dos-protect/index.js

DOS Protector for NPM

var listCache = [];
var rateLimit = 5; //5 MiliSecond

var _ = require('lodash');
var moment = require('moment');

function authenticateV1(ip) {
    var found = listCache.filter((res) => {
        return res.ip == ip;
    })
    var currentTime = Date.now();
    var res = {};
    if (found.length < 1) {
        listCache.push({
            "ip": ip,
            "timestmp": currentTime
        });
        res.status = "200";
        res.message = "IP Validated";
    } else {
        var diff = (currentTime) - (found[0].timestmp);
        if (diff < rateLimit) {
            res.status = "429";
            res.message = "Too Many Request from Same Address";
        } else {
            res.status = "200";
            res.message = "IP Validated";
        }
    }
    return (res);
}

function authenticateV2(ip, maxHits, timeAllowed) {
    maxHits = validateValue(maxHits) ? maxHits : 5;
    timeAllowed = validateValue(timeAllowed) ? timeAllowed : 5;
    var res = {};
    var isValidated = true;
    var ipFound = _.find(listCache, function (o) {
        return (
            o.ip == ip
        )
    });
    if (validateValue(ipFound)) {
        if (moment().format("X") - ipFound.timestmp > timeAllowed) {
            isValidated = true
            listCache = _.remove(listCache, function (n) {
                return n.ip != ip;
            });
            listCache.push({
                "ip": ip,
                "timestmp": moment().format("X"),
                count: 1
            })
        } else {
            var index = _.findIndex(listCache, {
                ip: ip
            });
            listCache[index]["count"] = parseInt(listCache[index]["count"]) + 1;
            if (ipFound.count <= maxHits) {
                isValidated = true
            } else {
                isValidated = false;
            }
        }
    } else {
        isValidated = true
        listCache.push({
            "ip": ip,
            "timestmp": moment().format("X"),
            count: 1
        })
    }
    if (isValidated) {
        res.status = "200";
        res.ip = ip;
        res.message = "IP Validated";
    } else {
        res.status = "429";
        res.ip = ip;
        res.message = "Too Many Request from Same Address";
    }
    return (res);
}

module.exports = {
    authenticateV1,
    authenticateV2
};

function validateValue(val) {
    if (!val || val == undefined || val == null || val == 'undefined' || val == 'null' || val == "" || val.length < 1 || val == NaN || val == 'NaN' || val == 'false' || val == false) {
        return (false);
    } else {
        return (true);
    }
}