URL memory leak

Question

Instruments shows that these lines of code cause memory leaks, what am I doing wrong?

   required init(data: JSON) {
        self.type = data["type"].stringValue
        self.name = data["name"].stringValue
        self.numberOfRestaraunts = data["length"].intValue
        self.isFavourited = data["isFavourited"].boolValue
        self.image = URL(string: data["img"].stringValue)! //<- this
        self.id = data["id"].stringValue
        self.headerImage = URL(string: data["header"].stringValue)! //<- this
        if data["colorSchema"].stringValue == "Dark" {
            self.colorTheme = .dark
        } else {
            self.colorTheme = .light
        }
        self.color = data["color"].stringValue
        self.metaScore = data["metaScore"].intValue
        self.typeMetaScore = data["typeMetaScore"].int ?? 0
    }

It actually shows, that leaks are NSURL class.

EDIT: Screenshots:

What kind of leaks is instruments showing? – Eendje Mar 10 '17 at 13:14 — Eendje, Mar 10 '17 at 13:14
@Eendje added screenshots – JuicyFruit Mar 10 '17 at 13:18 — JuicyFruit, Mar 10 '17 at 13:18

score 0 · Answer 1 · answered Mar 10 '17 at 12:59

0

You are force unwrapping the optional objects. Try to change the line self.image = URL(string: data["img"].stringValue)! to

if let url = URL(string: data["img"].stringValue) {
   self.image = url
}

and this self.headerImage = URL(string: data["header"].stringValue)! line to

if let url = URL(string: data["header"].stringValue) {
   self.headerImage = url
}

Force unwrapping is not a good practice, you should avoid it when possible. Hope this helps!

answered Mar 10 '17 at 12:59

Fahri Azimov

11,470
2
21
29

still leaks, in `if let` line – JuicyFruit Mar 10 '17 at 13:13
I don't agree that using force unwrapping is bad practice. If you are sure that in specific situation object must always not be nil, then I would user force unwrapping over optional unwrapping. That is because if later I get error in this place in code, I know that something is wrong with code logic - because I assume that there must not be nil, then when it appears it's better to get an error - then you know that you need to find out why it's not. In any other situation, when optional could be nil, you should use optional unwrapping, but if you are sure - use force. – Damian Dudycz Jul 11 '18 at 13:38
I'm not talking about this situation - but about overall practice. – Damian Dudycz Jul 11 '18 at 13:39

score 0 · Answer 2 · answered Mar 10 '17 at 12:59

0

Could you try this?

if let image_url = URL(string: data["img"].stringValue)
{
    self.image = image_url
}

...and this too...

if let header_url = URL(string: data["header"].stringValue)
{
    self.headerImage = image_url
}

Could you chech if JSON type subscript returns an Optional?

answered Mar 10 '17 at 12:59

Adolfo

1,862
13
19

still leaks, `JSON` returns `String`, not `Optional` – JuicyFruit Mar 10 '17 at 13:13

URL memory leak

2 Answers2