Ashley Mills reachability not sending notification when wifi turns back on? - xcode

Question

I have a set up, using Ashley Mills Reachability, which is supposed to send a notification, using NotificationCenter, to the application when the connection of the app changes. It is set up as follows:
func reachabilityChanged(note: Notification) {
let reachability = note.object as! Reachability
switch reachability.connection {
case .wifi:
print("Reachable via WiFi")
case .cellular:
print("Reachable via Cellular")
case .none:
print("Network not reachable")
}
}
override func viewDidLoad() {
super.viewDidLoad()
NotificationCenter.default.addObserver(self, selector: #selector(self.reachabilityChanged), name: .reachabilityChanged, object: reachability)
do{
try reachability.startNotifier()
}catch{
print("could not start reachability notifier")
}
}
With my computer (which is what I am running the simulator on) connected to wifi, the console accurately prints "Reachable via Wifi". Turning off the wifi causes the console to, again, accurately print "Network not reachable". I run into an issue, though, when I turn the wifi back on. "Reachable via Wifi" does not get printed to the log... in fact, nothing gets printed to the log. I do not know why this is happening nor how to fix it. Anyone have any ideas?
This is the reachability code:
import SystemConfiguration
import Foundation
public enum ReachabilityError: Error {
case FailedToCreateWithAddress(sockaddr_in)
case FailedToCreateWithHostname(String)
case UnableToSetCallback
case UnableToSetDispatchQueue
}
#available(*, unavailable, renamed: "Notification.Name.reachabilityChanged")
public let ReachabilityChangedNotification = NSNotification.Name("ReachabilityChangedNotification")
extension Notification.Name {
public static let reachabilityChanged = Notification.Name("reachabilityChanged")
}
func callback(reachability:SCNetworkReachability, flags: SCNetworkReachabilityFlags, info: UnsafeMutableRawPointer?) {
guard let info = info else { return }
let reachability = Unmanaged<Reachability>.fromOpaque(info).takeUnretainedValue()
reachability.reachabilityChanged()
}
public class Reachability {
public typealias NetworkReachable = (Reachability) -> ()
public typealias NetworkUnreachable = (Reachability) -> ()
#available(*, unavailable, renamed: "Conection")
public enum NetworkStatus: CustomStringConvertible {
case notReachable, reachableViaWiFi, reachableViaWWAN
public var description: String {
switch self {
case .reachableViaWWAN: return "Cellular"
case .reachableViaWiFi: return "WiFi"
case .notReachable: return "No Connection"
}
}
}
public enum Connection: CustomStringConvertible {
case none, wifi, cellular
public var description: String {
switch self {
case .cellular: return "Cellular"
case .wifi: return "WiFi"
case .none: return "No Connection"
}
}
}
public var whenReachable: NetworkReachable?
public var whenUnreachable: NetworkUnreachable?
#available(*, deprecated: 4.0, renamed: "allowsCellularConnection")
public let reachableOnWWAN: Bool = true
/// Set to `false` to force Reachability.connection to .none when on cellular connection (default value `true`)
public var allowsCellularConnection: Bool
// The notification center on which "reachability changed" events are being posted
public var notificationCenter: NotificationCenter = NotificationCenter.default
#available(*, deprecated: 4.0, renamed: "connection.description")
public var currentReachabilityString: String {
return "\(connection)"
}
#available(*, unavailable, renamed: "connection")
public var currentReachabilityStatus: Connection {
return connection
}
public var connection: Connection {
guard isReachableFlagSet else { return .none }
// If we're reachable, but not on an iOS device (i.e. simulator), we must be on WiFi
guard isRunningOnDevice else { return .wifi }
var connection = Connection.none
if !isConnectionRequiredFlagSet {
connection = .wifi
}
if isConnectionOnTrafficOrDemandFlagSet {
if !isInterventionRequiredFlagSet {
connection = .wifi
}
}
if isOnWWANFlagSet {
if !allowsCellularConnection {
connection = .none
} else {
connection = .cellular
}
}
return connection
}
fileprivate var previousFlags: SCNetworkReachabilityFlags?
fileprivate var isRunningOnDevice: Bool = {
#if (arch(i386) || arch(x86_64)) && os(iOS)
return false
#else
return true
#endif
}()
fileprivate var notifierRunning = false
fileprivate let reachabilityRef: SCNetworkReachability
fileprivate let reachabilitySerialQueue = DispatchQueue(label: "uk.co.ashleymills.reachability")
required public init(reachabilityRef: SCNetworkReachability) {
allowsCellularConnection = true
self.reachabilityRef = reachabilityRef
}
public convenience init?(hostname: String) {
guard let ref = SCNetworkReachabilityCreateWithName(nil, hostname) else { return nil }
self.init(reachabilityRef: ref)
}
public convenience init?() {
var zeroAddress = sockaddr()
zeroAddress.sa_len = UInt8(MemoryLayout<sockaddr>.size)
zeroAddress.sa_family = sa_family_t(AF_INET)
guard let ref = SCNetworkReachabilityCreateWithAddress(nil, &zeroAddress) else { return nil }
self.init(reachabilityRef: ref)
}
deinit {
stopNotifier()
}
}
public extension Reachability {
// MARK: - *** Notifier methods ***
func startNotifier() throws {
guard !notifierRunning else { return }
var context = SCNetworkReachabilityContext(version: 0, info: nil, retain: nil, release: nil, copyDescription: nil)
context.info = UnsafeMutableRawPointer(Unmanaged<Reachability>.passUnretained(self).toOpaque())
if !SCNetworkReachabilitySetCallback(reachabilityRef, callback, &context) {
stopNotifier()
throw ReachabilityError.UnableToSetCallback
}
if !SCNetworkReachabilitySetDispatchQueue(reachabilityRef, reachabilitySerialQueue) {
stopNotifier()
throw ReachabilityError.UnableToSetDispatchQueue
}
// Perform an initial check
reachabilitySerialQueue.async {
self.reachabilityChanged()
}
notifierRunning = true
}
func stopNotifier() {
defer { notifierRunning = false }
SCNetworkReachabilitySetCallback(reachabilityRef, nil, nil)
SCNetworkReachabilitySetDispatchQueue(reachabilityRef, nil)
}
// MARK: - *** Connection test methods ***
#available(*, deprecated: 4.0, message: "Please use `connection != .none`")
var isReachable: Bool {
guard isReachableFlagSet else { return false }
if isConnectionRequiredAndTransientFlagSet {
return false
}
if isRunningOnDevice {
if isOnWWANFlagSet && !reachableOnWWAN {
// We don't want to connect when on cellular connection
return false
}
}
return true
}
#available(*, deprecated: 4.0, message: "Please use `connection == .cellular`")
var isReachableViaWWAN: Bool {
// Check we're not on the simulator, we're REACHABLE and check we're on WWAN
return isRunningOnDevice && isReachableFlagSet && isOnWWANFlagSet
}
#available(*, deprecated: 4.0, message: "Please use `connection == .wifi`")
var isReachableViaWiFi: Bool {
// Check we're reachable
guard isReachableFlagSet else { return false }
// If reachable we're reachable, but not on an iOS device (i.e. simulator), we must be on WiFi
guard isRunningOnDevice else { return true }
// Check we're NOT on WWAN
return !isOnWWANFlagSet
}
var description: String {
let W = isRunningOnDevice ? (isOnWWANFlagSet ? "W" : "-") : "X"
let R = isReachableFlagSet ? "R" : "-"
let c = isConnectionRequiredFlagSet ? "c" : "-"
let t = isTransientConnectionFlagSet ? "t" : "-"
let i = isInterventionRequiredFlagSet ? "i" : "-"
let C = isConnectionOnTrafficFlagSet ? "C" : "-"
let D = isConnectionOnDemandFlagSet ? "D" : "-"
let l = isLocalAddressFlagSet ? "l" : "-"
let d = isDirectFlagSet ? "d" : "-"
return "\(W)\(R) \(c)\(t)\(i)\(C)\(D)\(l)\(d)"
}
}
fileprivate extension Reachability {
func reachabilityChanged() {
guard previousFlags != flags else { return }
let block = connection != .none ? whenReachable : whenUnreachable
DispatchQueue.main.async {
block?(self)
self.notificationCenter.post(name: .reachabilityChanged, object:self)
}
previousFlags = flags
}
var isOnWWANFlagSet: Bool {
#if os(iOS)
return flags.contains(.isWWAN)
#else
return false
#endif
}
var isReachableFlagSet: Bool {
return flags.contains(.reachable)
}
var isConnectionRequiredFlagSet: Bool {
return flags.contains(.connectionRequired)
}
var isInterventionRequiredFlagSet: Bool {
return flags.contains(.interventionRequired)
}
var isConnectionOnTrafficFlagSet: Bool {
return flags.contains(.connectionOnTraffic)
}
var isConnectionOnDemandFlagSet: Bool {
return flags.contains(.connectionOnDemand)
}
var isConnectionOnTrafficOrDemandFlagSet: Bool {
return !flags.intersection([.connectionOnTraffic, .connectionOnDemand]).isEmpty
}
var isTransientConnectionFlagSet: Bool {
return flags.contains(.transientConnection)
}
var isLocalAddressFlagSet: Bool {
return flags.contains(.isLocalAddress)
}
var isDirectFlagSet: Bool {
return flags.contains(.isDirect)
}
var isConnectionRequiredAndTransientFlagSet: Bool {
return flags.intersection([.connectionRequired, .transientConnection]) == [.connectionRequired, .transientConnection]
}
var flags: SCNetworkReachabilityFlags {
var flags = SCNetworkReachabilityFlags()
if SCNetworkReachabilityGetFlags(reachabilityRef, &flags) {
return flags
} else {
return SCNetworkReachabilityFlags()
}
}
}

Answer 1

it get's triggered only for one time per run in the simulator, but on a real iOS device, it works normally.