Class JsonTransformer

Provides functionality for applying a JMESPath expression to transform a JSON document into another JSON document

Inheritance

System.Object

JsonTransformer

Inherited Members

System.Object.Equals(System.Object)

System.Object.Equals(System.Object, System.Object)

System.Object.GetHashCode()

System.Object.GetType()

System.Object.MemberwiseClone()

System.Object.ReferenceEquals(System.Object, System.Object)

System.Object.ToString()

Namespace: JsonCons.JmesPath

Assembly: JsonCons.JmesPath.dll

Syntax

public sealed class JsonTransformer

Examples

The following example shows how to apply a JMESPath expression to transform a JSON document into another JSON document.

using System;
using System.Text.Json;
using JsonCons.JmesPath;

public class Example
{
    public static void Main()
    {
   string jsonString = @"
{
""people"": [
{
  ""age"": 20,
  ""other"": ""foo"",
  ""name"": ""Bob""
},
{
  ""age"": 25,
  ""other"": ""bar"",
  ""name"": ""Fred""
},
{
 ""age"": 30,
 ""other"": ""baz"",
 ""name"": ""George""
}
]
}
   ";

   using JsonDocument doc = JsonDocument.Parse(jsonString);

   var transformer = JsonTransformer.Parse("people[?age > `20`].[name, age]");

   using JsonDocument result = transformer.Transform(doc.RootElement);

   var serializerOptions = new JsonSerializerOptions() {WriteIndented = true};
   Console.WriteLine(JsonSerializer.Serialize(result.RootElement, serializerOptions));
}

Output:

[
  [
    "Fred",
    25
  ],
  [
    "George",
    30
  ]
]

Methods

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Parse(String)

Parses a JMESPath string into a JsonTransformer, for "parse once, use many times". A JsonTransformer instance is thread safe and has no mutable state.

Declaration

public static JsonTransformer Parse(string jmesPath)

Parameters

Type	Name	Description
System.String	jmesPath	A JMESPath string.

Returns

Type	Description
JsonTransformer	A JsonTransformer.

Exceptions

Type	Condition
JmesPathParseException	The `jmesPath` parameter is not a valid JMESPath expression.
System.ArgumentNullException	The `jmesPath` is null.

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Transform(JsonElement)

Applies a JMESPath expression to a JSON document to transform it into another Json document.

Declaration

public JsonDocument Transform(JsonElement doc)

Parameters

Type	Name	Description
System.Text.Json.JsonElement	doc	The provided JSON document.

Returns

Type	Description
System.Text.Json.JsonDocument	The transformed JSON document. If a type error is detected in a function call, a JSON null value is returned.

Remarks

It is the users responsibilty to properly Dispose the returned System.Text.Json.JsonDocument value

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Transform(JsonElement, String)

Applies a JMESPath expression to a JSON document to transform it into another Json document. This method parses and applies the expression in one operation.

Declaration

public static JsonDocument Transform(JsonElement doc, string jmesPath)

Parameters

Type	Name	Description
System.Text.Json.JsonElement	doc	The provided JSON document.
System.String	jmesPath	A JMESPath string.

Returns

Type	Description
System.Text.Json.JsonDocument	The transformed JSON document.

Remarks

It is the users responsibilty to properly Dispose the returned System.Text.Json.JsonDocument value

Exceptions

Type	Condition
JmesPathParseException	The `jmesPath` parameter is not a valid JMESPath expression.
System.ArgumentNullException	The `jmesPath` is null.