JsonCons.JsonPath 1.0.0-preview.2

JsonCons.JsonPath

The JsonCons.JsonPath library complements the functionality of the System.Text.Json namespace with an implementation of Stefan Goessner's JsonPath. This implementation has the following features:

• It is based on a hand-constructed finite state machine that follows a formal grammar described in an ABNF grammar with specification.

• The basic features are largely compatible with the loose consensus seen in Christoph Burgmer's comparison of 41 JSONPath implementations.

• Names in the dot notation may be unquoted (no spaces), single-quoted, or double-quoted.

• Names in the square bracket notation may be single-quoted or double-quoted.

• Unions of separate JSONPath expressions are allowed, e.g.

  $..[@.firstName,@.address.city]

• Fiter expressions, e.g. $..book[?(@.price<10)], may omit the enclosing parentheses, like so $..book[?@.price<10].

• It supports a parent operator ^ for providing access to the parent node, borrowed from JSONPath Plus.

For example, given a system.text.json.JsonDocument obtained as

string jsonString = @"
{
    ""books"":
    [
        {
            ""title"" : ""A Wild Sheep Chase"",
            ""author"" : ""Haruki Murakami"",
            ""price"" : 22.72
        },
        {
            ""title"" : ""The Night Watch"",
            ""author"" : ""Sergei Lukyanenko"",
            ""price"" : 23.58
        },
        {
            ""title"" : ""The Comedians"",
            ""author"" : ""Graham Greene"",
            ""price"" : 21.99
        },
        {
            ""title"" : ""The Night Watch"",
            ""author"" : ""David Atlee Phillips"",
            ""price"" : 260.90
        }
    ]
}";

using JsonDocument doc = JsonDocument.Parse(jsonString);

the JsonCons.JsonPath.JsonSelector class provides functionality to retrieve elements in the JSON document selected according to some criteria,

var selector = JsonSelector.Parse("$.books[?(@.price >= 22 && @.price < 30)]");

IList<JsonElement> elements = selector.Select(doc.RootElement);

The JsonCons.JsonPath library targets .Net Standard 2.1. Reference documentation is available here

Code examples may be found at:

JSONPath examples

Acknowledgements

• Credit to Stefan Goessner's JsonPath, the original JSONPath.

• The specification of JsonCons JsonPath draws heavily on Christoph Burgmer's JSONPath Comparison. Many of the test cases and some of the examples are borrowed from this resource.

• The specification of JSONPath filter expressions is greatly influenced by James Saryerwinnie's JMESPath