dino-express/dist/policies/RateLimitPolicy.js

DinO enabled REST framework based on express

"use strict";
//    Copyright 2018 Quirino Brizi [quirino.brizi@gmail.com]
//
//    Licensed under the Apache License, Version 2.0 (the "License");
//    you may not use this file except in compliance with the License.
//    You may obtain a copy of the License at
//
//        http://www.apache.org/licenses/LICENSE-2.0
//
//    Unless required by applicable law or agreed to in writing, software
//    distributed under the License is distributed on an "AS IS" BASIS,
//    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
//    See the License for the specific language governing permissions and
//    limitations under the License.
Object.defineProperty(exports, "__esModule", { value: true });
exports.RateLimitPolicy = void 0;
const AbstractPolicy_1 = require("./AbstractPolicy");
const dino_core_1 = require("dino-core");
/**
 * Allows to control the number of requests received by the API in the time
 * interval
 */
class RateLimitPolicy extends AbstractPolicy_1.AbstractPolicy {
    configuration;
    buckets;
    constructor() {
        super();
        this.buckets = new Map();
    }
    apply(req) {
        const now = Date.now();
        const key = (req.headers['x-forwarded-for'] ?? req.socket.remoteAddress);
        const weight = 1;
        const windowSize = this.configuration.interval / 1000 / this.configuration.allow;
        let allowed = true;
        let bucket = this.buckets.get(key);
        if (bucket === undefined) {
            bucket = { used: 0, windowExpires: 0 };
            this.buckets.set(key, bucket);
        }
        dino_core_1.Logger.debug('Bucket', bucket);
        if (now < bucket.windowExpires) {
            bucket.used = bucket.used + weight;
            allowed = false;
        }
        else {
            this.buckets.set(key, bucket);
            bucket.windowExpires = now + weight * windowSize;
            bucket.used = weight;
        }
        return allowed;
    }
    configure(configuration) {
        this.configuration = configuration;
    }
    onDeny(res) {
        res.status(429);
        res.body = { message: 'Too Many Requests' };
    }
}
exports.RateLimitPolicy = RateLimitPolicy;
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