Django Ratelimit

Django Ratelimit provides a decorator to rate-limit views. Limiting can be based on IP address or a field in the request--either a GET or POST variable.

If the rate limit is exceded, either a 403 Forbidden can be sent, or the request can be annotated with a limited attribute, allowing you to take another action like adding a captcha to a form.

Using Django Ratelimit

from ratelimit.decorators import ratelimit is the biggest thing you need to do. The @ratelimit decorator provides several optional arguments with sensible defaults (in italics).

ip:	Whether to rate-limit based on the IP. True
block:	Whether to block the request instead of annotating. False
method:	Which HTTP method(s) to rate-limit. May be a string or a list. all
field:	Which HTTP field(s) to use to rate-limit. May be a string or a list. none
rate:	The number of requests per unit time allowed. 5/m

Examples

@ratelimit()
def myview(request):
    # Will be true if the same IP makes more than 5 requests/minute.
    was_limited = getattr(request, 'limited', False)
    return HttpResponse()

@ratelimit(block=True)
def myview(request):
    # If the same IP makes >5 reqs/min, will return HttpResponseForbidden
    return HttpResponse()

@ratelimit(field='username')
def login(request):
    # If the same username OR IP is used >5 times/min, this will be True.
    # The `username` value will come from GET or POST, determined by the
    # request method.
    was_limited = getattr(request, 'limited', False)
    return HttpResponse()

@ratelimit(method='POST')
def login(request):
    # Only apply rate-limiting to POSTs.
    return HttpResponseRedirect()

@ratelimit(field=['username', 'other_field'])
def login(request):
    # Use multiple field values.
    return HttpResponse()

@ratelimit(rate='4/h')
def slow(request):
    # Allow 4 reqs/hour.
    return HttpResponse()

Acknowledgements

I would be remiss not to mention Simon Willison's ratelimitcache, on which this is largely based.