EAI-NODEJS SDK Documentation

Overview

This SDK provides a RabbitMQ message processor, API adapter for fetching data with authentication, and a transformer for applying dynamic transformations to data using JSONata expressions.

It enables easy integration with external APIs, processes RabbitMQ messages, and transforms data dynamically.

Table of Contents

1. Modules
2. Installation
3. API Reference
   • getAuthToken(apiUrl, apiKey)
   • fetchData(apiUrl, token)
   • transformData(data, expression)
   • processMessage(message)
   • startListener(rabbitMQUrl, queueName, handleMessage)
   • sendMessage(msg, config)

Modules

1. Adapter Module (/lib/adapter/apiAdapter.js)

Handles authentication and data fetching from an API.

2. Queue Processor (/lib/queue/processMessage.js)

Processes the RabbitMQ messages by fetching data, transforming it, and further processing it.

3. RabbitMQ Listener (/lib/queue/rabbitmqListener.js)

Listens to RabbitMQ queues and triggers the message processing.

4. Data Transformer (/lib/transformer/dataTransformer.js)

Transforms data using dynamic JSONata expressions.

Installation

To install this package, run:

npm install eai-sdk

API Reference

getAuthToken(apiUrl, apiKey)

Fetches an authentication token from the specified API URL using the provided API key.

Parameters:

• apiUrl: String - The URL of the API to authenticate against.
• apiKey: String - The API key used for authentication.

Returns:

• Object - The response object containing the token.

Example:

const token = await getAuthToken('https://api.example.com/auth', 'your-api-key');

fetchData(apiUrl, token)

Fetches data from the specified API URL using the provided token.

Parameters:

• apiUrl: String - The URL of the API to fetch data from.
• token: String - The authentication token.

Returns:

• Object - The data fetched from the API.

Example:

const data = await fetchData('https://api.example.com/data', token);

transformData(data, expression)

Transforms data using a JSONata expression.

Parameters:

• data: Object - The data to be transformed.
• expression: String - A JSONata expression used to transform the data.

Returns:

• Object - The transformed data.

Example:

const transformedData = transformData(data, '$.name');

processMessage(message)

Processes a RabbitMQ message by fetching data using the API adapter, transforming it, and logging the transformed data.

Parameters:

• message: Object - The message received from RabbitMQ containing the token, apiUrl, and transformationExpression.

Example:

const message = {
  token: 'your-token-key',
  apiUrl: 'https://api.example.com/data',
  transformationExpression: '$.name'
};
await processMessage(message);

startListener(rabbitMQUrl, queueName, handleMessage)

Starts a RabbitMQ listener that processes messages from the specified queue.

Parameters:

• rabbitMQUrl: String - The RabbitMQ server URL.
• queueName: String - The name of the queue to listen to.
• handleMessage: Function - A callback function to process each message.

Example:

startListener('amqp://localhost', 'my_queue', processMessage);

sendMessage(msg, config)

Sends a message to a specified RabbitMQ queue.

Parameters:

• msg: Object - The message to send.
• config: Object - Configuration object containing url (RabbitMQ server URL) and outputQueue (the queue name).

Returns:

• Promise - Resolves when the message is successfully sent.

Example:

const config = {
  url: 'amqp://localhost',
  outputQueue: 'output_queue'
};

const message = { key: 'value' };

await sendMessage(message, config);

Error Handling

Each module includes basic error handling, ensuring that errors encountered during API requests, message processing, or message sending are caught and logged.

Example:

try {
    const token = await getAuthToken(apiUrl, apiKey);
} catch (error) {
    console.error('Failed to fetch auth token:', error);
}

This documentation outlines how to use each component of the library, with examples for setting up RabbitMQ listeners, fetching API data, transforming it, and pushing messages back to RabbitMQ.