node-red-s1seven-api

Introduction

This is a custom node that wraps the S1Seven API in several custom nodes that can be used in Node-Red. There is a separate node available for each endpoint which can be found in the S1Seven category in the Palette on the left-hand side of the screen.

The endpoints that are currently available are POST certificates/hash, POST certificates/validate, POST certificates/notarize, GET companies/:id, GET identities and POST tokens All of these nodes share a common API config node.

API config

This node must be declared at least once in your flow when you drop and configure a node from the S1Seven palette. It is used to store the clientId, clientSecret and environment that are required to authenticate with the S1Seven API. The environment property can be set to either production or staging. The clientId and clientSecret are the credentials generated in your application, you can learn more about these credentials in the user-manual. You can create as many API config as the number of applications you have. The name property is used to identify the properties store under the global context. Here's a list of the properties stored in the global context:

• S1SEVEN_ACCESS_TOKEN_${API_config_name} - The access token used to authenticate to the S1Seven API.
• S1SEVEN_BASE_URL_${API_config_name} - The base URL of the API where the requests will be sent.
• S1SEVEN_COMPANY_ID_${API_config_name} - The company id attached to the application from which the credentials originate.
• S1SEVEN_MODE_${API_config_name} - The mode under which the application is scopes (test or live).

Usage

To notarize, hash or validate a certificate, simply pass in a valid JSON certificate as msg.payload or add it to global.certificate. Each node is thoroughly documented with a help text in the sidebar. To access it, select an S1Seven node, and click on the book icon on the top right of the screen (underneath the Deploy button). There you can see what input is required by each individual node.

Each node simply takes the required input via the config ui or the msg object, and outputs the data property of the response.

Authentication

To authenticate a request, the nodes look for an access token in the msg.accessToken property or in the global context property bound to the config node. The access token is automatically set in the global context when a request is made from the get access token node. To use the get access token node, declare an API config node, and send a request.

Access tokens expire after 24 hours. There are several ways to automate the renewal of access tokens, one example can be seen below:

In the screenshot, the hash node has 2 outputs, the first labeled success, and the second fail. The fail output is linked to a switch node. The switch looks at the property msg.payload.statusCode and checks to see if the code is 401, which means the request is unauthorized. If the code is 401, it sends the payload to the get access token node, which automatically requests a new access token and makes available in the global context, along with the mode.

A minimal example of the above workflow can be imported here.

MQTT connection

You can connect to S1SEVEN Async API (via MQTT) dynamically by using the mqtt-connect subflow, a simple example can be copy pasted here

For this example to work you need to create an API config by using any of the methods described in the API config section. Then you need to configure the following properties :

• ApiConfigName to the name of the API config you which to reuse.
• Vhost which is mandatory field to authenticate to our broker. Note: you must contact S1SEVEN to get access to the Vhost.

Development

For development and testing purposes, the URL can be overridden by adding a .env file with an S1SEVEN_BASE_URL property. For example, having S1SEVEN_BASE_URL="http://localhost:4200" in your .env file will mean http://localhost:4200 is used instead of the default URL. If the S1SEVEN_BASE_URL property is not present in your .env file, the default URL will be used. NOTE: If S1SEVEN_BASE_URL is present in the .env file, the tests will fail. Remove the property if necessary so the tests will pass.

The constants.js file can be found in the resources folder, as that allows the variables to be shared with the frontend using Node-Red.

Creating new nodes

When adding new nodes, the following steps should be followed:

• If it doesn't exist create a folder with the name of the API resource in the lib folder. For example, if the API resource is users, create a folder called users in the lib folder.
• Create a file called <action>-<resource>.js in the folder created in the previous step. For example, if the action is get and the resource is users, create a file called get-users.js in the users folder.
• Follow the steps in the Node-RED documentation to create a new node.
• Text displayed to the user should be added to the locales, see the Internationalisation section for more information.
• The node should be added to the package.json file in the nodes property.
• A new tests suite should be added to the test folder. The tests should be named <action>-<resource>.test.js. For example, if the action is get and the resource is users, create a file called get-users.test.js in the test folder.

Node Abstraction

The []super-node.js](./lib/utils/super-node.js) file contains the common logic for the nodes. It is used to abstract the logic for the nodes, so that the nodes themselves are as simple as possible. It provides the following functions:

• retrieve dependencies from DI container (AsyncLocalStorage, Getters, AxiosHelpers) that makes interacting with the Node-RED runtime and S1SEVEN API easier.
• initialize AsyncLocalStore context and ensure it is cleaned up when the node event has been handled.
• retrieve the node configuration and credentials
• provide various getters to access node configuration
• provide an axios factory that configures default headers and base URL
• forward NodeRed node input event to the SuperNode msg event.

Usage example

/* This file is used to setup the DI container,
 * due to our tests setup we need to ensure that the container is set up before we require the node
 */
require('../utils/container').setupContainer();

module.exports = function (RED) {
  const { SuperNode } = require('../utils/super-node');

  function MyNode(config) {
    const node = new SuperNode(RED, config, this);
    node.on('msg', async (msg, send, done) => {
      const accessToken = node.getAccessToken();
      const mode = node.getApiMode();
      if (!accessToken) {
        node.warn('Bearer token not found');
        done();
        return;
      }

      const axios = node.createAxiosInstance();
      /* the requestHandler function is a wrapper around axios that handles the response and error cases
       * it will return an object with the following properties:
       * success: boolean
       * data: the response data if the request was successful, otherwise the error message
       *
       * It will also the send the msg to the first output if the request was successful, otherwise it will send it to the second output
       * The msg contains the following properties:
       * payload: the response data if the request was successful, otherwise the error response
       * headers: the response headers
       */
      const { success, data } = await node.requestHandler(
        axios.get('/applications'),
        send
      );

      !success && node.error(data);
      done();
    });
  }

  RED.nodes.registerType('my-node', MyNode);
};