throttled 0.1.16a37

A rate limiter for FastAPI

ThrottledAPI

This repo aims to be an audacious rate limiter for FastAPI. Check our features to see the use-cases already tested.

Why another rate limiter for FastAPI?

Why another rate limiter for FastAPI, if we already have slowapi and fastapi-limiter? This limiter glues what is good from both projects and adds a bit more. Here is a list of reasons:

• The throttled-api rate limiter takes full advantage from the composable dependency injection system in FastAPI. That means you can also create limiters per resource.
  • Want to limit requests per IP or per user? Got it!
  • Want to limit requests based on another weird parameter you are receiving? Just extend our FastAPILimiter and you are good to go!
• You can use different storage storages backends (different implementations for BaseStorage) for each limiter.
  • Want to each API instance to 2000 requests per second? You don´t need more than a in-memory counter. Just use MemoryStorage for the task.
  • Want to limit calls to all your API instances by user or IP? A shared cache is what you need. Our RedisStorage implementation is an adapter for the famous redis package. Other implementations + asyncio support are comming...

Instalation

Just use your favorite python package manager. Here are two examples:

• With pip: pip install throttled
• With poetry: poetry add throttled

Usage

Middleware vs Dependency

Although FastAPI dependency injection is really powerfull, some limiters doesn´t require any special resource in other to use it. In that case you cut some latency if using the limiter as a Middleware. To do that, just extend our MiddlewareLimiter, which is a extension of FastAPILimiter to work as a middleware.

When implementing a custom limiter, how to choose between extending FastAPILimiter or MiddlewareLimiter?

stateDiagram-v2
    state FirstCondition <<choice>>
    state SecondCondition <<choice>>
    
    FirstQuestion: What type of limiter should I choose?
    FirstQuestion --> FirstCondition
    
    FirstCondition: Limitting depends on resources other\nthan Request object from Starlette?
    FirstCondition --> FastAPILimiter: yes
    FirstCondition --> MiddlewareLimiter : no
    FastAPILimiter --> SecondQuestion
    MiddlewareLimiter --> SecondQuestion
    
    SecondQuestion: What storage should I pick?
    SecondQuestion --> SecondCondition
    SecondCondition: The parameters you are limitting spams a parameter space.\n Is that space too large?
    SecondCondition --> RedisStorage : yes
    SecondCondition --> ThirdCondition : no
    
    ThirdCondition: You want to share the limiter\nbetween different API instances (pods)?
    ThirdCondition --> RedisStorage : yes
    ThirdCondition --> MemoryStorage : no
    
    RedisStorage --> End
    MemoryStorage --> End
    End: Attach the limiter to your API