licensing system

api.php

<?php

error_reporting(E_ALL);

if (!(isset($_GET["pl"]))) die("error");
if (!(isset($_GET["token"]))) die("error");

$handle = @fopen("someplugin.txt", "r");
if ($handle && $_GET["pl"] == "someplugin") {
    while (($buffer = fgets($handle, 4096)) !== false) {

      if (strcmp(trim($buffer), $_GET["token"]) == 0) {
        echo "ok";
      }

    }
    if (!feof($handle)) {
        echo "error: unexpected fgets() fail\n";
    }
    fclose($handle);
} else {

  echo "error";

}

Client.java

String token = ...;

try {

            boolean license = false;

            URL oracle = new URL("http://your.server/api.php?pl=someplugin&token=" + token);
            BufferedReader in = new BufferedReader(
                    new InputStreamReader(oracle.openStream()));

            String inputLine;
            while ((inputLine = in.readLine()) != null) {
                if (inputLine.contains("ok")) {

                    license = true;
                    getLogger().info("License ok");

                }

            }
            in.close();

            if (!license) {

                getLogger().info("== [ == ] == [ == ] ==");
                getLogger().info("UNKNOWN LICENSE KEY!");
                getLogger().info("== [ == ] == [ == ] ==");


                getPluginLoader().disablePlugin(this);

                return;


            }

        }
        catch (Exception ex) {

            ex.printStackTrace();

            getLogger().info("== [ == ] == [ == ] ==");
            getLogger().info("COULD NOT CONTACT LICENSING SERVERS");
            getLogger().info("== [ == ] == [ == ] ==");


            getPluginLoader().disablePlugin(this);

            return;

        }

someplugin.txt

key1 
key2
key3
...