Services - Definition

Services are the main components of your Eicrud application. They host a CRUD entity as well as CMDs for non-crud operations.

Generate a new service

You can use the CLI to quickly generate a new service.

eicrud generate service profile

An Eicrud service (CrudService) has 3 main components:

An Entity:

services/profile/profile.entity.ts

@Entity()
export class Profile implements CrudEntity {

    @PrimaryKey({ name: '_id' })
    @IsString()
    @IsOptional()
    id: string;

    @Property()
    createdAt: Date;

    @Property()
    updatedAt: Date;

}

It is the database schema as well as the DTO for CRUD operations. In that case, a profile table is created.

A Security:

services/profile/profile.security.ts

export function getSecurity(PROFILE: string): CrudSecurity { 
    return {
        rolesRights: {
            guest: {
                async defineCRUDAbility(can, cannot, ctx) {
                    //rules for guests

                }
            }
        },
    }
}

This is where you define the access rules for your entity. By default, nothing is allowed unless specified in the security.

A Service:

services/profile/profile.service.ts

@Injectable()
export class ProfileService extends CrudService<Profile> {
    constructor(protected modRef: ModuleRef) {
        const serviceName = CrudService.getName(Profile);
        super(modRef, Profile, getSecurity(serviceName));
    }
}

The actual service implementation, it's a NestJS provider that you can use everywhere in your app. This is where the service's configuration is specified.

Info

In a CrudService any function starting with $ may be replaced by an HTTP call, depending on your microservice configuration.

You should always:

• await the result of $ functions
• pass parameters that can be serialized
• return values that can be serialized

Check out this guide to ensure your application can smoothly transition from monolithic to microservices.

Operations

A CrudService handles all CRUD operations out of the box :

• Create: $create, $createBatch
• Read: $findOne, $find, $findIn
• Update: $patchOne, $patch, $patchIn, $patchBatch
• Delete: $deleteOne, $delete, $deleteIn

You can extend it with CMDs for everything else.

Import your service

Since services are NestJS providers, you can inject them anywhere in your app:

@Injectable()
export class UserService extends CrudUserService<User> {
    constructor(
        protected modRef: ModuleRef,
        protected profileService: ProfileService 
    ) {
        super(modRef, User, userSecurity(CrudService.getName(User)));
    }

    async findProfile(query){
        return await this.profileService.$find(query);
    }
}

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