Hi I have the following code in NestJS.I am using moduleRef and have declared a custom provider named 'blogService'.However I am getting an error that says:
'Nest can't resolve dependencies of the blogService (?). Please make sure that the argument BlogModel at index [0] is available in the AppModule context.'
.What exactly am I doing wrong while declaring the custom provider which is leading to this error as it seems that I am injecting the Mongoose Model as well?
app.module.ts
import { BlogService } from './blog/service/blog.service';
import { Blog } from './blog/schema/blog.schema';
import { AppController } from './app.controller';
import { AppService } from './app.service';
import { ConfigModule } from '@nestjs/config';
import { MongooseModule, getModelToken } from '@nestjs/mongoose';
@Module({
imports: [
ConfigModule.forRoot({ isGlobal: true, load: [configuration], }),
MongooseModule.forRoot(process.env.DATABASE_URL)
],
controllers: [AppController],
providers: [AppService, {
provide: 'blogService',
useFactory: () => BlogService,
inject: [getModelToken(Blog.name)]
}],
})
app.controller.ts
import { Controller, Get } from '@nestjs/common';
import { ModuleRef } from '@nestjs/core';
import { BlogService } from './blog/service/blog.service';
@Controller()
export class AppController {
constructor(private readonly modelRef: ModuleRef) { }
@Get('blogs')
async getAllBlogs(): Promise<any> {
const response = await this.modelRef.get('blogService', { strict: false }).getAllBlogs();
return response;
}
}
blog.service.ts
import { Injectable, HttpException, HttpStatus, Logger } from '@nestjs/common';
import { Blog } from '../schema/blog.schema';
import { InjectModel } from '@nestjs/mongoose';
import { Model, Types } from 'mongoose';
@Injectable()
export class BlogService {
private readonly logger = new Logger(BlogService.name);
constructor(@InjectModel(Blog.name) private blogModel: Model<Blog>) { }
async getAllBlogs() {
try {
const blogs = await this.blogModel.find().exec();
return blogs;
} catch (error) {
this.logger.error(error.message);
}
}
}
Not really sure why you're making a custom provider for this, other than possibly academic purposes. Either way, for anything you want to @InjectModel() or use getModelToken() for, you needx to have a MongooseModule.forFeature() call to register the custom provider the @nestjs/mongoose package will create for you. Once you have this you can use @InjectModel() or a custom provider like
{
provide: 'blogService',
inject: [getModelToken(Blog.name)],
useFactory: (model: Model<Blog>) => new BlogService(model)
}