Swift NSURL giving error on valid urls

Question

Look at this code:

let url = NSURL(string: physicst.image as String) if let url = url { let request = NSMutableURLRequest(URL: url) let task = session.dataTaskWithRequest(request, completionHandler: {(data, response, error) in if let data = data { cell.imageView?.image = UIImage(data: data) } }) task.resume() }else { print ("nill URL \(physicst.image)") }

so I have a string, and that string is a url, and I want to load it.

that code is in a table view cells, so it is being called for each cell.

as you see, i am checking if the url is nil or not, and if not, i am making a print statement. almost all the urls are not nil, exception the following ones (which are complemetly valid)

http://commons.wikimedia.org/wiki/Special:FilePath/Kai_Manne_Börje_Siegbahn.jpg?width=300

http://commons.wikimedia.org/wiki/Special:FilePath/Виталий_Лазаревич_Гинзбург.jpg?width=300

http://commons.wikimedia.org/wiki/Special:FilePath/赤崎記念研究館.jpg?width=300

http://commons.wikimedia.org/wiki/Special:FilePath/Kai_Manne_Börje_Siegbahn.jpg?width=300

http://commons.wikimedia.org/wiki/Special:FilePath/赤崎記念研究館.jpg?width=300

The first thing you may argue is to encode the url, and that is what I did like this:

var image = oneBinding["p"]!!["value"] as! NSString image = image.stringByAddingPercentEncodingWithAllowedCharacters(.URLHostAllowedCharacterSet())!

but then even the urls that were working, stopped working. what i am missing please ?

Update

Here is the whole code of my UITableViewController (it is easy)

class PhysicistTableViewController: UITableViewController { var physicsts : [Physicst]? @IBOutlet var physicstsTableView: UITableView! override func viewDidLoad() { super.viewDidLoad() loadDataFromDBPedia() } func loadDataFromDBPedia() { let session = NSURLSession.sharedSession() var url = "http://dbpedia.org/sparql/" let query = "http://dbpedia.org&query=select * {?o dbo:thumbnail ?p . ?o dbo:award dbr:Nobel_Prize_in_Physics}" url = url + "?default-graph-uri=" + query.stringByAddingPercentEncodingWithAllowedCharacters(.URLHostAllowedCharacterSet())! url = url + "&format=JSON&CXML_redir_for_subjs=121&CXML_redir_for_hrefs=&timeout=30000&debug=on" let request = NSMutableURLRequest(URL: NSURL(string: url)!) let task = session.dataTaskWithRequest(request, completionHandler: {(data, response ,error) in if let error = error { print ("\(error)") } if let response = response { let httpResponse = response as! NSHTTPURLResponse let statusCode = httpResponse.statusCode print("Status code = \(statusCode)") } if let data = data { do { let jsonResponse = try NSJSONSerialization.JSONObjectWithData(data, options: NSJSONReadingOptions()) let binding = jsonResponse["results"]!!["bindings"] as! NSArray for oneBinding in binding { let name = oneBinding["o"]!!["value"] as! NSString let image = oneBinding["p"]!!["value"] as! NSString //image = image.stringByAddingPercentEncodingWithAllowedCharacters(.URLHostAllowedCharacterSet())! let physicst = Physicst(image: image, name: name) if self.physicsts == nil { self.physicsts = [Physicst]() } self.physicsts!.append(physicst) } self.physicstsTableView.reloadData() }catch _ { print ("not well json-formatted response") } } }) task.resume() } override func numberOfSectionsInTableView(tableView: UITableView) -> Int { return 1 } override func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int { if self.physicsts == nil { return 0 }else { return self.physicsts!.count } } override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell { let cell = tableView.dequeueReusableCellWithIdentifier("physicstCell")! as UITableViewCell let row = indexPath.row let physicst = self.physicsts![row] cell.textLabel?.text = physicst.name as String if (physicst.imageData == nil) { let session = NSURLSession.sharedSession() let url = NSURL(string: physicst.image as String) if let url = url { let request = NSMutableURLRequest(URL: url) let task = session.dataTaskWithRequest(request, completionHandler: {(data, response, error) in if let data = data { let imageData = UIImage(data: data) cell.imageView?.image = imageData physicst.imageData = imageData self.physicstsTableView.reloadRowsAtIndexPaths([indexPath], withRowAnimation: UITableViewRowAnimation.None) } }) task.resume() }else { print ("nill URL \(physicst.image)") } }else { cell.imageView?.image = physicst.imageData! } return cell } }

When working with async merhods dont forget to update the UI from the mainqueue — Leo Dabus
– Leo Dabus, Commented Jun 1, 2016 at 9:37
@TheRohanSanap there is no error, but the else statement is beign executed in the mentioned URLs, thought they are 100% valid urls — sarah
– sarah, Commented Jun 1, 2016 at 9:39
stackoverflow.com/a/27712427/2303865 Just use the image view extension — Leo Dabus
– Leo Dabus, Commented Jun 1, 2016 at 9:39
@LeoDabus yes but that has nothing to do with the problem in hand :) — sarah
– sarah, Commented Jun 1, 2016 at 9:39

Community · Accepted Answer · 2017-05-23 10:28:58Z

URLHostAllowedCharacterSet only contains this "#%/<>?@\^{|}

And your URL string contains : .. So make custom set for this

 let yourString = "http://commons.wikimedia.org/wiki/Special:FilePath/Kai_Manne_Börje_Siegbahn.jpg?width=300" let customSet = NSCharacterSet(charactersInString:"=\"#%/:<>?@\\^`{|}").invertedSet let finalString = yourString.stringByAddingPercentEncodingWithAllowedCharacters(customSet)

For more info. check this answer

Your code neither makes the else execute, no makes me see the downloaded images.
@sarah this is same as allowedCharacterSet but just add some custom characters in set ... So url encode with custom character set ... I tried it ...it works for me ...

Antzi · Accepted Answer · 2016-06-01 10:00:32Z

The method you should use is

stringByAddingPercentEncodingWithAllowedCharacters(NSCharacterSet.URLQueryAllowedCharacterSet())

Taken from the playground:

NSURL(string:"http://commons.wikimedia.org/wiki/Special:FilePath/Kai_Manne_Börje_Siegbahn.jpg?width=300".stringByAddingPercentEncodingWithAllowedCharacters(NSCharacterSet.URLQueryAllowedCharacterSet())!)

Gives the result

http://commons.wikimedia.org/wiki/Special:FilePath/Kai_Manne_B%C3%B6rje_Siegbahn.jpg?width=300

Which is valid :)

Adapted to your code it gives:

let url = NSURL(string: (physicst.image as String).stringByAddingPercentEncodingWithAllowedCharacters(NSCharacterSet.URLQueryAllowedCharacterSet()!)

Beware of the forced unwrapping tho !

well interestinly the else statment wasn't called at all. but yet, your code is using a deprecated function. any alternative please ?
You need to use a different character set for each part of the url
Btw i think that method still available if you cast it to NSString
+1 for your efforts, if i get another answer with not depressed code, i will check, otherwise, i will accept your answer, appreciate the efforts
@sarah you are right, I edited the code. This is not perfect since we should split query string and host string, but it should work anyway.

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