Vapor 4/Fluent, function with nested database lookup to return return EventLoopFuture<bool>

Question

I'm attempting to write a function that takes in my UserModel, and preforms a couple of checks to see if the user

Is locked
Hasn't attempted too many logins within a time period.

and then returns a Boolean indication of the result.

The lookups work within my Authentication process. But I wanted to break out the code that determines if the user is allowed to (attempt) login so I can use it in more than one place without repeating code.

However (being new to Vapor/Swift) i am getting an error and I cannot work out what I'm doing wrong: Cannot convert return expression of type 'EventLoopFuture' to return type 'Bool'

The Error is on the line }.all().map { (separated onto a line by itself so its easier to find).

Database structure wise I have 2 tables involved:

UserAccess which holds my user profile details (how many bad attempts this user can have, and how far back in the log do we look for login attempts)
UserLog, which hows the login attempts for each user and when they made the attempt

This is my code snippet so far:

func CanUserLogin(user: UserModel, req: Request) -> EventLoopFuture<Bool> {
  if(!(user.locked ?? false)) {
    let userProfileId = user.userprofile

    return Usertype.query(on: req.db)
      .filter(\.$profilenum == userProfileId)
      .first().map { useraccess in
        let badloginperiod = Double((useraccess!.badloginperiod ?? 0) * -1 * 60) // convert minutes to seconds (we need a negative number)
        let lookUpDate = Date().addingTimeInterval(badloginperiod)

        return Userlog.query(on: req.db).group(.and) {
          and in
          and.filter(\.$username == user.username)
          and.filter(\.$datecreated >= lookUpDate)
        }.all().map {
          UserLogs -> Bool in
          let value = userLogs.count

          // the account is locked or the max attempts for the time peroid
          if(value >= (useraccess.maxloginattempts ?? 3)) {
            return false
          } else {
            return true
          }
        }
    }
  }
}

Any direction would be greatly appreciated.

You could read this great article about futures, it should clarify a lot of things 🙂 — imike

imike imike · Accepted Answer · 2020-06-04T06:25:40

You tried to return EventLoopFuture from map block, but you can return only non-future values from it. So instead of map you have to use flatMap on Usertype query.

Checkout this code

func canUserLogin(user: UserModel, req: Request) -> EventLoopFuture<Bool> {
    guard user.locked != true else {
        return req.eventLoop.makeFailedFuture(Abort(.badRequest, reason: "User is locked"))
    }
    let userProfileId = user.userprofile
    return Usertype.query(on: req.db)
        .filter(\.$profilenum == userProfileId)
        .first()
        .unwrap(or: Abort(.forbidden, reason: "No access"))
        .flatMap { userAccess in
            let badloginperiod = Double((useraccess.badloginperiod ?? 0) * -1 * 60) // convert minutes to seconds (we need a negative number)
            let lookUpDate = Date().addingTimeInterval(badloginperiod)
            return Userlog.query(on: req.db).group(.and) {
              $0.filter(\.$username == user.username)
              $0.filter(\.$datecreated >= lookUpDate)
            }.all().map { attempts -> Bool in
                // the account is locked or the max attempts for the time peroid
                if attempts.count >= (userAccess.maxloginattempts ?? 3) {
                    return false
                } else {
                    return true
                }
            }
    }
}

Vapor 4/Fluent, function with nested database lookup to return return EventLoopFuture<bool>

1 Answers