Description

Express Cassandra utilities module for NestJS based on the express-cassandra package.

Installation

$ npm i --save @iaminfinity/express-cassandra

Usage

Import ExpressCassandraModule:

@Module({
  imports: [
    ExpressCassandraModule.forRoot({...})
  ],
  providers: [...]
})
export class AppModule {}

Async options

Quite often you might want to asynchronously pass your module options instead of passing them beforehand. In such case, use registerAsync() method, that provides a couple of various ways to deal with async data.

1. Use factory

ExpressCassandraModule.forRootAsync({
  useFactory: () => ({...}),
})

Obviously, our factory behaves like every other one (might be async and is able to inject dependencies through inject).

ExpressCassandraModule.forRootAsync({
  imports: [ConfigModule],
  useFactory: (configService: ConfigService) => configService.getDbConfig(),
  inject: [ConfigService],
})

2. Use class

ExpressCassandraModule.forRootAsync({
  useClass: ConfigService,
})

Above construction will instantiate ConfigService inside ExpressCassandraModule and will leverage it to create options object.

class ConfigService implements ExpressCassandraOptionsFactory {
  createExpressCassandraOptions(): ExpressCassandraModuleOptions {
    return {...};
  }
}

3. Use existing

ExpressCassandraModule.forRootAsync({
  imports: [ConfigModule],
  useExisting: ConfigService
})

It works the same as useClass with one critical difference - ExpressCassandraModule will lookup imported modules to reuse already created ConfigService, instead of instantiating it on its own.

ORM Options

import { Entity, Column } from '@iaminfinity/express-cassandra';

@Entity({
  table_name: 'photo',
  key: ['id'],
})
export class PhotoEntity {
  @Column({
    type: 'uuid',
    default: { $db_function: 'uuid()' },
  })
  id: any;

  @Column({
    type: 'text',
  })
  name: string;
}

Let's have a look at the PhotoModule

import { Module } from '@nestjs/common';
import { ExpressCassandraModule } from '@iaminfinity/express-cassandra';
import { PhotoService } from './photo.service';
import { PhotoController } from './photo.controller';
import { PhotoEntity } from './photo.entity';

@Module({
  imports: [ExpressCassandraModule.forFeature([PhotoEntity])],
  providers: [PhotoService],
  controllers: [PhotoController],
})
export class PhotoModule {}

This module uses forFeature() method to define which entities shall be registered in the current scope. Thanks to that we can inject the PhotoEntity to the PhotoService using the @InjectModel() decorator:

import { Injectable } from '@nestjs/common';
import { InjectModel, BaseModel } from '@iaminfinity/express-cassandra';
import { PhotoEntity } from './photo.entity';

@Injectable()
export class PersonService {
  constructor(
    @InjectModel(PhotoEntity)
    private readonly photoEntity: BaseModel<PhotoEntity>
  ) {}

  getByName(name: string): Promise<PhotoEntity> {
    return this.photoEntity.findOneAsync({ name: name }, { raw: true });
  }
}

Using Column Decorators: To auto-generate uuid/timeuuid column, you need to decorate an entity's properties you want to make into a auto-generated uuid/timeuuid column with a @GeneratedUUidColumn decorator.

import { Entity, Column, GeneratedUUidColumn } from '@iaminfinity/express-cassandra';

@Entity({
  table_name: 'photo',
  key: ['id'],
})
export class PhotoEntity {
  @GeneratedUUidColumn()
  id: any;

  @GeneratedUUidColumn('timeuuid')
  time_id: any;

  @Column({
    type: 'text',
  })
  name: string;
}

To auto-generate createdDate/updatedDate column, you need to decorate an entity's properties you want to make into a auto-generated createdDate/updatedDate column with a @CreateDateColumn or @UpdateDateColumn decorator.

To index a column, you need to decorate an entity's properties you want to index with a @IndexColumn decorator.

To auto-generate version column, you need to decorate an entity's properties you want to make into a auto-generated version column with a @VersionColumn decorator.

import { 
  Entity,
  Column,
  GeneratedUUidColumn,
  CreateDateColumn,
  UpdateDateColumn,
  IndexColumn,
  VersionColumn,
} from '@iaminfinity/express-cassandra';

@Entity({
  table_name: 'photo',
  key: ['id'],
})
export class PhotoEntity {
  @GeneratedUUidColumn()
  id: any;

  @GeneratedUUidColumn('timeuuid')
  time_id: any;

  @Column({
    type: 'text',
  })
  @IndexColumn()
  name: string;

  @CreateDateColumn()
  created_at: Date;

  @UpdateDateColumn()
  updated_at: Date;

  @VersionColumn()
  __v1: any;
}

Using Hook Function Decorators: An entity of express-cassandra support multiple hook function. For more details see.

To create hook function in an entity use @BeforeSave, @AfterSave, @BeforeUpdate, @AfterUpdate, @BeforeDelete, @AfterDelete decorators.

import { 
  Entity,
  Column,
  GeneratedUUidColumn,
  BeforeSave,
  AfterSave,
  BeforeUpdate,
  AfterUpdate,
  BeforeDelete,
  AfterDelete,
} from '@iaminfinity/express-cassandra';

@Entity({
  table_name: 'photo',
  key: ['id'],
})
export class PhotoEntity {
  @GeneratedUUidColumn()
  id: any;

  @GeneratedUUidColumn('timeuuid')
  time_id: any;

  @BeforeSave()
  beforeSave(instance: this, options: any) {}

  @AfterSave()
  afterSave(instance: this, options: any) {}

  @BeforeUpdate()
  beforeUpdate(query: any, updateValues: any, options: any) {}

  @AfterUpdate()
  afterUpdate(query: any, updateValues: any, options: any) {}

  @BeforeDelete()
  beforeDelete(query: any, options: any) {}

  @AfterDelete()
  afterDelete(query: any, options: any) {}
}

Using Repository

import { Module } from '@nestjs/common';
import { ExpressCassandraModule } from '@iaminfinity/express-cassandra';
import { PhotoService } from './photo.service';
import { PhotoController } from './photo.controller';
import { PhotoEntity } from './photo.entity';

@Module({
  imports: [ExpressCassandraModule.forFeature([PhotoEntity])],
  providers: [PhotoService],
  controllers: [PhotoController],
})
export class PhotoModule {}

import { Injectable } from '@nestjs/common';
import { InjectRepository, Repository } from '@iaminfinity/express-cassandra';
import { PhotoEntity } from './photo.entity';
import { Observable } from 'rxjs';

@Injectable()
export class PersonService {
  constructor(
    @InjectRepository(PhotoEntity)
    private readonly photoRepository: Repository<PhotoEntity>,
  ) {}

  getById(id: id): Observable<PhotoEntity> {
    return this.photoRepository.findOne({id});
  }
}

Using Custom Repository

Let's create a repository:

import { Repository, EntityRepository } from '@iaminfinity/express-cassandra';
import { PhotoEntity } from './photo.entity';
import { Observable } from 'rxjs';

@EntityRepository(PhotoEntity)
export class PhotoRepository extends Repository<PhotoEntity> {
  findById(id: any): Observable<PhotoEntity> {
    return this.findOne({ id: id });
  }
}

Let's have a look at the PhotoModule:

import { Module } from '@nestjs/common';
import { ExpressCassandraModule } from '@iaminfinity/express-cassandra';
import { PhotoService } from './photo.service';
import { PhotoController } from './photo.controller';
import { PhotoEntity } from './photo.entity';
import { PhotoRepository } from './photo.repository';

@Module({
  imports: [ExpressCassandraModule.forFeature([PhotoEntity, PhotoRepository])],
  providers: [PhotoService],
  controllers: [PhotoController],
})
export class PhotoModule {}

Now let's use PhotoRepository in PhotoService:

import { Injectable } from '@nestjs/common';
import { InjectRepository } from '@iaminfinity/express-cassandra';
import { PhotoEntity } from './photo.entity';
import { PhotoRepository } from './photo.repository';
import { Observable } from 'rxjs';

@Injectable()
export class PersonService {
  constructor(
    @InjectRepository(PhotoRepository)
    private readonly photoRepository: PhotoRepository,
  ) {}

  getById(id: any): Observable<PhotoEntity> {
    return this.photoRepository.findById(id);
  }
}

Injecting connection:

import { Injectable } from '@nestjs/common';
import { InjectRepository, InjectConnection } from '@iaminfinity/express-cassandra';
import { PhotoEntity } from './photo.entity';
import { PhotoRepository } from './photo.repository';
import { Observable } from 'rxjs';

@Injectable()
export class PersonService {
  constructor(
    @InjectConnection()
    private readonly connection: Connection,
    @InjectRepository(PhotoRepository)
    private readonly photoRepository: PhotoRepository,
  ) {}

  getById(id: any): Observable<PhotoEntity> {
    return this.photoRepository.findById(id);
  }
}

Using Elassandra

Express cassandra support Elassandra. For more details see.

@Module({
  imports: [
    ExpressCassandraModule.forRoot({
      clientOptions: {
        // omitted other options for clarity
      },
      ormOptions: {
        // omitted other options for clarity
        migration: 'alter',
        manageESIndex: true,
      }
    })
  ],
  providers: [...]
})
export class AppModule {}

import { Entity, Column } from '@iaminfinity/express-cassandra';

@Entity<PhotoEntity>({
  table_name: 'photo',
  key: ['id'],
  es_index_mapping: {
    discover: '.*',
    properties: {
      name : {
        type : 'string',
        index : 'analyzed',
      },
    },
  }
})
export class PhotoEntity {
  @Column({
    type: 'uuid',
    default: { $db_function: 'uuid()' },
  })
  id: any;

  @Column({
    type: 'text',
  })
  name: string;
}

import { Module } from '@nestjs/common';
import { ExpressCassandraModule } from '@iaminfinity/express-cassandra';
import { PhotoService } from './photo.service';
import { PhotoController } from './photo.controller';
import { PhotoEntity } from './photo.entity';

@Module({
  imports: [ExpressCassandraModule.forFeature([PhotoEntity])],
  providers: [PhotoService],
  controllers: [PhotoController],
})
export class PhotoModule {}

import { Injectable } from '@nestjs/common';
import { InjectModel, BaseModel } from '@iaminfinity/express-cassandra';
import { PhotoEntity } from './photo.entity';

@Injectable()
export class PersonService {
  constructor(
    @InjectModel(PhotoEntity)
    private readonly photoEntity: BaseModel<PhotoEntity>
  ) {}

  searchName(name: string): Promise<any> {
    return new Promise((resolve, reject) => {
      this.catModel.search({ q: `name:${name}` }, (err, response) => {
        if (err) {
          return reject(err);
        } else {
          return response(response);
        }
      });
    });
  }
}

Stay in touch

• Author - Fahim Rahman