I am using the iTunes search API, and for testing I am searching for "Angry Birds" and printing the results. But when I convert the urlPath into NSURL I get a nil value. How do I fix this? The urlPath has the link, but it is nil in the url variable. This is the exact error:
fatal error: unexpectedly found nil while unwrapping an Optional value.
var searchTerm: String = "Angry Birds"
var itunesSearchTerm = searchTerm.stringByReplacingOccurrencesOfString(" ", withString: "+", options: NSStringCompareOptions.CaseInsensitiveSearch, range: nil)
var escapedSearchTerm = itunesSearchTerm.stringByAddingPercentEscapesUsingEncoding(NSUTF8StringEncoding)
var urlPath = "https://itunes.apple.com/search?term=\(escapedSearchTerm)&media=software"
var url: NSURL = NSURL(string: urlPath)!
var request: NSURLRequest = NSURLRequest(URL: url)
var connection: NSURLConnection = NSURLConnection(request: request, delegate: self, startImmediately: false)!
print("Search iTunes API at URL \(url)")
connection.start()
stringByAddingPercentEscapesUsingEncoding returns an Optional String, so what you get is actually this:
https://itunes.apple.com/search?term=Optional("Angry+Birds")&media=software
The solution is to safely unwrap the Optional:
if let escapedSearchTerm = itunesSearchTerm.stringByAddingPercentEscapesUsingEncoding(NSUTF8StringEncoding) {
let urlPath = "https://itunes.apple.com/search?term=\(escapedSearchTerm)&media=software"
let url = NSURL(string: urlPath)
// ...
}
Result:
https://itunes.apple.com/search?term=Angry+Birds&media=software
NSURL returns nil when URL contain illegal characters like space. Verify that your URlString is correct one.
Related
My application is using an NSURL like this:
var url = NSURL(string: "http://www.geonames.org/search.html?q=Aïn+Béïda+Algeria&country=")
When I tried to make a task for getting data from this NSURL like this:
let task = NSURLSession.sharedSession().dataTaskWithURL(url!, completionHandler: { (data: NSData!, response: NSURLResponse!, error: NSError!) -> Void in
if error == nil {
var urlContent = NSString(data: data, encoding: NSUTF8StringEncoding)
println("urlContent \(urlContent!)")
} else {
println("error mode")
}
but I got error when trying to got data from that address, although when I using safari go to link: "http://www.geonames.org/search.html?q=Aïn+Béïda+Algeria&country=" I can see the data. How can I fix that?
Swift 2
let original = "http://www.geonames.org/search.html?q=Aïn+Béïda+Algeria&country="
if let encodedString = original.stringByAddingPercentEncodingWithAllowedCharacters(
NSCharacterSet.URLFragmentAllowedCharacterSet()),
url = NSURL(string: encodedString)
{
print(url)
}
Encoded URL is now:
"http://www.geonames.org/search.html?q=A%C3%AFn+B%C3%A9%C3%AFda+Algeria&country="
and is compatible with NSURLSession.
Swift 3
let original = "http://www.geonames.org/search.html?q=Aïn+Béïda+Algeria&country="
if let encoded = original.addingPercentEncoding(withAllowedCharacters: .urlFragmentAllowed),
let url = URL(string: encoded)
{
print(url)
}
I'm working in swift and originally got the warning "'stringByAddingPercentEscapesUsingEncoding' was deprecated..." so I changed my code from
let url = NSURL(string: (urlString as NSString).stringByAddingPercentEscapesUsingEncoding(NSASCIIStringEncoding)!)
to
var url = urlString.stringByAddingPercentEncodingWithAllowedCharacters(NSCharacterSet.URLQueryAllowedCharacterSet())
But now I'm getting the error "Cannot convert value of type 'String' to expected argument type 'NSURL'.
let urlRequest = NSURLRequest(URL: url!)
My current code:
private func handleTextFieldInterfaces(){
autocompleteTextField.onTextChange = {[weak self] text in
if !text.isEmpty{
if self!.connection != nil{
self!.connection!.cancel()
self!.connection = nil
}
let urlString = "\(self!.baseURLString)?key=\(self!.googleMapsApiKey)&input=\(text)"
//let url = NSURL(string: (urlString as NSString).stringByAddingPercentEscapesUsingEncoding(NSASCIIStringEncoding)!)
var url = urlString.stringByAddingPercentEncodingWithAllowedCharacters(NSCharacterSet.URLQueryAllowedCharacterSet())
if url != nil{
let urlRequest = NSURLRequest(URL: url!) //Error on this line
self!.connection = NSURLConnection(request: urlRequest, delegate: self)
}
}
}
}
Try casting it to NSURL see if it works
var url = NSURL(urlString.stringByAddingPercentEncodingWithAllowedCharacters(NSCharacterSet.URLQueryAllowedCharacterSet()))
My application is using an NSURL like this:
var url = NSURL(string: "http://www.geonames.org/search.html?q=Aïn+Béïda+Algeria&country=")
When I tried to make a task for getting data from this NSURL like this:
let task = NSURLSession.sharedSession().dataTaskWithURL(url!, completionHandler: { (data: NSData!, response: NSURLResponse!, error: NSError!) -> Void in
if error == nil {
var urlContent = NSString(data: data, encoding: NSUTF8StringEncoding)
println("urlContent \(urlContent!)")
} else {
println("error mode")
}
but I got error when trying to got data from that address, although when I using safari go to link: "http://www.geonames.org/search.html?q=Aïn+Béïda+Algeria&country=" I can see the data. How can I fix that?
Swift 2
let original = "http://www.geonames.org/search.html?q=Aïn+Béïda+Algeria&country="
if let encodedString = original.stringByAddingPercentEncodingWithAllowedCharacters(
NSCharacterSet.URLFragmentAllowedCharacterSet()),
url = NSURL(string: encodedString)
{
print(url)
}
Encoded URL is now:
"http://www.geonames.org/search.html?q=A%C3%AFn+B%C3%A9%C3%AFda+Algeria&country="
and is compatible with NSURLSession.
Swift 3
let original = "http://www.geonames.org/search.html?q=Aïn+Béïda+Algeria&country="
if let encoded = original.addingPercentEncoding(withAllowedCharacters: .urlFragmentAllowed),
let url = URL(string: encoded)
{
print(url)
}
I'm trying to create a Simple HTTP Framework.
At first I have the following typealias:
typealias successBock = ([Any]) -> ()
typealias errorBlock = (NSError) -> ()
typealias requestResponseTuple = (con: NSURLConnection, success: successBock?, error: errorBlock?)
And I have an error in this method:
func performHttpRequest<T>(method: HTTPRequestMethod, path: String?, parameter:Dictionary<String, String>,
success:successBock?, error:errorBlock?) -> Int {
var url = NSURL(string: baseURL.stringByAppendingPathComponent((path != nil) ? path! : ""))
var request = NSURLRequest(URL: url!, cachePolicy: NSURLRequestCachePolicy.ReloadIgnoringLocalCacheData, timeoutInterval: 20.0)
var con = NSURLConnection(request: request, delegate: self, startImmediately: true)
var requestId = newRequestId()
currentActiveRequests[requestId] = requestResponseTuple(con, successBock.self, errorBlock.self)
return requestId;
}
The error goes here:
requestResponseTuple(con, success, errorBlock.self)
Error: "'successBock.Type' is not convertible to 'successBock'"
I want to pass the block, so that i'm able to call it later. In objective-c i never had a problem like that.
To be honest, i have no idea why this occurs. I checked several pages, but didn't found a solution.
Best regards,
Maik
edit2:
changed one method:
func performHttpRequest<T>(method: HTTPRequestMethod, path: String?, parameter:Dictionary<String, String>,
success:successBock?, error:errorBlock?) -> Int {
var url = NSURL(string: baseURL.stringByAppendingPathComponent((path != nil) ? path! : ""))
var request = NSURLRequest(URL: url!, cachePolicy: NSURLRequestCachePolicy.ReloadIgnoringLocalCacheData, timeoutInterval: 20.0)
var con = NSURLConnection(request: request, delegate: self, startImmediately: true)
var requestId = newRequestId()
currentActiveRequests[requestId] = requestResponseTuple(con, success, error)
return requestId;
}
Error now: Could not find an overload for 'subscript' that accepts the supplied arguments
Edit:
CodeLink:
http://pastebin.com/c5a0fn1N http://pastebin.com/d0QGQ2AR
Ok if i understand well you just have to change
requestResponseTuple(con, successBock.self, errorBlock.self)
by
requestResponseTuple(con!, success, error)
Your parameter Names are success and error. successBock and errorBlock are the types.
So i Suggest you to capitalize them.
Hope it helps you.
edit: Since NSURLConnection returns an optional, you have to unwrap it.
You should check if con is equal to nil before unwrapping it.
if let con = NSURLConnection(request: request, delegate: self, startImmediately: true)
{
currentActiveRequests[requestId] = RequestResponseTuple(con, success, error)
}
else
{
// there was an error, the NSURLConnection has not been created
}
So I have converted an NSURL to a String.
So if I println it looks like file:///Users/... etc.
Later I want this back as an NSURL so I try and convert it back as seen below, but I lose two of the forward slashes that appear in the string version above, that in turn breaks the code as the url is invalid.
Why is my conversion back to NSURL removing two forward slashes from the String I give it, and how can I convert back to the NSURL containing three forward slashes?
var urlstring: String = recordingsDictionaryArray[selectedRow]["path"] as String
println("the url string = \(urlstring)")
// looks like file:///Users/........etc
var url = NSURL.fileURLWithPath(urlstring)
println("the url = \(url!)")
// looks like file:/Users/......etc
In Swift 5, Swift 4 and Swift 3
To convert String to URL:
URL(string: String)
or,
URL.init(string: "yourURLString")
And to convert URL to String:
URL.absoluteString
The one below converts the 'contents' of the url to string
String(contentsOf: URL)
fileURLWithPath() is used to convert a plain file path (e.g. "/path/to/file") to an URL. Your urlString is a full URL string including the scheme, so you should use
let url = NSURL(string: urlstring)
to convert it back to NSURL. Example:
let urlstring = "file:///Users/Me/Desktop/Doc.txt"
let url = NSURL(string: urlstring)
println("the url = \(url!)")
// the url = file:///Users/Me/Desktop/Doc.txt
There is a nicer way of getting the string version of the path from the NSURL in Swift:
let path:String = url.path
2021 | SWIFT 5.1:
FOR LOCAL PATHS
String --> URL :
let url1 = URL(fileURLWithPath: "//Users/Me/Desktop/Doc.txt")
let url2 = URL(fileURLWithPath: "//Users/Me/Desktop", isDirectory: true)
// !!!!!NEVER DO THIS!!!!!!
let url3 = URL(string: "file:///Users/Me/Desktop/Doc.txt")!
// !!!!!NEVER DO THIS!!!!!!
URL --> String :
let a = String(describing: url1) // "file:////Users/Me/Desktop/Doc.txt"
let b = "\(url1)" // "file:////Users/Me/Desktop/Doc.txt"
let c = url1.absoluteString // "file:////Users/Me/Desktop/Doc.txt"
// Best solution in most cases
let d = url1.path // "/Users/Me/Desktop/Doc.txt"
FOR INTERNET URLs
String --> URL :
let url = URL(string: "https://stackoverflow.com/questions/27062454/converting-url-to-string-and-back-again")!
URL --> String :
url.absoluteString // https://stackoverflow.com/questions/27062454/converting-url-to-string-and-back-again
url.path // /questions/27062454/converting-url-to-string-and-back-again
NOTICE: pay attention to the url, it's optional and it can be nil.
You can wrap your url in the quote to convert it to a string. You can test it in the playground.
Update for Swift 5, Xcode 11:
import Foundation
let urlString = "http://ifconfig.me"
// string to url
let url = URL(string: urlString)
//url to string
let string = "\(url)"
// if you want the path without `file` schema
// let string = url.path
let url = URL(string: "URLSTRING HERE")
let anyvar = String(describing: url)
Swift 3 (forget about NSURL).
let fileName = "20-01-2017 22:47"
let folderString = "file:///var/mobile/someLongPath"
To make a URL out of a string:
let folder: URL? = Foundation.URL(string: folderString)
// Optional<URL>
// ▿ some : file:///var/mobile/someLongPath
If we want to add the filename. Note, that appendingPathComponent() adds the percent encoding automatically:
let folderWithFilename: URL? = folder?.appendingPathComponent(fileName)
// Optional<URL>
// ▿ some : file:///var/mobile/someLongPath/20-01-2017%2022:47
When we want to have String but without the root part (pay attention that percent encoding is removed automatically):
let folderWithFilename: String? = folderWithFilename.path
// ▿ Optional<String>
// - some : "/var/mobile/someLongPath/20-01-2017 22:47"
If we want to keep the root part we do this (but mind the percent encoding - it is not removed):
let folderWithFilenameAbsoluteString: String? = folderWithFilenameURL.absoluteString
// ▿ Optional<String>
// - some : "file:///var/mobile/someLongPath/20-01-2017%2022:47"
To manually add the percent encoding for a string:
let folderWithFilenameAndEncoding: String? = folderWithFilename.addingPercentEncoding(withAllowedCharacters: CharacterSet.urlQueryAllowed)
// ▿ Optional<String>
// - some : "/var/mobile/someLongPath/20-01-2017%2022:47"
To remove the percent encoding:
let folderWithFilenameAbsoluteStringNoEncodig: String? = folderWithFilenameAbsoluteString.removingPercentEncoding
// ▿ Optional<String>
// - some : "file:///var/mobile/someLongPath/20-01-2017 22:47"
The percent-encoding is important because URLs for network requests need them, while URLs to file system won't always work - it depends on the actual method that uses them. The caveat here is that they may be removed or added automatically, so better debug these conversions carefully.
Swift 3 version code:
let urlString = "file:///Users/Documents/Book/Note.txt"
let pathURL = URL(string: urlString)!
print("the url = " + pathURL.path)
Swift 5.
To convert a String to a URL:
let stringToURL = URL(string: "your-string")
To convert a URL to a String:
let urlToString = stringToURL?.absoluteString
Swift 3 used with UIWebViewDelegate shouldStartLoadWith
func webView(_ webView: UIWebView, shouldStartLoadWith request: URLRequest, navigationType: UIWebViewNavigationType) -> Bool {
let urlPath: String = (request.url?.absoluteString)!
print(urlPath)
if urlPath.characters.last == "#" {
return false
}else{
return true
}
}