JSON Parser

The JSON parser is used for parsing incoming JSON data. To use it set decoder to json and use a JSON path in your schema’s source.

To parse newline delimited JSON data set the engine to ndjson. Each row will be treated as a separate JSON document.

JSON Path Syntax

Code	Description
.	The dot operator is used to denote a child element of the current element e.g. parent.child.
*	Wildcard matching 0+ characters e.g. foo* matches foo as well as foobar.
?	Wildcard matching any 1 character e.g. fo? matches foo, not foobar.
\	Used to escape special characters such as ., * and ?.

Any source starting with a dot (.) will be considered a relative path and use the parent schema’s source as the root.
If the parent schema has the array type it will resolve to an element of that array.

You can test out your JSON paths on the GJSON Playground.

Examples

JSON

Incoming data:

{
  "data": {
    "person": {
      "name": "Alice",
      "age": 29,
      "friends": [
        {
          "name": "Bob",
          "age": 34
        },
        {
          "name": "Carol",
          "age": 47
        }
      ]
    }
  }
}

Decoder configuration:

decoder: json
schema:
  type: object
  source: data.person # could be omitted if we weren't using a relative path for the `name` property below
  properties:
    name:
      type: string
      source: .name # as the path starts with a dot it is a relative path from the parent (i.e. `data.person`)
    age:
      type: integer
      source: data.person.age
    friends:
      type: array
      source: data.person.friends
      items:
        type: object
        properties:
          name:
            type: string
            source: .name # since the parent is an array paths starting with a dot will be resolved to the array's items
          age:
            type: integer
            source: .age

Output:

name: Alice
age: 29
friends:
  - name: Bob
    age: 34
  - name: Carol
    age: 47

Newline Delimited JSON

Incoming data:

{ "name": "Alice", "age": 29 }
{ "name": "Bob", "age": 34 }
{ "name": "Carol", "age": 47 }

Decoder configuration:

decoder: json
schema:
  type: object
  properties:
    name:
      type: string
    age:
      type: integer

Output:

- name: Alice
  age: 29

- name: Bob
  age: 34

- name: Carol
  age: 47