Hi, I was working on some new filtering logic for my Content Filter that I would like to add. It involves making requests to remote DNS resolvers. Is it possible to use it within sync override func handleNewFlow(_ flow: NEFilterFlow) -> NEFilterNewFlowVerdict
of the NEFilterDataProvider
?
As of right now, I have a concept working in Command Line Tool and playground, however, when I try to add working module to the main project, it's not working (connections are not loading).
Function that makes requests to the servers: In this function I use DispatchGroup and notify for non-main queue
@available(iOS 12, *)
public class NetworkService {
private let nonMainQueue: DispatchQueue = DispatchQueue(label: "non-main-queue")
func isBlocked(hostname: String, completion: @escaping (Bool) -> Void) {
var isAnyBlocked = false
let group = DispatchGroup()
for server in servers {
group.enter()
let endpoint = NWEndpoint.Host(server)
query(host: endpoint, domain: hostname, queue: .global()) { response, error in
defer {
group.leave()
}
/*
* some code that determines the filtering logic
* if condition is true => isAnyBlocked = true & return
*/
}
}
group.notify(queue: nonMainQueue) {
completion(isAnyBlocked)
}
}
}
And, for example, in playground Semaphores
make it work as expected, but the same approach doesn't work with the NEFilterDataProvider
playground code sample
let hostname = "google.com"
func returnResponse() -> String {
var result = ""
let semaphore = DispatchSemaphore(value: 0)
DispatchQueue.global().async {
NetworkService.isBlocked(hostname: hostname) { isBlocked in
result = isBlocked ? "blocked" : "allowed"
semaphore.signal()
}
}
semaphore.wait()
return result
}
print(returnResponse())
Output: allowed