Nodes - Codeblock

This document describes a Codeblock flow-node and provides information on Codeblock flow-node configuration, metadata, and functionality.

Name Description
Codeblock A flow-node that can be used for executing user code and returns the response. This flow-node allows custom business logic to be executed as part of the flow.

Instance configuration (config)

Property Description Required Type
method The name of the Codeblock to execute. yes string

The typical usage of code blocks in a flow involves setting parameters, mapping responses, and setting required configs as noted in the example below.

Configuration example

"block.0": {
 "type": "Codeblock",
 "config": {
   "method": "Greet"
 },
 "parameters": [
   {
     "name": "username",
     "value": "$.params.username"
   }
 ],
 "response": {
   "context": {
     "$": "greeting"
   },
   "routes": null
 }
}

Metadata

Codeblock metadata should be included in the /codeblocks directory of an API Builder Project. It is defined as a JSON file with the following properties:

Property

Description

Required

Type

name

The name of the Codeblock

yes

string

description

The description of the Codeblock

yes

string

path

The relative path to the function to be invoked.

yes

string

Metadata example

{
  "name": "Greet",
  "description": "Some codeblock to run with Greet flow",
  "path": "Greet.js"
}

Functionality

The functional part of a Codeblock should be a .js file which exports a function of the following signature:

invoke(arrow, params, cb);

  • arrow <Arrow> - The API Builder instance.

  • params <Object> - Key/value pairs of parameters passed to the flow-node instance.

  • cb <Function> - Callback.

    • err - Error. Passing this will cause the flow to cease processing and a 500 error to be returned from the endpoint which called it.

    • response - The data to be returned as the flow-node response.

Icon

Most of the time errors should be returned in the callback as a standard response. Using the first parameter to return errors is the same as throwing an error in the Codeblock and should rarely need to be used.

Functionality example

 

function invoke(arrow, params, cb) {
    const salutation = arrow.config.helloworld.salutation;
    if (!params.username) {
        return cb(null, {
            error: 'Invalid name'
        });
    }
    const body = salutation + ' ' + params.username;
    cb(null, body);
}
exports = module.exports = invoke

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