Leaderboard API

Simple Serverless Leaderboard API. It uses

• AWS API Gateway and AWS Lambda to serve this Web API with Serverless model.
• Redis to control the concurrent updates on the same ranking document.
• S3 to store it as permanently.

Since you are using Redis, strictly speaking, this is not Serverless. This dependency will be removed in the future by implementing the web-based state management for ActorSystem's concurrency control.

Documentation

GET

Get all

Request GET to /{serviceId}/{period}?limit=<number> with a header X-User for userId, then it returns by this form.

interface IRankRecord {
  rank: number;
  user: string;
  score: string;
}
interface IRankView {
  me: IRankRecord;
  top: IRankRecord[];
  around: IRankRecord[];
}

• around means some records near my rank which contains my rank, too.
• score should be string because its value is bigger than Number.MAX_SAFE_INTEGER.
• me and around field can be undefined when there is no my record.

$ curl "https://API-DOMAIN/STAGE/service_id/period" -H "X-User: test"
{
  "top": [
    {
      "rank": 321,
      "user": "test",
      "score": "123456789123456789"
    },
    ...
  ],
  "around": [
    ...,
    {
      "rank": 321,
      "user": "test",
      "score": "123456789123456789"
    },
    ...
  ],
  "my": {
    "rank": 321,
    "user": "test",
    "score": "123456789123456789"
  },
}

Get me only

Request GET to /{serviceId}/{period}/me with a header X-User for userId.

$ curl "https://API-DOMAIN/STAGE/service_id/period/me" -H "X-User: test"
{
  "rank": 321,
  "user": "test",
  "score": "123456789123456789"
}

Get top with offset and limit

Request GET to /{serviceId}/{period}/top?offset=<number>&limit=<number>.

$ curl "https://API-DOMAIN/STAGE/service_id/period/top?offset=0&limit=10"
[{
  "rank": 1,
  "user": "test",
  "score": "123456789123456789"
}, ...]

Get around with limit

Request GET to /{serviceId}/{period}/around?limit=<number> with a header X-User for userId.

$ curl "https://API-DOMAIN/STAGE/service_id/period/around?limit=10" -H "X-User: test"
[..., {
  "rank": 321,
  "user": "test",
  "score": "123456789123456789"
}, ...]

Scrolling from the result

If you want to see more rankings from the current result, please request GET to /{serviceId}/{period}/{direction}?cursor=<user>&limit=<number> where direction is one of up and down.

For example, if we want to see more 10 higher rankings from the test user, it should request to /{serviceId}/{period}/up?cursor=test&limit=10. This is because this user field should be unique.

$ curl "https://API-DOMAIN/STAGE/service_id/period/up?limit=10"
[..., {
  "rank": 320,
  "user": "test2",
  "score": "123456789123456799"
}]

PUT

Request PUT to /{serviceId}/{period} with a header X-User for userId, then it returns by the form that is same with GET my API. The type of payload for score is string because it can be bigger than Number.MAX_SAFE_INTEGER.

• This API doesn't update a record when an old score is higher than a new score.
• This API can be slow if there is so many concurrent PUT calls. It is because it is on the actor model to manage the consistency of ranks whiel updating concurrently. Please see details in benchmark.

$ curl -XPUT "https://API-DOMAIN/STAGE/service_id/period" -H "X-User: test" -d "123456789123456789"
{
  "rank": 321,
  "user": "test",
  "score": "123456789123456789"
}

CLEAR

For admin purpose, it supports CLEAR command via DELETE request.

curl -XDELETE "https://API-DOMAIN/STAGE/service_id/period" -H "X-Auth: admin-secret"

But if process.env.AUTH_KEY isn't set while deploying, X-Auth can be omitted and it can lead very horrible problem, that is resetting all of ranks by anonymous.

Deployment

1. Install dependencies via yarn command from your shell.
2. After editing some codes, deploy this stack via yarn deploy command.

yarn
yarn deploy

Development

It contains serverless-offline plugin, you test it locally using yarn start command.

yarn
yarn start

Also, you can debug this stack using yarn debug command.

License

MIT