so I set Firebase remote config default in my iOS like this:
let remoteConfig = RemoteConfig.remoteConfig()
// set remote config default value
let defaultRemoteConfig : [String:NSObject] = [
"number_of_recommended_events_to_show_per_page" : 15 as NSObject
]
remoteConfig.setDefaults(defaultRemoteConfig)
// Activate and refetch remote config data.
// I use 'Load Value for next time' loading strategy
remoteConfig.activate()
remoteConfig.fetch()
and then I want to get the value from remote like this
// get the value from remote config
let numberOfDocumentsPerQuery = remoteConfig.configValue(forKey: "number_of_recommended_events_to_show_per_page").numberValue as! Int
I need the value in Integer format, but it crash when I cast it to Int like that
here is how I set the value in the console
why is it nil ? how to fix this ?
try this!
let numberOfDocumentsPerQuery = remoteConfig.configValue(forKey: "number_of_recommended_events_to_show_per_page").numberValue?.intValue ?? 0
Make sure you've fetched in this block before getting a remote value.
func fetchCloudValues() {
// WARNING: Don't actually do this in production!
let fetchDuration: TimeInterval = 0
RemoteConfig.remoteConfig().fetch(withExpirationDuration: fetchDuration) { [weak self] status, error in
if let error = error {
print ("Uh-oh. Got an error fetching remote values \(error)")
return
}
RemoteConfig.remoteConfig().activateFetched()
print ("Retrieved values from the cloud!")
let numberOfEvents = RemoteConfig.remoteConfig()
.configValue(forKey: "number_of_recommended_events_to_show_per_page")
.intValue ?? 0
print("Our app's number of events is \(numberOfEvents)")
}
}
Other answers didn't quite work for me. However the following did...
let numberOfDocumentsPerQuery = remoteConfig.configValue(forKey: "number_of_recommended_events_to_show_per_page").numberValue.intValue
Related
I have a default value in remote config console like the image above, I need to get that double value. in Android, I can get it like this
val remoteConfig = FirebaseRemoteConfig.getInstance()
val value = remoteConfig.getDouble("parameter_name")
but now I am confused how to get that double value for iOS, it seems there is no getDouble equivalent in swift, so what should I do ?
let remoteConfig = RemoteConfig.remoteConfig()
let value = // what should i write in here ?
You could read it as a String form the config, and then parse the String into a Double.
if let valueAsString = RemoteConfig.remoteConfig().configValue(forKey: "yourKey").stringValue {
if let valueAsDouble = Double(valueAsString) {
// you have your value as a Double now
} else {
print("Not a valid number: \(valueAsString)")
}
}
Firebase also offers "numberValue". The firebase code internally is:
[NSNumber numberWithDouble:self.stringValue.doubleValue]
This means: it returns 0 if the value cannot be converted. You have more control with the String way.
The input to dictionary(fromTXTRecord:) comes from the network, potentially from outside the app, or even the device. However, Apple's docs say:
... Fails an assertion if txtData cannot be represented as an NSDictionary object.
Failing an assertion leaves the programmer (me) with no way of handling the error, which seems illogic for a method that processes external data.
If I run this in Terminal on a Mac:
dns-sd -R 'My Service Name' _myservice._tcp local 4567 asdf asdf
my app, running in an iPhone, crashes.
dictionary(fromTXTRecord:) expects the TXT record data (asdf asdf) to be in key=val form. If, like above, a word doesn't contain any = the method won't be able to parse it and fail the assertion.
I see no way of solving this problem other than not using that method at all and implementing my own parsing, which feels wrong.
Am I missing something?
Here's a solution in Swift 4.2, assuming the TXT record has only strings:
/// Decode the TXT record as a string dictionary, or [:] if the data is malformed
public func dictionary(fromTXTRecord txtData: Data) -> [String: String] {
var result = [String: String]()
var data = txtData
while !data.isEmpty {
// The first byte of each record is its length, so prefix that much data
let recordLength = Int(data.removeFirst())
guard data.count >= recordLength else { return [:] }
let recordData = data[..<(data.startIndex + recordLength)]
data = data.dropFirst(recordLength)
guard let record = String(bytes: recordData, encoding: .utf8) else { return [:] }
// The format of the entry is "key=value"
// (According to the reference implementation, = is optional if there is no value,
// and any equals signs after the first are part of the value.)
// `ommittingEmptySubsequences` is necessary otherwise an empty string will crash the next line
let keyValue = record.split(separator: "=", maxSplits: 1, omittingEmptySubsequences: false)
let key = String(keyValue[0])
// If there's no value, make the value the empty string
switch keyValue.count {
case 1:
result[key] = ""
case 2:
result[key] = String(keyValue[1])
default:
fatalError()
}
}
return result
}
I'm still hoping there's something I'm missing here, but in the mean time, I ended up checking the data for correctness and only then calling Apple's own method.
Here's my workaround:
func dictionaryFromTXTRecordData(data: NSData) -> [String:NSData] {
let buffer = UnsafeBufferPointer<UInt8>(start: UnsafePointer(data.bytes), count: data.length)
var pos = 0
while pos < buffer.count {
let len = Int(buffer[pos])
if len > (buffer.count - pos + 1) {
return [:]
}
let subdata = data.subdataWithRange(NSRange(location: pos + 1, length: len))
guard let substring = String(data: subdata, encoding: NSUTF8StringEncoding) else {
return [:]
}
if !substring.containsString("=") {
return [:]
}
pos = pos + len + 1
}
return NSNetService.dictionaryFromTXTRecordData(data)
}
I'm using Swift 2 here. All contributions are welcome. Swift 3 versions, Objective-C versions, improvements, corrections.
I just ran into this one using Swift 3. In my case the problem only occurred when I used NetService.dictionary(fromTXTRecord:) but did not occur when I switched to Objective-C and called NSNetService dictionaryFromTXTRecord:. When the Objective-C call encounters an entry without an equal sign it creates a key containing the data and shoves it into the dictionary with an NSNull value. From what I can tell the Swift version then enumerates that dictionary and throws a fit when it sees the NSNull. My solution was to add an Objective-C file and a utility function that calls dictionaryFromTXTRecord: and cleans up the results before handing them back to my Swift code.
I have parser in Objc, parser returns NSDictionary. I am using this parser in swift class. But when some value is missing on that dictionary, it shows nil value. e.g. ->
wirlessData = {
"anon" = {
};
"channel" = {
"text" = 1;
};
}
I am checking through
if let wepauthValue = wirlessData["wepauth"] {
if let value = wepauthValue["text"] {
print("\(value)") // nil
}
}
I don't how it satisfy the if let condition. Any one faced this types of problem can help me out.
Thanks,
vikash
You don't need any special code to do this, because it is what a dictionary already does. When you fetch dict[key] you know whether the dictionary contains the key, because the Optional that you get back is not nil (and it contains the value).
So, if you just want to answer the question whether the dictionary contains the key, ask:
let keyExists = dict[key] != nil
If you want the value and you know the dictionary contains the key, say:
let val = dict[key]!
But if, as usually happens, you don't know it contains the key - you want to fetch it and use it, but only if it exists - then use something like if let:
if let val = dict[key] {
// now val is not nil and the Optional has been unwrapped, so use it
}
I have tested it and found that value is still optional.Take a look at screenshot below to understand it better.
"anon" would be an empty dictionary. An empty dictionary is not nil, it is a dictionary. Just an empty one. A JSON parser will never, ever give nil values unless you ask for a key that is not in a dictionary. For example wirlessData ["nonexistingkey"] would give you nil.
If you be more type-strong about it with the if..let's then:
if let anonValue = wirlessData["anon"] {
if let value = anonValue["text"] as? String {
// This won't execute if value isn't converted from `anonvalue["text"]` to String specifically. This includes null been a false match too
print("\(value)") // nil
}else{
print("Value did't match string at all")
}
}
or even more specifically in your case:
if let anonValue = wirlessData["anon"] {
if let value = anonValue["text"] as? Int {
// This won't execute if value isn't converted from `anonvalue["text"]` to String specifically. This includes null been a false match too
print("\(value)") // nil
}else{
print("Value did't match int at all")
}
}
The value your parser is returning not nil, its empty so you need to check on count if inner data type is dictionary or array, I have past 1 sample here
Please use below code and correct your logic accordingly to get it work properly
let wirlessData:[String:AnyObject] = [
"anon" : [],
"channel" : [
"text" : 1
]
]
if wirlessData["anon"]?.count > 0 {
if let value = wirlessData["anon"]!["text"] {
print("\(value)") // nil
}
}
Try this below code using type check operator (is) -
if wirlessData["anon"] is [String:AnyObject]
{
let anon = wirlessData["anon"]!
print(anon)
if anon["random"] is String {
let stringValue = anon["random"]!
print("\(stringValue)")
}
else if anon["random"] is Int
{
let intValue = anon["random"]!
print("\(intValue)") // nil
}
else
{
print(" may be value did't match string & Int or nil ")
}
}
I am trying to get access to a record value in CloudKit, here MyPin, it has a title & subtitle attribute/field value.
However it may happen that sometimes the record value is empty(here subtitle), and it crashes at the line when I call:
var tempS: String = Annot["Subtitle"] as! String
because Annot["Subtitle"] doesn exist ...
When I do
println(Annot["Subtitle"])
it returns nil
but if I do :
if (Annot["Subtitle"] == nil) {
println("just got a nil value")
}
I never enter the if statement:
Can someone help me how to identify if the record has an empty value?
Here is my line of codes:
let container = CKContainer.defaultContainer()
let publicData = container.publicCloudDatabase
let query = CKQuery(recordType: "MyPin", predicate: NSPredicate(format: "TRUEPREDICATE", argumentArray: nil))
publicData.performQuery(query, inZoneWithID: nil) { results, error in
if error == nil { // There is no error
for Annot in results {
var tempS: String = Annot["Subtitle"] as! String
}}
when you get Annot["Subtitle"] it will give you a CKRecordValue? return which has a base class of NSObjectProtocol. So in your case the field does exist but it's not a String so casting it using as! String will crash your app. Since the field exists the CKRecordValue will not be nil. However the content of that field is nil. When you print the field, it will output the .description of that field. In your case that is nil. Could you try this code instead:
if let f = Annot["Subtitle"] {
print("f = \(f) of type \(f.dynamicType)")
}
then set a breakpoint on the print line and when it stops try the following three statements in your output window:
po Annot
po f
p f
After the po Annot you should see what's in that record. Including your subtitle field. The po f is not so interesting. It will just output a memory address. The p f however will show you the actual type. If it's a string you should see something like: (__NSCFConstantString *) $R3 = 0xafdd21e0
P.S. Maybe you should call it record instead of Annot. It's a local variable so it should start with a lower case character. And it's still a record and not an Annot.
I think you are doing the right thing, but you don't see the println as it is executed in another thread (the completion part is executed asynchronously).
Try this:
if (Annot["Subtitle"] == nil) {
dispatch_async(dispatch_get_main_queue()) {
println("just got a nil value")
}
}
and see if it works!
The way I get values from cloudkit is this way. This both take care of the nil values and all other eventualities. Just note I have implemented a delegate to get my results back to the calling object asynchronously
privateDB.performQuery(query, inZoneWithID: nil) { (result, error) -> Void in
if error == nil{
for record in result{
let rec = record as! CKRecord
if let xxxVar = rec.valueForKey("fieldName") as? String{
myArray.append( xxxVar! ) //append unwrapped xxxVar to some result or whatever
}else{
//handle nil value
}
}
dispatch_async(dispatch_get_main_queue()) {
//do something with you data
self.delegate?.myResultCallBack(myArray)
return
}
}else{
dispatch_async(dispatch_get_main_queue()) {
self.delegate?.myErrorCallBack(error)
return
}
}
}
Beware, there are some changes in Swift2
I keep getting this error :
fatal error: unexpectedly found nil while unwrapping an Optional value
and cannot figure out how to debug it!
Here's my code :
func readCSV() -> Array<String> {
// Creates a new array of strings
var csvArray : Array<String> = Array<String>()
if let url: NSURL = NSURL(string : "URLFROMCSV" ) {
// Creates an Input Stream that will load the datas from our URL
let data :NSData! = NSData(contentsOfURL: url)!
let stream : NSInputStream! = NSInputStream(data: data)
// Opens the receiving stream
stream.open()
// Sets a buffer with a given size size
let bufferSize = 1024
var buffer = Array <UInt8>(count: bufferSize, repeatedValue: 0)
// String variable initialization
var csvFullString : String = ""
// While the stream receives datas, parses datas, convert them into strings and then concatenate them into one big string
while (stream.hasBytesAvailable) {
let readSize = stream.read(&buffer, maxLength: bufferSize)
let csvRaw = NSString (bytes: &buffer, length: readSize, encoding: NSUTF8StringEncoding)
let csvString = csvRaw as String!
csvFullString = csvFullString + csvString
}
// Fills the array with each strings. Separation between strings is made when a Θ character is parsed
csvArray = csvFullString.componentsSeparatedByString("Θ")
// Delete each null string
for(var i = 0 ; i < csvArray.count; i++) {
if(csvArray[i] == "") {
csvArray.removeAtIndex(i)
}
}
}
return csvArray
}
After searching on the web, I'm pretty sure it has something to do with unwrapping elements but the fact is when I debug it, i don't get any nil value anywhere.
PS: Would like to upload a screen but can't because i don't have 10 reputation, so bad!
Thanks in advance!
EDIT : Line let data :NSData! = NSData(contentsOfURL: url)! got the error.
Terry
You're probably creating the error in one of these two lines (though it may show up later):
let data :NSData! = NSData(contentsOfURL: url)!
let stream : NSInputStream! = NSInputStream(data: data)
You're assigning an optional value to an implicitlyUnwrappedOptional type and then using it without checking if you have a valid value.
This is why if let exists. It's a little funny that you've started to indent as if you're using if let but aren't.
Try this instead:
if let url = NSURL(string : "http://gorillaapplications.com/etablissements.csv" ) {
// Creates an Input Stream that will load the datas from our URL
if let data = NSData(contentsOfURL: url) {
let stream = NSInputStream(data: data)
stream.open()
// rest of your code here
}
else {
println("Didn't get a data object")
}
}
else {
println("Didn't get a URL object")
}
You really need to grasp Optionals for Swift. I'd recommend reading my Optionals chapter in this iBook: https://itunes.apple.com/us/book/swift-optionals-generics-for/id943445214?mt=11&uo=4&at=11lMGu
Update:
Since you added a bit more in your comments above, you're saying you get the error on this line: let data: NSData! = NSData(contentsOfURL: url)!. This is because of the ! at the end, which tells Swift you're sure that this function will return a valid value, so just use it, without checking if it's nil first. In your case, the function is returning nil and so your app crashes. Using the sample code I've provided above, you'll see that you'll no longer get a crash, but your code will execute the "Didn't get a data object" line. You'll need to correctly handle the case where you can't load data from that URL.