README.rst
ratelimit |build| |maintainability|
===================================
APIs are a very common way to interact with web services. As the need to
consume data grows, so does the number of API calls necessary to remain up to
date with data sources. However many API providers constrain developers from
making too many API calls. This is know as rate limiting and in a worst case
scenario your application can be banned from making further API calls if it
abuses these limits.
This packages introduces a function decorator preventing a function from being
called more often than that allowed by the API provider. This should prevent
API providers from banning your applications by conforming to their rate
limits.
Installation
------------
PyPi
~~~~
Add this line to your application's requirements.txt:
.. code:: python
ratelimit
And then execute:
.. code:: bash
$ pip install -r requirements.txt
Or install it yourself:
.. code:: bash
$ pip install ratelimit
GitHub
~~~~~~
Installing the latest version from Github:
.. code:: bash
$ git clone https://github.com/tomasbasham/ratelimit
$ cd ratelimit
$ python setup.py install
Usage
-----
To use this package simply decorate any function that makes an API call:
.. code:: python
from ratelimit import limits
import requests
FIFTEEN_MINUTES = 900
@limits(calls=15, period=FIFTEEN_MINUTES)
def call_api(url):
response = requests.get(url)
if response.status_code != 200:
raise Exception('API response: {}'.format(response.status_code))
return response
This function will not be able to make more then 15 API call within a 15 minute
time period.
The arguments passed into the decorator describe the number of function
invocation allowed over a specified time period (in seconds). If no time period
is specified then it defaults to 15 minutes (the time window imposed by
Twitter).
If a decorated function is called more times than that allowed within the
specified time period then a ``ratelimit.RateLimitException`` is raised. This
may be used to implement a retry strategy such as an `expoential backoff
<https://pypi.org/project/backoff/>`_
.. code:: python
from ratelimit import limits, RateLimitException
from backoff import on_exception, expo
import requests
FIFTEEN_MINUTES = 900
@on_exception(expo, RateLimitException, max_tries=8)
@limits(calls=15, period=FIFTEEN_MINUTES)
def call_api(url):
response = requests.get(url)
if response.status_code != 200:
raise Exception('API response: {}'.format(response.status_code))
return response
Alternatively to cause the current thread to sleep until the specified time
period has ellapsed and then retry the function use the ``sleep_and_retry``
decorator. This ensures that every function invocation is successful at the
cost of halting the thread.
.. code:: python
from ratelimit import limits, sleep_and_retry
import requests
FIFTEEN_MINUTES = 900
@sleep_and_retry
@limits(calls=15, period=FIFTEEN_MINUTES)
def call_api(url):
response = requests.get(url)
if response.status_code != 200:
raise Exception('API response: {}'.format(response.status_code))
return response
License
-------
This project is licensed under the `MIT License <LICENSE.txt>`_.
.. |build| image:: https://travis-ci.com/tomasbasham/ratelimit.svg?branch=master
:target: https://travis-ci.com/tomasbasham/ratelimit
.. |maintainability| image:: https://api.codeclimate.com/v1/badges/21dc7c529c35cd7ef732/maintainability
:target: https://codeclimate.com/github/tomasbasham/ratelimit/maintainability
:alt: Maintainability