Codeblock flow-node

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This document describes a Codeblock flow-node and provides information on Codeblock flow-node.

The Codeblock flow-node configuration, metadata, functionality, methods, parameters, and outputs for the Greet Codeblock flow-node are described in the following sections. Each method in a Codeblock flow-node corresponds to a single codeblock. The Greet Codeblock flow-node is created when a new application is created, but it can be deleted.

Instance configuration (config)

The typical usage of code block flow-nodes 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:

Metadata example

// Greet.json

{
  "name": "Greet",
  "description": "Some codeblock to run with Greet flow",
  "path": "Greet.js",
  "parameter": {
    "additionalProperties": false,
    "properties": {
      "username": {
        "type": "string"
      }
    }
  },
  "outputs": {
    "next": {},
  "error": {}
  }
}

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

invoke(apibuilder, params, cb);

• apibuilder <APIBuilder> - The API Builder instance.
• params <Object> - Key/value pairs of parameters passed to the 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 node response.

Functionality example

// Greet.js

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

Method

The default method for the Greet Codeblock flow-node is:

• Greet - The codeblock to run with the greet flow.

Parameter

The Greet method parameter is:

Outputs

The Greet method outputs are: