Saving Alamofire request data into a variable - swift

Question

I'm having troubles with getting password salt from my VM server via Alamofire. I'm making a request to server and it should return me salt, so I can salt my password, hash it and send it back to server.
The problem is that I do not understand how to save the salt, that Alamofire receives, into a variable, so I can just add it to password and hash it like that:
let salted_password = user_password + salt
let hash = salted_password.sha1()
Where user_password is what the user entered into password field and salt is what I got from Alamofire salt request.
Here is my code:
func getSalt(completionHandler: #escaping (DataResponse<String>, Error?) -> Void) {
Alamofire.request("http://192.168.0.201/salt", method: .post, parameters: salt_parameters).responseString { response in
switch response.result {
case .success(let value):
completionHandler(response as DataResponse<String>, nil)
case .failure(let error):
completionHandler("Failure", error)
}
}
}
let salt = getSalt { response, responseError in
return response.result.value!
}
It gives me the following error:
Binary operator '+' cannot be applied to operands of type 'String' and '()'.
So is it possible to save a request value into a variable? What should I do?
Thank you for your attention.

Answer 1

The problem here is because of how you implemented your completion block
For example:
func someAsynchronousCall(a: Int, b: Int, #escaping block: (_ result: Int) -> Void) {
... some code here
... {
// let's just say some async call was done and this code is called after the call was done
block(a + b)
}
}
To use this code it would look like this:
var answer: Int = 0
someAsynchronousCall(100, b: 200) { result in // the `result` is like what you're returning to the user since API calls need to be called asynchronously you do it like this rather than creating a function that has a default return type.
answer = result
print(answer)
}
print(answer)
The print would look like this
0
300
Since we declared answer as 0 it printed that first since the async call wasn't done yet, after the async call was done (usually a few milliseconds after) it then printed 300
So all in all your code should look something like this
var salt: String?
getSalt { response, responseError in
salt = response.result.value
}