This package offers you a simple decorator to set cache control on your resolvers.
npm install nestjs-gql-cache-controlThis package offers you a simple decorator to set cache control on your resolvers.
On Yarn:
``shell`
yarn add nestjs-gql-cache-control
On NPM:
`shell`
npm install nestjs-gql-cache-control
To use caching, you are gonna need these packages too:
`
@nestjs/graphql
apollo-server-core
apollo-server-plugin-response-cache
First, register graphql module and cache plugins in your app module:
`ts
import responseCachePlugin from 'apollo-server-plugin-response-cache';
import { ApolloServerPluginCacheControl } from 'apollo-server-core/dist/plugin/cacheControl';
GraphQLModule.forRoot({
// ...
plugins: [
ApolloServerPluginCacheControl({ defaultMaxAge: 5 }), // optional
responseCachePlugin(),
],
}),
`
> To add Redis or other caching stores, check Apollo's docs
Then, you can use the decorator on your queries and field resolvers:
`ts
import { CacheControl } from 'nestjs-gql-cache-control';
@Resolver((type) => Post)
export class PostResolver {
@Query(() => [Post])
@CacheControl({ maxAge: 10 })
posts() {
// database calls
return posts;
}
@ResolveField(() => User)
@CacheControl({ inheritMaxAge: true })
owner() {
// database calls
return owner;
}
@ResolveField(() => boolean)
@CacheControl({ maxAge: 5, scope: 'PRIVATE' })
hasLiked() {
// database calls
return hasLiked;
}
}
`
Please carefully read Apollo's docs about caching to understand how caching works, since it has a set of rules for cache calculation. In a brief:
> a response should only be considered cacheable if every part of that response opts in to being cacheable. At the same time, we don't think developers should have to specify cache hints for every single field in their schema.
> So, we follow these heuristics:
> Root field resolvers are extremely likely to fetch data (because these fields have no parent), so we set their default maxAge to 0 to avoid automatically caching data that shouldn't be cached.
> Resolvers for other non-scalar fields (objects, interfaces, and unions) also commonly fetch data because they contain arbitrarily many fields. Consequently, we also set their default maxAge to 0.
> Resolvers for scalar, non-root fields rarely fetch data and instead usually populate data via the parent argument. Consequently, these fields inherit their default maxAge from their parent to reduce schema clutter.
If you happen to use nestjs-gql-connections, edges and node will automatically inherit cache control from their parents. but otherwise you should set inheritMaxAge` on your connection fields to prevent connections from cancelling your cache.
Why you should do that? because you probably don't want your connections to cancel your cache control. (learn more)