I want to get the IP address (like 192.168.0.1 or 87.12.56.50) from DNS query in Swift. I tried 100 times with 100 different methods ... Nothing helped me, so I'll have to ask for help. This is my code so far:
let host = CFHostCreateWithName(nil,"subdomain.of.stackoverflow.com").takeUnretainedValue();
CFHostStartInfoResolution(host, .Addresses, nil);
var success: Boolean = 0;
let addresses = CFHostGetAddressing(host, &success).takeUnretainedValue() as NSArray;
if(addresses.count > 0){
let theAddress = addresses[0] as NSData;
println(theAddress);
}
OK ... These are the links for the code I tried to implement without success:
https://gist.github.com/mikeash/bca3a341db74221625f5
How to perform DNS query on iOS
Create an Array in Swift from an NSData Object
Does CFHostGetAddressing() support ipv6 DNS entries?
Do a simple DNS lookup in Swift
Your code retrieves the address as a "socket address" structure.
getnameinfo()
can be used to convert the address into a numerical IP string
(code recycled from https://stackoverflow.com/a/25627545/1187415,
now updated to Swift 2):
let host = CFHostCreateWithName(nil,"www.google.com").takeRetainedValue()
CFHostStartInfoResolution(host, .Addresses, nil)
var success: DarwinBoolean = false
if let addresses = CFHostGetAddressing(host, &success)?.takeUnretainedValue() as NSArray?,
let theAddress = addresses.firstObject as? NSData {
var hostname = [CChar](count: Int(NI_MAXHOST), repeatedValue: 0)
if getnameinfo(UnsafePointer(theAddress.bytes), socklen_t(theAddress.length),
&hostname, socklen_t(hostname.count), nil, 0, NI_NUMERICHOST) == 0 {
if let numAddress = String.fromCString(hostname) {
print(numAddress)
}
}
}
Output (example): 173.194.112.147
Note also the usage of takeRetainedValue()
in the first line, because
CFHostCreateWithName()
has "Create" in its name the therefore returns a (+1) retained
object.
Update for Swift 3/Xcode 8:
let host = CFHostCreateWithName(nil,"www.google.com" as CFString).takeRetainedValue()
CFHostStartInfoResolution(host, .addresses, nil)
var success: DarwinBoolean = false
if let addresses = CFHostGetAddressing(host, &success)?.takeUnretainedValue() as NSArray?,
let theAddress = addresses.firstObject as? NSData {
var hostname = [CChar](repeating: 0, count: Int(NI_MAXHOST))
if getnameinfo(theAddress.bytes.assumingMemoryBound(to: sockaddr.self), socklen_t(theAddress.length),
&hostname, socklen_t(hostname.count), nil, 0, NI_NUMERICHOST) == 0 {
let numAddress = String(cString: hostname)
print(numAddress)
}
}
Or, to get all IP addresses for the host:
let host = CFHostCreateWithName(nil,"www.google.com" as CFString).takeRetainedValue()
CFHostStartInfoResolution(host, .addresses, nil)
var success: DarwinBoolean = false
if let addresses = CFHostGetAddressing(host, &success)?.takeUnretainedValue() as NSArray? {
for case let theAddress as NSData in addresses {
var hostname = [CChar](repeating: 0, count: Int(NI_MAXHOST))
if getnameinfo(theAddress.bytes.assumingMemoryBound(to: sockaddr.self), socklen_t(theAddress.length),
&hostname, socklen_t(hostname.count), nil, 0, NI_NUMERICHOST) == 0 {
let numAddress = String(cString: hostname)
print(numAddress)
}
}
}