emote-server

Backend for the Emote Widget

Installation & Deployment

Manual Deployment

1. Create an Heroku application:

heroku create <app-name>

2. Add Heroku Key-Value Support:

heroku addons:create heroku-redis:mini

3. Add Apache Kafka on Heroku Support:

heroku addons:create heroku-kafka:basic-0

4. Create an Apache Kafka Topic

heroku kafka:topics:create emotes

5. Deploy to Heroku

git push heroku main

Local Development

Enable pnpm with corepack:

corepack use pnpm

Install dependencies:

pnpm install

Run Server in development mode:

pnpm run start:dev

Configuration

• REDIS_URL - A Redis connection string
• KAFKA_CLIENT_CERT - Kafka client certificate
• KAFKA_CLIENT_CERT_KEY - Kafka client private key
• KAFKA_PREFIX - Kafka prefix (For multitenant plans on Heroku)
• KAFKA_TRUSTED_CERT - Kafka trusted certificate
• KAFKA_URL - Kafka brokers urls
• RATE_LIMIT_ENABLE - Enable rate limitting (Default: true)
• RATE_LIMIT_MAX - Max number of requests per time window (Default: 400)
• RATE_LIMIT_WINDOW - Duration of the Rate Limit time window (Default: 1 minute)
• HEARTBEAT_TIMEOUT - Duration of the Heartbeat (Default: 30 seconds)
• EVENT_ID_LENGTH - Max length of an Event ID (Default: 32 characters)
• EVENTS_MAX - Max number of Event Streams (Default: 32)

API

GET /api/emote/:id

Returns the votes by Event

Url Parameters

• id - Represents an Event by ID

Output

{
  "smile": 100,
  "love": 103,
  "plus_one": 5,
  "question": 1
}

POST /api/emote/:id

Submit a vote by Event

Url Parameters

• id - Represents an Event by ID

Body

{
  "emote": "smile"
}

Output (200 - Success)

Body

{
  "message": "emote received"
}

Output (429 - Rate Limit)

Headers

retry-after: 60000
x-ratelimit-limit: 100
x-ratelimit-remaining: 0
x-ratelimit-reset: 39

Body

{
  "error": "Too Many Requests",
  "message": "Rate limit exceeded, retry in 1 minute",
  "statusCode": 429
}

GET /api/events/:id

Connect to an event stream by Event ID

Events

• emote - An emote has been received - (data: smile)
• votes - A votes state object has been received (data: {"smile": 1, "question": 3})