IFrame to build rich text client

Friday, December 14, 2007, 12:02 AM

Today I found a cool site which helps you build a simple rich text client based WYSIWYG HTML editor.

I had been researching for some time on IFRAME's and did find some good material but this particular site IFrame based editor was just excellent.

Go ahead and have a look at this site.

Look out for my next project which is going to be an SQR editor using IFrames.

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Apache HTTP Server (2.2.4) + Tomcat 5.5.23 + SSL

Friday, August 10, 2007, 02:27 AM

Tomcat with Apache HTTP server is a very common configuration for getting a J2EE application up and running. Though Tomcat is not a complete J2EE server(does not support EJB's) it is a very stable J2EE web server. It can also act as a standalone web server without the need for a proxy server like Apache's HTTP server.

I personally however feel that is a better J2EE server out there in the open source market namely Resin but Tomcat has one major advantage which Resin does not have which is proper support and docuemntation. This is what makes it more popular than Resin which beats Tomcat on performance grounds.

Enough gyan on servers. Lets get our hands dirty in setting up Tomcat with Apache Http server having SSL for encription and security.

We will tackle the setup in two stages:-

1. Get the HTTP server working with Tomcat so that it can re-route the jsp and servlet requests to Tomcat.

2. Get SSL working with Apache's HTTP server.

Before we start doing anything make sure you have all the necessary software.

My software setup had the was as follows:-

Windows 2003 Server

Apache HTTP server 2.2.4 with SSL

Apache Tomcat 5.5.23

mod_jk

The reason I chose Apache with SSL so that I need not download and install the ssl module seperately.

mod_jk would be responsible for forwarding the requests from the HTTP server to the J2EE server(Tomcat).

Download three other files which should serve as referneces for your setup :-

workers.properties

httpd.conf

httpd-ssl.conf

The files workers.properties and httpd.conf have the necessary info redirect servlet requests to the J2EE server through HTTP server.

The line LoadModule jk_module modules/mod_jk.so enables the jk module which is a tomcat connector to the apache http server. You would need to download the jk module file which is specific to your Apache HTTP server version from any of the mirrors from the link mentioned above for mod_jk and rename the file to mod_jk.so.

The sample workers.properties file contains just one worker which would handle the servlet requests. The lines

JkWorkersFile "C:/Program Files/Apache Software Foundation/Apache2.2/conf/workers.properties" and

JkMount /ARNT|/* worker1

tell the http server what needs to go where. /ARNT|/* tells the URL patterns which need to be redirected to Tomcat. Have a look at the file httpd.conf to know what goes where.

Try accessing any JSP now through the http server that is on port 80 to see if the request goes through.

Now its time to setup SSL.

Before proceeding make sure you have the certificate and the private key for implementing SSL.

Since we have installed a version of apache with SSL we need not install the ssl module seperately however we need to uncomment the line LoadModule ssl_module modules/mod_ssl.so in the http.conf file to tell apache that it needs to lead that module.

Open the file httpd-ssl.conf which you downloaded for reference and go to the line

SSLCertificateFile "C:/Program Files/Apache Software Foundation/Apache2.2/conf/10.186.133.143.crt".

This line tells Apache where the certificate is stored.

SSLCertificateKeyFile "C:/Program Files/Apache Software Foundation/Apache2.2/conf/10.186.133.143.key"

tells apache where the private key is stored.

And you are done. Restart Apache and tomcat after any change to the configuration file so that your changes can take effect.

Hope it works. If not post your comments and I will try to help you out.

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NSE Stock Updater

Sunday, May 27, 2007, 08:30 AM

Download daily (bhavcopy) NSE quotes

Here's a small program which downloads daily NSE quotes or in other words the bhavcopy directly from the NSE site (www.nse-india.com).

Download NseStockUpdater here.

Just type:-

java -jar nsestockupdater.jar

If you want the bhavcopy for a particular date then just type:-

java -jar nsestockupdater.jar 22-05-2007

Note that the date should be in dd-mm-yyyy format.

The output file is created in the same folder where the .jar file exists.

The source code and the class files are in the jar file.

Most of the code has been reused from other sources as I am a very lazy programmer. :)

Let me know if you face any problems.

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List Zip file contents

Wednesday, April 18, 2007, 09:54 AM

try {
// Open the ZIP file
ZipFile zf = new ZipFile("filename.zip");

// Enumerate each entry
for (Enumeration entries = zf.entries(); entries.hasMoreElements();) {
// Get the entry name
String zipEntryName = ((ZipEntry)entries.nextElement()).getName();
}
} catch (IOException e) {
}

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Java and Zip files

Wednesday, April 18, 2007, 09:52 AM

Unzipping Files with java.util.zip.ZipFile

The Java core packages include jave.util.zip, which is useful for creating and reading compressed files or archives in the ZIP and GZIP formats. This saves you the time of creating custom file archive formats for your applications.

by Daniel F. Savarese

The Java core packages include jave.util.zip, which is useful for creating and reading compressed files or archives in the ZIP and GZIP formats. ZIP files form the basis for the JAR file format, so it was natural to include classes for manipulating ZIP files as part of the standard Java APIs. This functionality is enormously useful, because it saves you the time of creating custom file archive formats for your applications. You can use the ZipFile [more]class to read entries in a ZIP file. The entries are represented by instances of the ZipEntry class, which contains information such as the size, name, compression method, and timestamp of the entry. ZipFile.entries() will return the entries as an Enumeration which you can step through to access all of the entries. Once you have found an entry of interest, ZipFile.getInputStream(ZipEntry) will produce an InputStream, from which the archived entry can be read.

The following program demonstrates how to use the ZipFile class to create a simple unzip utility. It simply cycles through all of the entries in the file and copies each entry to a new file by reading its input stream. If an entry is a directory, it is created. The example is not robust and is only intended to demonstrate the ZipFile class. Obvious additions would include checking if a file already exists before creating it, prompting the user if it should be overwritten, as well as other error checking. View the example>:

import java.io.*;
                                import java.util.*;
                                import java.util.zip.*;

                                public class Unzip {
public static final void copyInputStream(InputStream in, OutputStream out)
                            throws IOException
                            {
byte[] buffer = new byte[1024];
                            int len;

                            while((len = in.read(buffer)) >= 0)
                            out.write(buffer, 0, len);

                            in.close();
                            out.close();
                            }

                            public static final void main(String[] args) {
                            Enumeration entries;
                            ZipFile zipFile;

                            if(args.length != 1) {
                            System.err.println("Usage: Unzip zipfile");
                            return;
                            }

                            try {
                            zipFile = new ZipFile(args[0]);

                            entries = zipFile.entries();

                            while(entries.hasMoreElements()) {
                            ZipEntry entry = (ZipEntry)entries.nextElement();

                            if(entry.isDirectory()) {
                            // Assume directories are stored parents first then children.
          System.err.println("Extracting directory: " + entry.getName());
          // This is not robust, just for demonstration purposes.
          (new File(entry.getName())).mkdir();
          continue;
        }

        System.err.println("Extracting file: " + entry.getName());
        copyInputStream(zipFile.getInputStream(entry),
           new BufferedOutputStream(new FileOutputStream(entry.getName())));
      }

      zipFile.close();
    } catch (IOException ioe) {
      System.err.println("Unhandled exception:");
      ioe.printStackTrace();
      return;
    }
  }

}

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