如何通过我的flex air应用程序通过域名来查找服务器的IP地址？

Question

I'm working on file transfer application where client sends files to cpp server. At client side I can give the server's domain name but not IP address cuz it may vary. So any one can tell me how can I get my server's IP address through it's domain name. I have to put this logic into air application. Thank you.

Answer 1

You might consider the NativeProcess API as a potential solution to your problem.

Open that page and scroll to the bottom; notice they're calling a Python script. You can call any Terminal/Console app you want through the NativeProcess API, and you can feed the process any number of arguments as a Vector.<string>() . Basically, I'm suggesting you might try calling cmd.exe and passing it ping www.your_unique_server.com . Then, you can then catch the responses coming back through nativeProcess.standardOutput and you're Flex/AIR app will have the resolved IP to work with. Here's a simple AIR app I wrote to do this:

<?xml version="1.0" encoding="utf-8"?>
<s:WindowedApplication 
   xmlns:fx="http://ns.adobe.com/mxml/2009" 
   xmlns:s="library://ns.adobe.com/flex/spark" 
   xmlns:mx="library://ns.adobe.com/flex/mx">

<s:layout>
  <s:VerticalLayout paddingTop="20" paddingLeft="20" 
       paddingRight="20" paddingBottom="20"/>
</s:layout>

<s:Label text="Enter a Domain Name:"/>
<s:TextInput id="domainTI" width="100%" text="www.google.com"/>
<s:Spacer height="20"/>
<s:TextArea id="pingsTA" width="100%" height="100%"
      text="Provide a domain name and click 'Ping!'"/>
<s:Button label="Ping!" click="initializeAndPing();"/>

<fx:Script>
<![CDATA[
private var nativeProcess:NativeProcess;

// called by the button.
private function initializeAndPing():void
{
  if(NativeProcess.isSupported)
  {
    // make NativeProcess ready for use.
    nativeProcess = new NativeProcess();

    nativeProcess.addEventListener(
        ProgressEvent.STANDARD_OUTPUT_DATA, onPingResult);
    nativeProcess.addEventListener(
        ProgressEvent.STANDARD_ERROR_DATA, onStdError);
    nativeProcess.addEventListener(
        IOErrorEvent.STANDARD_INPUT_IO_ERROR, onStdInError);

    pingTheHost();
  }
}

private function pingTheHost():void
{
  pingsTA.text="";

  var cmdFile:File = new File("C:\\Windows\\System32\\cmd.exe");

  var startInfo:NativeProcessStartupInfo;
  startInfo = new NativeProcessStartupInfo();
  startInfo.executable = cmdFile;

  // The \n special chars are necessary
  // for the command to be executed.
  var ping:String = "ping " + domainTI.text + "\n" ;

  nativeProcess.start(startInfo);
  nativeProcess.standardInput.writeUTFBytes(ping);
}

private function onPingResult(e:ProgressEvent):void
{
  // you would need to parse the IP from the text string
  // captured here to make it available as a variable.

  pingsTA.text += 
     nativeProcess.standardOutput.readUTFBytes(
            nativeProcess.standardOutput.bytesAvailable);
}

private function onStdError(e:ProgressEvent):void
{
  trace("StdError: " + 
     nativeProcess.standardError.readUTFBytes(
            nativeProcess.standardError.bytesAvailable));
}

private function onStdInError(e:IOErrorEvent):void
{
  trace("StdInError: " + e.toString());
}

]]>
</fx:Script>

</s:WindowedApplication>

To use NativeProcess, such as in the app above, you'll need an AIR v2+ SDK (you can overlay a new AIR SDK if you have a <2 SDK) and you'll also need to enable the extendedDesktop profile in your app-descriptor.xml file:

<!-- uncomment this node and remove all but "extendedDesktop" -->
<supportedProfiles>extendedDesktop</supportedProfiles>

One last thought: I believe NativeProcess API requires your AIR app be installed as a native application (ie installed by an .exe file). But as you see in the screenshot, this is easy to accomplish with Flash Builder 4+.

However, if you don't have Flash Builder 4, you can always write a build script for ADT , which ships with the AIR SDK. That post by Rich Tretola does a nice job of encapsulating the basics.

Finally, here's what my little app looks like in use: