Rules and Helpers

ruleGist.js

'use strict';

const _ = require('lodash');

/**
 * Marks products as highRisk based on stored rules
 * stored in db
 * @param feed Product object
 * @param next Callback
 */
module.exports = (feed, next) => {

    getRules((err, docs) => {

        if (err) {
            return next(err);
        } else if (docs.length === 0) {
            // No rules no need to process
            return next(null, true);
        } else {
            let isHighRisk = false;
            _.forEach(docs, (doc) => {
                if (doc.glue === '||') {
                    isHighRisk = processOr(feed, doc.rules);
                } else {
                    isHighRisk = processAnd(feed, doc.rules);
                }
                // exit loop if determined high-risk
                if (isHighRisk) {
                    feed.highRiskFlag = true;
                    feed.riskClassification = doc.riskClassification;
                    return false;
                }
            });
            next(null, true);
        }
    });

    /**
     * caching method to fetch drop fules
     * @param cb
     */
    function getRules (cb) {
        // try cache
        let rules = helpers.cacheGet('highRiskRules');
        if (rules) {
            return cb(null, rules)
        }

        // Get the rules from persistent datasource
        let rulesCollection = config.mongoDb.collection('HighRiskRule');
        rulesCollection.find({}, {}).toArray(function (err, docs) {
            if (err) {
                return cb(err);
            }
            helpers.cacheSet('highRiskRules', docs);
            cb(null, docs);
        });
    }

    /**
     * Checks the ors
     * @param feed
     * @param rules
     * @return {boolean}
     */
    function processOr (feed, rules) {
        let drop = false;
        _.forEach(rules, (rule) => {
            let regex = new RegExp(rule.value, 'ig');
            let value = _.get(feed, rule.key);
            if (regex.test(value)) {
                drop = true;
                return false;
            }
        });
        return drop;
    }

        /**
         * Check the ands
         * @param feed
         * @param rules
         * @return {boolean}
         */
    function processAnd (feed, rules) {
        let dropEvaluations = [];
        _.forEach(rules, (rule) => {
            let regex = new RegExp(rule.value, 'ig');
            let value = _.get(feed, rule.key);
            if (regex.test(value)) {
                dropEvaluations.push(true);
            }
        });
        return (dropEvaluations.length === rules.length);
    }
};