My app will have an array of serviceUUIDs with which to discover selected peripherals. Once a peripheral from that set is discovered, how do I then determine which serviceUUID it has/had to allow it to be discovered? The UUID of the peripheral's identifier seems to be different than the serviceUUID I gave it in my test code.
You can read the detected service UUIDs out of the advertisement, but they might come in two places depending on whether the advertisement originated from backgrounded iOS devices (which transmit in the "overflow area").
Try something like this to get the list of service UUIDs from both places:
func centralManager(_ central: CBCentralManager, didDiscover peripheral: CBPeripheral, advertisementData: [String : Any], rssi RSSI: NSNumber) {
var detectedServiceUuids = advertisementData[CBAdvertisementDataServiceUUIDsKey] as? [CBUUID] ?? []
if let detectedOverflowUuids = advertisementData[CBAdvertisementDataOverflowServiceUUIDsKey] as? [CBUUID] {
detectedServiceUuids.append(contentsOf: detectedOverflowUuids)
}
for detectedServiceUuid in detectedServiceUuids {
print("I detected serviceUuid: \(detectedServiceUuid)")
}
}
I watched a tutorial on youtube and I did exaclty like the tutor said.I even copied his code from the source file he provided and I get an error...but if I run his project then it works.
Why these things happens?
I have a segmented component and when I change it from login to register this code runs:
#IBAction func signinSelectorChange(_ sender: UISegmentedControl) {
// Flip the boolean
isSignIn = !isSignIn
// Check the bool and set the button and labels
if isSignIn {
signinLabel.text = "Sign In"
loginButton.setTitle("Sign In", for: .normal)
}
else {
signinLabel.text = "Register"
loginButton.setTitle("Register", for: .normal)
}
}
when I switch I get this error message :
2017-04-27 21:30:34.932 FIREBASE - Read and Write[38283] [Firebase/Analytics][I-ACS023012] Firebase Analytics enabled
fatal error: unexpectedly found nil while unwrapping an Optional value
what is wrong?
thank you
I am using Xcode 7.3 for iOS 9.3 to try and encrypt a Core Data file. I am trying to use NSPersistentStoreFileProtectionKey and set it to NSFileProtectionComplete to enable the encryption. It is not working for some reason and I can always see the .sqlite file generated by the app and browse through the content in sqlitebrowser or iexplorer. Here is my code :
lazy var persistentStoreCoordinator: NSPersistentStoreCoordinator = {
// The persistent store coordinator for the application. This implementation creates and returns a coordinator, having added the store for the application to it. This property is optional since there are legitimate error conditions that could cause the creation of the store to fail.
// Create the coordinator and store
let coordinator = NSPersistentStoreCoordinator(managedObjectModel: self.managedObjectModel)
let url = self.applicationDocumentsDirectory.URLByAppendingPathComponent("SingleViewCoreData.sqlite")
var failureReason = "There was an error creating or loading the application's saved data."
let dict: [NSObject : AnyObject] = [
NSPersistentStoreFileProtectionKey : NSFileProtectionComplete
]
do {
try coordinator.addPersistentStoreWithType(NSSQLiteStoreType, configuration: nil, URL: url, options: dict)
} catch {
// Report any error we got.
var dict = [String: AnyObject]()
dict[NSLocalizedDescriptionKey] = "Failed to initialize the application's saved data"
dict[NSLocalizedFailureReasonErrorKey] = failureReason
dict[NSUnderlyingErrorKey] = error as NSError
let wrappedError = NSError(domain: "YOUR_ERROR_DOMAIN", code: 9999, userInfo: dict)
// Replace this with code to handle the error appropriately.
// abort() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development.
NSLog("Unresolved error \(wrappedError), \(wrappedError.userInfo)")
abort()
}
do {
let url = self.applicationDocumentsDirectory.URLByAppendingPathComponent("SingleViewCoreData.sqlite")
try NSFileManager.defaultManager().setAttributes([NSFileProtectionKey : NSFileProtectionComplete], ofItemAtPath: url.path!)
} catch {
}
do {
let url = self.applicationDocumentsDirectory.URLByAppendingPathComponent("SingleViewCoreData.sqlite-wal")
try NSFileManager.defaultManager().setAttributes([NSFileProtectionKey : NSFileProtectionComplete], ofItemAtPath: url.path!)
// try print(NSFileManager.defaultManager().attributesOfFileSystemForPath(String(url)))
} catch {
}
do {
let url = self.applicationDocumentsDirectory.URLByAppendingPathComponent("SingleViewCoreData.sqlite-shm")
try NSFileManager.defaultManager().setAttributes([NSFileProtectionKey : NSFileProtectionComplete], ofItemAtPath: url.path!)
// try print(NSFileManager.defaultManager().attributesOfFileSystemForPath(String(url)))
} catch {
}
return coordinator
}()
I have also enabled Data Protection for my target in the "Capabilities". I have regenerated the provisioning profile from the Apple Developer portal and am using that with Enabled Data Protection.
I am also using the following code to check the file attributes of .sqlite , .sqlite-wal and .sqlite-shm files. NSFileProtectionKey is correctly set for all 3 of them.
func checkProtectionForLocalDb(atDir : String){
let fileManager = NSFileManager.defaultManager()
let enumerator: NSDirectoryEnumerator = fileManager.enumeratorAtPath(atDir)!
for path in enumerator {
let attr : NSDictionary = enumerator.fileAttributes!
print(attr)
}
}
I also tried disabling the Journal mode to prevent -wal and -shm files from being created. But I can still read the .sqlite file. Even though the attributes read NSFileProtectionComplete.
As described in the Apple Documentation at Apple Docs under "Protecting Data using On Disk Encryption", I tried to check whether the value of variable protectedDataAvailable changes as shown in the code below
public func applicationDidEnterBackground(application: UIApplication) {
// Use this method to release shared resources, save user data, invalidate timers, and store enough application state information to restore your application to its current state in case it is terminated later.
// If your application supports background execution, this method is called instead of applicationWillTerminate: when the user quits.
NSThread.sleepForTimeInterval(10)
sleep(10)
let dataAvailable : Bool = UIApplication.sharedApplication().protectedDataAvailable
print("Protected Data Available : " + String(dataAvailable))
}
If I check the value without the delay it's set to true but after adding the delay it's set to false. This is kind of encouraging, however, right after, when I download the container, to show the content, it still has .sqlite file that still shows the content when opened in sqlitebrowser.
Ok, I finally understand this.
Using Xcode 7.3.1
Enabling File Protection
Enable File Protection using the Capabilities tab on your app target
If you do not want the default NSFileProtectionComplete, change this setting in the developer portal under your app id
Make sure Xcode has the new provisioning profile this creates.
For protecting files your app creates, that's it.
To protect Core Data, you need to add the NSPersistentStoreFileProtectionKey: NSFileProtectionComplete option to your persistent store.
Example:
var options: [NSObject : AnyObject] = [NSMigratePersistentStoresAutomaticallyOption: true,
NSPersistentStoreFileProtectionKey: NSFileProtectionComplete,
NSInferMappingModelAutomaticallyOption: true]
do {
try coordinator!.addPersistentStoreWithType(NSSQLiteStoreType, configuration: nil, URL: url, options: options)
Testing File Protection
I am not able to test this using a non-jailbroken device connected to a computer. Every attempt to access the device this way requires that I "trust" the computer and I believe that trusted computers are always able to read the phone's data ("Trusted computers can sync with your iOS device, create backups, and access your device's photos, videos, contacts, and other content" - https://support.apple.com/en-us/HT202778). I think the other answers on SO referencing this technique are no longer valid with more recent versions of iOS. Indeed, I am always able to download the container using XCode and view the app's data using iPhone Explorer. So how to test...
1 - Create an archive and ensure that it is has the proper entitlements by running the following on the .app file from the command line:
codesign -d --entitlements :- <path_to_app_binary>
You should see a key/value pair that represents your Data Protection level. In this example, NSFileProtectionComplete:
<key>com.apple.developer.default-data-protection</key>
<string>NSFileProtectionComplete</string>
In addition, I used the following two techniques to satisfy myself that the data protection is indeed working. They both require code changes.
2 - Add some code to verify that the proper NSFileProtectionKey is being set on your files and/or core data store:
NSFileManager.defaultManager().attributesOfItemAtPath(dbPath.path!)
If I print this out on one of my files I get:
["NSFileCreationDate": 2016-10-14 02:06:39 +0000, "NSFileGroupOwnerAccountName": mobile, "NSFileType": NSFileTypeRegular, "NSFileSystemNumber": 16777218, "NSFileOwnerAccountName": mobile, "NSFileReferenceCount": 1, "NSFileModificationDate": 2016-10-14 02:06:39 +0000, "NSFileExtensionHidden": 0, "NSFileSize": 81920, "NSFileGroupOwnerAccountID": 501, "NSFileOwnerAccountID": 501, "NSFilePosixPermissions": 420, "NSFileProtectionKey": NSFileProtectionComplete, "NSFileSystemFileNumber": 270902]
Note the "NSFileProtectionKey": "NSFileProtectionComplete" pair.
3 - Modify the following code and hook it up to some button in your app.
#IBAction func settingButtonTouch(sender: AnyObject) {
updateTimer = NSTimer.scheduledTimerWithTimeInterval(0.5, target: self,
selector: #selector(TabbedOverviewViewController.runTest), userInfo: nil, repeats: true)
registerBackgroundTask()
}
var backgroundTask: UIBackgroundTaskIdentifier = UIBackgroundTaskInvalid
var updateTimer: NSTimer?
func registerBackgroundTask() {
backgroundTask = UIApplication.sharedApplication().beginBackgroundTaskWithExpirationHandler {
[unowned self] in
self.endBackgroundTask()
}
assert(backgroundTask != UIBackgroundTaskInvalid)
}
func endBackgroundTask() {
NSLog("Background task ended.")
UIApplication.sharedApplication().endBackgroundTask(backgroundTask)
backgroundTask = UIBackgroundTaskInvalid
}
func runTest() {
switch UIApplication.sharedApplication().applicationState {
case .Active:
NSLog("App is active.")
checkFiles()
case .Background:
NSLog("App is backgrounded.")
checkFiles()
case .Inactive:
break
}
}
func checkFiles() {
// attempt to access a protected resource, i.e. a core data store or file
}
When you tap the button this code begins executing the checkFiles method every .5 seconds. This should run indefinitely with the app in the foreground or background - until you lock your phone. At that point it should reliably fail after roughly 10 seconds - exactly as described in the description of NSFileProtectionComplete.
We need to understand how Data Protection works.
Actually, you don't even need to enable it. Starting with iOS7, the default protection level is “File Protection Complete until first user authentication.”
This means that the files are not accessible until the user unlocks the device for the first time. After that, the files remain accessible even when the device is locked and until it shuts down or reboots.
The other thing is that you're going to see the app's data on a trusted computer always - regardless of the Data Protection level setting.
However, the data can’t be accessed if somebody tries to read them from the flash drive directly. The purpose of Data Protection is to ensure that sensitive data can’t be extracted from a password-protected device’s storage.
After running this code, I could still access and read the contents written to protectedFileURL, even after locking the device.
do {
try data.write(to: protectedFileURL, options: .completeFileProtectionUnlessOpen)
} catch {
print(error)
}
But that's normal since I ran iExplorer on a trusted computer.
And for the same reason, it's fine if you see your sqlite file.
The situation is different if your device gets lost or stolen. A hacker won't be able to read the sqlite file since it's encrypted. Well, unless he guesses your passcode somehow.
Swift 5.0 & Xcode 11:
Enable "Data Protection" in "Capabilities".
Use the following code to protect a file or folder at a specific path:
// Protects a file or folder + excludes it from backup.
// - parameter path: Path component of the file.
// - parameter fileProtectionType: `FileProtectionType`.
// - returns: True, when protected successful.
static func protectFileOrFolderAtPath(_ path: String, fileProtectionType: FileProtectionType) -> Bool {
guard FileManager.default.fileExists(atPath: path) else { return false }
let fileProtectionAttrs = [FileAttributeKey.protectionKey: fileProtectionType]
do {
try FileManager.default.setAttributes(fileProtectionAttrs, ofItemAtPath: path)
return true
} catch {
assertionFailure("Failed protecting path with error: \(error).")
return false
}
}
(Optional) Use the following code to check whether the file or folder at the specific path is protected (note: This only works on physical devices):
/// Returns true, when the file at the provided path is protected.
/// - parameter path: Path of the file to check.
/// - note: Returns true, for simulators. Simulators do not have hardware file encryption. This feature is only available for real devices.
static func isFileProtectedAtPath(_ path: String) -> Bool {
guard !Environment.isSimulator else { return true } // file protection does not work on simulator!
do {
let attributes = try FileManager.default.attributesOfItem(atPath: path)
if attributes.contains(where: { $0.key == .protectionKey }) {
return true
} else {
return false
}
} catch {
assertionFailure(String(describing: error))
return false
}
}
Rather than encrypt a file at the local level I set NSFileProtectionComplete for the app as a whole.
Create the file 'entitlements.plist' in your apps root folder with the following content.
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
<key>DataProtectionClass</key>
<string>NSFileProtectionComplete</string>
</dict>
</plist>
Then if you haven't already done so already (this could be the problem with your file level encryption) enable Data Protection in your apps capabilities.
I'm trying to connect to a D-Bus signal this way:
bool result = QDBusConnection::systemBus().connect(
"foo.bar", // service
"/foo/bar", // path
"foo.bar", // interface
"SignalSomething",
this,
SLOT(SignalSomethingSlot()));
if( !result )
{
// Why!?
}
QDBusConnection::connect() returns a boolean, how do I get extended error information? If a check QDBusConnection::lastError() it returns no useful information (as QDBusError::isValid() is false).
I had the same issue and it turned out that the slot I connected to had the wrong parameter types. They must match according to Qt's documentation and it looks like connect() verifies that, despite not explicitly mentioned.
Warning: The signal will only be delivered to the slot if the parameters match.
I suggest d-feet to list signals and check their parameter types. dbus-monitor does list signals, paths and such too, but not always the exact type of parameters.
One important observation though: I fixed the issue in my particular case by using different slot parameters than the actual signal has!
I wanted to connect to a com.ubuntu.Upstart0_6 signal mentioned here to detect when the screen in Ubuntu is locked/unlocked. dbusmonitor prints the following and d-feet shows parameters (String, Array of [String])
// dbusmonitor output
signal time=1529077633.579984 sender=:1.0 -> destination=(null destination) serial=809 path=/com/ubuntu/Upstart; interface=com.ubuntu.Upstart0_6; member=EventEmitted
string "desktop-unlock"
array [
]
Hence the signal should be of type
void screenLockChangedUbuntu(QString event, QVector<QString> args) // connect() -> false
This however made connect() return false. The solution was to remove the array parameter from the slot:
void screenLockChangedUbuntu(QString event) // works
I am aware that the array parameter was always empty, but I cannot explain why it only worked when removing it.
You could try these tricks:
1) Set QDBUS_DEBUG environment variable before running your application.
export QDBUS_DEBUG=1
2) Start dbus-monitor to see what's happening on the bus. You may need to set a global policy to be able to eavesdrop system bus depending on your distro.
Update:
Are you sure connecting to the system bus succeeded? If it fails you should probably check system.conf policy and possibly create own conf in system.d. This post might be helpful.
You could first connect to the system bus with QDBusConnection::connectToBus and check if it succeeded with QDBusConnection::isConnected. Only after that you try to connect to the signal and check if that succeeded.
QDBusConnection bus = QDBusConnection::connectToBus(QDBusConnection::systemBus, myConnectionName);
if (bus.isConnected())
{
if(!bus.connect( ... ))
{
// Connecting to signal failed
}
}
else
{
// Connecting to system bus failed
}
i'm developing a website that use geolocation, but nothing happens if i access it with location service disabled. It should show user alert message to enable location service.
What you can do, if geolocation is supported by browser, is check the error code of getCurrentPosition
PERMISSION_DENIED - if the user clicks that “Don’t Share” button or otherwise denies you access to their location.
POSITION_UNAVAILABLE - if the network is down or the positioning satellites can’t be contacted.
TIMEOUT - if the network is up but it takes too long to calculate the user’s position. How long is “too long”? I’ll show you how to
define that in the next section.
if(navigator.geolocation){
navigator.geolocation.getCurrentPosition(
docode, handle_error)
}
function handle_error(err) {
if (err.code == 1) {
// PERMISSION_DENIED
}
else if (err.code == 2) {
// POSITION_UNAVAILABLE
}
else if (err.code == 3) {
// TIMEOUT
}
}