Nest: Middleware : DI not working

[fmeynard]

I'm submitting a...

[x] Bug report
[x] Documentation issue or request

## Current behavior Dependency injection is not working inside a middleware, app is not starting with following error :

web_1    | (node:819) UnhandledPromiseRejectionWarning: Error: Nest can't resolve dependencies of the undefined (?). Please make sure that the argument at index [0] is available in the current context.
web_1    |     at Injector.lookupComponentInExports (/app/node_modules/@nestjs/core/injector/injector.js:146:19)
web_1    |     at process._tickCallback (internal/process/next_tick.js:178:7)
web_1    |     at Function.Module.runMain (internal/modules/cjs/loader.js:721:11)
web_1    |     at Object. (/app/node_modules/ts-node/src/bin.ts:157:12)
web_1    |     at Module._compile (internal/modules/cjs/loader.js:678:30)
web_1    |     at Object.Module._extensions..js (internal/modules/cjs/loader.js:689:10)
web_1    |     at Module.load (internal/modules/cjs/loader.js:589:32)
web_1    |     at tryModuleLoad (internal/modules/cjs/loader.js:528:12)
web_1    |     at Function.Module._load (internal/modules/cjs/loader.js:520:3)
web_1    |     at Function.Module.runMain (internal/modules/cjs/loader.js:719:10)

Expected behavior

As mentioned in the official documentation DI should work

Minimal reproduction of the problem with instructions

HttpLoggerMiddleware

import { Injectable, MiddlewareFunction, NestMiddleware, LoggerService } from '@nestjs/common';

@Injectable()
export class HttpLoggerMiddleware implements NestMiddleware {
  constructor(private readonly logger: LoggerService) {}

  resolve(...args: any[]): MiddlewareFunction {
    return (req, res, next) => {
        this.logger.log(res);

        next();
    };
  }
}


UtilsModule

import { Module, Global, MiddlewareConsumer, RequestMethod } from '@nestjs/common';
import { LoggerService } from './services/logger.service';
import { HttpLoggerMiddleware } from './middlewares/http-logger.middleware';

@Global()
@Module({
  providers: [LoggerService],
  exports: [LoggerService],
})
export class UtilsModule {
    configure(consumer: MiddlewareConsumer) {
        consumer
            .apply(HttpLoggerMiddleware)
            .forRoutes({ path: '*', method: RequestMethod.ALL });
    }
}


LoggerService


import { Injectable } from '@nestjs/common';

@Injectable()
export class LoggerService {
    log(message: string) {
         console.debug(message);
    }   
}

Others:

Code example is obviously a simplified version of the my project, the original goal is to have a custom http logger to send request in a precise format to ELK (gelf).
Middleware is working as soon as i remove the dependency to my LoggerService
In the case that i did something wrong, i think it can be great to add a working example of the DI in the middleware section of the documentation

[weeco]

You have to inject your dependencies into the HttpLoggerMiddleware somewhere. You could try to use an inject token for your LoggerService. I am not sure how the dependency injection inside of a module (instead of a service) works, but personally I'd try to use an inject token in the constructor of your middleware

[fmeynard]

This is exactly what i'm doing with constructor(private readonly logger: LoggerService) {} from HttpLoggerMiddleware
As Logger service is declared as a provider & exported i don't understand why its not working. Same "setup" is working for controllers, services... just not working for middlewares

[weeco]

I don't see any usage of Inject tokens in your pasted code using @Inject()

As I already said: The context is different because you are trying to inject dependencies in a module and not in a service

[kamilmysliwiec]

Duplicate of https://github.com/nestjs/nest/issues/266

[fmeynard]

@kamilmysliwiec

don't think thats a duplicate i'm using target: es6

{ "compilerOptions": { "module": "commonjs", "declaration": true, "noImplicitAny": false, "removeComments": true, "noLib": false, "allowSyntheticDefaultImports": true, "emitDecoratorMetadata": true, "experimentalDecorators": true, "target": "es6", "sourceMap": true, "outDir": "./dist", "baseUrl": "./src" }, "include": [ "src/**/*" ], "exclude": [ "node_modules", "**/*.spec.ts" ] }

And my projects deps :

"dependencies": { "@nestjs/common": "^5.1.0", "@nestjs/core": "^5.1.0", "@nestjs/mongoose": "^5.2.2", "dotenv": "^6.0.0", "mongoose": "^5.2.14", "reflect-metadata": "^0.1.12", "rxjs": "^6.2.2", "typescript": "^3.0.1", "winston": "^3.1.0" },

[kamilmysliwiec]

Notice that:

import { Injectable, MiddlewareFunction, NestMiddleware, LoggerService } from '@nestjs/common';

and

import { LoggerService } from './services/logger.service';

are different (you are trying to inject LoggerService interface from common package)

[lock[bot]]

This thread has been automatically locked since there has not been any recent activity after it was closed. Please open a new issue for related bugs.