Upgrade Notes

See also the CHANGELOG <../CHANGELOG>.

From 2.0 to 3.0

Quickly:

• Ratelimit now supports Django >=1.11 and Python >=3.4.

• @ratelimit no longer works directly on class methods, add @method_decorator.

• RatelimitMixin is gone, migrate to @method_decorator.

• Moved is_ratelimted method from ratelimit.utils to ratelimit.core.

@ratelimit decorator on class methods

In 3.0, the decorator has been simplified and must now be used with Django’s excellent @method_decorator utility. Migrating should be relatively straight-forward:

from django.views.generic import View
from ratelimit.decorators import ratelimit

class MyView(View):
    @ratelimit(key='ip', rate='1/m', method='GET')
    def get(self, request):
        pass

changes to

from django.utils.decorators import method_decorator
from django.views.generic import View
from ratelimit.decorators import ratelimit

class MyView(View):
    @method_decorator(ratelimit(key='ip', rate='1/m', method='GET'))
    def get(self, request):
        pass

RatelimitMixin

RatelimitMixin is a vestige of an older version of Ratelimit that did not support multiple rates per method. As such, it is significantly less powerful than the current @ratelimit decorator. To migrate to the decorator, use the @method_decorator from Django:

class MyView(RatelimitMixin, View):
    ratelimit_key = 'ip'
    ratelimit_rate = '10/m'
    ratelimit_method = 'GET'

    def get(self, request):
        pass

becomes

class MyView(View):
    @method_decorator(ratelimit(key='ip', rate='10/m', method='GET'))
    def get(self, request):
        pass

The major benefit is that it is now possible to apply multiple limits to the same method, as with :ref:`the decorator <usage-decorator>`_.

From <=0.4 to 0.5

Quickly:

• Rate limits are now counted against fixed, instead of sliding, windows.

• Rate limits are no longer shared between methods by default.

• Change ip=True to key='ip'.

• Drop ip=False.

• A key must always be specified. If using without an explicit key, add key='ip'.

• Change fields='foo' to post:foo or get:foo.

• Change keys=callable to key=callable.

• Change skip_if to a callable rate=<callable> method (see Rates.

• Change RateLimitMixin to RatelimitMixin (note the lowercase l).

• Change ratelimit_ip=True to ratelimit_key='ip'.

• Change ratelimit_fields='foo' to post:foo or get:foo.

• Change ratelimit_keys=callable to ratelimit_key=callable.

Fixed windows

Before 0.5, rates were counted against a sliding window, so if the rate limit was 1/m, and three requests came in:

1.2.3.4 [09/Sep/2014:12:25:03] ...
1.2.3.4 [09/Sep/2014:12:25:53] ... <RATE LIMITED>
1.2.3.4 [09/Sep/2014:12:25:59] ... <RATE LIMITED>

Even though the third request came nearly two minutes after the first request, the second request moved the window. Good actors could easily get caught in this, even trying to implement reasonable back-offs.

Starting in 0.5, windows are fixed, and staggered throughout a given period based on the key value, so the third request, above would not be rate limited (it’s possible neither would the second one).

Warning

That means that given a rate of X/u, you may see up to 2 * X requests in a short period of time. Make sure to set X accordingly if this is an issue.

This change still limits bad actors while being far kinder to good actors.

Staggering windows

To avoid a situation where all limits expire at the top of the hour, windows are automatically staggered throughout their period based on the key value. So if, for example, two IP addresses are hitting hourly limits, instead of both of those limits expiring at 06:00:00, one might expire at 06:13:41 (and subsequently at 07:13:41, etc) and the other might expire at 06:48:13 (and 07:48:13, etc).

Sharing rate limits

Before 0.5, rate limits were shared between methods based only on their keys. This was very confusing and unintuitive, and is far from the least-surprising thing. For example, given these three views:

@ratelimit(ip=True, field='username')
def both(request):
    pass

@ratelimit(ip=False, field='username')
def field_only(request):
    pass

@ratelimit(ip=True)
def ip_only(request):
    pass

The pair both and field_only shares one rate limit key based on all requests to either (and any other views) containing the same username key (in GET or POST), regardless of IP address.

The pair both and ip_only shares one rate limit key based on the client IP address, along with all other views.

Thus, it’s extremely difficult to determine exactly why a request is getting rate limited.

In 0.5, methods never share rate limits by default. Instead, limits are based on a combination of the group, rate, key value, and HTTP methods to which the decorator applies (i.e. not the method of the request). This better supports common use cases and stacking decorators, and still allows decorators to be shared.

For example, this implements an hourly rate limit with a per-minute burst rate limit:

@ratelimit(key='ip', rate='100/m')
@ratelimit(key='ip', rate='1000/h')
def myview(request):
    pass

However, this view is limited separately from another view with the same keys and rates:

@ratelimit(key='ip', rate='100/m')
@ratelimit(key='ip', rate='1000/h')
def anotherview(request):
    pass

To cause the views to share a limit, explicitly set the group argument:

@ratelimit(group='lists', key='user', rate='100/h')
def user_list(request):
    pass

@ratelimit(group='lists', key='user', rate='100/h')
def group_list(request):
    pass

You can also stack multiple decorators with different sets of applicable methods:

@ratelimit(key='ip', method='GET', rate='1000/h')
@ratelimit(key='ip', method='POST', rate='100/h')
def maybe_expensive(request):
    pass

This allows a total of 1,100 requests to this view in one hour, while this would only allow 1000, but still only 100 POSTs:

@ratelimit(key='ip', method=['GET', 'POST'], rate='1000/h')
@ratelimit(key='ip', method='POST', rate='100/h')
def maybe_expensive(request):
    pass

And these two decorators would not share a rate limit:

@ratelimit(key='ip', method=['GET', 'POST'], rate='100/h')
def foo(request):
    pass

@ratelimit(key='ip', method='GET', rate='100/h')
def bar(request):
    pass

But these two do share a rate limit:

@ratelimit(group='a', key='ip', method=['GET', 'POST'], rate='1/s')
def foo(request):
    pass

@ratelimit(group='a', key='ip', method=['POST', 'GET'], rate='1/s')
def bar(request):
    pass

Using multiple decorators

A single @ratelimit decorator used to be able to ratelimit against multiple keys, e.g., before 0.5:

@ratelimit(ip=True, field='username', keys=mykeysfunc)
def someview(request):
    # ...

To simplify both the internals and the question of what limits apply, each decorator now tracks exactly one rate, but decorators can be more reliably stacked (c.f. some examples in the section above).

The pre-0.5 example above would need to become four decorators:

@ratelimit(key='ip')
@ratelimit(key='post:username')
@ratelimit(key='get:username')
@ratelimit(key=mykeysfunc)
def someview(request):
    # ...

As documented above, however, this allows powerful new uses, like burst limits and distinct GET/POST limits.