Question

I created a Tcp Client & Tcp Server in Groovy awhile back and had no issues with it. I was only connecting to one machine at the time to gather data. This time I am attempting to connect to the script on multiple hosts and it is only saving one of the hosts information in my grails app.

My Grails application is simple, it has a domain class for Machines (basically the computers and the information on them that I seek) and it will use my TcpClient.groovy script to connect and gather information from the TcpServer.groovy on the other computers. For each host, it should save the information gathered, however, it seems to skip right over saving any host aside from the last one.

Tcp Client :

//TCP CLIENT    

public void queryData(def hosts) {

 for(int aHost = 0; aHost < hosts.size; aHost++) {
         cristalClient(hosts[aHost]);
 }
}


public void cristalClient(String host) {

 commands = ["dateScan", "computerName", "ip", "quit"]

 answers = [commands.size]

 requestSocket = new Socket(host, 2000)

 r = new BufferedReader(new InputStreamReader(requestSocket.getInputStream()));
 w = new BufferedWriter(new OutputStreamWriter(requestSocket.getOutputStream()));

 String message = "Connection was successful"

 message = readAvailable(r)
 println("Sever>" + message)

 for(int n = 0; n < commands.size; n++) {
     sendMessage(commands[n]);
 answers[n] = readAvailable(r)
 }

 lastRead = answers[0]
 machineName = answers[1]
 ipAddress = answers[3]

 w.flush()
 w.close()
}


public String readAvailable(r) {

    String out = ""
    String dum = null

    while((dum = r.readLine()) !=null) {
        if(dum == ">>EOF<<") return out
        if(out.length() > 0) out += "\r\n"
            out += dum
    }
    return out
}


public void sendMessage(msg) {
    w.write(msg+"\r\n");
    w.flush();
    println("Client>" + msg);
}



public void printData(abc) {

    abc.eachWithIndex { it, index ->
    println "Drive $index"
    it.each { k, v ->
        println "\t$k = $v"
    }
    }

}

Tcp Server :

//TCP Server

def server = new ServerSocket(2000)

println("Waiting for connection")

    server.accept() { socket ->
        socket.withStreams { input, output ->   

            w = new BufferedWriter(new OutputStreamWriter(output))

            String message = "Connection was successful"

            r = new BufferedReader(new InputStreamReader(input))

            while(true) {

                if(message != null) {
                    sendMessage(message)
                    message = null
                }

                String a = r.readLine()

                if(a == "dateScan") {
            message = new Date
        } else if(a == "computerName") {
            message = InetAddress.getLocalHost().hostName
        } else if(a == "ip") {
            message = InetAddress.getLocalHost().getHostAddress()           
                } else if(a == "quit") {
                    server.close()
                    return
                } else {                    
                    message = "$a command unknown."
                    println message
                }
            }
        }
    }


def sendMessage(String msg) {
    println( "sending: >" + msg + "<" )
    w.writeLine(msg)
    w.writeLine(">>EOF<<")
    w.flush();
} 

Grails Controller :

//Grails Controller

CollectMachines {

    def w = new tcpClient()
    def hosts = ["winXp", "Win7"]

    w.queryData(hosts)
    def abc = w.hardDrive
    abc.each { println it }

    int numberOfDrives = abc.size()

    //add new machine 
    numberOfDrives.times {

        def machineName = abc.computerName[it]
        def machineInstance = Machine.findByMachineName(machineName)

        if (!machineInstance) {
            machineInstance = new Machine(machineName)
        }

        def lastScan = abc.lastScan[it]                                
        def scanDate = new Date().parse("E MMM dd H:m:s z yyyy", lastScan)

        def ipAddress = abc.ipAddress[it]                              

        machineInstance.setIpAddress(ipAddress)                     
        machineInstance.setDateScanned(scanDate)                    
        machineInstance.save()                                      

    }
    redirect(action: "list")
}

Do I need to put a pause in so that the server has time to send a response? My Tcp Client does send out all the commands but only gets responses for the last set of commands.

Also, sorry for the indentation issues with my code snippets, I’m not sure why they are messed up.

.

Answer 1

There are a few problems with your code. tcpClient never assigns to hardDrive, for example. Assuming this is an oversight, I think the real problem is that tcpClient is querying data for multiple hosts, and storing all the results in the same instance variables answers, and ultimately lastRead, machineName, and ipAddress.

You need to store the results for each host separately. One way would be to have answers be a map of lists. For example, answers[host][0] would be the first answer for a given host.

I don’t think any kind of pause is necessary.