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Index › Programming Questions & Help › Syntax Questions › how to ping a host

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how to ping a host? (Read 1131 times)

Bojarovski YaBB Newbies Offline Posts: 6	how to ping a host? Oct 11^th, 2007, 12:44am Are there any libraries that offer functions that can tell: -if a host is alive? -what is the response time for the connection to the host? More importantly, can i somehow do this in processing without importing extra libraries? Any help is much apretiated...

koogy God Member Offline Posts: 788	Re: how to ping a host? Reply #1 - Oct 11^th, 2007, 3:36pm a quick google ('java ping') says that there is no way java can be used for pinging a server, at least natively, because the networking protocol is at too high a level. a couple of pages suggest getting around it by calling system functions and parsing the results, 'ping -n 1 hostname' in windows or linux for instance.

JohnG

Re: how to ping a host?
Reply #2 - Oct 11^th, 2007, 4:14pm

Whilst you can't ping per-se, you could time how long it takes to get a (simple) webpage from a webserver.

Code:

int start=millis();
loadString("http://www.google.com/");
int end=millis();
println("Took: "+(end-start)+"ms");

That's not so hlepful if the systems you want to time don't have a webserver running, or only serve large pages (but then, you could get a non-existanrt page, since most 404s are small)

Bojarovski

Re: how to ping a host?
Reply #3 - Oct 13^th, 2007, 5:47pm

koogy wrote on Oct 11^th, 2007, 3:36pm:

a quick google ('java ping') says that there is no way java can be used for pinging a server, at least natively, because the networking protocol is at too high a level. a couple of pages suggest getting around it by calling system functions and parsing the results, 'ping -n 1 hostname' in windows or linux for instance.

well calling system functions will have to do then, but now i need to find out what is the pinging command for different OS-s and what is the formatting of the results...

Thank you for the help koogs.

@JohnG: Thank you for your advice but i actually need to ping hosts whether or not they had webservers running - i need the response time for the connection to them which is quite different...

jomo

Re: how to ping a host?
Reply #4 - Oct 18^th, 2007, 4:47am

I don't know if this will be helpful for you but I wrote a class to perform a traceroute. It's not the most beautiful code but maybe you will find it useful (works on Windows, Unixes).

The class:
Code:


import java.util.regex.*;

class TraceRoute{
  Runtime r = Runtime.getRuntime();
  private String url;
  private ArrayList hopsList = new ArrayList();
  private String hopsString = " ";
  private boolean doBucketLimit = false;//if # of consecutive hops == bucketLimit go into the bit bucket abort
  private int bucketLimit;

  TraceRoute(String myurl){
    url = myurl;
  }
  
  TraceRoute(){}

  public void setURL(String thisurl){
    url = thisurl;
  }

  public void setBucketLimit(int bLimit){
    doBucketLimit = true;
    bucketLimit = bLimit;
  }

  public void findRoute(){
    String osName = System.getProperty("os.name");
    String commandName;  //windows ? tracert traceroute

	try{
	if(osName.equals("Windows XP") || osName.equals("Windows NT") || osName.equals("Windows 2000")){
	  commandName = "tracert";
	}
	else{
	  commandName = "traceroute";
	}

	Process proc = r.exec(commandName + " " + url);
	InputStream is = proc.getInputStream();
	InputStreamReader isr = new InputStreamReader(is);
	BufferedReader br = new BufferedReader(isr);
	String line;
	int cantReachCounter = 0;
	//reset hopsString + hopsList berfore next traceroute
	hopsString = "";
	hopsList.clear();
	while((line = br.readLine()) != null){
	  if(doBucketLimit == true){
	    if(Pattern.matches(".+\\*.\\*.\\*",line)){
		cantReachCounter++;
		if(cantReachCounter == bucketLimit){
		  break;
		}
	    }
	    else{
		cantReachCounter = 0;
	    }
	    hopsList.add(line);
	    hopsString += (line + "\r\n");
	  }
	  else{
	    hopsList.add(line);
	    hopsString += (line + "\r\n");
	  }
	}
    }
    catch(Throwable t){ 
	t.printStackTrace();
    }
  }
  //method with modifers these are platform specific
  public void findRoute(String modifers){
    String osName = System.getProperty("os.name");
    String commandName;

    try{
	if(osName.equals("Windows XP") || osName.equals("Windows NT") || osName.equals("Windows 2000")){
	  commandName = "tracert";
	}
	else{
	  commandName = "traceroute";
	}
	Process proc = r.exec(commandName + " " + modifers + " " + url);
	InputStream is = proc.getInputStream();
	InputStreamReader isr = new InputStreamReader(is);
	BufferedReader br = new BufferedReader(isr);
	String line;
	int cantReachCounter = 0;
	//reset hopsString + hopsList
	hopsString = "";
	hopsList.clear();
	while((line = br.readLine()) != null){
	  if(doBucketLimit == true){
	    if(Pattern.matches(".+\\*.\\*.\\*",line)){
		cantReachCounter++;
		if(cantReachCounter == bucketLimit){
		  break;
		}
	    }
	    else{
		cantReachCounter = 0;
	    }
	    hopsList.add(line);
	    hopsString += (line + "\r\n");
	  }
	  else{
	    hopsList.add(line);
	    hopsString += (line + "\r\n");
	  }
	}
    }
    catch(Throwable t){ 
	t.printStackTrace();
    }
  }

  public ArrayList getRouteList(){
    return hopsList;
  }
  public String getRouteString(){
    return hopsString;
  }
}

Usage:
Code:


TraceRoute tr;

void setup(){
  tr = new TraceRoute();
  tr.setBucketLimit(1);
  tr.setURL("nytimes.com");
  tr.findRoute();
  size(200,200);
}

void draw(){
  background(0);
  String myRoute = tr.getRouteString();
  println(myRoute);
  noLoop();
}

To use this outside of the processing environment you will need to sign the applet.

Bojarovski YaBB Newbies Offline Posts: 6	Re: how to ping a host? Reply #5 - Oct 24^th, 2007, 6:04pm Thank you, jomo.

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