Hmm. I knew about JSON-LD, but I was wanting to build up otherwise-json-serializable python objects that happened to contain rdflib.term objects, and serialize that to json. I suppose that is playing on hard mode though, and I'm better off building up rdflib graphs of what I need, serializing them to json-ld, and then picking at them from that point.
Thanks, Donny On Fri, Oct 15, 2021, at 3:43 PM, Niklas Lindström wrote: > Hello Donny, > > Perhaps you're in need of JSON-LD (https://json-ld.org/)? Check out how to > use that in RDFLib with the examples at: > > > https://rdflib.readthedocs.io/en/stable/apidocs/rdflib.plugins.parsers.html#module-rdflib.plugins.parsers.jsonld > > and: > > > https://rdflib.readthedocs.io/en/stable/apidocs/rdflib.plugins.serializers.html#module-rdflib.plugins.serializers.jsonld > > Cheers, > Niklas > > > On Fri, Oct 15, 2021 at 8:19 PM Donny Winston <do...@polyneme.xyz> wrote: >> __ >> Hi all, >> >> Perhaps this is hidden somewhere in the rdflib repo and I wasn’t able to >> find it, but I found myself wanting to encode rdflib.term.Literal values to >> JSON as e.g. {“value”: literal.value, “datatype”: literal.datatype, …}. I >> ended up adapting the advice of a SO post. Here is my answer on SO with an >> rdflib example: >> [https://stackoverflow.com/a/69588931/1820042](https://stackoverflow.com/a/69588931/1820042). >> >> Also reproduced below. I hope folks find it useful. Also feel free to point >> out where this has already been done, and I’ll pip install that instead of >> my custom code! >> >> `*from* json.encoder *import* (_make_iterencode, JSONEncoder, >> encode_basestring_ascii, INFINITY, >> encode_basestring) >> >> *class* *CustomObjectEncoder*(JSONEncoder): >> >> *def* *iterencode*(self, o, _one_shot=False): >> """Encode the given object and yield each string >> representation as available. >> >> For example:: >> >> for chunk in JSONEncoder().iterencode(bigobject): >> mysocket.write(chunk) >> >> Change from json.encoder.JSONEncoder.iterencode is setting >> _one_shot=False and isinstance=self.isinstance >> in call to `_make_iterencode`. >> And not using `c_make_encoder`. >> >> """ >> *if* self.check_circular: >> markers = {} >> *else*: >> markers = *None* >> *if* self.ensure_ascii: >> _encoder = encode_basestring_ascii >> *else*: >> _encoder = encode_basestring >> >> *def* *floatstr*(o, allow_nan=self.allow_nan, >> _repr=float.__repr__, _inf=INFINITY, _neginf=-INFINITY): >> *# Check for specials. Note that this type of test is processor* >> *# and/or platform-specific, so do tests which don't depend on >> the* >> *# internals.* >> >> *if* o != o: >> text = 'NaN' >> *elif* o == _inf: >> text = 'Infinity' >> *elif* o == _neginf: >> text = '-Infinity' >> *else*: >> *return* _repr(o) >> >> *if* *not* allow_nan: >> *raise* ValueError( >> "Out of range float values are not JSON compliant: " + >> repr(o)) >> >> *return* text >> >> _iterencode = _make_iterencode( >> markers, self.default, _encoder, self.indent, floatstr, >> self.key_separator, self.item_separator, self.sort_keys, >> self.skipkeys, _one_shot=*False*, isinstance=self.isinstance) >> *return* _iterencode(o, 0) ` >> Example subclass: >> >> `*import* datetime >> >> *from* rdflib.term *import* Literal, BNode >> >> *class* *RDFTermEncoder*(CustomObjectEncoder): >> *def* *isinstance*(self, o, cls): >> *if* isinstance(o, (Literal, BNode)): >> *return* *False* >> *return* isinstance(o, cls) >> *def* *default*(self, o): >> *if* isinstance(o, Literal): >> rv = {"value": o.value} >> *if* o.datatype *is* *not* *None*: >> rv["datatype"] = o.datatype >> *if* o.language *is* *not* *None*: >> rv["lang"] = o.language >> *return* rv >> *if* isinstance(o, BNode): >> *return* "http://localhost/bnode/"; + str(o) >> *if* isinstance(o, datetime.datetime): >> *return* o.isoformat() >> *if* isinstance(o, datetime.date): >> *return* str(o) >> *# Let the base class default method raise the TypeError* >> *return* super().default(o) ` >> I just used this successfully for my work as >> >> `db_json = json.loads(json.dumps(db_custom, cls=RDFTermEncoder)) ` >> >> Best, >> Donny >> >> >> — >> Donny Winston, PhD (he/him/his) | Polyneme LLC >> https://donnywinston.com | https://polyneme.xyz >> >> >> If I’ve emailed you, I’d love to speak with you. >> Schedule a meeting (15min+): https://meet.polyneme.xyz >> >> >> >> >> -- >> http://github.com/RDFLib >> --- >> You received this message because you are subscribed to the Google Groups >> "rdflib-dev" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to rdflib-dev+unsubscr...@googlegroups.com. >> To view this discussion on the web visit >> https://groups.google.com/d/msgid/rdflib-dev/5a70d567-652c-45da-b500-7776447210dd%40www.fastmail.com >> >> <https://groups.google.com/d/msgid/rdflib-dev/5a70d567-652c-45da-b500-7776447210dd%40www.fastmail.com?utm_medium=email&utm_source=footer>. > > > -- > http://github.com/RDFLib > --- > You received this message because you are subscribed to the Google Groups > "rdflib-dev" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to rdflib-dev+unsubscr...@googlegroups.com. > To view this discussion on the web visit > https://groups.google.com/d/msgid/rdflib-dev/CADjV5jeHfZUZgYnABPZoJxgJxxouLcvODAXXyaYb-RYx7W-aVw%40mail.gmail.com > > <https://groups.google.com/d/msgid/rdflib-dev/CADjV5jeHfZUZgYnABPZoJxgJxxouLcvODAXXyaYb-RYx7W-aVw%40mail.gmail.com?utm_medium=email&utm_source=footer>. -- Donny Winston, PhD (he/him/his) | Polyneme LLC https://donnywinston.com | https://polyneme.xyz If I've emailed you, I'd love to speak with you. Schedule a meeting (15min+): https://meet.polyneme.xyz -- http://github.com/RDFLib --- You received this message because you are subscribed to the Google Groups "rdflib-dev" group. To unsubscribe from this group and stop receiving emails from it, send an email to rdflib-dev+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/rdflib-dev/31808f71-da01-474f-87ea-600188645a1f%40www.fastmail.com.
