@andreafspeziale/nestjs-memcached

Memcached module and service for Nest,
a progressive Node.js framework for building efficient and scalable server-side applications.

Installation

npm

npm install @andreafspeziale/nestjs-memcached

yarn

yarn add @andreafspeziale/nestjs-memcached

pnpm

pnpm install @andreafspeziale/nestjs-memcached

How to use?

Module

The module is Global by default.

MemcachedModule.forRoot(options)

import { Module } from '@nestjs/common';
import { MemcachedModule } from '@andreafspeziale/nestjs-memcached';
import { AppController } from './app.controller';

@Module({
  imports: [
    MemcachedModule.forRoot({
      connections: [
        {
          host: 'localhost',
          port: '11211',
        },
      ],
      ttl: 60,
      ttr: 30,
      superjson: true,
      keyProcessor: (key) => `prefix_${key}`,
      wrapperProcessor: ({ value, ttl, ttr }) => ({
        content: value,
        ttl,
        ...(ttr ? { ttr } : {}),
        createdAt: new Date(),
      }),
    }),
  ],
  controllers: [AppController],
})
export class AppModule {}

• For signle connection you can omit the connections property.
• For multiple connections you can omit the port property if the server is using the default one.
• ttl is the global time to live.
• ttr is the global optional time to refresh.
• Typically when caching a JS object like Date you will get back a string from the cache, superjson will stringify on cache sets adding metadata in order to later parse on cache gets and retrieve the initial "raw" data.
• wrapperProcessor is the global optional wrapper processor function which wraps the value to be cached and adds metadata.
• keyProcessor is the global optional key processor function which process your cache keys.

MemcachedModule.forRootAsync(options)

import { Module } from '@nestjs/common';
import { ConfigModule, ConfigService } from '@nestjs/config';
import { MemcachedModule } from '@andreafspeziale/nestjs-memcached';
import { Config } from './config';
import { AppController } from './app.controller';

@Module({
  imports: [
    ConfigModule.forRoot({
      ...
    }),
    MemcachedModule.forRootAsync({
      useFactory: (configService: ConfigService<Config>) => configService.get('memcached'),
      inject: [ConfigService],
    }),
  ],
  controllers: [AppController],
})
export class AppModule {}

Decorators

InjectMemcachedOptions() and InjectMemcached()

import { Injectable } from '@nestjs/common';
import { InjectMemcachedOptions, InjectMemcached } from '@andreafspeziale/nestjs-memcached';

@Injectable()
export class SampleService {
  constructor(
    @InjectMemcachedOptions()
    private readonly memcachedModuleOptions: MemcachedModuleOptions,
    @InjectMemcached() private readonly memcachedClient: MemcachedClient
  ) {}

  ...
}

Service

MemcachedService

import { MemcachedService } from '@andreafspeziale/nestjs-memcached';
import { SampleReturnType, CachedItemType } from './interfaces'

@Injectable()
export class SampleFacade {
  constructor(
    private readonly memcachedService: MemcachedService
  ) {}

  async sampleMethod(): Promise<SampleReturn> {
    const cachedItem = await this.memcachedService.get<CachedPlainOrWrappedItem>(cachedItemKey);

    if(cachedItem === null) {
      ...
      await this.memcachedService.set<string>('key', 'value');
      ...
    }
}

You can also set all the proper Processors and CachingOptions inline in order to override the global values specified during the MemcachedModule import

await this.memcachedService.set<string>('key', 'value', { ttl: 100 });

The provided MemcachedService is an opinionated wrapper around memcached trying to be unopinionated as much as possibile at the same time.

setWithMeta enables refresh-ahead cache pattern in order to let you add a logical expiration called ttr (time to refresh) to the cached data and more.

So each time you get some cached data it will contain additional properties in order to help you decide whatever business logic needs to be applied.

Test

• docker compose -f docker-compose.test.yml up -d
• pnpm test

Stay in touch

• Author - Andrea Francesco Speziale
• Website - https://nestjs.com
• Twitter - @nestframework

License

nestjs-memcached MIT licensed.