Java HTTP Port Find writeContactFile(int port, String appName)

Description

Write contact details to a file only readable by the owner process and privileged local users.

License

LGPL

Parameter

Parameter	Description
port	the port number being used by a server process that is listening for connections.

Return

the cookie for authenticating connections. This is null if a failure to write the contact file is encountered.

Declaration

public static String writeContactFile(int port, String appName)

Method Source Code

//package com.java2s;
//License from project: LGPL 

import java.io.File;
import java.io.FileOutputStream;

import java.io.PrintStream;

import java.net.InetAddress;

import java.util.Properties;

public class Main {
    /**//w ww.  j  ava  2 s .  co  m
     * System properties
     */
    static Properties javaProp = System.getProperties();

    /**
     * Write contact details to a file only readable by the owner
     * process and privileged local users.
     * <p>
     * These details are used to authenticate any requests.
     * <p>
     * The file contains the simple line:
     * <pre>
     *    hostname port_number cookie
     * </pre>
     * The cookie is generated by this method and returned as its
     * result.
     *
     * @param port the port number being used by a server process that
     *             is listening for connections.
     * @return the cookie for authenticating connections. This is null
     *         if a failure to write the contact file is encountered.
     */
    public static String writeContactFile(int port, String appName) {
        String cookie = null;

        //  Open the contact file. This needs protection from prying
        //  eyes, so the next is _UNIX_ specific (TODO: something
        //  about this?).  The file is re-created every time, so
        //  connections are only available to the last instance.
        File contactFile = getConfigFile(appName + ".remote");
        if (contactFile != null) {
            try {
                contactFile.createNewFile();
                Runtime.getRuntime().exec("chmod 600 " + contactFile.getPath());
            } catch (Exception e) {
                // Do nothing, chmod can fail validly under Windows.
                //e.printStackTrace();
            }

            //  Add the information we want.
            try {
                PrintStream out = new PrintStream(new FileOutputStream(contactFile));
                InetAddress addr = InetAddress.getLocalHost();
                String hexVal = Integer.toHexString((int) (Math.random() * 12345));
                cookie = hexVal + addr.hashCode();
                out.println(addr.getHostName() + " " + port + " " + cookie);

            } catch (Exception e) {
                //  Do nothing
            }
        }
        //  Return the cookie which should be used to authenticate any
        //  remote connections.
        return cookie;
    }

    /**
     * Construct the proper name of a file stored in the configuration
     * directory. 
     *
     * @param name the name of the file to be stored/located in the
     *             the configuration directory.
     */
    public static File getConfigFile(String name) {
        return new File(getConfigDirectory(), name);
    }

    /**
     * The name of the directory used for storing configuration
     * information. This directory is created if it doesn't exist
     * already.
     */
    public static File getConfigDirectory() {
        File dir = null;
        if (javaProp.getProperty("adam.user") != null) {
            dir = new File(javaProp.getProperty("adam.user"));
        } else {
            dir = new File(javaProp.getProperty("user.home"), ".soap");
        }
        if (!dir.exists()) {
            try {
                dir.mkdir();
            } catch (Exception e) {
                e.printStackTrace();
                dir = null;
            }
        } else if (!dir.isDirectory()) {
            System.err.println(
                    "Cannot create a directory: " + dir.getName() + "as a file with " + "this name already exists");
            dir = null;
        }
        return dir;
    }
}