NSURL return nil while the URL is correct

Question

Created May ’16

Replies 4

Boosts 0

Views 2.6k

Participants 4

Hi, I'm using a database to get some values, and i don't understand why the NSURL return nil. Here the code that works :

let urlString = "https://api.mlab.com/api/1/databases/lampadaire/collections/lampadaire?&apiKey=0HW9bYZVJEvmmV93Yo8jYADX3gWczJie"
print(urlString) // this return https://api.mlab.com/api/1/databases/lampadaire/collections/lampadaire?&apiKey=0HW9bYZVJEvmmV93Yo8jYADX3gWczJie
print(NSURL(string: urlString)) // return a thing

You can try the URL in the adress bar, it returns JSON, but when i tried to put a query inside, it doesn't work :

rlString = "https://api.mlab.com/api/1/databases/lampadaire/collections/lampadaire?q={\"lampadaire_id\":1}&apiKey=0HW9bYZVJEvmmV93Yo8jYADX3gWczJie"
print(urlString) // this return https://api.mlab.com/api/1/databases/lampadaire/collections/lampadaire?q={"lampadaire_id":1}&apiKey=0HW9bYZVJEvmmV93Yo8jYADX3gWczJie
print(NSURL(string: urlString)) // return nil

You can try the URL in the adress bar, it returns JSON too. I think it's because of the double quote in the query, how can I pass it please ?

Answered by guywithmazda in 137951022

You probably need to "escape" the string using % encoding. The old (deprecated but still allowed) is to use stringByAddingPercentEscapesUsingEncoding(NSUTF8StringEndocding). The replacement is stringByAddingPercentEncodingWithAllowedCharacters(...). With the new way, there are predifined allowed character sets for each part of the url, such as NSCharacterSet.URLHostAllowedCharacterSet() and NSCharacterSet.URLQueryAllowedCharacterSet()

Boost

Answer 1

guywithmazda OP

May ’16

Accepted Answer

You probably need to "escape" the string using % encoding. The old (deprecated but still allowed) is to use stringByAddingPercentEscapesUsingEncoding(NSUTF8StringEndocding). The replacement is stringByAddingPercentEncodingWithAllowedCharacters(...). With the new way, there are predifined allowed character sets for each part of the url, such as NSCharacterSet.URLHostAllowedCharacterSet() and NSCharacterSet.URLQueryAllowedCharacterSet()

1

Answer 2

DTS Engineer OP

Apple

May ’16

guywithmazda has some great suggestions but I wanted to point out an alternative. The way I handle this sort of this is via NSURLComponents. That takes all the guesswork out of this process.

For example:

import Foundation

let components = NSURLComponents(string: "https://api.mlab.com/api/1/databases/lampadaire/collections/lampadaire")!
components.queryItems = [
    NSURLQueryItem(name: "q", value: "{\"lampadaire_id\":1}"),
    NSURLQueryItem(name: "apiKey", value: "0HW9bYZVJEvmmV93Yo8jYADX3gWczJie")
]
print(components.URL!)
// https://api.mlab.com/api/1/databases/lampadaire/collections/lampadaire?q=%7B%22lampadaire_id%22:1%7D&apiKey=0HW9bYZVJEvmmV93Yo8jYADX3gWczJie

Share and Enjoy
—
Quinn “The Eskimo!”
Apple Developer Relations, Developer Technical Support, Core OS/Hardware

let myEmail = "eskimo" + "1" + "@apple.com"

1

Answer 3

J.Converset OP

May ’16

Thanks eskimo, your answer works too, but the guywithmazda's answer is easier and faster for me ;p

0

Answer 4

J.Converset OP

May ’16

That works well, thanks.

0