NestJS:通过请求(子域)连接数据库(TypeORM) [英] NestJS : database connection (TypeORM) by request (subdomain)

问题描述

我正在尝试通过 Nest/TypeORM 构建 SAAS 产品，我需要按子域配置/更改数据库连接.

I'm trying to build a SAAS product over Nest/TypeORM and I need to configure/change database connection by subdomain.

customer1.domain.com => connect to customer1 database
customer2.domain.com => connect to customer2 database
x.domain.com => connect to x database

我该怎么做?使用拦截器或请求上下文(或 Zone.js)?

How can I do that ? With interceptors or request-context (or Zone.js) ?

我不知道如何开始.有人已经这样做了吗?

I don't know how to start. Is someone already do that ?

WIP:我目前在做什么:

WIP : what I am currently doing :

1. 将所有连接设置添加到 ormconfig 文件中

2. 在所有路由上创建中间件以将子域注入 res.locals(实例名称)并创建/警告 typeorm 连接

1. add all connections settings into ormconfig file

2. create Middleware on all routes to inject subdomain into res.locals (instance name) and create/warn typeorm connection

import { Injectable, NestMiddleware, MiddlewareFunction } from '@nestjs/common';
import { getConnection, createConnection } from "typeorm";

@Injectable()
export class DatabaseMiddleware implements NestMiddleware {
    resolve(): MiddlewareFunction {
      return async (req, res, next) => {
          const instance = req.headers.host.split('.')[0]
          res.locals.instance = instance

          try {
              getConnection(instance)
          } catch (error) {
              await createConnection(instance)
          }

          next();
      };
    }
}

在控制器中:从@Response 获取实例名称并将其传递给我的服务

in Controller : get instance name from @Response and pass it to my Service

@Controller('/catalog/categories')
export class CategoryController {
    constructor(private categoryService: CategoryService) {}

    @Get()
    async getList(@Query() query: SearchCategoryDto, @Response() response): Promise<Category[]> {
      return response.send(
        await this.categoryService.findAll(response.locals.instance, query)
      )
    }

在服务中:通过 Repository 获取给定实例的 TypeORM Manager 和查询数据库

in Service : get TypeORM Manager for given instance and query database through Repository

@Injectable()
export class CategoryService {
  // constructor(
  //   @InjectRepository(Category) private readonly categoryRepository: Repository<Category>
  // ) {}

  async getRepository(instance: string): Promise<Repository<Category>> {
      return (await getManager(instance)).getRepository(Category)
  }

  async findAll(instance: string, dto: SearchCategoryDto): Promise<Category[]> {
    let queryBuilder = (await this.getRepository(instance)).createQueryBuilder('category')

    if (dto.name) {
        queryBuilder.andWhere("category.name like :name", { name: `%${dto.name}%` })
    }

    return await queryBuilder.getMany();
  }

它似乎有效，但我不确定几乎所有内容:

It seems to work but I not sure about pretty much everything :

• 连接池(我可以在 ConnectionManager 中创建多少个连接?)
• 将子域传递给 response.locals... 不好的做法?
• 可读性/理解性/添加大量额外代码...
• 副作用:我害怕在多个子域之间共享连接
• 副作用:性能

处理 response.send() + Promise + await(s) + 到处传递子​​域不是一件乐事...

It's not a pleasure to deals with response.send() + Promise + await(s) + pass subdomain everywhere...

有没有办法让子域直接进入我的服务?

Is there a way to get subdomain directly into my Service ?

有没有办法让正确的子域连接/存储库直接进入我的服务并将其注入我的控制器?

Is there a way to get correct subdomain Connection/Repository directly into my Service and Inject it into my Controller ?

推荐答案

我想出了另一个解决方案.

I came up with another solution.

我创建了一个中间件来获取特定租户的连接:

I created a middleware to get the connection for a specific tenant:

import { createConnection, getConnection } from 'typeorm';
import { Tenancy } from '@src/tenancy/entity/tenancy.entity';

export function tenancyConnection(...modules: Array<{ new(...args: any[]): 
any; }>) {

  return async (req, res, next) => {

    const tenant = req.headers.host.split(process.env.DOMAIN)[0].slice(0, -1);

    // main database connection
    let con = ...

    // get db config that is stored in the main db
    const tenancyRepository = await con.getRepository(Tenancy);
    const db_config = await tenancyRepository.findOne({ subdomain: tenant });

    let connection;
    try {
       connection = await getConnection(db_config.name);
    } catch (e) {
      connection = await createConnection(db_config.config);
    }

    // stores connection to selected modules
    for (let module of modules) {
      Reflect.defineMetadata('__tenancyConnection__', connection, module);
    }

    next();
  };
}

我将它添加到 main.ts 中:

I added it to the main.ts:

const app = await NestFactory.create(AppModule);
app.use(tenancyConnection(AppModule));

要访问连接，您可以通过以下方式扩展任何服务:

To access the connection you can extend any service by:

export class TenancyConnection {

  getConnection(): Connection {
    return Reflect.getMetadata('__tenancyConnection__', AppModule);
  }
}

它仍然是一个草稿，但使用此解决方案，您可以在运行时为每个租户添加、删除和编辑连接.我希望这能进一步帮助您.

It is still a draft, but with this solution you can add, delete and edit the connection for each tenant at runtime. I hope this helps you further.

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