nestjs-cache-decorator

nestjs-cache-decorator

NestJS Cache Decorator ·
A custom decorator is implemented in Nestjs to provide convenience for caching, called the 'cache decorator'.

Table of Contents

1. Installation
2. Configuration
3. Usage (Controller)
4. Usage (Provider)
5. License

Installation

npm install nestjs-cache-decorator

pnpm install nestjs-cache-decorator

Configuration

Static redis cache configuration

import {Module} from "@nestjs/common";
import {LocalCacheDecoratorModule} from "nestjs-cache-decorator";
import redisStore from "cache-manager-redis-store";

@Module({
    imports: [
        CacheDecoratorModule.register({
            host: "host",
            port: 6379,
            password: "password",
            db: 0,
            store: redisStore,
        }),
    ],
})
export class AppModule {
}

Static local cache configuration

import {Module} from "@nestjs/common";
import {LocalCacheDecoratorModule} from "nestjs-cache-decorator";

@Module({
    imports: [
        CacheDecoratorModule.register({}), // default `store: "memory"`
    ],
})
export class AppModule {
}

Async redis cache configuration

import {Module} from "@nestjs/common";
import {LocalCacheDecoratorModule} from "nestjs-cache-decorator";
import redisStore from "cache-manager-redis-store";

@Module({
    imports: [
        CacheDecoratorModule.registerAsync({
            imports: [ConfigModule],
            inject: [ConfigService],
            useFactory: async (configService: ConfigService): Promise<CacheModuleOptions> => {
                const config = configService.get("redis");
                return {...config, store: redisStore};
            },
        }),
    ],
})
export class AppModule {
}

Usage (Controller)

@APICache({})

The first cache module that is imported will serve as the storage for the controller cache.

For instance, in this scenario, the controller's cache storage would be set to "memory".

@Module({
    imports: [
        CacheDecoratorModule.register({ store: "memory"}),
        CacheDecoratorModule.register({ store : redisStore}),
    ],
})
export class AppModule {

If the key field is empty, the default cache key will be HTTP URL Path where / is replaced to :. If the key field exists, the cache key will be {http url path}:{http url path}:...:{key}.

Use the validate filed function to verify the result of the method.

The logger creates a log when data is cached or when there is a cache hit. When the logger is set to console.log, the output will be as follows:

• When data is cached : Cached { cacheKey: 'example:redis' }
• When cache hit : Cache Hit { cacheKey: 'example:redis' }

@Controller("example")
@UseInterceptors(ControllerCacheInterceptor)
export class ExampleController {

    @RedisCache({
        ttl: 60,
        validate: (value: any) => Boolean(value),
        logger: console.log,
    })
    @Get("redis")
    async example() {
    }
}

Usage (Provider)

@RedisCache({}), @LocalCache({})

If the key field is empty, the default cache key will be {className}:{methodName}:{methodArgs}. If the key field exists, the cache key will be {className}:{methodName}:{key}.

Use the validate filed function to verify the result of the method.

The logger creates a log when data is cached or when there is a cache hit. When the logger is set to console.log, the output will be as follows:

• When data is cached : Cached { cacheKey: 'ExampleService:cacheExample:test' }
• When cache hit : Cache Hit { cacheKey: 'ExampleService:cacheExample:test' }

Cache by TTL

Caching takes place when the function cacheExample() is called and the result is not already cached.

The cache will expire after the TTL (Time To Live) duration.

@Injectable()
export class ExampleService {

    @RedisCache({
        ttl: 60,        // expire after 60s
        key: "test",   // cache key : `ExampleService:cacheExample:test`
        validate: (value: any) => Boolean(value),
        logger: console.log,
    })
    redisCacheExample() {
    }

    @LocalCache({
        ttl: 60,        // expire after 60s
        key: "test",   // cache key : `ExampleService:cacheExample:test`
        validate: (value: any) => Boolean(value),
        logger: console.log,
    })
    localCacheExample() {
    }
}

Cache by Cron

For the example below, cacheExample() method will be called each time the current second is 45. In other words, the method will be run once per minute, at the 45 second mark.

The cron field supports all standard cron patterns:

• Asterisk (e.g. *)
• Ranges (e.g. 1-3,5)
• Steps (e.g. */2)

@Injectable()
export class ExampleService {

    @RedisCache({
        cron: "45 * * * * *",   // The method is executed every 45 second, and the result is cached.
        key: "test",
        validate: (value: any) => Boolean(value),
        logger: console.log,
    })
    redisCacheExample() {
    }

    @LocalCache({
        cron: "45 * * * * *",   // The method is executed every 45 second, and the result is cached.
        key: "test",
        validate: (value: any) => Boolean(value),
        logger: console.log,
    })
    localCacheExample() {
    }
}

In the example above, we passed 45 * * * * * to the decorator. The following key shows how each position in the cron pattern string is interpreted:

* * * * * *
| | | | | |
| | | | | day of week
| | | | months
| | | day of month
| | hours
| minutes
seconds (optional)

Decorator options

export interface CacheOptions {
    cron?: string;

    key?: string;

    ttl?: number;

    validate?: Function;

    logger?: Function;
}