feature wish: JSONPath

[tesch1]

A simple query() function would be a fantastic addition. Maybe it's totally out of scope for this project, but searching the issues didn't turn up any discussion, so maybe this issue is just a place to say it wont be done :)

Some related refs:
http://goessner.net/articles/JsonPath/
https://chromium.googlesource.com/external/mozc/+/master/src/net/jsonpath.cc
https://www.genivia.com/doc/xml-rpc-json/html/

[nlohmann]

Currently, only JSON Pointer is implemented. JSON Path sounds interesting, but I currently do not have the time to look into it.

[nlohmann]

I had another look at this. It seems doable, but also a lot of work. I shall postpone this ticket until after the 3.0.0 release.

[tesch1]

No worries! It'd definitely a lot of work. Really cool of you to look at it tho, open source is awesome :)

[nlohmann]

Is there an agreed upon reference for JSON Path?

[tesch1]

I think this is the first - http://goessner.net/articles/JsonPath/

[nlohmann]

This less of a specification, but rather a list of examples.

Furthermore:

XPath has a lot more to offer (Location pathes in not abbreviated syntax, operators and functions) than listed here.

[nlohmann]

I'm closing this for now in lieu of a proper specification of "JSONPath", see #343 (comment).

[yangbodong22011]

Hi, @nlohmann Would you consider supporting or accepting the PR of JSONPath?

[nlohmann]

Why not? Is there a proper specification now?

[yangbodong22011]

It is still not a standard, but we have "conventional" examples: https://github.com/freestrings/jsonpath/wiki/rust-examples

Including those implemented by RedisJSON.

[nlohmann]

I see. In any case, it would be best to implement this as free functions; that is, not to add any member functions, because the API is already pretty bloated. Do you think this is possible?

[yangbodong22011]

I haven't dig into the code details yet, and I don't quite understand what you mean by free functions.

But I think as a parsing path, under the premise that JSONPointer is already supported, it would be best if it can be automatically recognized as JSONPath or JSONPointer and successfully access the element.

[nlohmann]

I meant I'd rather have something like

json authors = json::selector(j, "$.store.book[*].author");

rather than

json authors = j.selector("$.store.book[*].author");

[yangbodong22011]

Oh, I think I agree with you, after all, json::parse is like this.

[yangbodong22011]

Why not? Is there a proper specification now?

FYI：
https://www.ietf.org/id/draft-ietf-jsonpath-base-03.html

[oiwg]

Now up to draft 6, progress tracked at https://datatracker.ietf.org/wg/jsonpath/about/ , standards track document due in November.

[jianbingfang]

Is the JsonPath feature available now?

[udem1234]

Hi.

@nlohmann : Any news on this ? :-)

(btw, I just came across this cool jsonpath online evaluator : JSONPath Online Evaluator by Kazuki Hamasaki for those who might be interested)

Thank you.

[nlohmann]

It's not on my todo list, but merge requests are welcome.