Converting curl command to iOS

Question

The following curl works

curl -G -H "api_key: MYAPIKEY" https://api.semantics3.com/test/v1/products -d 'q={"upc":"70411576937"}'

However, upon trying to convert it to iOS I get the following error:

Error Domain=NSURLErrorDomain Code=-1005 "The network connection was lost." {NSErrorFailingURLStringKey=https://api.semantics3.com/test/v1/products,...}

I have attached my code below but I believe that my problem is the "q=" right before the json data that is being submitted to the URL. If so, what is this called and how do I put "q=" before my json data? I can't exactly tell though, due to iOS' unfaltering ability to provide us with unrelated error messages. Thank you.

    var urlString = "https://api.semantics3.com/test/v1/products"
    var request = NSMutableURLRequest(URL: NSURL(string: urlString)!)
    var response: NSURLResponse?
    var error: NSErrorPointer = nil
    var reqText = ["upc": "70411576937"]
    var err: NSError?

    request.HTTPBody = NSJSONSerialization.dataWithJSONObject(reqText, options: nil, error: &err)
    request.HTTPMethod = "GET"
    request.addValue("MYAPIKEY", forHTTPHeaderField: "api_key")
    request.addValue("application/json", forHTTPHeaderField: "Content-Type")
    request.addValue("application/json", forHTTPHeaderField: "Accept")
    var session = NSURLSession.sharedSession()

    var task = session.dataTaskWithRequest(request, completionHandler: {data, response, error -> Void in
        var strData = NSString(data: data, encoding: NSUTF8StringEncoding)
        if(err != nil) {
            println(err!.localizedDescription)
        }
        else {
            //this is where the error is printed
            println(error)
            var parseError : NSError?
            // parse data
            let unparsedArray: AnyObject? = NSJSONSerialization.JSONObjectWithData(data, options: NSJSONReadingOptions.AllowFragments, error: &parseError)
            println(parseError)
            if let resp = unparsedArray as? NSDictionary {
                println(resp)
            }
        }
    })
    task.resume()

I know it sounds silly, but try quitting the simulator & running the app again. Sometimes my simulator loses its connection after a night or so sitting idle. — AdamPro13
– AdamPro13, Commented Jun 9, 2015 at 0:07

John Difool · Accepted Answer · 2015-11-28 21:35:56Z

1

Body is not used in GET http methods. Use the following code to concat your params:

extension String {

    /// Percent escape value to be added to a URL query value as specified in RFC 3986
    ///
    /// This percent-escapes all characters besize the alphanumeric character set and "-", ".", "_", and "~".
    ///
    /// http://www.ietf.org/rfc/rfc3986.txt
    ///
    /// :returns: Return precent escaped string.

    func stringByAddingPercentEncodingForURLQueryValue() -> String? {
        let characterSet = NSMutableCharacterSet.alphanumericCharacterSet()
        characterSet.addCharactersInString("-._~")

        return self.stringByAddingPercentEncodingWithAllowedCharacters(characterSet)
    }

}

extension Dictionary {

    /// Build string representation of HTTP parameter dictionary of keys and objects
    ///
    /// This percent escapes in compliance with RFC 3986
    ///
    /// http://www.ietf.org/rfc/rfc3986.txt
    ///
    /// :returns: String representation in the form of key1=value1&key2=value2 where the keys and values are percent escaped

    func stringFromHttpParameters() -> String {
        let parameterArray = map(self) { (key, value) -> String in
            let percentEscapedKey = (key as! String).stringByAddingPercentEncodingForURLQueryValue()!
            let percentEscapedValue = (value as! String).stringByAddingPercentEncodingForURLQueryValue()!
            return "\(percentEscapedKey)=\(percentEscapedValue)"
        }

        return join("&", parameterArray)
    }

}


var urlString = "https://api.semantics3.com/test/v1/products"
var reqText = ["upc": "70411576937"]
var err: NSError?

let parameterString = reqText.stringFromHttpParameters()
let requestURL = NSURL(string:"\(urlString)?\(parameterString)")!

var request = NSMutableURLRequest(URL: NSURL(string: urlString)!)
var response: NSURLResponse?
var error: NSError?

request.HTTPMethod = "GET"
request.addValue("MYAPIKEY", forHTTPHeaderField: "api_key")
request.addValue("application/json", forHTTPHeaderField: "Content-Type")
request.addValue("application/json", forHTTPHeaderField: "Accept")
var session = NSURLSession.sharedSession()

PARTIAL EDIT: SWIFT 2.1 (updated)

extension Dictionary {

    func stringFromHttpParameters() -> String {
        let parameterArray = self.map { (key, value) -> String in
            let percentEscapedKey = (key as! String).stringByAddingPercentEncodingForURLQueryValue()!
            let percentEscapedValue = (value as! String).stringByAddingPercentEncodingForURLQueryValue()!
            return "\(percentEscapedKey)=\(percentEscapedValue)"
        }

        return parameterArray.joinWithSeparator("&")
    }

}

edited Nov 28, 2015 at 21:35

answered Jun 9, 2015 at 0:23

John Difool

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4 Comments

Jason Javier Over a year ago

Thank you. My problem was that my NSURL was not recognizing the curly brackets, but the stringByAddingPercentEncodingForURLQueryValue() method fixed this for me.

SMKS Over a year ago

With Swift 2 I'm getting an error on the second line in the extension Dictionary that says: "Cannot invoke 'map' with an argument list of type '(Dictionary<Key,Value),(,) -> String)" Any idea how to fix this?

John Difool Over a year ago

I updated the Dictionary extension to compile with Swift 2.1. Still not quite sure why i had to break the function in two to compile. As soon as I declare a variable with let in the map's closure, the compiler complains. I may post another question just for that.

John Difool Over a year ago

I think I found the problem. The closure needs to specify the return type which I believe it could infer from the code. This seems to be a bug in the compiler.

Michael Robinson · Accepted Answer · 2015-06-08 23:48:56Z

0

Convert your JSON to a string, prepend the q= to this, then convert the resulting string to Data before assigning it to the request's HTTPBody.

Something like this perhaps:

let array = [ "one", "two" ]
let data = NSJSONSerialization.dataWithJSONObject(array, options: nil, error: nil)
let body= "q=" + NSString(data: data!, encoding: NSUTF8StringEncoding)
request.HTTPBody = body.dataUsingEncoding(NSUTF8StringEncoding)

edited Jun 8, 2015 at 23:48

answered Jun 8, 2015 at 23:43

Michael Robinson

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