How do I configure NestJS to run mongosh scripts

Question

I have the need to dynamically create mongo databases when a new user is registered on a SaaS platform.

How do I configure NestJS to run the scripts needed, to create the database, as well as how to dynamically connect with database created for each user?

And are there any better approaches to my usecase?

New User => Create New Database for them, and store details in the main SaaS database.

When user login, fetch DB details from main database, and create a connection to it, to read their data.

Please provide enough code so others can better understand or reproduce the problem. — Community, Sep 10 '21 at 09:04
Kindly check the correct answer, I was able to work around it. — Muhammad Khalil, Sep 10 '21 at 14:13

score 0 · Answer 1 · answered Sep 09 '21 at 11:25

0

I don't see the need to create a new db for each user. Why not craeting a users collection and than for each user create a new object. Mongo object can store quite a lot of information.

I'm not a pro in nestjs, but I don't think that there is a way to dynamically connect more db's. When you start your app a mongoDB instance is initiated, don't forget that all classes in nestjs are singletones.

answered Sep 09 '21 at 11:25

Stefan Drl

53
7

Please provide additional details in your answer. As it's currently written, it's hard to understand your solution. – Community Sep 09 '21 at 12:43
Happens that I was able to work it out, I'll post the workaround shortly. – Muhammad Khalil Sep 10 '21 at 14:00

score 0 · Accepted Answer · edited Sep 10 '21 at 14:17

So, I was able to make it thus.

I created a database service class, in it, I used the MongooseModuleOptions to create a new connection, and injecting the Request Scope to it, I extracted the database name from the request and dynamically pass it to the uri in the createMongooseOptions method and that dynamically creates a connection.

import { Inject } from '@nestjs/common';
import { MongooseOptionsFactory, MongooseModuleOptions } from '@nestjs/mongoose';
import { REQUEST } from '@nestjs/core';
import { Request } from 'express';


export class DatabaseService implements MongooseOptionsFactory{
    constructor(
        @Inject(REQUEST) private readonly request: Request) {
    }

    createMongooseOptions(): MongooseModuleOptions {
        const urii = process.env.CLUSTER+'/'+this.request.body.dbName+"?retryWrites=true&w=majority"
        return {
            uri: urii
        };
    }  
}

Then inside the users module, I insert data into a collection specified inside the schema, and that automatically uses the connection to create a database, collection and entry, if it exists, it uses the database and collection.

import { Inject, Injectable } from '@nestjs/common';
import { CreateUserDto } from './dto/create-user.dto';
import { User, UserDocument } from './schemas/user.schema';
import { InjectConnection, InjectModel } from '@nestjs/mongoose';
import { Model } from 'mongoose';

@Injectable()
export class UserService {
  constructor(@InjectModel(User.name) private userModel:Model<UserDocument>){}
  
  async create(createUserDto: CreateUserDto) {
    const createdUser = new this.userModel(createUserDto)
    return createdUser.save()
  }

}

That worked perfectly for me.

Thank you all

How do I configure NestJS to run mongosh scripts

2 Answers2