Trying to Imitate the html POST method with an applet

Question

I am trying to imitate the POST method with an applet, so that I can eventually send sound from a microphone to a PHP script which will store it in a file on a server. I am starting out by trying to post a simple line of text by making the PHP script think that it is receiving the text within a POST-ed file. The reason I am doing things this way is in part because I am, for the time being, limited to a shared server without any support for servlets or any other server side java.
The code I am trying is based in part on an old thread found elsewhere in this forum, concerning sending data to a PHP file by imitating the POST method:
link:
http://forum.java.sun.com/thread.jspa?threadID=530399&messageID=2603608
someone named "harmmeijer" provided most of the answers on that thread. If that person is still around hope they take a look at this,also I have some questions to clarify what they said on the other thread..
My first attempt at code is below. The applet is in a signed jar file and is trying to pass a text line to the PHP script in the same directory and on the same server that the applet came from. It is doing this by sending header information that is supposed to be identical to what an html form would send if it was uploading a .txt file with the line of text within it. The applet displays one button. When you press it, it sucessfully starts up the postsim method (defined at the end), which is supposed to send the info to the PHP script at the server.
I have two questions:
1) I know that the PHP script is starting up, because it prints out a few messages depending on what happens. However, the script does not recognize any file coming down the line, so it does not save anyting on the server, and prints out a message saying the no file was uploaded.
Any idea what might be going wrong? I'm not getting any error messages from the applet. I've tried a few different variations of the 'header' information contained in the line:
osToServer.writeBytes("--****4353\r\nContent-Disposition: form-data; name=\"testfile\"; filename=\"C:testfile.txt\"\r\nContent-Type: text/plain\r\n");
The commented out line below it shows one variation (which was given in the thread mentioned above).
2) You'll notice that I've commented out the two lines having to do with the input line:
//InputStream isFromServer;
and
//isFromServer = uc.getInputStream();
The reason is that the program crahes whenever I put the latter line in - to the extent that Opera closes down the JVM and then crashes when I tried to exit it.. I must be doing something horribly wrong there! I first tried using isFromServer = new DataInputStream(uc.getInputStream());
becuase it was consistent with the output stream, but that caused the same problem.
Here's the code:
public class AudioUptest1 extends Applet{
//There are a few spurious things defined in this section, having to do with the fact the microphone data is evenuatly going to be sent. haven't yet insterted code to get input from a microphone.
AudioFormat audioFormat;
TargetDataLine targetDataLine;
SourceDataLine sourceDataLine;
DataOutputStream osToServer;
//InputStream isFromServer;
URLConnection uc;
final JButton captureBtn = new JButton("Capture");
final JPanel btnPanel = new JPanel();
public void init(){
System.out.println("Started the applet");
try
URL url = new URL( "http://www.mywebsite.com/handleapplet.php" );
uc = url.openConnection();
//Post multipart data
uc.setDoOutput(true);
uc.setDoInput(true);
uc.setUseCaches(false);
//set request headers
uc.setRequestProperty("Connection", "Keep-Alive");
uc.setRequestProperty("HTTP_REFERER", "http://applet.getcodebase");
uc.setRequestProperty("Content-Type","multipart/form-data; boundary=****4353");
osToServer = new DataOutputStream(uc.getOutputStream());
//isFromServer = uc.getInputStream();
catch(IOException e)
System.out.println ("Error etc. etc.");
return;
//Start of GUI stuff
captureBtn.setEnabled(true);
//Register listeners
captureBtn.addActionListener(
new ActionListener(){
public void actionPerformed(
ActionEvent e){
captureBtn.setEnabled(false);
//Postsim method will send simulated POST to PHP script on server.
postsim();
}//end actionPerformed
}//end ActionListener
);//end addActionListener()
add(captureBtn);
add(btnPanel);
// getContentPane().setLayout(new FlowLayout());
// setDefaultCloseOperation(EXIT_ON_CLOSE);
setSize(250,70);
setVisible(true);
}//end of GUI stuff, constructor.
//These buffers might be made larger.
byte tempOutBuffer[] = new byte[100];
byte tempInBuffer[] = new byte[100];
private void postsim(){
System.out.println("Got to the postsim method");
try{
//******The next four lines are supposed to imitate a POST upload from a form******
osToServer.writeBytes("--****4353\r\nContent-Disposition: form-data; name=\"testfile\"; filename=\"C:testfile.txt\"\r\nContent-Type: text/plain\r\n");
//osToServer.writeBytes("Content-Disposition: form-data; name=\"testfile\"; filename=\"C:testfile.txt\"\r\nContent-Type: text/plain\r\n");
//This is the text that's cupposed to be written into the file.
osToServer.writeBytes("This is a test file");
osToServer.writeBytes("--****4353--\r\n\r\n");
osToServer.flush();
osToServer.close();
catch (Exception e) {
System.out.println(e);
System.out.println("did not sucessfully connect or write to server");
System.exit(0);
}//end catch
}//end method postsim
}//end AudioUp.java

Answer 1

Hi All,
I was trying to write a signed applet that helps the
user of the applet to browse the local hard disk and
select a file from the same. The JFileChooser class
from Swing is what I used in my applet. The problem
is with the policy file. I am not able to trace the
exact way to write a policy file which gives a total
access to read,write,delete,execute on all the drives
of the local hard disk.
I am successful in signing the applets and performing
operations : read,write,delete & execute on a single
file but failing to grant permission for the entire
file.
Any help would be highly appreciated.Which policy file are you using? there might be more than one policy file.
also, u have to specify the alias of the signed certificate in the policy file to grant the necessary priviledges to the signed applet.