Menu
Most examples deal with the book store example from Stefan Gössner, however I'm struggling to define the correct JsonPath expression for a simple object (no array):
{ "Id": 1, "Name": "Test" }
To check if this json contains Id = 1.
I tried the following expression: $..?[(@.Id == 1]), but this does find any matches using Json.NET?
Also tried Manatee.Json for parsing, and there it seems the jsonpath expression could be like $[?($.Id == 1)] ?
917
JsonPath expressions always refer to a JSON structure in the same way as XPath expression are used in combination with an XML document. The "root member object" in JsonPath is always referred to as $ regardless if it is an object or array. JsonPath expressions can use the dot–notation.
3.3. JsonPath also has functions that we can use at the end of a path to synthesize that path's output expressions: min(), max(), avg(), stddev() and length(). Finally, we have filters. These are boolean expressions to restrict returned lists of nodes to only those that calling methods need.
You use a JSONPath expression to traverse the path to an element in the JSON structure. You start at the root node or element, represented by $, and reach the required element in the JSON structure to extract data from it. You can use either the dot-notation or the bracket-notation to form the expressions.
JSONPath creates a uniform standard and syntax to define different parts of a JSON document. JSONPath defines expressions to traverse through a JSON document to reach to a subset of the JSON. This topic is best understood by seeing it in action. We have created a web page which can help you evaluate a JSONPath.
The path that you posted is not valid. I think you meant $..[?(@.Id == 1)] (some characters were out of order). My answer assumes this.
The JSON Path that you're using indicates that the item you're looking for should be in an array.
$ start
.. recursive search (1)
[ array item specification
?( item-based query
@.Id == 1 where the item is an object with an "Id" with value == 1 at the root
) end item-based query
] end array item specification
(1) the conditions following this could match a value no matter how deep in the hierarchy it exists
You want to just navigate the object directly. Using $.Id will return 1, which you can validate in your application.
All of that said...
It sounds to me like you want to validate that the Id property is 1 rather than to search an array for an object where the Id property is 1. To do this, you want JSON Schema, not JSON Path.
JSON Path is a query language for searching for values which meet certain conditions (e.g. an object where Id == 1.
JSON Schema is for validating that the JSON meet certain requirements (your data's in the right shape). A JSON Schema to validate that your object has a value of 1 could be something like
{
"properties": {
"Id": {"const":1}
}
}
Granted this isn't very useful because it'll only validate that the Id property is 1, which ideally should only be true for one object.
65
If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
Donate Us With
