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

``bash
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

`typescript
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);
`

$3

`typescript
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!" }
);
`

$3

`typescript
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:

`bash
npm test
`

For development with continuous testing:

`bash
npm run test:watch
``

Documentation

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

License

ISC