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Basically I have a code for posting simple data to a server and will return a boolean value success if the post request was successful but it seems to be that the boolean value is returned before even the data is processed, am I doing something wrong?
public func postRequest(rawText: String) -> Bool {
var success = true
let destUrl = "http://api.getquesto.com:8080/upload/"
var request = URLRequest(url: URL(string: destUrl)!)
request.httpMethod = "POST"
let postString = rawText
request.setValue("text/plain", forHTTPHeaderField: "Content-Type")
// request.setValue("compute", forHTTPHeaderField: "Questo-Query")
// request.setValue("Fuck you", forHTTPHeaderField: "quizTitle")
request.httpBody = postString.data(using: .utf8)
print(request.httpBody!)
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=\(error)")
success = false
print(success)
return
}
if let httpStatus = response as? HTTPURLResponse, httpStatus.statusCode != 200 { // check for http errors
print("statusCode should be 200, but is \(httpStatus.statusCode)")
print("response = \(response)")
}
let responseString = String(data: data, encoding: .utf8)
do {
if let json = try JSONSerialization.jsonObject(with: data, options: JSONSerialization.ReadingOptions(rawValue: UInt(0))) as? [String: Any] {
print("json \(json)")
} else {
print("can not cast data")
success = false
}
} catch let error {
print("cant parse json \(error)")
success = false
print(success)
}
print("responseString = \(responseString)")
let dataString = NSString(data: data, encoding: String.Encoding.utf8.rawValue)
//print(dataString)
//print("responseString = \(responseString)")
constantVariables.rawQuestionData = dataString as! String
let processedResults = dataString?.replacingOccurrences(of: "\\n", with: " ")
print("processed results = " + (processedResults! as String))
let newArray = processedResults!.components(separatedBy: ", \"")
//print(newArray)
for index in 0...(newArray.count - 1) {
if index%2 == 0 {
constantVariables.questions.insert(newArray[index].replacingOccurrences(of: "\"", with: "").replacingOccurrences(of: "]", with: "").replacingOccurrences(of: "[", with: ""), at: index/2)
// ConstantsArray.questionArray.append(newArray[index])
// print("question array: " + ConstantsArray.answerArray[index/2])
}else{
constantVariables.answers.insert(newArray[index].replacingOccurrences(of: "\"", with: "").replacingOccurrences(of: "]", with: "").replacingOccurrences(of: "[", with: ""), at: (index-1)/2)
// ConstantsArray.questionArray.append(newArray[index])
print("answer array: " + constantVariables.answers[(index-1)/2])
}
}
}
task.resume()
print(success)
return success
}
659
If you want to return your own value from a function, you need to do two things: Write an arrow then a data type before your function's opening brace, which tells Swift what kind of data will get sent back. Use the return keyword to send back your data.
Show activity on this post. Answer extracted from question: It seems the problem is, that swift does not exit the function instantly on a return statement in a void function and uses the consecutive void value as the function parameter and terminates as expected if it is non-void.
Swift's functions have a single return type, such as Int or String , but that doesn't mean we can only return a single value. In fact, there are two ways we can send back multiple pieces of data: Using a tuple, such as (name: String, age: Int) Using some sort of collection, such as an array or a dictionary.
All of this information is rolled up into the function's definition, which is prefixed with the func keyword. You indicate the function's return type with the return arrow -> (a hyphen followed by a right angle bracket), which is followed by the name of the type to return.
This is happening because the function directly returns the value of success, dataTask works asynchronously, so, the function should NOT wait until dataTask finishes the parsing to edit the value of success, i.e: return success is executed before dataTask edits the value of success.
I suggest to let the function handles a completion closure instead of direct returning of Bool.
Your function should be similar to:
public func postRequest(rawText: String, completion: @escaping (_ success: Bool) -> ()) {
var success = true
let destUrl = "http://api.getquesto.com:8080/upload/"
var request = URLRequest(url: URL(string: destUrl)!)
request.httpMethod = "POST"
let postString = rawText
request.setValue("text/plain", forHTTPHeaderField: "Content-Type")
// request.setValue("compute", forHTTPHeaderField: "Questo-Query")
// request.setValue("Fuck you", forHTTPHeaderField: "quizTitle")
request.httpBody = postString.data(using: .utf8)
print(request.httpBody!)
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=\(error)")
success = false
print(success)
return
}
if let httpStatus = response as? HTTPURLResponse, httpStatus.statusCode != 200 { // check for http errors
print("statusCode should be 200, but is \(httpStatus.statusCode)")
print("response = \(response)")
}
let responseString = String(data: data, encoding: .utf8)
do {
if let json = try JSONSerialization.jsonObject(with: data, options: JSONSerialization.ReadingOptions(rawValue: UInt(0))) as? [String: Any] {
print("json \(json)")
} else {
print("can not cast data")
success = false
}
} catch let error {
print("cant parse json \(error)")
success = false
print(success)
}
print("responseString = \(responseString)")
let dataString = NSString(data: data, encoding: String.Encoding.utf8.rawValue)
//print(dataString)
//print("responseString = \(responseString)")
constantVariables.rawQuestionData = dataString as! String
let processedResults = dataString?.replacingOccurrences(of: "\\n", with: " ")
print("processed results = " + (processedResults! as String))
let newArray = processedResults!.components(separatedBy: ", \"")
//print(newArray)
for index in 0...(newArray.count - 1) {
if index%2 == 0 {
constantVariables.questions.insert(newArray[index].replacingOccurrences(of: "\"", with: "").replacingOccurrences(of: "]", with: "").replacingOccurrences(of: "[", with: ""), at: index/2)
// ConstantsArray.questionArray.append(newArray[index])
// print("question array: " + ConstantsArray.answerArray[index/2])
}else{
constantVariables.answers.insert(newArray[index].replacingOccurrences(of: "\"", with: "").replacingOccurrences(of: "]", with: "").replacingOccurrences(of: "[", with: ""), at: (index-1)/2)
// ConstantsArray.questionArray.append(newArray[index])
print("answer array: " + constantVariables.answers[(index-1)/2])
}
}
completion(success)
}
task.resume()
print(success)
}
In Swift 3, you should use @escaping, for more information, you might want to check this answer.
Calling:
postRequest(rawText: "rawText", completion: { success in
print(success)
})
Now, it should wait untill dataTask finish it's parsing, and then, the code in the completion will be called.
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