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Overview
Use a
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There are three types of supported looping:
Polling, repeating the same operation multiple times with the same parameters until a desired result is obtained and then generating a single output record. Output results are only generated at the end of the iterations. For example, polling an HTTP API until the results are available.
Accumulation, repeating the same operation multiple times, where each iteration accumulates the progress results and triggers the next iteration with the updated result. Generates a single output record. For example, calling the DB to get the parent record, and repeating with the parent until the root has been reached.
Paging, repeating an operation multiple times with different parameters and generating the next parameters with a set of output records for each iteration of the loop. For example, reading from a paging API, where each iteration gives you the link for the next iteration, and a set of output records.
Start Loop and End Loop
Loops consist of a
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The key concept of a loop is that the attributes passed into it are available as a passthrough and mapped in attributes. This allows for the original passthrough value to be referenced and if the loop is manipulating the incoming attribute, for example incrementing a number, this is also available. The mapped attributes that are manipulated by the loop are shown with a loop icon, passthrough attributes will be shown with the icon of where they come from for example a calculated action.
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Basic Settings
Field | Description | Example Value |
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Name | Name The name given to the action node . This will be and displayed on the actionflow canvas. | MyJSONReader |
Input Expression | 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 an HTTP Action or the body from an API request. | // consist of the name of the pipe and the name of a // mapped attribute.
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Use Strict JSON parsing | Defines the parsing of the JSON, disabled will be lenient and enabled will be strict. Lenient parsing relaxes validation allowing the following to be present in the JSON data:
| // leaving the default option Disabled. |
Path | The JSON Path expression is evaluated against the data provided by the Input Expression and returns a list of JSON node items. It can be used to specify which nodes are extracted from the JSON. | // JSON Path $.main_page.title My Loop |
End Loop Action | A read-only field that states the end loop action associated with the start loop action. | // The End Loop Action will initially take the name of the Start Loop // Action and prefix it with "end".
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Output Connection Points
This section has a toolbar with standard buttons. The grid contains a list of all output connection points.
- To add a new output path, in the section toolbar click
to open a new output path and set the expression; see Output Connection Points.Insert excerpt _add _add nopanel true - To edit an existing output path, double-click it in the list to open its properties.
- To remove an output path, select one and in the section toolbar click
.Insert excerpt _delete _delete nopanel true
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Basic Settings
Field | Description | Example Value |
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Name | The name given to the action node and displayed on the canvas. The name will default to the Start Loop name prefixed with end. | End My Loop |
Output Mode | A read-only field that states the end loop action associated with the start loop action. | // The End Loop Action will initially take the name of the Start Loop // Action and prefix it with "end".
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Until Expression | An expression that is checked on each cycle of the loop, and once the expression returns true the loop will end. | // Where myValue is being sent into the End Loop Action on a pipe // called in.
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Max Loops | This is a safety net designed to stop infinite loops. The number entered here will stop | //Defaults to 10000 10000 |
Input Connection Points
Can Accept a single
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The grid contains a list of all input connection points and their type.
- To add a new input connection point, in the section toolbar click
to open a new input connection point and set its properties; see Input Connection Points.Insert excerpt _add _add nopanel true - To edit an existing input connection point, double-click it in the list to open its properties.
- To remove an input connection point, select one and in the section toolbar click
.Insert excerpt _delete _delete nopanel true
Output Connection Points
This section has a toolbar with standard buttons. The grid contains a list of all output connection points.
- To add a new output path, in the section toolbar click
to open a new output path and set the expression; see Output Connection Points.Insert excerpt _add _add nopanel true - To edit an existing output path, double-click it in the list to open its properties.
- To remove an output path, select one and in the section toolbar click
.Insert excerpt _delete _delete nopanel true
Output Attributes
JSON is converted into data objects that can be used by PhixFlow, this information is accessed using the syntax, _result.
AttributeName.
Worked Example
Below is an example JSON object passed to the JSON Action Node:
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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:
_result
.name
, returns PF Title Text_result
.^.page
, returns PF Main Page- The ^ traverses up the JSON hierarchy.
listToString(_result.data.initials)
, returns "AA, BB"- Because there are multiple JSON nodes under
_result.data.initials
, an array of data is returned. See Array Handling Functions.
- Because there are multiple JSON nodes under
title | Note the use of |
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^
traverses up the hierarchy 1 layer.- .
Learn More
For links to all pages in this topic, see Understanding Actionflows.