The '#' char gets converted to %23 causing the GET Request to fail - ios

Question

I am a new Swift developer using Swift 3 developing an iOS app. I need to make a URL Request to get some data from the web. That URL contains a # character.
I use URLComponents with URLQueryItems to build the request URL. During this process the # char gets converted to %23 which I think is valid utf8 encoding. Unfortunately, this causes the GET to fail.
To test I pasted the URL into my browser and changed %23 back to # and it worked just fine.
How can I fix this so it does not change # to URL. I did find a post from a couple years ago but it was using old framework items so it does not apply to me.
Below is the playground I made to illustrate and test this.
// ------------------------------------------------------------------
//: Playground - TestBuildURLWithParameters
//
// I am using this playground to build the proper
// URL for the GET request to get the detailed
// rtesults for a specific athlete where the "Key"
// is their Bib Nbr. If the GET cant find the specific
// Atlete with that URL it redirects you to the list
// of athlete results (which is no go to me in this case)
//
// Currently, there is a big "gotcha". In building the URL
// using component and query items, the foundation classes
// replace the '#' sign in the URL with the %23 which represents
// the pound sign. Unfortunately, the causes the GET to fail
// and redirects to athlete list which is not helpful
// I am still trying to figure out how to FORCE it to keep
// the '#" character in the URL so it will work
//
// ------------------------------------------------------------------
import Foundation
import UIKit
let baseURLString = "http://www.ironman.com/triathlon/events/americas/ironman-70.3/augusta/results.aspx"
let rd = "20150927"
let race = "augusta70.3"
let bibID = "93"
var detail = "1#axzz4FGGcjBOn"
print("Detail w/o unicocde: \(detail)")
detail = "1\u{0023}axzz4FGGcjBOn"
print("Detail with unicocde: \(detail)")
var components = URLComponents(string: baseURLString)!
var queryItems: [URLQueryItem] = [] // All Items after the "?"
let baseParams =
[
"rd": rd,
"race": race,
"bidID": bibID, // Note: HTML mispelled bib with bid so "bidID" is the URL search
"detail": detail
]
for (key, value) in baseParams
{
let item = URLQueryItem(name: key, value: value)
queryItems.append(item)
}
components.queryItems = queryItems // what does this look like
print("components: \(components)") // see it

Answer 1

It is not a good way to include fragment part of URL into query items.
Try this:
import Foundation
let baseURLString = "http://www.ironman.com/triathlon/events/americas/ironman-70.3/augusta/results.aspx"
let rd = "20150927"
let race = "augusta70.3"
let bibID = "93"
var detail = "1"
//# split the last query item and the fragment
let fragment = "axzz4FGGcjBOn"
var components = URLComponents(string: baseURLString)!
var queryItems: [URLQueryItem] = []
let baseParams =
[
"rd": rd,
"race": race,
"bidID": bibID,
"detail": detail
]
for (key, value) in baseParams
{
let item = URLQueryItem(name: key, value: value)
queryItems.append(item)
}
components.queryItems = queryItems
components.fragment = fragment
print("components: \(components)")

Answer 2

If you need you can choose the character that will receive the encoding.
In the charactersIn: you put all characters you want to encode.
Then you use the .inverted so all the others characters will go normal like this:
let customAllowedSet = NSCharacterSet(charactersIn:"=\"%/<>?#\\^`{|}").inverted
let encondedString = originalString.addingPercentEncoding(withAllowedCharacters: customAllowedSet)
print("enconded string: \(encondedString)")

Answer 3

Encode your parameters and then add it to URL, this will encode # before hitting API and you'll get desired result.
To encode parameters, you can use below code.
var parameterString = "your parameter string"
var encodedString = parameterString .addingPercentEncoding(withAllowedCharacters: .urlHostAllowed)
print(encodedString !)

Answer 4

I did get an answer via email from a friend that works for now. Basically, I added the query items manually to the URL using the URL extension below so it didn't monkey with the '#' char:
extension URL {
func appendingNonEscapedQueryItems(_ queryItems: [URLQueryItem]) -> URL {
let url = self
var urlString = url.absoluteString
for queryItem in queryItems {
let queryName = queryItem.name
guard let queryValue = queryItem.value else {
continue
}
let query = queryName + "=" + queryValue
if queryItem == queryItems.first {
urlString = urlString + "?" + query
}
else
{
urlString = urlString + "&" + query
}
}
return URL(string: urlString)!
}
}
...
let requestURL = components.url!.appendingNonEscapedQueryItems(queryItems)
print("URL \(requestURL)")