Why can't I convert this String to a URL? - ios

Question

I have x 2 questions about urls and webViews.
Question 1:
I have a string which I am getting from an API that is supposed to be a url. The string is https://godochurch.blob.core.windows.net/sermons/1031/30-1-2017-Vision Sunday-Devotion.mp3
When trying to convert to a url I'm getting nil.
Here is the code:
if let sermonUrl = sermonUrl {
if let url = URL(string: sermonUrl) {
let requestObj = URLRequest(url: url)
webView.loadRequest(requestObj)
}
}
I have worked out that the space between 'Vision' and 'Sunday' is the problem.
Should I be encoding the string in some way before trying to convert it to a URL? What's confusing is that if I paste the string into my browser it works just fine, but I notice the browser is percent encoding the space.
If I am supposed to be encoding the string, how do I do that?
Question 2:
I see that URL(string: "urlStringHere") is only available from iOS 10. My app needs to work for iOS 9. How can I convert the above code so it works on iOS 9 and 10.
Thanks in advance for your time.

Answer 1

1: escape that space with %20 or +:
if let url = URL(string: "https://godochurch.blob.core.windows.net/sermons/1031/30-1-2017-Vision%20Sunday-Devotion.mp3") {
// ...
}
2: URL was introduced with Swift 3, which is compatible with iOS 8 and later. See this question on how to make it work with older versions of iOS.
Edit: the easiest way to percent-escape a URL is to use URLComponents:
var components = URLComponents(string: "https://godochurch.blob.core.windows.net")!
components.path = "/sermons/1031/30-1-2017-Vision Sunday-Devotion.mp3"
if let url = components.url {
// ...
}
If you happen to get you URL strings from a webservice and it contains a space, that service is bad. Space is not allowed in an URL. Web browsers relax that rule because they know there are bad URLs out there. Swift won't take it.