Applet Communication with RequestHandlers

ScenarioI have a requirement where the applet needs to take the values from the database and do some manipulations with it. Approach Adopted.I have an applet, which follows the concept of URL Re-Writing. It makes a call to the request handler for the database values. Request handler gets values from the Database and sends it to the applet.Problem When I make call from applet to Request Handler, The request handler is just not called at all As a result I don?t get any message back. Can anyone guide as to how to solve this problem.PS:- All exception handling has been taken care of

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Martin_Gäckler

Hi,here is an example source that I use to fetch some data from a livelink server:// fetch the data from a URLprivate String fetchUrl( String theUrl ){ int index, port; URL newUrl, docBase; String newUrlStr, docBaseStr; URLConnection connection; InputStream theStream; int byteData; String contents = ""; showStatus( "Loading menu, please wait" ); docBase = getDocumentBase(); docBaseStr = docBase.toString(); try { if( theUrl.indexOf(':') >= 0 ) // url contains protocol newUrl = new URL( theUrl ); else if( theUrl.substring(0,1).equals("/") ) { // url contains absolute path newUrlStr = docBase.getProtocol() + "://"; newUrlStr += docBase.getHost(); port = docBase.getPort(); if( port > 0 && port != 80 ) newUrlStr += ":" + port; newUrlStr += theUrl; newUrl = new URL( newUrlStr ); } else { // url contains relative path index = docBaseStr.lastIndexOf('/'); docBaseStr = docBaseStr.substring(0,index); newUrl = new URL( docBaseStr + "/" + theUrl ); } connection = newUrl.openConnection(); theStream = connection.getInputStream(); while( (byteData = theStream.read()) >= 0 ) if( (char)byteData == '\n' ) contents += '\r'; else contents += String.valueOf((char)byteData); } catch( Exception badUrl ) { System.out.println( badUrl.getMessage() ); } return contents;}Hope this helpsMartin

Mahmoud_Dayeh_(ecead_mad_-_(deleted))

Hello Martin, Thanks for the prompy reply. However the code still doesn?t solve my problem. The request handler is just not called for some reason. ? don?t know why ?. If I make use URLEncoder.encode function of java and then use the url object, in such case I don?t get any response back not even any error. However when I call the url without encoding it I get a file back as a stream which is nothing but livelink login page. I am putting my code , please let me know where I am going wrong. I am making use of webdsp request handler. So I don?t think logging should be an issue.My Code.I am calling the following code on click of a button //URL url=new URL("http://localhost/Livelink/livelink.exe?func=sandy.requestHandler&Username=Admin&Password=livelink");url=new URL("http://sandeep/Livelink/livelink.exe?func=LL.login&username=Admin&password=livelink&nexturl="+URLEncoder.encode("/livelink/livelink.exe?func=sandy.RH"));URLConnection urlcon=url.openConnection();urlcon.setDoInput(true);urlcon.setDoOutput(true);urlcon.setUseCaches(false);urlcon.setAllowUserInteraction( false );urlcon.setRequestProperty("Content-type","application/octet-stream");//Sending the request DataOutputStream objOutStream=new DataOutputStream(urlcon.getOutputStream());objOutStream.writeUTF("ID = "+String.valueOf(2533));objOutStream.flush();objOutStream.close();//Reading the value from request handlerSystem.out.println("Object Send");DataInputStream dataInputStream = new DataInputStream(urlcon.getInputStream());String strRequestObj=dataInputStream.readLine() ;String str="";StringBuffer buffer=new StringBuffer();while((str=dataInputStream.readLine())!=null){ buffer.append(str);} System.out.println("Input recieved =" +buffer.toString());dataInputStream.close();System.out.println("Over");

eLink User

Message from Hans Stoop <<A HREF="mailto:hstoop@opentext.com">hstoop@opentext.com> via eLink

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">eLink

If you get the Livelink loging page back, it means that you didn't send the LL cookie that contains the users credentials. If your request doesn't contains the cookie, Livelink repsonse with the login page. This is the same as you first go to Livelink with the browser.

If you have single signon enabled, the story may get a little bit more complicated.

Hans

--------
Livelink Appearance: the easiest way to skin Livelink.
Contact hstoop@opentext.com for more information.

-----Original Message-----
From: eLink Discussion: Development Discussion [mailto:development@elinkkc.opentext.com]
Sent: maandag 25 november 2002 12:54
To: eLink Recipient
Subject: Request Handler doesn?t get invoke

Request Handler doesn?t get invoke Posted by ecead_mad (Dayeh, Mahmoud) on 11/25/2002 06:48 AM
In reply to: Applet Communication with RequestHandlers Posted by ecead_mad (Dayeh, Mahmoud) on 11/23/2002 05:38 AM

Hello Martin,
Thanks for the prompy reply. However the code still doesn?t solve my problem.
The request handler is just not called for some reason. ? don?t know why ?.

If I make use URLEncoder.encode function of java and then use the url object, in such case I don?t get any response back not even any error. However when I call the url without encoding it I get a file back as a stream which is nothing but livelink login page.

I am putting my code , please let me know where I am going wrong. I am making use of webdsp request handler. So I don?t think logging should be an issue.

My Code.

I am calling the following code on click of a button

//URL url=new URL("http://localhost/Livelink/livelink.exe?func=sandy.requestHandler&Username=Admin&Password=livelink");
url=new URL("http://sandeep/Livelink/livelink.exe?func=LL.login&username=Admin&password=livelink&nexturl="+URLEncoder.encode("/livelink/livelink.exe?func=sandy.RH"));

URLConnection urlcon=url.openConnection();
urlcon.setDoInput(true);
urlcon.setDoOutput(true);
urlcon.setUseCaches(false);
urlcon.setAllowUserInteraction( false );
urlcon.setRequestProperty("Content-type","application/octet-stream");
//Sending the request
DataOutputStream objOutStream=new DataOutputStream(urlcon.getOutputStream());
objOutStream.writeUTF("ID = "+String.valueOf(2533));
objOutStream.flush();
objOutStream.close();
//Reading the value from request handler
System.out.println("Object Send");
DataInputStream dataInputStream = new DataInputStream(urlcon.getInputStream());
String strRequestObj=dataInputStream.readLine() ;
String str="";
StringBuffer buffer=new StringBuffer();
while((str=dataInputStream.readLine())!=null)
{
buffer.append(str);
}
System.out.println("Input recieved =" +buffer.toString());
dataInputStream.close();
System.out.println("Over");

Martin_Gäckler

Hello,I did not debug your source code but I asume one or more of the following reasons:- neither the web server nor your web client handle the redirect that comes from livelink's getLogin request handler correctly. Solution: you should create a valid program session in your request handler without using the getLogin handler. (My applet whose code I sent in a previous message sends the url to the same livelink machine as it came from and thus there is no need for another login)- LL's getLogin cannot handle input stream of type "application/octet-stream". Solution: use mime type "application/x-www-form-urlencoded"- LL cannot merge QUERY_STRING parameter passing with input stream. Solution: Add your paramater ID and its value to your URL.- LL getLogin does not forward the paramter ID. Your code sends the parameter id and its value to getLogin and getLogin makes nothing with it, thus your request handler sandy.RH will never see this parameter. Solution: Add ID=... to the paramter you have passed to URLEncoder.encode.- The applet's security context does not allow to send a request to another machine. Solution 1: Send the request to the same machine from where you have loaded the applet. Solution 2: Maybe, a signed applet can send this request to another machine.Another hint: Check the JavaConsole output, maybe there are some error messages that helps you to solve your problem.Last (but not least) hint: Do not encode your Admin-user's password in your source code. If you have no other chance, create a less powerful user, that does the job. Best: Do not use a new login, but use the current user who has loaded the applet from your livelink server.Hope this helpsMartin

Martin_Gäckler

Hello,Wow, do I have a time machine?Posted by Martin Gaeckler on 11/25/2002 09:31 PMin reply to ... Posted by Mahmoud Dayeh on 11/25/2002 12:48 PMconfused 8-)Martin