Get

Overview

The Get Block extracts data from a JSON object or list using a JSONPath expression. JSONPath is a query language for navigating and extracting elements from JSON structures. This implementation uses the jsonpath-ng library from PyPI.

You can configure the JSONPath expression via the path parameter, and the Block will return the extracted data based on that path.

Description

Uses JSONPath to extract data from a JSON object or list. JSONPath implementation is from https://pypi.org/project/jsonpath-ng/

Metadata

• Category: Function

Configuration Options

Name	Data Type	Description	Default Value
path	str

Inputs

Name	Data Type	Description
data	list[Any] or dict[str, Any]

Outputs

Name	Data Type	Description
result	Any

State Variables

No state variables available.

Example(s)

Example 1: Extract a field from a JSON object

• Create a Get Block.
• Set the path to $.name (this JSONPath expression extracts the "name" field).
• Provide the input JSON object: {"name": "John", "age": 30}.
• The Block will output "John", extracting the "name" field.

Example 2: Extract multiple fields from a list of JSON objects

• Set up a Get Block.
• Set the path to $[*].name (this JSONPath expression extracts the "name" field from all objects in the list).
• Provide the input JSON list: [{"name": "John"}, {"name": "Jane"}].
• The Block will output ["John", "Jane"].

Example 3: Handle nested fields in a complex JSON structure

• Create a Get Block.
• Set the path to $.address.city.
• Provide the input: {"address": {"city": "Auckland", "postcode": "1010"}}.
• The Block will output "Auckland", extracting the "city" field from the nested "address" object.

Error Handling

• If the path is not a valid JSONPath expression, the Block will raise an error.
• If no match is found for the JSONPath, the Block will return None for individual JSON objects or an empty list for lists.
• Ensure the input JSON is well-formed; otherwise, the Block may raise an error.

FAQ

What happens if the JSONPath expression doesn't match any field?

If the JSONPath expression does not match any field in the input, the Block will return None for a single JSON object and an empty list for a list of JSON objects.

Can I use this Block for both JSON objects and lists?

Yes, the Get Block supports both JSON objects and lists. For lists, it will return all matching fields as a list of values. For single JSON objects, it will return the first match or None if no match is found.

How does the Block handle nested fields?

The Get Block uses JSONPath expressions to navigate and extract fields from nested JSON structures. By specifying the correct path, you can extract deeply nested fields from JSON objects.

What happens if multiple matches are found?

For lists, the Get Block will return all matching elements. For a single JSON object, the Block returns only the first match found. If you need all matches from an object, you should ensure the input is structured as a list.