AppSync Events Request

A lightweight TypeScript library for signing and publishing events to AWS AppSync Events APIs from Node.js environments (such as AWS Lambda functions).

Installation

npm install ob-appsync-events-request

Features

• Create signed requests to publish events to AppSync Events APIs
• Compatible with the Fetch API
• Includes TypeScript types
• Automatic credential resolution from environment
• Support for both standard AppSync domains and custom domains
• Batching of up to 5 events in a single request
• Designed for Node.js environments (AWS Lambda, EC2, etc.)
• Improved error messages for easier troubleshooting

Usage

import { PublishRequest } from "ob-appsync-events-request";

// Create a signed request
const request = await PublishRequest.signed(
  "https://your-appsync-domain.appsync-api.region.amazonaws.com/event",
  "/your/channel/path",
  { message: "Hello, world!" }
);

// Send the request using fetch
const response = await fetch(request);
const result = await response.json();
console.log(result);

Using with custom domains and IAM auth

const request = await PublishRequest.signed(
  {
    url: "https://your-custom-domain.com/event",
    region: "us-east-1", // Region is required for custom domains
  },
  "/your/channel/path",
  { message: "Hello, world!" }
);

Batch publishing (up to 5 events)

const request = await PublishRequest.signed(
  "https://your-appsync-domain.appsync-api.region.amazonaws.com/event",
  "/your/channel/path",
  { messageId: 1, content: "First message" },
  { messageId: 2, content: "Second message" },
  { messageId: 3, content: "Third message" }
);

Error Handling

The library provides clear error messages for common issues:

• When no events or more than 5 events are provided: The number of events to publish must be between 1 and 5
• When no input URL is provided: No input or url provided
• When region is missing for custom domains: Region not provided and not found in input url

Testing

The library includes a comprehensive test suite. To run the tests:

npm test

For development with continuous testing:

npm run test:watch

Documentation

For more information on AppSync Events, refer to the AWS AppSync Events API documentation.

License

ISC