JsonPath

Nuget: https://www.nuget.org/packages/JsonPath

Goal

Extract values from JSON:

• with single line expressions and simple CLR objects
• without foreach/if/cast constructs.
• Like XPath for XML, but for JSON and type safe.
• A wrapper for Json.NET.

Example

Extract the 42 from:

[ "1st", "2nd", { "aString": "Hello World", "aNumber": 42 } ]

with C#:

int fourtytwo = new Node(data)[2]["aNumber"];

Installation

From the Package Manager Console:

PM> Install-Package JsonPath

Requirements:

• .NET >= 3.5
• Json.NET (aka Newtonsoft.Json)

Syntax Examples

Extract the 42 from:

[ "1st", "2nd", { "aString": "Hello World", "aNumber": 42 } ]

You can do:

var json = new Node(data);
int fourtytwo = json[2]["aNumber"];

If you want to be more explicit:

var fourtytwo = json.AsList[2].AsDictionary["aNumber"].AsInt; // will return (int) 42
var fourtytwo = (int)json.AsList[2].AsDictionary["aNumber"]; // will return (int) 42
var fourtytwo = json.AsList[2].AsDictionary["aNumber"].AsString; // will return (string) "42"

Invalid keys do not throw exceptions. They return 0, empty string, or empty list:

int zero = json[1000]["noNumber"];

Of course, you can foreach a dictionary (aka JS object):

foreach (var pair in json[2]) {}

And iterate over a list (aka JS array):

for (int i = 0; i < json.Count; i++) {
    string value = json[i];
}

You can even LINQ it:

json[2].Where(pair => pair.Key == "aNumber").First().Value
(from x in json[2] where x.Key == "aNumber" select x.Value).First()

More Examples

Dive deep into this JSON with a single line of code:

var data = "[ { 
        aInt: 41, 
        bLong: 42000000000, 
        cBool: true, 
        dString: '43', 
        eFloat: 3.14159265358979323 
    }, { 
        fInt: 44, 
        gLong: 45000000000, 
        hString: "46"
    }, { 
        iList: [ 
            { jInt: 47, kString: '48' }, 
            { lInt: 49, mString: '50' }
        ], 
    }
]";

Using index notation:

 41  = (long) new JsonTree.Node(data)[0]["aInt"]
"50" = (string) new JsonTree.Node(data)[2]["iList"][1]["mString"]

The same with explicit notation:

 41  = (long) new JsonTree.Node(data).AsList[0].AsDictionary["aInt"].AsInt
"50" = (string) new JsonTree.Node(data).AsList[2].AsDictionary["iList"].List[1].Dictionary["mString"].AsString

The same with standard enumerators on CLR objects:

 41  = (long) new JsonTree.Node(data).AsList.ElementAt(0).AsDictionary.ElementAt(0).Value
"50" = (string) new JsonTree.Node(data).AsList.ElementAt(2).AsDictionary.ElementAt(0).Value.AsList.ElementAt(1).AsDictionary.ElementAt(1).Value

(testing VSGit 2)