I have a NestJS App and I have a Class where the app generates multiple instances from. Inside that class I need to access a service method but I dont know how to inject a service into a plain class.
This is the service I want to use inside the class "Stream"
import { Injectable } from '#nestjs/common';
import * as technicalindicators from 'technicalindicators';
import { CandleIndex } from 'src/utils/CandleIndex';
import * as ccxt from 'ccxt';
#Injectable()
export class AnalysisService {
async RSI(ohlcv: ccxt.OHLCV[], period: number) {
const close = ohlcv.map((candle) => candle[CandleIndex.CLOSE]);
const result = technicalindicators.rsi({ values: close, period: period });
return result;
}
}
import { AnalysisService } from './analysis.service';
import { Module } from '#nestjs/common';
#Module({
imports: [],
controllers: [],
providers: [AnalysisService],
exports: [AnalysisService],
})
export class AnalysisModule {}
Here is the class I want to get access to the analysis service. The class is a normal typescript class, its not part of any module.
export class Stream {
private exchange: ccxt.Exchange;
private market: ccxt.Market;
private timeframe: string;
private ohlcv_cache: ccxt.OHLCV[];
private createdAt: Date;
private stream;
#Inject(AnalysisService)
private readonly analysisService: AnalysisService;
constructor(exchange: ccxt.Exchange, market: ccxt.Market, timeframe: string) {
this.exchange = exchange;
this.market = market;
this.timeframe = timeframe;
this.createdAt = new Date();
this.initialize();
console.log(this.analysisService);
}
}
When I do this and call a method of the analysis service inside of the Stream class, analysisService is undefined.
As you're calling new Stream() yourself, Nest will do no injection for you. You'd need to either pass the AnalysisService instance yourself, or you'd need to create a setter for that property before running any methods that need the AnalysisService.
Related
In NestJS, I have to use a module service into an entity/model to populate data into elastic-search index. populating elastic search index logic is written in Job.service.ts.
I want to call that onCreate method from Job.service.ts from sequelize hooks present in models.
Here is code for Job.ts model/entity -
import { Table, Model, Column, AutoIncrement, PrimaryKey } from "sequelize-typescript";
#Table({ schema: "job", tableName: "job" })
export class Job extends Model<Job> {
#AutoIncrement
#PrimaryKey
#Column
id: number;
#Column
title: string;
#AfterCreate
static async jobAfterCreate(instance, options) {
// <--- need to call job service onCreate method here
}
#AfterUpdate
static async jobAfterUpdate() {}
#AfterDestroy
static async jobAfterDestroy() {}
}
and here is code for Job.service.ts -
//imports not added
#Injectable()
export class JobService {
constructor(
#Inject("SEQUELIZE")
private readonly sequelizeInstance: Sequelize,
#Inject(forwardRef(() => ElasticsearchService))
private readonly elasticsearchService: ElasticsearchService,
#InjectModel(Job)
private jobModel: typeof Job
) {}
// here will write logic for updating elastic search index
async onCreate(instance, options){
console.log("ON CREATE INSTANCE:", instance);
console.log("ON CREATE OPTIONS:", options);
}
async onDestroy(instance, options){
console.log("ON DESTROY INSTANCE:", instance);
console.log("ON DESTROY OPTIONS:", options);
}
}
I tried injecting service into Job model but it did not worked.
And I cannot write elastic search logic inside model directly because for that I need ElasticsearchService.
The Solution is To Override the provider
The primary way to inject information into the models is by overriding the injection behavior.
First, you would need to add a static property referencing the service in your model.
I am going to use the event emitter as an example here.
Your Model Class
import {Model, Table, Column, AfterCreate} from "sequelize-typescript";
import { EventEmitter2 } from "#nestjs/event-emitter";
#Table()
export class SomeModel extends <SomeModel> {
// this would be your referencing
public static EventEmitter: EventEmitter2;
#Column
public someColumn: string;
#AfterCreate
public static triggerSomeEvent(instance: SomeModel) {
SomeModel.EventEmitter.emit('YourEvent', instance);
}
}
The module where you are going to use the model
Now we are overriding the default injection process.
import { EntitiesMetadataStorage } from '#nestjs/sequelize/dist/entities-metadata.storage';
import {
getConnectionToken,
getModelToken,
SequelizeModule,
} from '#nestjs/sequelize';
import { EventEmitter2 } from '#nestjs/event-emitter';
// The provider override
const modelInjector: Provider = {
provide: getModelToken(AccountabilityPartnerModel, DEFAULT_CONNECTION_NAME),
useFactory: (connection: Sequelize, eventEmitter: EventEmitter2) => {
SomeModel.EventEmitter = eventEmitter;
if (!connection.repositoryMode) {
return SomeModel;
}
return connection.getRepository(SomeModelas any);
},
inject: [getConnectionToken(DEFAULT_CONNECTION_NAME), EventEmitter2],
};
// Updating the meta information of sequelize-typescript package to handle connection injection in to the model overridden.
EntitiesMetadataStorage.addEntitiesByConnection(DEFAULT_CONNECTION_NAME, [
SomeModel,
]);
// our custom module being used rather than the Sequelize.forFeature([SomeModel])
const someModelModule: DynamicModule = {
module: SequelizeModule,
providers: [modelInjector],
exports: [modelInjector],
};
#Module({
imports: [someModelModule],
providers: [SomeService],
})
export class SomeModule {
}
Inject your model into your service as you would do using Sequlize.forFeature and InjectModel indicated as below.
#Injectable()
export class SomeService {
constructor(#InjectModel(SomeModel) someModel: typeof SomeModel) {}
public someFunction(data: any) {
this.someModel.EventEmitter.emit('YourEvent', data);
}
}
I have a class that is not related to any nest modules. I wanted to import and use my ConfigService inside of this class. Can I do this without adding this class to any module or do I need to have a module in order to use nest generated classes?
Thanks
You can create on class like below
import { Injectable } from '#nestjs/common';
import { ConfigService } from '#nestjs/config';
#Injectable()
export class AppConfig {
static service: ConfigService;
constructor(service: ConfigService) {
AppConfig.service = service;
}
static get(key: string): any {
return AppConfig.service.get(key);
}
}
add this class as a provider in your root module AppModule,
...
providers: [AppConfig],
...
now once the app is booted, you can use it as following anywhere inside app,
AppConfig.get('database.port');
Hope this helped!
Yep, you can get anything from Nest.js DI container using app.get method.
e.g.
const configService = app.get(ConfigService)
Building on Vinayak Sarawagi's solution, you can even do this inside your custom ConfigModule:
import { Injectable } from '#nestjs/common'
import { ConfigService } from '#nestjs/config'
#Injectable()
export class MyConfigService {
static config: MyConfigService
constructor(private configService: ConfigService) {
MyConfigService.config = this
}
get isDevelopment(): boolean {
return this.configService.get('NODE_ENV') === 'development'
}
}
you can then use whatever private property you have on that service
AppConfig.config.isDevelopment
See the linked answer for details how to export the module globally.
I have an app that receives a service as a dependency on the controller, so far so good, but I would like to find a way to instead of declaring the specific implementation of that service, to be able to "ask" from the controller for the interface that this service implements to decouple of the concrete implementation of that service. How is this done in nest js?
To do this you have to create an injection token for your interface and use the #Inject() decorator with the injection token when injecting your service. Then in your module you can declare which implementation to provide for that injection token.
Below is a simple greeting service interface and our injection token that will be used when registering our service as a provider.
greeting-service.interface.ts
// This will be our injection token.
export const GREETING_SERVICE = 'GREETING SERVICE';
export interface IGreetingService {
greet(name: string): Promise<string>;
}
A basic service that will implements our greeting interface...
professional-greeting.service.ts
import { Injectable } from '#nestjs/common';
import { IGreetingService } from './greeting-service.interface';
#Injectable()
export class ProfessionalGreetingService implements IGreetingService {
public async greet(name: string): Promise<string> {
return `Hello ${name}, how are you today?`;
}
}
And our greeting module where we register our service using the token...
greeting.module.ts
import { Module } from '#nestjs/common';
import { ProfessionalGreetingService } from './services/professional-greeting.service';
import { GREETING_SERVICE } from './services/greeting-service.interface';
import { GreetingController } from './controllers/greeting.controller';
#Module({
providers: [
{
// You can switch useClass to different implementation
useClass: ProfessionalGreetingService,
provide: GREETING_SERVICE
}
],
controllers: [
GreetingController
]
})
export class GreetingModule {}
Now when we inject our service, we can use the #Inject() decorator with our injection token. Whichever implementation you provived to useClass in our GreetingModule will be injected...
greeting.controller.ts
import { Controller, Get, Inject, Query } from '#nestjs/common';
import { GREETING_SERVICE, IGreetingService } from '../services/greeting-service.interface';
#Controller('greeting')
export class GreetingController {
constructor(
#Inject(GREETING_SERVICE)
private readonly _greetingService: IGreetingService
) {}
#Get()
public async getGreeting(#Query('name') name: string): Promise<string> {
return await this._greetingService.greet(name || 'John');
}
}
https://jasonwhite.xyz/posts/2020/10/20/nestjs-dependency-injection-decoupling-services-with-interfaces/
https://github.com/jmw5598/nestjs-di-decoupling-with-interfaces
https://docs.nestjs.com/fundamentals/custom-providers
I am working on an API with NestJS, and because I have DTO's I am using an AutoMapper (made by #nartc and/or nestjsx), I have tried to make my example as small as I could with the Foo example, because I use multiple files.
This is my module:
// foo.module.ts
import { Module } from "#nestjs/common";
import { MongooseModule } from "#nestjs/mongoose";
import { Foo, FooSchema } from "./foo.entity.ts";
import { FooController } from "./foo.controller.ts";
import { FooService } from "./foo.service.ts";
import { FooProfile } from "./foo.profile.ts";
#Module({
imports: [
MongooseModule.forFeature([
{
name: Foo.name,
schema: FooSchema,
collection: "foos",
}
])
// FooProfile <-- if I uncomment this, the program will give the error (shown at the bottom of this question)
],
controllers: [FooController],
providers: [FooProivder],
})
export class FooModule {}
This is my entity:
// foo.entity.ts
import { Schema, SchemaFactory, Prop } from "#nestjs/mongoose";
import { Document } from "mongoose";
#Schema()
export class Foo extends Document { // if I remove the `extends Document` it works just fine
#Prop({ required: true })
name: string;
#Prop()
age: number
}
export const FooSchema = SchemaFactory.createForClass(Foo);
This is my DTO:
// foo.dto.ts
export class FooDTO {
name: string;
}
This is my controller:
// foo.controller.ts
import { Controller, Get } from "#nestjs/common";
import { InjectMapper, AutoMapper } from "nestjsx-automapper";
import { Foo } from "./foo.entity";
import { FooService } from "./foo.service";
import { FooDTO } from "./dto/foo.dto";
#Controller("foos")
export class FooController {
constructor(
private readonly fooService: FooService
#InjectMapper() private readonly mapper: AutoMapper
) {}
#Get()
async findAll() {
const foos = await this.fooService.findAll();
const mappedFoos = this.mapper.mapArray(foos, Foo, FooDTO);
// ^^ this throws an error of the profile being undefined (duh)
return mappedFoos;
}
}
This is my profile:
// foo.profile.ts
import { Profile, ProfileBase, InjectMapper, AutoMapper } from "nestjsx-automapper";
import { Foo } from "./foo.entity";
import { FooDTO } from "./foo.dto";
#Profile()
export class FooProfile extends ProfileBase {
constructor(#InjectMapper() private readonly mapper: AutoMapper) {
// I've read somewhere that the `#InjectMapper() private readonly` part isn't needed,
// but if I exclude that, it doesn't get the mapper instance. (mapper will be undefined)
super();
this.mapper.createMap(Foo, FooDTO);
}
}
If I uncomment the line I highlighted in the module, it will result in the following error..
[Nest] 11360 - 2020-08-18 15:53:06 [ExceptionHandler] Cannot read property 'plugin' of undefined +1ms
TypeError: Cannot read property 'plugin' of undefined
at Foo.Document.$__setSchema ($MYPATH\node_modules\mongoose\lib\document.js:2883:10)
at new Document ($MYPATH\node_modules\mongoose\lib\document.js:82:10)
at new Foo($MYPATH\dist\foo\foo.entity.js:15:17)
I have also referred to this answer on stackoverflow, but that doesn't work for me either. I have also combined that with the documentation, but with no luck.. How would I get the AutoMapper to register my profiles?
Update
The error seems to originate from the foo entity, if I remove the extends Document and the Schema(), Prop({ ... }) from the class it works fine, it seems like I have to inject mongoose or something?
In your module, just import the path to the profile like below:
import 'relative/path/to/foo.profile';
By importing the path to file, TypeScript will include the file in the bundle and then the #Profile() decorator will be executed. When #Profile() is executed, AutoMapperModule keeps track of all the Profiles then when it's turn for NestJS to initialize AutoMapperModule (with withMapper() method), AutoMapperModule will automatically add the Profiles to the Mapper instance.
With that said, in your FooProfile's constructor, you'll get AutoMapper instance that this profile will be added to
#Profile()
export class FooProfile extends ProfileBase {
// this is the correct syntax. You would only need private/public access modifier
// if you're not going to use this.mapper outside of the constructor
// You DON'T need #InjectMapper() because that's Dependency Injection of NestJS.
// Profile isn't a part of NestJS's DI
constructor(mapper: AutoMapper) {
}
}
The above answer will solve your problems with AutoMapper. As far as your Mongoose problem, I would need a sample repro to tell for sure. And also, visit our Discord for this kind of question.
What worked for me.
1. Updated all the absolute paths for models, schemas, entities (is easy if you search for from '/src in your projects, and update all the routes to relative paths)
from:
import { User } from 'src/app/auth/models/user/user.entity';
to:
import { User } from './../../auth/models/user/user.entity';
2. mongoose imports:
from:
import mongoose from 'mongoose';
to:
import * as mongoose from 'mongoose';
3. Remove validation pipe if you don't use it. For some reason (I think i don't use them on the controller, I didn't investigate, I've removed from one controller the Validation Pipe) so If you have this try it:
from:
#Controller('someroute')
#UsePipes(new ValidationPipe())
export class SomeController {}
to:
#Controller('someroute')
export class SomeController {}
I hope my solution worked for you ^_^
i'm pretty new in nestJS, so you can address me directly to documentation if my question was covered there, but i can't figure out how to create instance of none-injectable class.
Here is simplified version of code
export default class BoardingPass {
constructor(
orderId: string,
companyIATa: string,
token: string,
private readonly checkinOrder = new CheckinOrder(orderId, companyIATa, token) // <-- i need to instantiate CheckinOrder
) {}
}
So i need to instantiate the CheckinOrder class but it requires ApolloClient which can be provided only via nestJS DI mechanism
export default class CheckinOrder implements ICheckinOrder {
private order: CheckinOrderObject;
constructor(
private readonly id: string,
private readonly carrierIATACode: string,
private readonly accessToken: string,
private readonly apolloClient: ApolloClient<NormalizedCacheObject> // can't figure out how to pass it via DI
) {}
}
update
Read about custom providers, it seems like it what i need, but as you can see there is some dynamic arguments passed to init method of CheckinOrder
const checkinOrderProvider: Provider<CheckinOrder> = {
useFactory: apolloClient => new CheckinOrder('1', '2', '3', apolloClient),
provide: CheckinOrder,
inject: [ApolloClient]
};
#Module({
imports: [ConfigModule.forRoot(), ApolloClientModule],
providers: [checkinOrderProvider],
exports: [checkinOrderProvider]
})
export class GooglePayModule {}
and only Apollo client is static, so its still unclear how to implement regular interface composition when class Boarding pass has instance of class CheckinOrder as property :(
You can provide the factory method and use it somewhere to create your service just in time. As we do here:
https://github.com/valueadd-poland/pimp-my-pr/blob/master/libs/server/repository/infrastructure/src/lib/repositories/repository-repository.adapter.ts#L18