Re: Light weight support for JSON

[Saint Michael]

He has a point, though. To have some of the functionality of jq inside Bash
may be very useful.
If he can supply a patch, why not?
Philip Orleans

On Sun, Aug 28, 2022, 3:22 PM John Passaro <john.a.passaro@gmail.com> wrote:

> interfacing with an external tool absolutely seems like the correct answer
> to me. a fact worth mentioning to back that up is that `jq` exists. billed
> as a sed/awk for json, it fills all the functions you'd expect such an
> external tool to have and many many more. interfacing from curl to jq to
> bash is something i do on a near daily basis.
>
> https://stedolan.github.io/jq/
>
> On Sun, Aug 28, 2022, 09:25 Yair Lenga <yair.lenga@gmail.com> wrote:
>
> > Hi,
> >
> > Over the last few years, JSON data becomes a integral part of processing.
> > In many cases, I find myself having to automate tasks that require
> > inspection of JSON response, and in few cases, construction of JSON. So
> > far, I've taken one of two approaches:
> > * For simple parsing, using 'jq' to extract elements of the JSON
> > * For more complex tasks, switching to python or Javascript.
> >
> > Wanted to get feedback about the following "extensions" to bash that will
> > make it easier to work with simple JSON object. To emphasize, the goal is
> > NOT to "compete" with Python/Javascript (and other full scale language) -
> > just to make it easier to build bash scripts that cover the very common
> use
> > case of submitting REST requests with curl (checking results, etc), and
> to
> > perform simple processing of JSON files.
> >
> > Proposal:
> > * Minimal - Lightweight "json parser" that will convert JSON files to
> bash
> > associative array (see below)
> > * Convert bash associative array to JSON
> >
> > To the extent possible, prefer to borrow from jsonpath syntax.
> >
> > Parsing JSON into an associative array.
> >
> > Consider the following, showing all possible JSON values (boolean,
> number,
> > string, object and array).
> > {
> >     "b": false,
> >     "n": 10.2,
> >     "s: "foobar",
> >      x: null,
> >     "o" : { "n": 10.2,  "s: "xyz" },
> >      "a": [
> >          { "n": 10.2,  "s: "abc", x: false },
> >          {  "n": 10.2,  "s": "def" x: true},
> >      ],
> > }
> >
> > This should be converted into the following array:
> >
> > -------------------------------------
> >
> > # Top level
> > [_length] = 6                            # Number of keys in object/array
> > [_keys] = b n s x o a            # Direct keys
> > [b] = false
> > [n] = 10.2
> > [s] = foobar
> > [x] = null
> >
> > # This is object 'o'
> > [o._length] = 2
> > [o._keys] = n s
> > [o.n] = 10.2
> > [o.s] = xyz
> >
> > # Array 'a'
> > [a._count] =  2                   # Number of elements in array
> >
> > # Element a[0] (object)
> > [a.0._length] = 3
> > [a.0._keys] = n s x
> > [a.0.n] = 10.2
> > [a.0.s] = abc
> > [a.0_x] = false
> >
> > -------------------------------------
> >
> > I hope that example above is sufficient. There are few other items that
> are
> > worth exploring - e.g., how to store the type (specifically, separate the
> > quoted strings vs value so that "5.2" is different than 5.2, and "null"
> is
> > different from null.
> >
> > I will leave the second part to a different post, once I have some
> > feedback. I have some prototype that i've written in python - POC - that
> > make it possible to write things like
> >
> > declare -a foo
> > curl http://www.api.com/weather/US/10013 | readjson foo
> >
> > printf "temperature(F) : %.1f Wind(MPH)=%d" ${foo[temp_f]}, ${foo[wind]}
> >
> > Yair
> >
>