How to manually intercept a query in a custom service, e.g., manually add relations or apply global filters

[kynt-lean]

How can I add some fixed business logic for query in a custom service like this:

@Injectable()
export class CustomersQueryService extends TypeOrmQueryService<Customer> {
  constructor(@InjectRepository(Customer) repo: Repository<Customer>) {
    super(repo);
  }

  query(query: Query<Customer>, opts?: QueryOptions<Customer> | undefined): Promise<Customer[]> {
    // how to add contract relation to query.relations
    // how to add contract filter with contract is not null to query.filter
    return super.query(query, opts);
  }
}

[TriPSs]

I think what you are looking for is @BeforeQueryMany?

[kynt-lean]

That's right, similarly to using @BeforeQueryMany, I want to know how to use low-level APIs of Query to add relations or filters.

@BeforeQueryMany((query: Query<CustomerDto>, context: any) => {
 // which api of query to filter with contract is not null
  return query;
})
export class CustomerDto {
  @IDField(() => String)
  id: string;

  @FilterableField()
  name: string;
}

[TriPSs]

Could you share some more info as I don't quite get the question.

[kynt-lean]

When I use the @BeforeQueryMany hook, I logged query.filter and received a data type of GraphQLFilter. Then I tried to add a filter like this but encountered an error.

@ObjectType('Customer')
@UnPagedRelation('contracts', () => ContractDto)
@BeforeQueryMany((query: Query<CustomerDto>, context: any) => {
  if (query.filter) {
    Object.assign(query.filter, {
      and: {
        contracts: {
          customerCode: {
            isNot: null,
          },
        },
      },
    });
  }
  return query;
})
export class CustomerDto {
  @IDField(() => String)
  code: string;

  @FilterableField()
  name: string;
}

2024-10-22T14:09:51.983Z error RequestExceptionFilter: graphql request finished with error http POST /receivables/graphql - application/json, text/plain, */* - {"key":"customers","typename":"Query"} - currFilterValue is not iterable 0ms
2024-10-22T14:09:52.025Z error RequestExceptionFilter: "TypeError: currFilterValue is not iterable
    at <anonymous> (/home/lean/projects/crm/packages/query-typeorm/src/query/filter-query.builder.ts:413:33)
    at Array.reduce (<anonymous>)
    at FilterQueryBuilder.getReferencedRelationsRecursive (/home/lean/projects/crm/packages/query-typeorm/src/query/filter-query.builder.ts:409:29)
    at FilterQueryBuilder.getReferencedRelationsWithAliasRecursive (/home/lean/projects/crm/packages/query-typeorm/src/query/filter-query.builder.ts:361:38)
    at FilterQueryBuilder.select (/home/lean/projects/crm/packages/query-typeorm/src/query/filter-query.builder.ts:106:12)
    at CustomersQueryService.query (/home/lean/projects/crm/packages/query-typeorm/src/services/typeorm-query.service.ts:87:40)
    at CustomersQueryService.query (webpack://becamex/nest.api.receivables/src/app/graphql/customers/customers-query.service.ts:27:1)
    at ConnectionType.createFromPromise.filter (/home/lean/projects/crm/packages/query-graphql/src/resolvers/read.resolver.ts:123:26)
    at OffsetPager.runQuery (/home/lean/projects/crm/packages/query-graphql/src/types/connection/offset/pager/pager.ts:40:25)
    at OffsetPager.page (/home/lean/projects/crm/packages/query-graphql/src/types/connection/offset/pager/pager.ts:26:32)"

[TriPSs]

Try this:

@ObjectType('Customer')
@UnPagedRelation('contracts', () => ContractDto)
@BeforeQueryMany((query: Query<CustomerDto>, context: any) => {
  if (query.filter) {
    return {
      ...query,
      filter: mergeFilter(query.filter, {
        contracts: {
          customerCode: {
            isNot: null
          }
        }
      })
    }
  }
  return query
})
export class CustomerDto {
  @IDField(() => String)
  code: string

  @FilterableField()
  name: string
}

[kynt-lean]

Thank you for the suggestion on using helpers related to query. I realized the issue was with the query layer of Persistence, not with filtering on the relation in GraphQL. Then I found an API related to FilterQueryBuilder, specifically filterQueryBuilder.select(query), which allows me to work directly with the query builder of the Persistence provider.

@Injectable()
export class CustomersQueryService extends TypeOrmQueryService<Customer> {
  constructor(@InjectFastRepository(Customer) repo: Repository<Customer>) {
    super(repo);
  }

  query(query: Query<Customer>, opts?: QueryOptions<Customer> | undefined): Promise<Customer[]> {
    const qb = this.filterQueryBuilder.select(query); // This is instance of typeorm SelectQueryBuilder

    qb.innerJoin(Contract, 'Contract', 'Customer.code = Contract.customerCode');

    if (opts?.withDeleted) {
      qb.withDeleted();
    }

    return qb.getMany();
  }
}