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What is a JSON Action?

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 actions process JSON data, and convert it into specific data objects that can be used by PhixFlow for processing. The JSON action extracts one or more records from the provided JSON object using the JSON path specified.

For the full list of JSON action

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, see JSON Action Properties.

Creating JSON Actions

  1. Click and drag the 
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     icon from the toolbar onto the canvas
  2. Enter a name for the JSON action, then select Create Action
  3. In the JSON action 
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     on the right, populate the following details:
FieldDescriptionExample Value
NameName given to the JSON Node. This will be displayed on the Actionflow canvas.MyJSONReader
Input Expression

This field is mandatory.

The input expression provides the JSON data to be operated upon. Typically, this will be a simple expression pointing at an incoming attribute, such as, the body from a HTTP Node.

// Consists of the name of the connector and mapped attribute

in.body

Use Strict JSON parsing

Defines the parsing of the JSON. Disabled is lenient and enabled is strict.

Lenient parsing relaxes validation allowing the following to be present in the JSON data:

  • Use of single quotes, for example: {'name': 'Some “quotes” in a string'}
  • Unquoted field names, for example:  {name: “value”}
  • Unescaped control characters, including literal new lines to appear within a string.
  • Allow trailing commas {“name”: ”value”,}

// Leaving the default option

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Path

The JSON Path expression is evaluated against the data provided by the Input Expression and returns a list of JSON elements. It determines which elements are extracted from the JSON.

The path starts at the root element represented by $ and each element in the path is separated by a full stop. The ^ traverses up a node and a . traverses down the node.

Note that the path determines the number of nodes that are processed, which directly correlates to the number of records returned by the JSON action. For example, if the path returns the root element of the JSON, only one record will be returned. Whereas a path that returns children nodes will return one record for each child element.

// JSON Path

$.main_page.title


Tip

Use literal values or expressions encapsulated within ${} syntax, for example ${in.MyValue}.

4. 

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 all settings

Path Syntax

Expression Description

$ 

symbol refers to the root element.
@symbol refers to the current element.
. is the dot-child operator, which is used to denote a child element of the current element.
[ ] is used to select a child element of the current element (by name or index number).
*a wildcard, returning all elements regardless of their name.
^symbol is used to traverse up 1 element in the JSON hierarchy from child to parent. 

Output Attributes

JSON is converted into data objects that can be used by PhixFlow, this information is accessed using the syntax, _result.elementName.

In PhixFlow 12.1+, you can reference the values of previously calculated output attributes by using the syntax, _out.attributeName.

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ZB I think the references to elements on this page should be replaced with references to "keys". JSON comes in key/value pairs in the syntax "key":"pair" - see https://www.w3schools.com/js/js_json_syntax.asp. Need to read up on this and make changes to this page.


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Extracting Data Example

Below is an example JSON object passed to the JSON action:

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titleExample JSON
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// Example JSON string.
{
    "main_page": {
        "page": "PF Main Page",
        "title": {
            "name": "PF Title Text",
            "data": [
                {"initials": "AA", "value" : "Alistair Andrews"},
                {"initials": "BB", "value" : "Bert Brown"}
            ]
        }
    }
}

JSON Path: $.main_page.title

This path will bring back all elements matching the JSON path including the parent/grandparents and all child elements. The path defines the starting point from which we reference the JSON nodes.

The following examples show how to reference the returned JSON data:

  1. _result.name, returns PF Title Text
  2. _result.^.page, returns PF Main Page
    1. The ^ traverses up the JSON hierarchy
  3. listToString(_result.data.initials), returns "AA, BB"
    1. Because there are multiple JSON nodes under  _result.data.initials, an array of data is returned, see Array Handling Functions
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titleNote the use of
  • ^traverses up the hierarchy 1 layer.
  • . is the separator between nodes
  • using .. traverses down the hierarchy 1 layer.

Retrieving Field Names

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{
	"a": "1",
	"b": 2,
	"c": "xxx",
	"d": {
		"x": 1,
		"y": 2,
		"z": 3
	}
}

To retrieve the field names held in element d:

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do(
	$json = jsonToItems(in.JsonIn),
	$fields = getFields($json.d),
	$fields[1]
)

Returns the first field name of d which is “x” - see getFields.

Worked Example

Note

This example is taken from HTTP Action Configuration. If you have already completed this chapter as part of the Actionflow course, ensure you are familiar with the content before moving onto the next chapter.


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