Thank you for reporting the issue. I found a similar case registered under ZBXNEXT-968 with suggestions how to process multiline, so we will close this ticket and continue the discussion there. Feel free to follow the original case and vote for it.

Dear mbuhholcs, how can these two issues be related? ZBXNEXT-968 talks about regular expressions in web scenarios, this one — about LLD and JSONPath preprocessing.

Thanks cyclone, I guess there was a mixup of regexp and JSONSPath.
Craig, can you please show exactly how you set this up with screenshots? $ should be supported in jsonpath

Screenshots uploaded

Dear craigmcfly, what do you want to achieve? JSONPath "$" will extract the whole JSON, i.e. it's useless as a preprocessing step since it does not alter the value in any way.

Dear zux, I guess at very least error message

unsupported character in json path starting with: ""

should be replaced with more understandable

unexpected end of JSONPath

I want to create a macro that extracts the IDs, i.e.

$.*~

so then I can query the API for each individual object and get all the extended information. Ideally, I'd love to be able to get the name, too, but I don't think you can extract two sets of information like that.

Hello cyclone, the problem is, that I tried to set this up the way I understand from the report, but wasn't able to see the same error.
So maybe I'm testing incorrectly.

This has a state of "Need Info" but I don't know what you're awaiting. Please can you elaborate?

There where actually some changes in latest release, please take a look:
https://www.zabbix.com/documentation/4.2/manual/appendix/items/jsonpath?s[]=jsonpath

Sorry for the maybe dumb question, but what do you expect the "~" symbol to do here?

Based on the example in your documentation, 

$.*~

would return

[
"books",
"services",
"filters",
"closed message",
"tags"
]

http://jsonpath.com is a good tool for debugging JSONPath. 

I don't see the symbol "~" in our documentation, that's why I'm asking, what do you expect it to do?
Actually in my case, the error is this, when I try to use your expression:

cannot extract value from json by path "$.*~": unsupported construct in jsonpath starting with: "~"

Zabbix has it's own implementation of JSONpath, so external tools might not work exactly the same way. There are some improvements in recent versions: ZBXNEXT-4502

Yes, but what it should do based on the JSONPath spec is give the top level item names. I don't understand why that doesn't work. i.e. it seems to have been missed during the updates to JSONPath in 4.2

I suppose my question is, simply, how do I get the top level items for building discovery?

This topic was raised in 4502:

Roberto Cremasco added a comment - 2019 Jun 04 14:11 - edited
Supporting paths like "$.*~" would allow to create any number of dependent items.

The official examples at https://www.zabbix.com/documentation/4.2/manual/appendix/items/jsonpath stated as "supported" does not work.

For example:

$.books[?(@.id == 2 || @.id == 4)].title

sets the item as "not supported" with error:

Failed: cannot extract value from json by path "$.books[?(@.id == 2 || @.id == 4)].title": unsupported character in json path starting with: "[?(@.id == 2 || @.id == 4)].title"
 

in Zabbix 4.2.6

Can you give more precise examples?
I tested similar setup and it worked
JSON:

{
    "store": {
        "book": [
            {
                "category": "reference",
                "author": "Nigel Rees",
                "title": "Sayings of the Century",
                "price": 8.95
            },
            {
                "category": "fiction",
                "author": "Evelyn Waugh",
                "title": "Sword of Honour",
                "price": 12.99
            },
            {
                "category": "fiction",
                "author": "Herman Melville",
                "title": "Moby Dick",
                "isbn": "0-553-21311-3",
                "price": 8.99
            },
            {
                "category": "fiction",
                "author": "J. R. R. Tolkien",
                "title": "The Lord of the Rings",
                "isbn": "0-395-19395-8",
                "price": 22.99
            }
        ],
        "bicycle": {
            "color": "red",
            "price": 19.95
        }
    },
    "expensive": 10
}

JSONpath:

$.store.book[?(@.price > 2 || @.price < 20)].title

Result:

[
   "Sayings of the Century",
   "Sword of Honour",
   "Moby Dick",
   "The Lord of the Rings"
]

The thread seems to have moved on to problems with json search. Please can I have a response to my question on the support for "$.*~" ?

It seems to work on some online evaluators, not on others. And on some that it does work, the results are different. So I'm not sure how is this suppose to work. I'll consult with the development team about it.

zux
The tilda (~) operator is a part of JsonPathPlus.
It is not supported by Zabbix JsonPath implementation.
This syntax and use case is described in this StackOverflow thread
If this is crucial, you may create a new feature request.

There already is a ZBXNEXT-5649 JsonPathPlus
Craig, can we agree, that the current implementation works as expected and close the case?

Yeah, close it off. I'll watch the new task with interest