reso.js

reso.js is a Node.js client for interacting with RESO Web API services, fully aligned with the current RESO Web API specification.

It includes features like custom request/response hooks, automatic authentication token refresh, and built-in rate limiting.

Table of Contents

• Installation
• Compatibility
• Usage
  • Getting Started
    • Bearer Token Authentication
    • Client Credentials Authentication
  • Querying the API
    • readByQuery
    • readById
  • Fetching $metadata
  • Rate Limiting
  • Hooks
  • Error Handling
• Contributing
• License

Installation

Install with your preferred package manager:

pnpm add reso.js
# or
npm install reso.js
# or
yarn add reso.js

Compatibility

This library works with any RESO-compliant server following the RESO Web API spec. Additionally, it provides official support for:

• Spark Platform
• Trestle
• Bridge Interactive
• MLS Grid

Usage

Getting Started

reso.js supports both Bearer Token and Client Credentials authentication strategies. Refer to your feed's documentation for your feeds supported strategy and how to obtain credentials.

Bearer Token Authentication

import { createFeed } from 'reso.js';

const feed = createFeed({
	http: {
		baseURL: 'http://my-reso-api.com',
	},
	auth: {
		type: 'token',
		credentials: {
			token: 'MY_TOKEN',
		},
	},
});

The bearer token provided must not expire.

Client Credentials Authentication

import { createFeed } from 'reso.js';

const feed = createFeed({
	http: {
		baseURL: 'http://my-reso-api.com',
	},
	auth: {
		type: 'credentials',
		 credentials :{
      tokenURL: 'http://my-reso-api.com/token'
      clientId: 'MY_CLIENT_ID'
      clientSecret: 'MY_CLIENT_SECRET'
    }
	},
});

You can optionally include grantType and scope. Tokens will automatically refresh 30 seconds before expiry by default.

To custom the refresh buffer it can be passed in the with the auth strategy:

import { createFeed } from 'reso.js';

const feed = createFeed({
	http: {
		baseURL: 'http://my-reso-api.com',
	},
	auth: {
		type: 'credentials',
    credentials :{
      tokenURL: 'http://my-reso-api.com/token'
      clientId: 'MY_CLIENT_ID'
      clientSecret: 'MY_CLIENT_SECRET'
    },
		refreshBuffer:40000,
	},
});

Querying the API

readByQuery

Perform a RESO-compliant query. The function is an async generator that will auto paginate any next pages if the nextLink is present every time .next() is called or the result is looped over.

for await (let properties of feed.readByQuery('Property', '$filter=ListPrice gt 100000')) {
	for (property of properties.values) {
		console.log(property);
	}
}

readById

Retrieve a specific record by ID:

const myProperty = await feed.readyById('Property', 123);
console.log(myProperty.value);

Fetching $metadata

Get the feed’s metadata XML:

const metadata = await feed.$metadata();
console.log(metadata);

Rate Limiting

Rate limiting is built-in for supported providers. You can also customize limits:

const feed = createFeed({
	http: {
		baseURL: 'http://my-reso-api.com',
	},
	limiter: {
		duration: 30000, // 30 seconds
		points: 5, // max 5 requests per duration
	},
});

duration defines the time window in milliseconds, and points sets the maximum number of requests allowed within that window.

Hooks

The clients behaviour can be customized with the following supported hooks:

• onRequest
• onRequestError
• onResponse
• onResponseError

These are backed by ofetch interceptors. Additional hooks will be added/supported as needed.

Example – Appending /replication to Property requests:

hooks: {
  onRequest: [
    ({ request }) => {
      if (request.toLowerCase().includes('property')) {
        request += '/replication';
      }
    },
  ],
},

Error Handling

The client throws a FeedError with detailed RESO error info:

try {
	const myProperty = await feed.readById('Property', 123);
	console.log(myProperty.value);
} catch (error) {
	if (error instanceof FeedError) {
		console.log(error.details);
	}
}

Contributing

Bug reports, pull requests and feature discussions are welcome on GitHub

License

MIT License