我基本上遵循本教程并进行了很小的修改:link
我在节点 12.10.0 上使用 Nest 6.14.2。 运行我的应用程序时,我得到:
> recon-backend@0.0.1 start C:\Users\e5553079\Desktop\Node_Projects\recon-backend
> nest start
[Nest] 8324 - 02/10/2020, 9:28:21 AM [NestFactory] Starting Nest application...
[Nest] 8324 - 02/10/2020, 9:28:21 AM [InstanceLoader] MongooseModule dependencies initialized +53ms
[Nest] 8324 - 02/10/2020, 9:28:21 AM [ExceptionHandler] Nest can't resolve dependencies of the ReconQueryService (?). Please make sure that the argument ReconQueryModel at index [0] is available in the AppModule context.
Potential solutions:
- If ReconQueryModel is a provider, is it part of the current AppModule?
- If ReconQueryModel is exported from a separate @Module, is that module imported within AppModule?
@Module({
imports: [ /* the Module containing ReconQueryModel */ ]
})
+2ms
Error: Nest can't resolve dependencies of the ReconQueryService (?). Please make sure that the argument ReconQueryModel at index [0] is available in the AppModule context.
我的文件如下所示:
<强>1。 app.module.ts
import { Module } from '@nestjs/common';
import { AppController } from './app.controller';
import { AppService } from './app.service';
import { MongooseModule } from '@nestjs/mongoose';
import { ReconQueryModule } from './reconQuery/reconQuery.module';
import { ReconQueryService } from './reconQuery/reconQuery.service';
import { ReconQueryController } from './reconQuery/reconQuery.controller';
@Module({
imports: [
MongooseModule.forRoot('mongodb://localhost/backend-app', { useNewUrlParser: true }),
ReconQueryModule
],
controllers: [AppController, ReconQueryController],
providers: [AppService, ReconQueryService],
})
export class AppModule {}
<强>2。 reconQuery.service.ts
import { Injectable } from '@nestjs/common';
import { Model } from 'mongoose';
import { InjectModel } from '@nestjs/mongoose';
import { ReconQuery } from './interfaces/reconQuery.interface';
import { CreateReconQueryDTO } from './dto/create-reconQuery.dto';
@Injectable()
export class ReconQueryService {
constructor(@InjectModel('ReconQuery') private readonly reconQueryModel: Model<ReconQuery>) { }
// Fetch all queries
async getAllQueries(): Promise<ReconQuery[]> {
const queries = await this.reconQueryModel.find().exec();
return queries;
}
...
<强>3。 reconQuery.interface.ts
import { Document } from 'mongoose';
export interface ReconQuery extends Document {
readonly id: number;
readonly name: string;
readonly sql: string;
}
<强>4。 reconQuery.module.ts
import { Module } from '@nestjs/common';
import { ReconQueryController } from './reconQuery.controller';
import { ReconQueryService } from './reconQuery.service';
import { MongooseModule } from '@nestjs/mongoose';
import { ReconQuerySchema } from './schemas/reconQuery.schema';
@Module({
imports: [
MongooseModule.forFeature([{ name: 'ReconQuery', schema: ReconQuerySchema }])
],
controllers: [ReconQueryController],
providers: [ReconQueryService]
})
export class ReconQueryModule {}
我想知道为什么它会提示 ReconQueryModel 因为我没有这样的实体,只有一个 ReconQuery 接口(interface)。
最佳答案
您还有额外的ReconQueryService
提供于AppModule
.
import { Module } from '@nestjs/common';
import { AppController } from './app.controller';
import { AppService } from './app.service';
import { MongooseModule } from '@nestjs/mongoose';
import { ReconQueryModule } from './reconQuery/reconQuery.module';
import { ReconQueryService } from './reconQuery/reconQuery.service';
import { ReconQueryController } from './reconQuery/reconQuery.controller';
@Module({
imports: [
MongooseModule.forRoot('mongodb://localhost/backend-app', { useNewUrlParser: true }),
ReconQueryModule
],
controllers: [AppController, ReconQueryController],
providers: [AppService, ReconQueryService], // <-- this causes the error
})
export class AppModule {}
@InjectModel()
通过调用MongooseModule.forFeature(...)
提供在某个@Module()
。 ReconQueryService
在ReconQueryModule
很好,因为那就是 MongooseModule.forFeature()
如此称呼@InjectModel()
已正确提供。然而,在 AppModule
,你没有MongooseModule.forFeature()
因此 Nest 无法解析 @InjectModel()
对于 ReconQueryService
.
检查您是否确实需要使用 ReconQueryService
在AppModule
(AppModule
中声明的服务和 Controller )。如果不这样做,请删除 ReconQueryService
来自providers
大批。如果您这样做,请转到ReconQueryModule
并执行以下操作:
import { Module } from '@nestjs/common';
import { ReconQueryController } from './reconQuery.controller';
import { ReconQueryService } from './reconQuery.service';
import { MongooseModule } from '@nestjs/mongoose';
import { ReconQuerySchema } from './schemas/reconQuery.schema';
@Module({
imports: [
MongooseModule.forFeature([{ name: 'ReconQuery', schema: ReconQuerySchema }])
],
controllers: [ReconQueryController],
providers: [ReconQueryService],
exports: [ReconQueryService] // <-- add this line
})
export class ReconQueryModule {}
导出的内容将可以在提供它们的模块之外使用。只需将该模块导入到其他地方即可。
关于javascript - Nest无法解析自定义服务的依赖关系,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/60148161/