Sanic-Limiter

A rate limiting extension inspired by flask-limiter Provides rate limiting features for Sanic. Supports in-memory, redis and memcache as storage based on alisaifee/limits.

Quickstart

Demo for quickstart:

from sanic import Sanic, Blueprint
from sanic.response import text

from sanic_limiter import Limiter, get_remote_address

app = Sanic(__name__)
limiter = Limiter(app, global_limits=['1 per hour', '10 per day'], key_func=get_remote_address)
bp = Blueprint('some_bp')
limiter.limit("2 per hour")(bp)


@bp.route("/bp1")
async def bp_t1(request):
    return text("bp_t1")


@app.route("/t1")
@limiter.limit("100 per hour;10/minute")
async def t1(request):
    return text("t1")


@app.route("/t2")
async def t2(request):
    return text("t2")


@app.route("/t3")
@limiter.exempt
async def t3(request):
    return text("t3")

app.blueprint(bp)

app.run(host="0.0.0.0", port=5000, debug=True)

Aboved demo provides:

• build Limiter instance with giving sanic app and global_limits;
• global_limits will be applied to all routes;
• /t1 has its own limit rules (using decorator provides by limiter.limit) which will NOT bypass the global_limits;
• /t2 uses global_limits;
• /t3 will exempt from any global_limits;
• all the rate limits are based on get_remote_address, you can customize yours;
• when any rate limit is triggered, the view function will not be called and responses with http code 429;

Install

pip install sanic_limiter

Initialization

There are two basic ways:

• constructor:

   from sanic_limiter import Limiter, get_remote_address
  
   limiter = Limiter(app, key_func=get_remote_address)

• init_app:

   from sanic_limiter import Limiter, get_remote_address
  
   limiter = Limiter(key_func=get_remote_address)
   limiter.init_app(app)

Key function

key function is customizable, an reasonable example is rate limiting by userid:

def get_request_userid(request):
    return request.args.get('userid', '')

@limiter.limit("50/minute", key_func=get_request_userid)
async def t1(request):
    return text(t1)

basicly, customized key function would like to access sanic request instance(not necessarily although), sanic request instance will be injected if key function has only one positional argument.

Danger:

if key function has more than one positional argument, an exception will be rasied.

Rate limit string notation

Rate limits are specified as strings following the format:

[count] [per|/] [n (optional)] [second|minute|hour|day|month|year]

You can combine multiple rate limits by separating them with a delimiter of your choice.

Examples:

• 10 per hour
• 10/hour
• 10/hour;100/day;2000 per year
• 100/day, 500/7days

Requirements:

• limits>=1.2.1 (https://github.com/alisaifee/limits)
• sanic>=0.4.0
• six>=1.4.1

References:

Flask-Limiter: http://flask-limiter.readthedocs.io/en/stable/recipes.html#keyfunc-customization