@norvento/nest-mssql
v1.0.0
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About
This module provides a thin wrapper around Knex.js. Knex.js is primarily a Query Builder that works with multiple databases.
The module was generated using @nestjsplus/dyn-schematics, a schematics package for NestJS that generates dynamic modules using the pattern described here. There's a complete tutorial on using the custom schematics here.
Installation
npm install @nestjsplus/knex
(or yarn equivalent)
Quick Start
To configure your DB connection, import the KnexModule
module using the familiar register()
/ registerAsync()
pattern. See the example repo for an example. Basically, you configure the module with a Knes.js connection
object, which maps directly to the connection options in the Knex.js docs.
Once configured, inject the SINGLETON
knex api interface object into any service using the KNEX_CONNECTION
injection token.
For example, your AppModule
might look like this (full example in the sample repo):
// src/app.module.ts
import { Module } from '@nestjs/common';
import { AppController } from './app.controller';
import { AppService } from './app.service';
import { ConfigModule } from './config/config.module';
import { ConfigService } from './config/config.service';
import { KnexModule } from '@nestjsplus/knex';
@Module({
imports: [
KnexModule.registerAsync({
useExisting: ConfigService,
}),
ConfigModule,
],
controllers: [AppController],
providers: [AppService],
})
export class AppModule {}
Now you have access to a KNEX_CONNECTION
token that is associated with the Knex.js API, which you can inject into any provider, and use the resulting Knex.js API object directly. For example, you might do this:
// src/app.service.ts
import { Inject, Injectable } from '@nestjs/common';
import { KNEX_CONNECTION } from '@nestjsplus/knex';
@Injectable()
export class AppService {
constructor(@Inject(KNEX_CONNECTION) private readonly knex) {}
async getCats() {
return await this.knex('cats')
.select('*')
.from('cats');
}
...
Here, you've injected the connection as a local property of the service class, and can access any of the Knex.js API through that property (e.g., return await this.knex('cats').select('*').from('cats')
, where knex
represents your Knex.js API object).
Configuring connection options
I'm not showing the ConfigService
in the AppModule
above, but it's just an injectable that implements the KnexOptionsFactory
interface, meaning it has methods to return a KnexOptions
object. A KnexOptions
object looks like:
{
client: 'pg',
debug: true,
connection: {
host: 'localhost',
user: 'john',
password: 'password',
database: 'nest',
port: 5432,
},
}
You can use any of the following methods to provide the KnexOptions
to the module. These follow the usual patterns for custom providers:
register()
: pass a plain JavaScript objectregisterAsync()
: pass a dynamic object via:useFactory
: supply a factory function to return the object; the factory should implement the appropriate options factory interfaceuseClass
: bind to a provider/service that supplies the object; that service should implement the appropriate options factory interfaceuseExisting
: bind to an existing (provided elsewhere) provider/service to supply the object; that service should implement the appropriate options factory interface
Connection availability on application startup
The KNEX_CONNECTION
is an asynchronous provider. This means that the Nest application bootstrap process (specifically, the Dependency Injection phase) won't complete until the DB connection is made. So your app, once it bootstraps, is guaranteed to have a DB connection via the KNEX_CONNECTION
injection token. Note that asynchronous providers must be injected with the @Inject()
decorator instead of normal constructor injection (again, see the example).
Working Example
See knex-cats for a full example. It shows an example of using the KNEX_CONNECTION
, a service that uses it to access a PostgreSQL database, and includes a few of the Knex.js Query Builder features.
About @nestjsplus/dyn-schematics
Nest Dynamic Package Generator Schematics generates a starter template for building NestJS dynamic packages. It uses the @nestjs/cli
core package, and provides customized schematics for generating modular NestJS applications. See here for the full set of available schematics, and documentation. Read these articles for more background:
- Advanced NestJS: How to build completely dynamic NestJS modules - covers the design pattern used by this module
- Build a NestJS Module for Knex.js (or other resource-based libraries) in 5 Minutes - covers a custom schematic that can be used to generate a module template based on this pattern
Change Log
See Changelog for more information.
Contributing
Contributions welcome! See Contributing.
Author
John Biundo (Y Prospect on Discord)
License
Licensed under the MIT License - see the LICENSE file for details.