JavaScript Object Notation (JSON) Pointer (2013) | Hacker News Reader

JavaScript Object Notation (JSON) Pointer (2013)

rfc-editor.org

17 pointsstefankuehnel11 comments

"Note that JSON pointers can contain the NUL (Unicode U+0000) character. Care is needed not to misinterpret this character in programming languages that use NUL to mark the end of a string."

What could possibly go wrong?

I wonder why it allows NUL... I'm pretty sure JSON itself doesn't: you need to do a \u escape to do the control characters including NUL.

It looks like that kind of escaping is just not supported at all in JSON Pointer. I kind of want to say that once you've noticed NUL is a problem enough to call it out the document, you should probably just ban it and pop in an escape to represent it.

I was wondering how this differs from JSONPath, found some answers on google:

> jsonpointer just defines how to access to a single value inside a json document, whereas jsonpath has more powerful features like union (extract multiple values), filters and deep search (recursively match a path).

> But jsonpath is missing a proper specification, so some behaviors are implementation specific with some parts heavily depending on some javascript constructs (mainly filters).

https://github.com/yalp/jsonpath/issues/1#issuecomment-13708...

A simple subset of JSONPath is nice, it looks just like code. e.g foo.bar[5].value and encodes that we expect a member name or a indice into the array or class. It’s common to have numeric string member names in JSON when dealing with associative structures of KV pairs.

There is an IETF working group developing a spec for jsonpath https://datatracker.ietf.org/wg/jsonpath/documents/

Abstract

   JSON Pointer defines a string syntax for identifying a specific value
   within a JavaScript Object Notation (JSON) document.

If you don't need multi-language support, it seems like there may be more natural ways to point at a particular part of a JSON object. This issue has a few different implementations and alternatives: https://github.com/akheron/optics-ts/issues/241

JSON Pointer is just not powerful enough except for the simplest use cases. I very much prefer JSON Path.

Looks like in this proposal a less common escape technique is used. I wonder if we can adopt a standardized escaping method across various standards, languages and data structures, so one doesn't need to learn specifics every time.

2013

I’m guessing no one wanted this, because stepping into JSON with forward slashes is trivial if you wanted to do it, and no one would do that. Making a standardized “safe” JSON query like json.array[3][“baz”] that is JS compatible might be interesting, but still really trivial to do.

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