Framework for Rate limiting middleware

[shalarewicz]

The primary entry point for our rate limiting middleware will be a function that accepts:

• rate limiting method
• GraphQL Schema
• optional TypeWeightConfig parameters and outputs Express middleware.
• redis client

Rate Limiter options should be presented as an enum consisting of Token Bucket, Leaky Bucket, Fixed Window, Sliding Window Log and Sliding Window Counter choices.

During configuration this function should:

• Setup a Redis Client
• Parse the schema using the provided or default TypeWeightConfig to obtain a TypeWeightObject.
• Configure the selected RateLimiter
• Configure complexity analysis algorithm using the TypeWeightObject
• Return express middleware based on the above configuration.

The middleware will need to be able to have access to the GraphQL query , a unique user identifier (such as IP) and request timestamp and will call the next middleware if the request is allowed or reject the request using a 429 status code if the rate limiter denies the request.