:j.0="http://example.org/"; > >>>> <rdf:Description rdf:about="http://example.org/titi";> >>>> <j.0:tata>coucou</j.0:tata> >>>> </rdf:Description> >>>> </rdf:RDF> >>>> >>>> >>>> #~~~~~~~ --header 'Accept: application/rdf+json' ~~~~~~~~~~~~~~~~~~~~~~ >>>> >>>> :~/Documents/fuseki/bin$ curl --header 'Accept: application/rdf+json' 'http://localhost:3030/test_tdb2?graph=http://test' >>>> { >>>> "http://example.org/titi"; : { >>>> "http://example.org/tata"; : [ { >>>> "type" : "literal" , >>>> "value" : "coucou" >>>> } >>>> ] >>>> } >>>> } >>>> >>>> >>>> >>>> Le 31/01/2019 à 12:58, vincent ventresque a écrit : >>>>> Thanks for your quick reply! >>>>> >>>>>> $mtAppJSON isn't used. >>>>> I think my previous msg wasn't clear : I meant raw json and not json-ld (my code works now for both, and I use $mtAppJSON ; but I had to replace 'application/json' with 'application/rdf+json' in order to get json instead of XML ; see the file here https://sourceforge.net/projects/ffl-misc/files/fuseki_scripts_custom-ruby/s-get/download) >>>>> >>>>>> The settings are: ... >>>>> I made a little test : comment these lines and the "names" part, and you'll get XML! >>>>> >>>>> >>>>> Le 31/01/2019 à 12:48, Andy Seaborne a écrit : >>>>>> On 31/01/2019 11:26, vincent ventresque wrote: >>>>>>> Hello, >>>>>>> >>>>>>> I found the origin of the problem for json : the $mtAppJSON had the value >>>>>>> >>>>>>> 'application/json' >>>>>> $mtAppJSON isn't used. >>>>>> >>>>>> "application/rdf+json" >>>>>> isn't JSON-LD (it's the old Talis format). >>>>>> >>>>>> There is: >>>>>> >>>>>> $mtJSONLD = 'application/ld+json' >>>>>> >>>>>>> it has to be replaced with >>>>>>> >>>>>>> 'application/rdf+json' >>>>>>> >>>>>>> I've updated the file here : >>>>>>> >>>>>>> https://sourceforge.net/projects/ffl-misc/files/fuseki_scripts_custom-ruby/s-get/download >>>>>>> >>>>>>> Maybe I'm going to submit a pull request as Andy suggested, but I'd like to understand why 'application/json' returns xml. Besides, it's the same thing for nquads : I tried to replace >>>>>>> >>>>>>> $mtNQuads = 'application/n-quads' >>>>>>> >>>>>>> with >>>>>>> >>>>>>> $mtNQuads = 'application/x-trig' >>>>>>> >>>>>>> but still have xml... >>>>>> The settings are: >>>>>> >>>>>> # Default for GET >>>>>> # At least allow anything (and hope!) >>>>>> $accept_rdf="#{$mtTurtle} , #{$mtNTriples};q=0.9 , #{$mtRDF};q=0.8 , #{$mtJSONLD};q=0.5" >>>>>> # Datasets >>>>>> $accept_ds="#{$mtTrig} , #{$mtNQuads};q=0.9 , #{$mtJSONLD};q=0.5" >>>>>> # For SPARQL query >>>>>> $accept_results="#{$mtSparqlResultsJ} , #{$mtSparqlResultsX};q=0.9 , #{$accept_rdf}" >>>>>> >>>>>> # Accept any in case of trouble. >>>>>> $accept_rdf="#{$accept_rdf} , */*;q=0.1" >>>>>> $accept_results="#{$accept_results} , */*;q=0.1" >>>>>> >>>>>> >>>>>>> Is there a kind of default setting somewhere (if content-type isn't recognized in Fuseki, the response is xml) ? >>>>>> Yes. >>>>>> >>>>>> RDF/XML for graphs, N-Quads for datasets. >>>>>> >>>>>> Run Fuseki/full with "-v" and it should print the content negotiation details. >>>>>> >>>>>> Andy >>>>>> >>>>>>> Thanks in advance >>>>>>> >>>>>>> VV >>>>>>> >>>>>>> >>>>>>> Ok, maybe I'm going to submit a pull request, but I'd >>>>>>> >>>>>>> Le 29/01/2019 à 17:11, vincent ventresque a écrit : >>>>>>>> Hi Andy, >>>>>>>> >>>>>>>> Thanks again for your idea to modify the s-get script, it helped me understand ruby utilities and http requests (I often use the ruby scripts but never really looked inside). >>>>>>>> >>>>>>>> Don't know how to submit a pull request, and I'm not a ruby expert! Therefore I've put a small test file here : >>>>>>>> >>>>>>>> https://sourceforge.net/projects/ffl-misc/files/fuseki_scripts_custom-ruby/s-get/download >>>>>>>> >>>>>>>> -- added "--output" in options + created a new function (set_output_format) >>>>>>>> >>>>>>>> -- it works for ntriples, xml, Json-LD, >>>>>>>> >>>>>>>> -- doesn't work for json (returns xml...) >>>>>>>> >>>>>>>> N.B. : in this test file, I've removed large parts of the original code in order to improve readability >>>>>>>> >>>>>>>> >>>>>>>> Le 28/01/2019 à 15:28, Vincent Ventresque a écrit : >>>>>>>>> Hi Andy, >>>>>>>>> >>>>>>>>> Many thanks for these ideas, I'm going to try the curl & riot solutions. >>>>>>>>> >>>>>>>>>> Modify the s-get script to handle --output and set the "Accept:" header then please submit a pull request for the changes >>>>>>>>> I had made an attempt to modify the s-get script in the same way as for s-query but it didn't work : if I have a moment I'll try to understand how the options are handled. >>>>>>>>> >>>>>>>>> >>>>>>>>> >>>>>>>>> >>>>>>>>> Le 28/01/2019 à 14:19, Andy Seaborne a écrit : >>>>>>>>>> On 28/01/2019 11:04, Vincent Ventresque wrote: >>>>>>>>>>> Hello, >>>>>>>>>>> >>>>>>>>>>> I want to export a named graph which is stored in a TDB dataset, and I want to store the output in several files (for the named graph contains +/- 9.5 M triples). >>>>>>>>>>> >>>>>>>>>>> My idea is to use "split" command in order to cut the output of the export into pieces. However, this solution with "split" requires ntriples or nquads (one triple per line, so that the files are not cut in the middle of an assertion ; besides, it's also more practical to have a triple per line if I want to transform the data with perl or sed). >>>>>>>>>>> >>>>>>>>>>> I found a solution with s-query but had to edit the ruby s-query script to get ntriples (see below). >>>>>>>>>>> >>>>>>>>>>> There are other possible solutions for an export via command-line utilities : "s-get" and "tdbdump". If I understand well, "tdbdump" gives nquads as output, but one can't export only a part of the data, everything is exported at once. The "s-get" solution allows to select a named graph in the dataset, but I couldn't change the output format. >>>>>>>>>>> >>>>>>>>>>> Are there better solutions to get an export in several files? >>>>>>>>>> Ways I can think of: >>>>>>>>>> >>>>>>>>>> 1/ Modify the s-get script to handle --output and set the "Accept:" header then please submit a pull request for the changes. >>>>>>>>>> >>>>>>>>>> 2/ Use curl >>>>>>>>>> >>>>>>>>>> curl --header 'Accept: application/n-triples' \ >>>>>>>>>> 'http://localhost:3030/ds?graph=http://bnf_titres' >>>>>>>>>> >>>>>>>>>> 3/ Parse the s-get output: >>>>>>>>>> >>>>>>>>>> s-get ... | riot --syntax TTL >>>>>>>>>> >>>>>>>>>> Andy >>>>>>>>>> >>>>>>>>>> >>>>>>>>>>> Thanks in advance, >>>>>>>>>>> >>>>>>>>>>> VV. >>>>>>>>>>> >>>>>>>>>>> >>>>>>>>>>> >>>>>>>>>>> ~~~~~~~~~~~ 1) SOLUTION WITH s-query ~~~~~~~~~~~~~~~~~~~~~ >>>>>>>>>>> >>>>>>>>>>> 1.1) Edit s-query ruby script (add nt) >>>>>>>>>>> >>>>>>>>>>> -- l. 572 : when "json","xml","text","csv","tsv","nt" >>>>>>>>>>> -- l. 574 : when :json,:xml,:text,:csv,:tsv,:nt >>>>>>>>>>> -- l. 515 : opts.on('--output=TYPE', [:json,:xml,:text,:csv,:tsv,:nt], >>>>>>>>>>> -- l. 519 : opts.on('--accept=TYPE', [:json,:xml,:text,:csv,:tsv,:nt], >>>>>>>>>>> >>>>>>>>>>> 1.2) Command >>>>>>>>>>> >>>>>>>>>>> /my/path/to/fuseki/bin/s-query --service=http://localhost:3030/BnF_text_v2/ "construct { ?s ?p ?o } where { graph <http://bnf_titres> { ?s ?p ?o }}" --output=nt | split -l 500000 - --additional-suffix=.nt BnfTextTitres- >>>>>>>>>>> >>>>>>>>>>> ~~~~~~~~~~~ 2) SOLUTION WITH tdbdump (nquads but no named graph) ~~~~~~~~~~~~~~~~~~~~~ >>>>>>>>>>> >>>>>>>>>>> /my/path/to/jena/bin/tdbdump --loc=/my/path/to/fuseki/run/databases/BnF_text_v2 --graph=http://bnf_titres | split -l 500000 - --additional-suffix=.nt BnfTextTitres- >>>>>>>>>>> >>>>>>>>>>> => Unknown argument: graph >>>>>>>>>>> >>>>>>>>>>> ~~~~~~~~~~~ 3) SOLUTION WITH s-get (named graph ok, but turtle output) ~~~~~~~~~~~~~~~~~~~~~ >>>>>>>>>>> >>>>>>>>>>> /my/path/to/fuseki/bin/s-get http://localhost:3030/BnF_text_v2/data http://bnf_titres --output=text | split -l 500000 - --additional-suffix=.nt BnfTextTitres- >>>>>>>>>>> >>>>>>>>>>> => /my/path/to/fuseki/bin/s-get:364:in `cmd_soh': invalid option: --output=text (OptionParser::InvalidOption) >>>>>>>>>>> from /my/path/to/fuseki/bin/fuseki/bin/s-get:715:in `<main>' >>>>>>>>>>>
