nu_plugin_json_path

This nushell plugin is an attempt to enable the use of JSONPath. You can read more about JSONPath in the specification here.

Example Input

This json file is taken from the JSONPath link above.

{
  "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": 399
    }
  }
}

Syntax and Description

This table shows some example JSONPath syntax and the intended results for testing below.

#	JSONPath	Intended result
1	$.store.book[*].author	the authors of all books in the store
2	$..author	all authors
3	$.store.*	all things in store, which are some books and a red bicycle
4	$.store..price	the prices of everything in the store
5	$..book[2]	the third book
6	$..book[-1]	the last book in order
7	$..book[0,1]	the first two books
8	$..book[:2]	the first two books
9	$..book[?(@.isbn)]	all books with an ISBN number
10	$..book[?(@.price<10)]	all books cheaper than 10
11	$..*	all member values and array elements

Plugin Examples

I saved the above json in a file named test.json, which is also in the repository.

Example 1

open test.json | json path '$.store.book[*].author'

╭───┬──────────────────╮
│ 0 │ Nigel Rees       │
│ 1 │ Evelyn Waugh     │
│ 2 │ Herman Melville  │
│ 3 │ J. R. R. Tolkien │
╰───┴──────────────────╯

Example 2

open test.json | json path '$..author'

╭───┬──────────────────╮
│ 0 │ Nigel Rees       │
│ 1 │ Evelyn Waugh     │
│ 2 │ Herman Melville  │
│ 3 │ J. R. R. Tolkien │
╰───┴──────────────────╯

Example 3

open test.json | json path '$.store.*'

╭───┬───────────────────╮
│ 0 │ {record 2 fields} │
│ 1 │ [table 4 rows]    │
╰───┴───────────────────╯

open test.json | json path '$.store.*' | get 0

╭───────┬─────╮
│ color │ red │
│ price │ 399 │
╰───────┴─────╯

open test.json | json path '$.store.*' | get 1

╭───┬──────────────────┬───────────┬───────┬────────────────────────┬───────────────╮
│ # │      author      │ category  │ price │         title          │     isbn      │
├───┼──────────────────┼───────────┼───────┼────────────────────────┼───────────────┤
│ 0 │ Nigel Rees       │ reference │  8.95 │ Sayings of the Century │            ❎ │
│ 1 │ Evelyn Waugh     │ fiction   │ 12.99 │ Sword of Honour        │            ❎ │
│ 2 │ Herman Melville  │ fiction   │  8.99 │ Moby Dick              │ 0-553-21311-3 │
│ 3 │ J. R. R. Tolkien │ fiction   │ 22.99 │ The Lord of the Rings  │ 0-395-19395-8 │
╰───┴──────────────────┴───────────┴───────┴────────────────────────┴───────────────╯

Example 4

open test.json | json path '$.store..price'

╭───┬───────╮
│ 0 │   399 │
│ 1 │  8.95 │
│ 2 │ 12.99 │
│ 3 │  8.99 │
│ 4 │ 22.99 │
╰───┴───────╯

Example 5

open test.json | json path '$..book[2]'

╭───┬─────────────────┬──────────┬───────────────┬───────┬───────────╮
│ # │     author      │ category │     isbn      │ price │   title   │
├───┼─────────────────┼──────────┼───────────────┼───────┼───────────┤
│ 0 │ Herman Melville │ fiction  │ 0-553-21311-3 │  8.99 │ Moby Dick │
╰───┴─────────────────┴──────────┴───────────────┴───────┴───────────╯

Example 6

open test.json | json path '$..book[-1]'

╭───┬──────────────────┬──────────┬───────────────┬───────┬───────────────────────╮
│ # │      author      │ category │     isbn      │ price │         title         │
├───┼──────────────────┼──────────┼───────────────┼───────┼───────────────────────┤
│ 0 │ J. R. R. Tolkien │ fiction  │ 0-395-19395-8 │ 22.99 │ The Lord of the Rings │
╰───┴──────────────────┴──────────┴───────────────┴───────┴───────────────────────╯

Example 7

open test.json | json path '$..book[0,1]'

╭───┬──────────────┬───────────┬───────┬────────────────────────╮
│ # │    author    │ category  │ price │         title          │
├───┼──────────────┼───────────┼───────┼────────────────────────┤
│ 0 │ Nigel Rees   │ reference │  8.95 │ Sayings of the Century │
│ 1 │ Evelyn Waugh │ fiction   │ 12.99 │ Sword of Honour        │
╰───┴──────────────┴───────────┴───────┴────────────────────────╯

Example 8

open test.json | json path '$..book[:2]'

╭───┬──────────────┬───────────┬───────┬────────────────────────╮
│ # │    author    │ category  │ price │         title          │
├───┼──────────────┼───────────┼───────┼────────────────────────┤
│ 0 │ Nigel Rees   │ reference │  8.95 │ Sayings of the Century │
│ 1 │ Evelyn Waugh │ fiction   │ 12.99 │ Sword of Honour        │
╰───┴──────────────┴───────────┴───────┴────────────────────────╯

Example 9

open test.json | json path '$..book[?(@.isbn)]'

╭───┬──────────────────┬──────────┬───────────────┬───────┬───────────────────────╮
│ # │      author      │ category │     isbn      │ price │         title         │
├───┼──────────────────┼──────────┼───────────────┼───────┼───────────────────────┤
│ 0 │ Herman Melville  │ fiction  │ 0-553-21311-3 │  8.99 │ Moby Dick             │
│ 1 │ J. R. R. Tolkien │ fiction  │ 0-395-19395-8 │ 22.99 │ The Lord of the Rings │
╰───┴──────────────────┴──────────┴───────────────┴───────┴───────────────────────╯

Example 10

open test.json | json path '$..book[?(@.price<10)]'

╭───┬─────────────────┬───────────┬───────┬────────────────────────┬───────────────╮
│ # │     author      │ category  │ price │         title          │     isbn      │
├───┼─────────────────┼───────────┼───────┼────────────────────────┼───────────────┤
│ 0 │ Nigel Rees      │ reference │  8.95 │ Sayings of the Century │            ❎ │
│ 1 │ Herman Melville │ fiction   │  8.99 │ Moby Dick              │ 0-553-21311-3 │
╰───┴─────────────────┴───────────┴───────┴────────────────────────┴───────────────╯

Example 11

open test.json | json path '$..*'

╭────┬────────────────────────╮
│  0 │ {record 2 fields}      │
│  1 │ {record 2 fields}      │
│  2 │ [table 4 rows]         │
│  3 │ red                    │
│  4 │                    399 │
│  5 │ {record 4 fields}      │
│  6 │ {record 4 fields}      │
│  7 │ {record 5 fields}      │
│  8 │ {record 5 fields}      │
│  9 │ Nigel Rees             │
│ 10 │ reference              │
│ 11 │                   8.95 │
│ 12 │ Sayings of the Century │
│ 13 │ Evelyn Waugh           │
│ 14 │ fiction                │
│ 15 │                  12.99 │
│ 16 │ Sword of Honour        │
│ 17 │ Herman Melville        │
│ 18 │ fiction                │
│ 19 │ 0-553-21311-3          │
│ 20 │                   8.99 │
│ 21 │ Moby Dick              │
│ 22 │ J. R. R. Tolkien       │
│ 23 │ fiction                │
│ 24 │ 0-395-19395-8          │
│ 25 │                  22.99 │
│ 26 │ The Lord of the Rings  │
╰────┴────────────────────────╯

Building, Installing, and Registering

Since this plugin isn't published on crates.io, you will have to have the nushell repository cloned in order to build it.

This is a nushell script provided in the first issue. In that issue @amtoine explains, "as my repos are located in $env.GIT_REPOS_HOME/<host>/<owner>/<repo>, i had to run the following".

[nu-plugin nu-protocol] | each {|crate|
    let local = ($env.GIT_REPOS_HOME | path join "github.com" "nushell" "nushell" "crates" $crate)
    cargo add $crate --path $local
}

Once the cargo.toml is updated, all you have to do is cargo install --path . and then, from within nushell do a register /path/to/nu_plugin_json_path.

Good luck!