在 Swift 中进行简单的 DNS 查找 [重复]

Question

我正在尝试使用 Swift 代码进行简单的 DNS 查找。到目前为止，我有

    if  host != "\0" {
        let hostRef = CFHostCreateWithName(kCFAllocatorDefault, host.bridgeToObjectiveC()).takeRetainedValue()
        var resolved = CFHostStartInfoResolution(hostRef, CFHostInfoType.Addresses, nil)
        let addresses = CFHostGetAddressing(hostRef, &resolved).takeRetainedValue() as NSArray

        for address: AnyObject in addresses {
            println(address)  // address is of type NSData.
        }
    }

根据Convert NSData to sockaddr struct in swift。 （host 是 NSString。）

但是，在执行if 语句并打印address 数据之后，在第一行以EXC_BAD_ACCESS (code=EXC_I386_GPFLT) 退出之前，我的调试器日志打印<10020000 4a7de064 00000000 00000000>。我想要得到的只是一个带有 IP 地址的字符串，或者如果主机不存在，则为一个空字符串。

Answer 1

我已经测试，发现AnyObject 是崩溃的原因。你不需要AnyObject，因为swift会从数组addresses推断类型

var host = "192.168.103.13"
    if  host != "\0" {
        let hostRef = CFHostCreateWithName(kCFAllocatorDefault, host.bridgeToObjectiveC()).takeRetainedValue()
        var resolved = CFHostStartInfoResolution(hostRef, CFHostInfoType.Addresses, nil)
        let addresses = CFHostGetAddressing(hostRef, &resolved).takeRetainedValue() as NSArray

        println(addresses)
        //Remove `AnyObject` as there is no need.Swift will infrence from array addresses
        for address in addresses {
            println(address)  // address is of type NSData.
        }
    }