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Right now I am making an Alamofire request with parameters. I need the final URL before the request is made because I need to hash the final URL and add it to the request header. This is how I was doing it but it does not give me the final URL to hash and put into a header. 

Alamofire.request(url, method: .get, parameters: parameters, encoding: URLEncoding.default, headers: headers).responseJSON

I want to get the encoded URL before I make this request so the request looks like this 

Alamofire.request(url, method: .get, headers: headers).responseJSON

Right now as a work around, I am creating the URL manually by appending each parameter manually. Is there a better way to do it?

let rexUrl = "https://www.google.com"
let requestPath = "/accounts"
let url = rexUrl + requestPath + "?apikey=\(apiKey)&market=USD&quantity=\(amount)&rate=\(price)&nonce=\(Date().timeIntervalSince1970)"
Nevin Jethmalani
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2 Answers2

6

Instead of writing your own URL "in hand" you can use URLComponents to ease adding URL parameters and so on.

Here is an example using your URL from above:

var apiKey = "key-goes-here"
var amount = 10 
var price = 20
var urlParameters = URLComponents(string: "https://google.com/")!
urlParameters.path = "/accounts"

urlParameters.queryItems = [
    URLQueryItem(name: "apiKey", value: apiKey),
    URLQueryItem(name: "market", value: "USD"),
    URLQueryItem(name: "quantity", value: "\(amount)"),
    URLQueryItem(name: "rate", value: "\(price)"),
    URLQueryItem(name: "nonce", value: "\(Date().timeIntervalSince1970)")
]

urlParameters.url //Gives you a URL with the value https://google.com/accounts?apiKey=key-goes-here&market=USD&quantity=10&rate=20&nonce=1513630030.43938

Granted, it does not make your life that much easier as you still have to write the URL yourself, but at least you don't have to wrestle with adding & and ? in the correct order anymore.

Hope that helps you.

pbodsk
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  • This is awesome! Why are you putting “/()” around items that already a string? – Nevin Jethmalani Dec 18 '17 at 21:31
  • @NevinJethmalani it is right :) `URLComponents` is a great tool for URLs. About the “wrapping Strings in \()”, sorry...copy paste :) I’ve changed it now – pbodsk Dec 18 '17 at 21:38
0

Here's a neat function for converting Dictionary parameters to a URL encoded string. But you'll have to put your parameters into a Dictionary.

func url(with baseUrl : String, path : String, parameters : [String : Any]) -> String? {
    var parametersString = baseUrl + path + "?"
    for (key, value) in parameters {
        if let encodedKey = key.addingPercentEncoding(withAllowedCharacters: .urlHostAllowed),
            let encodedValue = "\(value)".addingPercentEncoding(withAllowedCharacters: .urlHostAllowed) {
            parametersString.append(encodedKey + "=" + "\(encodedValue)" + "&")
        } else {
            print("Could not urlencode parameters")
            return nil
        }
    }
    parametersString.removeLast()
    return parametersString
}

And then you can use it like that

let parameters : [String : Any] = ["apikey" : "SomeFancyKey",
                                   "market" : "USD",
                                   "quantity" : 10,
                                   "rate" : 3,
                                   "nonce" : Date().timeIntervalSince1970]
self.url(with: "https://www.google.com", path: "/accounts", parameters: parameters)

Which will give you the output:

"https://www.google.com/accounts?apikey=SomeFancyKey&quantity=10&market=USD&nonce=1513630655.88432&rate=3"

zufox
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