I need suggestion in saving logs in NestJS - nestjs

Question

I need suggestion about how to properly or most efficient way to save user logs in database.
So I want to log every time the user do CRUD. I want to save the
userId
event or the action, if he did he remove or update
the Json response of the api
and also the request response of the api.
what I have, in user service layer I call another service name auditService which insert the logs in database.
async create(createUserDto: CreateUserDto): Promise<User> {
try {
const user = new User();
user.email = createUserDto.email;
user.role = createUserDto.role;
user.firstName = createUserDto.firstName;
user.lastName = createUserDto.lastName;
const rs = await this.usersRepository.save(user);
const audit = new AuditLog();
audit.userId = rs.id;
audit.eventType = CREATE_CUSTOMER_SUCESS;
audit.rqMessage = createUserDto;
audit.rsMessage = rs;
//Audit Service which save the logs.
await this.auditService.create(audit);
return rs;
} catch (err) {
// Error
}
Well, this works. but I know there is more efficient way than this. Thank you.

Answer 1

To have full access over request and Response, the best way is by setting a Logger Interceptor or Middleware.
For example, if you are keeping the log to MongoDB, here is an example:
#Injectable()
export class LoggingInterceptor implements NestInterceptor {
constructor(#InjectModel('Log') private logModel: Model<LogDocument>) {}
intercept(context: ExecutionContext, next: CallHandler): Observable<any> {
const req = context?.switchToHttp()?.getRequest<Request>();
const { statusCode } = context?.switchToHttp()?.getResponse<Response>();
const { originalUrl, method, params, query, body, headers, user } = req;
const requestTime = new Date();
const request: RequestInterface = {
originalUrl,
method,
params,
query,
body,
headers,
};
return next.handle().pipe(
tap((data) => {
const response = { statusCode, data };
this.insertMongo(originalUrl, request, response, requestTime);
}),
);
}
private async insertMongo(
endpoint: string,
request: RequestInterface,
response: ResponseInterface,
requestTime: Date,
): Promise<LogDocument> {
const logInfo: CreateLogDto = {
endpoint,
request,
response,
requestTime,
};
const createdLog = new this.logModel(logInfo);
return createdLog.save();
}
}
It will handle the Request, Response, Context, and Timestamp of every request intercepted.
To use it in a module, you just have to add an APP_INTERCEPTOR provider to it. In the case of the example logger, it should look like this:
providers: [
{ provide: APP_INTERCEPTOR, useClass: LoggingInterceptor },
],