Version 0.8.1

Federation support

Basic support of federation already in place. Just add to your method with @ResolveReference() one more decorator @GraphqlLoader()

Example

This examples is the reference to official example https://github.com/nestjs/nest/tree/master/sample/31-graphql-federation-code-first. Clone https://github.com/nestjs/nest/tree/master/sample/31-graphql-federation-code-first (download specific directory with https://download-directory.github.io/ or with chrome extention https://chrome.google.com/webstore/detail/gitzip-for-github/ffabmkklhbepgcgfonabamgnfafbdlkn)

1. Annotate method resolveReference of users-application/src/users/users.resolver.ts

// users-application/src/users/users.resolver.ts
@ResolveReference()
@GraphqlLoader()
async resolveReference(
   @Loader() loader: LoaderData<User, number>,
) {
 const ids = loader.ids;
 const users = this.usersService.findByIds(ids);
 return loader.helpers.mapManyToOneRelation(users, loader.ids, 'id')
}

1. Add method findByIds to users-application/src/users/users.service.ts

// users-application/src/users/users.service.ts
@Injectable()
export class UsersService {
  private users: User[] = [
    { id: 1, name: 'John Doe' },
    { id: 2, name: 'Richard Roe' },
  ];

  findByIds(idsList: number[]): User[] {
    return this.users.filter((user) => idsList.some(id => Number(id) === user.id));
  }
}

3. Install dependencies of 3 projects : npm ci in gateway, posts-application, users-application.

4. Run all projects in order :

   • cd users-application && npm run start
   • cd posts-application && npm run start
   • cd gateway && npm run start

5. Go to localhost:3001/graphql and send graphql request to gateway

{
  posts {
    id
    title
    authorId
    user {
      id
      name
    }
  }
}