Requests-Ratelimiter

Work in progress

This package is a thin wrapper around pyrate-limiter that adds convenient integration with the requests library.

Features

• pyrate-limiter implements the leaky bucket algorithm, supports multiple rate limits, and an optional Redis backend
• requests-ratelimiter can be used as a transport adapter, session, or session mixin for compatibility with other requests-based libraries.
• Rate limits can be automatically tracked separately per host, and different rate limits can be manually applied to different hosts

Installation

pip install requests-ratelimiter

Usage

Sessions

Example with LimiterSession:

from pyrate_limiter import Duration, RequestRate
from requests import Session
from requests_ratelimiter import LimiterSession

# Apply a rate-limit (5 requests per second) to all requests
session = LimiterSession(RequestRate(5, Duration.SECOND))

# Make rate-limited requests that stay within 5 requests per second
for _ in range(10):
    response = session.get('https://httpbin.org/get')
    print(response.json())

Adapters

Example with LimiterAdapter:

from pyrate_limiter import Duration, RequestRate
from requests import Session
from requests_ratelimiter import LimiterAdapter

session = Session()

# Apply a rate-limit (5 requests per second) to all requests
adapter = LimiterAdapter(RequestRate(5, Duration.SECOND))
session.mount('http://', adapter)
session.mount('https://', adapter)

# Make rate-limited requests
for user_id in range(100):
    response = session.get(f'https://api.some_site.com/v1/users/{user_id}')
    print(response.json())

Per-Host Rate Limits

With LimiterAdapter, you can apply different rate limits to different hosts or URLs:

# Apply different rate limits (2/second and 100/minute) to a specific host
adapter_2 = LimiterAdapter(
    RequestRate(2, Duration.SECOND),
    RequestRate(100, Duration.MINUTE),
)
session.mount('https://api.some_site.com', adapter_2)

Behavior for matching requests is the same as other transport adapters: requests will use the adapter with the most specific (i.e., longest) URL prefix for a given request. For example:

session.mount('https://api.some_site.com/v1', adapter_3)
session.mount('https://api.some_site.com/v1/users', adapter_4)

# This request will use adapter_3
session.get('https://api.some_site.com/v1/')

# This request will use adapter_4
session.get('https://api.some_site.com/v1/users/1234')

Per-Host Rate Limit Tracking

With either LimiterSession or LimiterAdapter, you can automatically track rate limits separately for each host; in other words, requests sent to one host will not count against the rate limit for any other hosts. This can be enabled with the per_host option:

session = LimiterSession(RequestRate(5, Duration.SECOND), per_host=True)

# Make requests for two different hosts
for _ in range(10):
    response = session.get(f'https://httpbin.org/get')
    print(response.json())
    session.get(f'https://httpbingo.org/get')
    print(response.json())

Compatibility

There are many other useful libraries out there that add features to requests, most commonly by extending or modifying requests.Session.

To use requests-ratelimiter with one of these libraries, you have at least two options:

1. Mount a LimiterAdapter on an instance of the library's Session class
2. Use LimiterMixin to create a custom Session class with features from both libraries

Requests-Cache

For example, to combine with requests-cache, which also includes a separate mixin class:

from requests_cache import CacheMixin
from requests_ratelimiter import LimiterMixin


class CachedLimiterSession(LimiterMixin, CacheMixin, Session):
    """Session class with caching and rate-limiting behavior. Accepts arguments for both
    LimiterSession and CachedSession.
    """


session = CachedLimiterSession(RequestRate(5, Duration.SECOND), backend='redis')

This example has an extra benefit: cache hits won't count against your rate limit!