I am sending a POST request to a server and get a response back. So far so good. When I convert the data to a (very long) string the response contains backslashes, which shouldn't be there.
“
Here is the snippet that handles the request:
let task = URLSession.shared.dataTask(with: request) { data, response, error in
if let response = response, let data = data {
print(response)
let str = String(data: data, encoding: .utf8)
let replaced = str?.replacingOccurrences(of: "\\", with: "")
print(replaced)
} else {
print(error)
}
}
Trying to replace the '\' character with
let replaced = str?.replacingOccurrences(of: "\", with: "")
works in the Playground, however a debug runtime it does not strip the backward slashes.
Question: Is there a bug in Xcode? In 2018 with Xcode 9 there was such a bug. I am using Xcode 11.3 on macOS 10.14 compiling a macOS app.
Second question, is there another way to decode the data than using
let str = String(data: data, encoding: .utf8)
Thanks
Figured it out. Needed to decode data, not encode.
let task = URLSession.shared.dataTask(with: request) { data, response, error in
if let response = response, let data = data {
print(response)
let str = String(decoding: data, as: UTF8.self)
print (str)
} else {
print(error)
}
}
Related
I am trying to perform an HTTP POST request in swift that will send some data to my server using PHP file, but it crashes with the error
Thread 1: Fatal error: Unexpectedly found nil while unwrapping an Optional value
The token and selectedAreaNames (the error is in the first line) are just regular strings. What could be the problem?
let url = URL(string: "https://xxxxxxx.xxx/register.php/\(token)|\ (selectedAreaNames)")! //error is here...
var request = URLRequest(url: url)
request.httpMethod = "POST"
let task = URLSession.shared.dataTask(with: request) { (data, response, error) in
if let error = error {
print("error: \(error)")
} else {
if let response = response as? HTTPURLResponse {
print("statusCode: \(response.statusCode)")
}
if let data = data, let dataString = String(data: data, encoding: .utf8) {
print("data: \(dataString)")
}
}
}
task.resume()
Assuming that’s really how your URL must look, you can do:
let url = URL(string: "https://xxxxxxx.xxx/register.php")!
.appendingPathComponent(token + "|" + selectedAreasNames)
That will percent escape those portions of the URL (including the |).
That having been said, this is an exceedingly unusual format for a POST request, which usually has the data being posted inside the body of the request, not just added as another path component of the URL. And if this was a GET request, where the parameters are added to the URL, you’d generally see this after a ? in the URL, separating the path of the request from the query. And this structure of simply TOKEN|VALUES is an unusual query structure, too.
I know how to get data response from url. But the data response contains html source. Although I can handle it to get what I need but will be better if I know how to get only text. I use:
let task = URLSession.shared.dataTask(with: request)
{
data, response, error in guard
let data = data, error == nil else
{
// check for fundamental networking error
print(error!)
return
}
result = String(data: data, encoding: .utf8) ?? ""
}
task.resume()
You could do it like this.
let text = String(decoding: data, as: UTF8.self) // Convert data to string
.components(separatedBy: "\n") // Split string into multiple line
.first // Get the first line
Unless the endpoint has an option (like a query parameter) to return only the text, then you will get whatever the server wants to send and you will need to sort it out client side.
I am using an online swift playground to test http post and get request, the post aspect works fine, but when i add the get request,it gives the following error"error: extraneous '}' at top level.
The post code works fine.
// Post method
var url = URL(string: "http://196.46.20.80:8085/fideldesign")!
var request = URLRequest(url: url)
request.setValue("application/x-www-form-urlencoded", forHTTPHeaderField: "Content-Type")
request.httpMethod = "POST"
let postString = "email=oshinowo_sola#yahoo.ca&amount=15000&description=swift¤cy=566&fee=0&returnurl=http://www.oleronesoftwares.com&secretkey=2BC80A5EB5BB6A64A772F9806A7E9A0B16702043AB475DC4" // which is your parameters
request.httpBody = postString.data(using: .utf8)
//Getting response for POST Method
DispatchQueue.main.async {
let task = URLSession.shared.dataTask(with: request) { data, response, error in
guard let data = data, error == nil else {
return // check for fundamental networking error
}
// Getting values from JSON Response
let responseString = String(data: data, encoding: .utf8)
print("responseString = \(String(describing: responseString))")
do {
let jsonResponse = try JSONSerialization.jsonObject(with: data, options: JSONSerialization.ReadingOptions()) as? NSDictionary
}catch _ {
print ("OOps not good JSON formatted response")
}
}
task.resume()
}
The code is to post dynamic records from user input like email address,amount,description into an external url and then return the get request in json format.
Try closing the project and opening it again.
I was getting this same error and also when I tried pressing Enter (typing newline character) on the line that was problematic (It was the last line in the file for me), Xcode would insert the characters
ker;")
into my editor.
I was getting this error, until I closed and reopened the project, in which these errors went away and the random characters stopped appearing also.
What worked for me was replacing the file.
Create new file, different name than current buggy file.
Copy/paste code into this new file.
Go ahead and delete that file with the error.
..For some reason using the same name transferred over the error, even if I deleted the other file.
I have a URL in the form of
foo://?data:application/x-foo;base64,OjAyMDAwMDA0MDAwMEZBDQo6MTAwMDA...
and now need to extract the base64 data into a Data object.
Unfortunately it seems the Data object does not support this yet as
let data = try Data(contentsOf: url)
returns NSURLConnection finished with error - code -1002 when trying.
While I could decode the URL manually I am wondering if I am missing a simple standard way of doing this. How would you do this?
Actually you can decode Base64 data from an URL (see for
example Base64 Decoding in iOS 7+ where this is demonstrated in Objective-C). The format is a bit different from what
you have:
let url = URL(string: "data:application/octet-stream;base64,SGVsbG8gd29ybGQh")!
let data = try! Data(contentsOf: url)
print(String(data: data, encoding: .utf8)!) // Hello world!
(Error checking omitted for brevity.)
You have to separate the base64 encoded part of the URL from the other parts, decode it, then join the original non-encoded part with the decoded part and get the data from there.
extension URL {
init?(partialBase64Url: String){
guard let base64part = base64Url.components(separatedBy: "base64,").last, let base64Data = Data(base64Encoded: base64part), let decodedString = String(data: base64Data, encoding: .utf8) else {
return nil
}
let decodedUrl = base64Url.components(separatedBy: "base64,").dropLast().joined() + decodedString
self.init(string: decodedUrl)
}
}
let decodedUrl = URL(partialBase64Url: "foo://?data:application/x-foo;base64,dGVzdFVybFN0cmluZw==")
Value of decodedUrl: "foo://?data:application/x-foo;testUrlString", as expected, since dGVzdFVybFN0cmluZw== is the base64 encoded value of testUrlString.
I am trying to create JSON Web Token using JSONSerialization class, Swift 3 and Xcode 8.1, but my project fails to build with error:
Command failed due to signal: Segmentation fault 11.
Anyone knows why my code is not correct?
If I comment out this code from the project, the project builds.
let customerError = "Custom Error"
enum headerError: Error {
case customerError
}
let headerJWT: [Dictionary] = ["alg":"RS256","typ":"JWT"]
//Convert headerJWT to Data
do {
let headerJWTData: Data = try? JSONSerialization.data(withJSONObject:headerJWT,options: JSONSerialization.WritingOptions.prettyPrinted)
} catch headerError.customerError {
print("could not make data")
}
//Convert headerData to string utf8
do {
let headerJWTString = try String(data: headerJWTData,encoding:String.Encoding.utf8) as! String
} catch {
print("string could not be created")
}
//Convert headerJWTString to base64EncodedString
do {
let headerJWTBase64 = try Data(headerJWTString.utf8).base64EncodedString()
} catch {
"base64 could not be created"
}
Once you create the Data from using JSONSerialization, you simply use the method from Data to get a base64 encoded string.
let headerJWT: [Dictionary] = ["alg":"RS256","typ":"JWT"]
do {
let headerJWTData: Data = try? JSONSerialization.data(withJSONObject:headerJWT,options: JSONSerialization.WritingOptions.prettyPrinted)
let headerJWTBase64 = headerJWTData.base64EncodedString()
} catch headerError.customerError {
print("could not make data")
}
You can pass different options to base64EncodedString() depending on what format you need the base64 string to be in.