JSONPath - bobbae/gcp GitHub Wiki

JSONPath is a query language for JSON, similar to XPath for XML.

JSONPath expressions always refer to a JSON structure in the same way as XPath expressions are used in combination with an XML document. Since a JSON structure is usually anonymous and doesn't necessarily have a "root member object" JSONPath assumes the abstract name $ assigned to the outer level object.

JSONPath expressions can use the dot–notation

$.store.book[0].title

or the bracket–notation

$['store']['book'][0]['title']

for input paths. Internal or output paths will always be converted to the more general bracket–notation.

Example

Given JSON structure:

{ "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
    }
  }
}

XPath	JSONPath	Result
/store/book/author	$.store.book[*].author	the authors of all books in the store
//author	$..author	all authors
/store/*	$.store.*	all things in store, which are some books and a red bicycle.
/store//price	$.store..price	the price of everything in the store.
//book[3]	$..book[2]	the third book
//book[last()]	$..book[(@.length-1)] or $..book[-1:]	the last book in order.
//book[position()<3]	$..book[0,1] or $..book[:2]	the first two books
//book[isbn]	$..book[?(@.isbn)]	filter all books with isbn number
//book[price<10]	$..book[?(@.price<10)]	filter all books cheapier than 10
//*	$..*	all Elements in XML document. All members of JSON structure.

jq

jq is like sed for JSON data - you can use it to slice and filter and map and transform structured data with the same ease that sed, awk, grep and friends let you play with text.

The syntax used by jq is not JSONPath. It is a custom syntax. https://stedolan.github.io/jq/manual/

jq, while being more powerful than JSONPath, nevertheless enables one to write queries that are usually as simple as, and sometimes even simpler than, the corresponding JSONPath queries.

For example, the XPath expression:

/store/book[1]/title

would look like this in JSONPath:

$.store.book[0].title

and like this in JSON Pointer:

/store/book/0/title

and like this in jq:

.store.book[0].title

One important point about jq here is that jq is stream-oriented: the jq expression shown above can be run not just against a single object, but also against a stream of objects.

In general, given a stream of JSON entities as input, jq will produce a stream of outputs. The input entities may be any mix of any JSON types, not just objects or arrays.

https://github.com/stedolan/jq/wiki/For-JSONPath-users

jp

jp is a program that can be used to grok json at the command line via path expressions.

Dpath

https://github.com/dpath-maintainers/dpath-python