u-mongoose-expressapi/src/common/utils/cache.js

Common functions for Express and Mongoose API

const mongoose = require('mongoose');
const { redis } = require('./redisconn');

const execAggregate = mongoose.Aggregate.prototype.exec;
const exec = mongoose.Query.prototype.exec;

// @ts-ignore
mongoose.Aggregate.prototype.cache = function (options = {}) {
  this.useCache = true;
  this.hashkey = JSON.stringify(options.key || '');
  return this;
};
exports.mongooseAggregationQuery = () => {
  mongoose.Aggregate.prototype.exec = async function () {
    if (!this.useCache) {
      return execAggregate.apply(this, arguments);
    }
    // console.log("I am inside a mongo Aggregation query function");
    // console.log("aggregation", this._pipeline);
    const key = JSON.stringify(this._pipeline);
    // console.log(key, this.hashkey);
    // console.log(key)
    const cacheValue = await redis.hget(this.hashkey, key);
    if (cacheValue) {
      console.log('aggregation cache');
      return JSON.parse(cacheValue);
    }

    const result = await execAggregate.apply(this, arguments);
    redis.hset(this.hashkey, key, JSON.stringify(result));
    return result;
  };
};

// @ts-ignore
mongoose.Query.prototype.cache = function (options = {}) {
  this.useCache = true;
  this.hashkey = JSON.stringify(options.key || '');
  return this;
};

exports.mongooseQuery = () => {
  mongoose.Query.prototype.exec = async function () {
    if (!this.useCache) {
      return exec.apply(this, arguments);
    }
    // console.log("I am inside a mongo query function");
    // console.log("query filter", this.getQuery());
    // console.log("query", this.mongooseCollection.name);
    const key = JSON.stringify(
      Object.assign({}, this.getQuery(), {
        collection: this.mongooseCollection.name
      })
    );
    // console.log(key)
    const cacheValue = await redis.hget(this.hashkey, key);
    // console.log(key, this.hashkey);
    if (cacheValue) {
      console.log('query cache');
      const doc = JSON.parse(cacheValue);
      return Array.isArray(doc) ? doc.map(d => new this.model(d)) : new this.model(doc);
    }
    const result = await exec.apply(this, arguments);
    // console.log(result)
    redis.hset(this.hashkey, key, JSON.stringify(result));
    return result;
  };
};

exports.clearHash = hashkey => {
  if (redis) {
    redis.del(JSON.stringify(hashkey));
  }
};

exports.flushcache = () => {
  console.log('Flushing cache...');

  if (!redis) {
    console.error('Redis object is not defined.');
    return;
  }

  redis.flushall(function (err, succeeded) {
    if (err) {
      console.error('Error flushing all keys:', err);
      return;
    } else {
      console.log('All keys flushed:', succeeded); // Will be 'OK' if successful
      redis.quit();
    }
  });
};