NestJS - 每个模块使用多个 MongoDB 连接

Question

有没有办法为每个模块连接多个 MongoDB 连接？

app.module.ts

@Module({
  imports: [
    MongooseModule.forRoot('mongodb://localhost/masterDB'),
    UserModule,
  ],
  controllers: [AppController],
  providers: [AppService],
})
export class AppModule { }

同样，我们可以在另一个模块中定义另一个连接，它是 app.module 的子模块吗？

子模块.ts

@Module({
  imports: [
    MongooseModule.forRoot('mongodb://localhost/childDB'),
    MongooseModule.forFeature([{ name: 'child', schema: ChildSchema }]),
  ],
  controllers: [ChildController],
  providers: [ChildService],
})
export class ChildModule { }

或以任何其他方式同时访问不同的数据库。

提前致谢！

Answer 1

[2021 年 3 月已解决]

在这里您将找到解决方案：

https://www.learmoreseekmore.com/2020/04/nestjs-multiple-mongodb-databases.html

import { Module } from '@nestjs/common';
import { MongooseModule } from '@nestjs/mongoose';
import { studentSchema } from './schemas/myworld/student.schema';
import { animalSchema } from './schemas/wildlife/animal.schema';

@Module({
  imports: [
    MongooseModule.forFeature([
      {
        name: 'Student',
        schema: studentSchema,
        collection: 'Student',
        
      },
    ],'myWorldDb'),
    MongooseModule.forFeature([
      {
        name: 'Animals',
        schema: animalSchema,
        collection: 'Animals'
      }
    ],'wildLifeDb'),
    MongooseModule.forRoot(
      'mongodb+srv://<userName>:<password>@cluster0-igk.mongodb.net/MyWorld?retryWrites=true&w=majority',
      {
        connectionName: 'myWorldDb'
      }
    ),
    MongooseModule.forRoot(
      'mongodb+srv://<username>:<password>@cluster0-igk.mongodb.net/WildLife?retryWrites=true&w=majority',
      {
        connectionName: 'wildLifeDb'
      }
    )

  ],
  controllers: [],
  providers: [],
})
export class AppModule {}

Answer 2

您必须手动执行此操作，您必须使用提供程序文件：

猫鼬.providers.ts

import * as mongoose from 'mongoose';

export const mongooseProviders = [
  {
    provide: 'MASTER_CONNECTION',
    useFactory: (): Promise<typeof mongoose> =>
      mongoose.connect('mongodb://localhost/masterDB'),
  },
  {
    provide: 'CHILD_CONNECTION',
    useFactory: (): Promise<typeof mongoose> =>
      mongoose.connect('mongodb://localhost/ChildDB'),
  },
];

猫鼬.module.ts

import { Module } from '@nestjs/common';
import { mongooseProviders } from './mongoose.providers';

@Module({
  providers: [...mongooseProviders],
  exports: [...mongooseProviders],
})
export class MongooseModule {}

模型.providers.ts

import { Connection } from 'mongoose';
import { ChildSchema } from './schemas/child/child.schema';
import { MasterSchema } from './schemas/master/master.schema';

export const modelProviders = [
  {
    provide: 'CHILD_MODEL',
    useFactory: (connection: Connection) => connection.model('Child', ChildSchema),
    inject: ['CHILD_CONNECTION'],
  },
  {
    provide: 'MASTER_MODEL',
    useFactory: (connection: Connection) => connection.model('Master', MasterSchema),
    inject: ['MASTER_CONNECTION'],
  },
];

在构造函数上，您使用 @Inject 而不是使用 @InjectModel：

@Injectable
export Class ModelService {
  constructor(@Inject('MASTER_MODEL') private masterModel: Model<Master>) {}
...

注意：在您提供服务的模块中，您应该导入 MongooseModule 并将其作为提供者 modelProviders。