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Plugins with Apollo

Plugins enable you to extend Apollo Server's core functionality by performing custom operations in response to certain events. Currently, these events correspond to individual phases of the GraphQL request lifecycle, and to the startup of Apollo Server itself (read more here). For example, a basic logging plugin might log the GraphQL query string associated with each request that's sent to Apollo Server.

Custom plugins#

To create a plugin, declare a class annotated with the @Plugin decorator exported from the @nestjs/apollo package. Also, for better code autocompletion, implement the ApolloServerPlugin interface from the @apollo/server package.

import { ApolloServerPlugin, GraphQLRequestListener } from '@apollo/server';
import { Plugin } from '@nestjs/apollo';

@Plugin()
export class LoggingPlugin implements ApolloServerPlugin {
  async requestDidStart(): Promise<GraphQLRequestListener<any>> {
    console.log('Request started');
    return {
      async willSendResponse() {
        console.log('Will send response');
      },
    };
  }
}

With this in place, we can register the LoggingPlugin as a provider.

@Module({
  providers: [LoggingPlugin],
})
export class CommonModule {}

Nest will automatically instantiate a plugin and apply it to the Apollo Server.

Using external plugins#

There are several plugins provided out-of-the-box. To use an existing plugin, simply import it and add it to the plugins array:

GraphQLModule.forRoot({
  // ...
  plugins: [ApolloServerOperationRegistry({ /* options */})]
}),

Hint The ApolloServerOperationRegistry plugin is exported from the @apollo/server-plugin-operation-registry package.

Plugins with Mercurius#

Some of the existing mercurius-specific Fastify plugins must be loaded after the mercurius plugin (read more here) on the plugin tree.

Warningmercurius-upload is an exception and should be registered in the main file.

For this, MercuriusDriver exposes an optional plugins configuration option. It represents an array of objects that consist of two attributes: plugin and its options. Therefore, registering the cache plugin would look like this:

GraphQLModule.forRoot({
  driver: MercuriusDriver,
  // ...
  plugins: [
    {
      plugin: cache,
      options: {
        ttl: 10,
        policy: {
          Query: {
            add: true
          }
        }
      },
    }
  ]
}),