A348/A548 Mastering the World-Wide Web (4/3 cr.)

Spring Semester 2003

Lecture Notes Twenty-Six: Content Syndication

Traditional (by now) business-to-business communication.

Suppose there's CompanyA and CompanyB.

CompanyA is essentially a Library: it receives and stores books.

CompanyB is in the process of selling books, second-hand.

We now investigate the companies one by one.

CompanyA allows its suppliers to enter new books on-line.

So we start with a portion of a file: interface.html

<html>
  <head>
    <title>CompanyA Public Library: Add Books Interface</title>
    <style>
       <!-- 
         body { font-family: Arial }
         h1   { color: #000080 }
       -->
    </style> 
  </head>

  <body link="#FFFF00" vlink="#FFFF00" alink="#FFFF00">
    <table border="0" width="100%" cellpadding="0" cellspacing="0"> 
      <tr> 

        <td width="15%" bgcolor="#000080" valign="top" align="center"> </td> 

        <td width="*" valign="top" align="center"> 

          <h1 align="center"> The CompanyA Public Library </h1>
          <h3 align="center"><i>- Add Books -</i></h3> 

           <form method="POST" action="/cgi-bin/CompanyA/addBook.pl">

             <p> 
             <input type="submit" value="Add This Book" name="AddBook">
             <input type="reset" value="Reset Form" name="reset"> 
             <input type="button" value="Cancel" name="cancel"> 
             </p> 

          </form> 

        </td> 

      </tr> 
    </table> 
  </body> 
</html>

This is the entry point located at

/u/username/apache/apache_1.3.26/htdocs/interface.html

Let's add all there is to it and finish it.

<html>
  <head>

    <title>CompanyA Public Library: Add Books Interface</title>

    <style>
       <!-- 
         body { font-family: Arial }
         h1   { color: #000080 }
       -->
    </style> 

  </head>
  <body link="#FFFF00" vlink="#FFFF00" alink="#FFFF00">

    <table border="0" width="100%" cellpadding="0" cellspacing="0"> 

      <tr> 

        <td width="15%" bgcolor="#000080" valign="top" align="center"> 
          <b><i><font color="#FFFFFF" size="4">Options</font></i></b>
          <p><b><font color="#FFFFFF"><a href="mainMenu.html">Main Menu</a></font></b></p>
          <p><b><font color="#FFFFFF"><a href="/cgi-bin/CompanyA/catalog.pl">Catalog</a></font></b></p>
          <p><b><i><font color="#FFFF00">Add Books</font></i></b></p> 
          <p><b><font color="#FFFFFF"><a href="logout.html">Log Out</a></font></b></p> 
        </td> 

        <td width="*" valign="top" align="center"> 

           <h1 align="center"> The CompanyA Public Library </h1>

           <h3 align="center"><i>- Add Books -</i></h3> 

           <form method="POST" action="/cgi-bin/CompanyA/addBook.pl">

             <table border="0" cellpadding="5" width="100%">
               <tr> 
                 <td width="100%" valign="top" align="center" colspan="2"> 
                   Title&nbsp;<input type="text" name="title" size="20">
                   <hr width="85%" />
                 </td> 
               </tr><tr> 
                 <td width="50%" valign="top" align="right"> 
                   Author&nbsp;<input type="text" name="author" size="20">
                 </td> <td width="50%" valign="top" align="left">
                   Subject&nbsp;<select size="1" name="subject">
                     <option>Fiction</option>
                     <option>Biography</option>
                     <option>Science</option>
                     <option>Industry</option>
                     <option>Computers</option>
                   </select>
                 </td> 
               </tr><tr> 
                 <td width="50%" valign="top" align="right">
                   Publisher&nbsp;<input type="text" name="publisher" size="20">
                 </td><td width="50%" valign="top" align="left">
                   ISBN&nbsp;<input type="text" name="isbn" size="20">
                 </td> 
               </tr><tr> 
                 <td width="50%" valign="top" align="right">
                   Price&nbsp;<input type="text" name="price" size="20">
                 </td><td width="50%" valign="top" align="left">
                   Pages&nbsp;<input type="text" name="numPages" size="20">
                 </td>
               </tr><tr> 
                 <td width="100%" valign="top" align="center" colspan="2">
                   Description&nbsp;<textarea rows="3" name="description" cols="45"></textarea>
                 </td> 
               </tr> 
             </table>

             <p> 
             <input type="submit" value="Add This Book" name="AddBook">  
             <input type="reset" value="Reset Form" name="reset">   
             <input type="button" value="Cancel" name="cancel"> 
             </p> 

           </form> 
 
        </td> 

      </tr> 

    </table> 

  </body> 
</html>

You can see it here. It calls an addBook.pl Perl script, so we better provide it, quickly.

#!/usr/bin/perl

use CGI; 

$query = new CGI; 

print $query->header, 
      $query->start_html,
      "Hello, how are you?<p>";

$title = $query->param('title');
$author = $query->param('author') ;
$subject = $query->param('subject');
$publisher = $query->param('publisher');
$isbn = $query->param('isbn');
$price = $query->param('price');
$pages = $query->param('pages');
$description = $query->param('description');

print qq{ 

  You seem to be entering the following book: 

  <dl>

  <dt>Title</dt> <dd> $title<p></dd> 
  <dt>Author</dt> <dd> $author<p></dd> 
  <dt>Subject</dt> <dd> $subject<p></dd> 
  <dt>Publisher</dt> <dd> $publisher<p></dd> 
  <dt>ISBN</dt> <dd> $isbn<p></dd> 
  <dt>Price</dt> <dd> $price<p></dd> 
  <dt>Pages</dt> <dd> $pages<p></dd> 
  <dt>Description</dt> <dd> $description <p></dd> 

  </dl>

}; 

print $query->end_html;

This was very easy. Let's now store the results in a file.

Let's decide on these things first:

where will this file be located?
what will its format be?
what does it stand for?

I will place the file in

/u/username/CompanyA/data/dataFile.txt

The format will be very simple. Here's an example:

title:author:subject:publisher:isbn:price:numPages:description

Let's assume now (for the purpose of this exercise) that colon (:) is a character that we own exclusively. We have bought this character and nobody can use it, except us. So we use it, as we are now guaranteed to be the only ones to do so, as a delimiter. Total fabrication, but let's agree to it.

Here's an example of a real book:

Title

The Armchair Universe - An Exploration of Computer Worlds

Author

A. K. Dewdney

Subject

Science

Publisher

W. H. Freeman and Company, New York

ISBN

0-7167-1939-8

Price

19.90

Number of Pages

330

Description

This is the first collection of A.K.Dewdney's popular "Computer Recreations" columns, drawn from Scientific American magazine between 1984 and 1987. Inspired by Martin Gardner's classic "Mathematical Games" column, which entertained millions of readers for more than 30 years, "Computer Recreations" has quickly become one of the most widely read and anticipated columns in Scientific American. The computer recreations described here range from purely entertaining brainteasers to more practical computer applications of scientific thought. And with Dewdney's lucid programming directions to follow, you can actually sit at your computer and try your hand at them all. Available in paperback and hardcover. Cover image shows Julia set bounding three basins of attraction on a Riemann sphere.

The ISBN will be the key.

Which brings us to the last question.

The real model behind this file is a table in a RDBMS like MySQL.

By the way, you know (as I hope you remember) that readParse taught us how we can make characters our own, anyway, so the story about needing a guarantee for colon is a non-issue, really.

So let's get started.

#!/usr/bin/perl

use CGI; 

$query = new CGI; 

print $query->header, 
      $query->start_html,
      "Hello, and how are you doing? <p> ";

$title = $query->param('title');
$author = $query->param('author') ;
$subject = $query->param('subject');
$publisher = $query->param('publisher');
$isbn = $query->param('isbn');
$price = $query->param('price');
$numPages = $query->param('numPages');
$description = $query->param('description');

print qq{ 

  You seem to be entering the following book: 

  <dl>

  <dt>Title</dt> <dd> $title<p></dd> 
  <dt>Author</dt> <dd> $author<p></dd> 
  <dt>Subject</dt> <dd> $subject<p></dd> 
  <dt>Publisher</dt> <dd> $publisher<p></dd> 
  <dt>ISBN</dt> <dd> $isbn<p></dd> 
  <dt>Price</dt> <dd> $price<p></dd> 
  <dt>Number of Pages</dt> <dd> $numPages<p></dd> 
  <dt>Description</dt> <dd> $description <p></dd> 

  </dl>

}; 

%library = (); 

open (AB, "/u/dgerman/CompanyA/data/dataFile.txt"); 
@x = <AB>;
close(AB); 

foreach $line (@x) {
    @line = split(/:/, $line); 
    $key = $line[4]; 
    $library{$key} = $line; 
}

#add new book

$library{$isbn} = "$title:$author:$subject:$publisher:$isbn:$price:$numPages:$description"; 
$newline = chr(13); 
$library{$isbn} =~ s/[\n\r$newline]/ /g; 
$library{$isbn} =~ s/\s/ /g; 
open (AB, ">/u/dgerman/CompanyA/data/dataFile.txt"); 
foreach $key (sort (keys %library)) {
    print AB $library{$key}, "\n"; 
}
close(AB); 

print "The book has been added, thank you. ", $query->end_html;

Let's add two books, then use this script to see them. Here's the second book:

Hello, and how are you doing?
You seem to be entering the following book:

Title

In Search of Lake Wobegon

Author

Garrison Keillor, Richard Olsenius (Photographer)

Subject

Biography

Publisher

Viking Press

ISBN

0-6700-3037-6

Price

29.95

Number of Pages

128

Description

In the twenty-five years since Garrison Keillor first brought it to life, the rural Minnesota town of Lake Wobegon has become a national treasure. In this lavishly produced photography book, word and image combine to illuminate the real Minnesota town-life, landscapes, and people who inspired its creation. Taking us on a tour of Stearns County, the Minnesota county he deems most "Wobegonic," Keillor meditates on the origins of the place where, as a young writer, he found the inspiration for his fiction and his radio show. As an artful evocation of Keillor's beloved invention, Richard Olsenius's elegantly composed black-and-white photographs of rural Minnesota capture the dignity of his subjects, the beauties of the landscape as well as the enduring values and eccentricities of the communities rooted there.

The book has been added, thank you.

There are a few issues that we won't even consider, such as:

efficiency, and
synchronized access (concurrency)

Our focus, once again, is content syndication.

And now the story.

Long, interesting, involving story about Best Book Buys comes here and touches the audience.

To summarize here are the facts:

CompanyA (aka CompanyA) is storing books.
(Data Entry is HTML with Perl, as we have seen.)
CompanyB (broker) needs access to data of CompanyA.
CompanyB does servlets, mostly. CompanyA does only Perl.

How do they interface?

Let's review servlets briefly, just so we know what we can count on.

burrowww.cs.indiana.edu% pwd
/nfs/paca/home/user1/dgerman/tomcat/jakarta-tomcat-4.0.4/webapps/CompanyB
burrowww.cs.indiana.edu% grep Company ../../conf/server.xml
<Context path="/CompanyB" docBase="CompanyB" debug="0" reloadable="true" /> 
burrowww.cs.indiana.edu%

We have this servlet, One:

import javax.servlet.*;
import javax.servlet.http.*; 
import java.io.*; 

public class One extends HttpServlet {
  
  public void doGet(HttpServletRequest one, 
                    HttpServletResponse two) 
              throws ServletException, IOException 
  {

     two.setContentType("text/html"); 

     PrintWriter out = two.getWriter(); 

     out.println("How are you?"); 

  }

}

We have this servlet, Two:

import javax.servlet.*;
import javax.servlet.http.*; 
import java.io.*; 

public class Two extends HttpServlet {
  
  public void doGet(HttpServletRequest one, 
                    HttpServletResponse two) 
              throws ServletException, IOException 
  {

     String p = one.getParameter("nom");

     two.setContentType("text/html"); 
     PrintWriter out = two.getWriter(); 
     out.println("How are you, " + p + "?"); 

  }

}

We understand them well, we reviewed them just now.

So now let's look at the third one. (Recall the chat applet, if you will, it could be handy.)

import java.io.*;
import java.net.*;
import javax.servlet.*;
import javax.servlet.http.*; 

public class Three extends HttpServlet {
  
    public void doGet(HttpServletRequest request, 
                      HttpServletResponse response) 
        throws IOException, ServletException {

        response.setContentType("text/html"); 

        PrintWriter out = response.getWriter(); 

        URL getBooksURL = new URL("http",
                                  "burrowww.cs.indiana.edu", 
                                  10400,
                                  "/cgi-bin/CompanyA/catalog.pl");


        URL url           = new URL(getBooksURL.toExternalForm()); 

        URLConnection con = url.openConnection(); 

        con.setUseCaches(false); 

        InputStream in       = con.getInputStream(); 
        DataInputStream data = new DataInputStream(new BufferedInputStream(in)); 

        String line = data.readLine(); 

        while (line != null) {

            out.println(line); 
            line = data.readLine(); 

        }

        out.println("<p> This is the end of the servlet"); 

    }

}

You can try it here.

But how difficult can parsing be in this case?
And what if they change the format of their reports?

CompanyA now produces output for humans.

#!/usr/bin/perl

use CGI; 

$query = new CGI; 

print $query->header, 
      $query->start_html,
      "This is the CompanyA Library Catalog. <p> "; 

open (AB, "/u/dgerman/CompanyA/data/dataFile.txt"); 
@x = <AB>;
close(AB); 

%library = (); 

foreach $line (@x) {

    if ($line =~ /^\s*$/) { next; } 

    @line = split(/:/, $line); 
    $isbn = $line[4]; 

    $title       = $line[0]; 
    $author      = $line[1]; 
    $subject     = $line[2]; 
    $publisher   = $line[3]; 
    $isbn        = $line[4]; 
    $price       = $line[5]; 
    $numPages    = $line[6]; 
    $description = $line[7]; 
    
    print qq{ <hr>
<dl>
  <dt>Title</dt> <dd> $title<p></dd> 
  <dt>Author</dt> <dd> $author<p></dd> 
  <dt>Subject</dt> <dd> $subject<p></dd> 
  <dt>Publisher</dt> <dd> $publisher<p></dd> 
  <dt>ISBN</dt> <dd> $isbn<p></dd> 
  <dt>Price</dt> <dd> $price<p></dd> 
  <dt>Number of Pages</dt> <dd> $numPages<p></dd> 
  <dt>Description</dt> <dd> $description <p></dd> 
</dl>

  }; 

}

print "<hr> This is the catalog, thank you. ", $query->end_html;

How do we become more systematic, so a computer program can figure it out for us?

Here's what we have thus far:

burrowww.cs.indiana.edu% pwd
/nfs/paca/home/user1/dgerman/apache/apache_1.3.26/cgi-bin/CompanyA
burrowww.cs.indiana.edu% ls -ld *
-rwxr-xr-x   1 dgerman  faculty      1454 Oct 19 19:36 addBook.pl
-rwx------   1 dgerman  faculty      1055 Oct 19 22:08 catalog.pl
-rwx------   1 dgerman  faculty      1055 Oct 19 21:53 report.pl
burrowww.cs.indiana.edu% diff catalog.pl report.pl
burrowww.cs.indiana.edu%

How do make it such that

changes in the structure of data
can be effectively absorbed by the program that reads the data?
And,
is that possible?
The answer is: yes, that's what XML was invented for.

So we switch to XML. First we need a report script that transforms the database in XML.

But wait. Let's see some examples before we go too far, so we know what we're talking about.

Important Note:

You will need

/u/dgerman/public/xerces.jar

This contains an archive of classes used for parsing.

The parser (what's that?) we use is called Xerces.

Were does the name come from?

The Apache Xerces parser is called after the now extinct Xerces Blue Butterfly. Wiped out by urban expansion, the last known specimens were taken in 1941 at the Presidio military base in San Francisco. The butterfly was named after a king. A French entomologist named the butterfly for the Persian King Xerxes, but with the French spelling "Xerces," which was retained.

King Xerxes, son of Darius, ascended to the throne of Persia after his father's death in 486 BC. By 480 BC, the army he assembled had approximately 100,000 to 180,000 men and a fleet of nearly 600 ships, quite a large army by Greek standards and he decided to invade Greece. The plan was for his massive army to cross the Hellespont, and march around the Aegean sea and conquer Greece by land.

Crossing the Hellespont proved to be troublesome to Xerxes and his army. They tried to cross the Hellespont with a bridge of boats, but alas, the sea became rough and the bridge broke apart. When King Xerxes heard of this, he was furious, and gave orders that the sea should receive 300 lashes with whips. The sea did calm down and the second attempt to build a bridge was successful.

This, however, happened a long, long time ago.

Place the xerces.jar file in $CATALINA_HOME/common/lib.

Re-start your tomcat.

I use the following for starting and stopping Tomcat:

setenv startTomcat $CATALINA_HOME/bin/startup.sh
setenv stopTomcat  $CATALINA_HOME/bin/shutdown.sh

Also make sure your CLASSPATH variable points to the xerces.jar file.

setenv CLASSPATH $CATALINA_HOME/common/lib/xerces.jar:$CLASSPATH

And now we need to make sure we have checked the XML examples of yesterday.

What you need to see now is two:

burrowww.cs.indiana.edu% pwd
/nfs/paca/home/user1/dgerman/apache/apache_1.3.26/cgi-bin/CompanyA
burrowww.cs.indiana.edu% ls -ld two
-rwx------   1 dgerman  faculty       751 Dec  4 07:23 two
burrowww.cs.indiana.edu% cat two
#!/usr/bin/perl

print "\n"; 

print qq{<?xml version="1.0"?>
<document>
  <customer> 
    <item> One   </item> 
    <item> Two   </item> 
    <item> Three </item> 
    <item> Four  </item> 
  </customer>
  <customer> 
    <item> One   </item> 
  </customer>
  <customer> 
    <item> One   </item> 
    <item> Two   </item> 
    <item> Three </item> 
  </customer>
  <customer> 
    <item> One   </item> 
    <item> Two   </item> 
    <item> Three </item> 
    <item> Four  </item> 
  </customer>
  <customer> 
    <item> One   </item> 
    <item> Two   </item> 
    <item> Three </item> 
    <item> Four  </item> 
  </customer>
  <customer> 
    <item> One   </item> 
    <item> Two   </item> 
  </customer>
</document>}; 

burrowww.cs.indiana.edu%

Let's now return to CompanyA (CompanyA).

After much thought they produced the following output script.

Script started on Tue Dec 04 09:42:17 2001
burrowww.cs.indiana.edu% pwd
/nfs/paca/home/user1/dgerman/apache/apache_1.3.26/cgi-bin/CompanyA
burrowww.cs.indiana.edu% ls -ld DOM*.pl
-rwxr-xr-x   1 dgerman  faculty       900 Dec  4 07:47 DOMreport.pl
burrowww.cs.indiana.edu% cat DOMreport.pl
#!/usr/bin/perl

print "Content-type: plain/text\n\n"; 

open (AB, "/u/dgerman/CompanyA/data/dataFile.txt"); 
@x = <AB>;
close(AB); 

print "<?xml version=\"1.0\"?>\n"; 

print "\n<document>\n"; 

%library = (); 

foreach $line (@x) {

    if ($line =~ /^\s*$/) { next; } 

    @line = split(/:/, $line); 
    $isbn = $line[4]; 

    $title       = $line[0]; 
    $author      = $line[1]; 
    $subject     = $line[2]; 
    $publisher   = $line[3]; 
    $isbn        = $line[4]; 
    $price       = $line[5]; 
    $numPages    = $line[6]; 
    $description = $line[7]; 
    
    print qq{
  <book> 

    <subject>$subject</subject>

    <title>$title</title>
    <author>$author</author>
    <publisher>$publisher</publisher>

    <numPages>$numPages</numPages>

    <saleDetails>
      <isbn>$isbn</isbn>
      <price>$price</price>
    </saleDetails>

    <description>$description</description>

  </book>};  
}

print "</document>";

Let's run it, so we can better see what's going on.

burrowww.cs.indiana.edu% ./DOMreport.pl
Content-type: plain/text

<?xml version="1.0"?>

<document>

  <book> 

    <subject>Biography</subject>

    <title>In Search of Lake Wobegon</title>
    <author>Garrison Keillor, Richard Olsenius (Photographer)</author>
    <publisher>Viking Press</publisher>

    <numPages>128</numPages>

    <saleDetails>
      <isbn>0-6700-3037-6</isbn>
      <price>29.95</price>
    </saleDetails>

    <description>In the twenty-five years since Garrison Keillor first brought it to life, the rural                Minnesota town of Lake Wobegon has become a national treasure. In this                lavishly produced photography book, word and image combine to illuminate                the real Minnesota town-life, landscapes, and people who inspired its                creation. Taking us on a tour of Stearns County, the Minnesota county he                deems most "Wobegonic," Keillor meditates on the origins of the place                where, as a young writer, he found the inspiration for his fiction and his radio                show. As an artful evocation of Keillor's beloved invention, Richard                Olsenius's elegantly composed black-and-white photographs of rural                Minnesota capture the dignity of his subjects, the beauties of the landscape                as well as the enduring values and eccentricities of the communities rooted                there. 
</description>

  </book>
  <book> 

    <subject>Science</subject>

    <title>The Armchair Universe - An Exploration of Computer Worlds  </title>
    <author>A. K. Dewdney </author>
    <publisher>W. H. Freeman and Company, New York </publisher>

    <numPages>330</numPages>

    <saleDetails>
      <isbn>0-7167-1939-8</isbn>
      <price>19.90</price>
    </saleDetails>

    <description>This is the first collection of A.K.Dewdney's popular "Computer Recreations"                columns, drawn from Scientific American magazine between 1984 and 1987.                Inspired by Martin Gardner's classic "Mathematical Games" column, which                entertained millions of readers for more than 30 years, "Computer                Recreations" has quickly become one of the most widely read and anticipated                columns in Scientific American. The computer recreations described here                range from purely entertaining brainteasers to more practical computer                applications of scientific thought. And with Dewdney's lucid programming                directions to follow, you can actually sit at your computer and try your hand at                them all. Available in paperback and hardcover. Cover image shows Julia set                bounding three basins of attraction on a Riemann sphere.   
</description>

  </book></document>burrowww.cs.indiana.edu% exit
burrowww.cs.indiana.edu% 
script done on Tue Dec 04 09:42:43 2001

(Sometimes raw data can be in just the right format.)

CompanyB can now easily interact with CompanyA.

The question is: how do we prove it.

Take a look at this:

burrowww.cs.indiana.edu% java org.apache.xalan.xslt.Process
Xalan-J command line Process class options:
    -IN inputXMLURL
   [-XSL XSLTransformationURL]
   [-OUT outputFileName]
   [-E (Do not expand entity refs)]
   [-QC (Quiet Pattern Conflicts Warnings)]
   [-TT (Trace the templates as they are being called.)]
   [-TG (Trace each generation event.)]
   [-TS (Trace each selection event.)]
   [-TTC (Trace the template children as they are being processed.)]
   [-TCLASS (TraceListener class for trace extensions.)]
   [-EDUMP {optional filename} (Do stackdump on error.)]
   [-XML (Use XML formatter and add XML header.)]
   [-TEXT (Use simple Text formatter.)]
   [-HTML (Use HTML formatter.)]
   [-PARAM name expression (Set a stylesheet parameter)]
   [-L use line numbers for source document]
   [-MEDIA mediaType (use media attribute to find stylesheet associated with a document.)]
   [-FLAVOR flavorName (Explicitly use s2s=SAX or d2d=DOM to do transform.)]
   [-DIAG (Print overall milliseconds transform took.)]
   [-URIRESOLVER full class name (URIResolver to be used to resolve URIs)]
   [-ENTITYRESOLVER full class name (EntityResolver to be used to resolve entities)]
   [-CONTENTHANDLER full class name (ContentHandler to be used to serialize output)]
burrowww.cs.indiana.edu%

That's CompanyB settting things up for reception.

Here's a test they make (read this in conjunction with the notes for next week).

burrowww.cs.indiana.edu% pwd
/nfs/paca/home/user1/dgerman/tomcat/jakarta-tomcat-4.0.4/webapps/CompanyB/WEB-INF/classes
burrowww.cs.indiana.edu% ls -ld *
-rw-r--r--   1 dgerman  faculty      1044 Oct 19 22:30 Nine.java
-rw-r--r--   1 dgerman  faculty      1350 Oct 19 21:24 Three.class
-rw-r--r--   1 dgerman  faculty      1119 Oct 19 21:24 Three.java
-rw-r--r--   1 dgerman  faculty       296 Oct 20 11:05 one.xml
-rw-r--r--   1 dgerman  faculty       674 Oct 20 11:08 one.xslt
burrowww.cs.indiana.edu% java org.apache.xalan.xslt.Process \
  -IN one.xml \
  -XSL one.xslt \
  -OUT one.html

burrowww.cs.indiana.edu% ls one*
one.html  one.xml  one.xslt
burrowww.cs.indiana.edu% cat one.html
<html>
<head>
<META http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Discussion Forum Home Page</title>
</head>
<body>
<h1>Discussion Forum Home Page</h1>
<h3>Please select a message board to view:</h3>
<ul>
<li>
<a href="viewForum?id=1">Java Programming</a>
</li>
<li>
<a href="viewForum?id=2">XML Programming</a>
</li>
<li>
<a href="viewForum?id=3">XSLT Questions</a>
</li>
</ul>
</body>
</html>
burrowww.cs.indiana.edu%

Note that the contents of the two files is as follows:

burrowww.cs.indiana.edu% pwd
/nfs/paca/home/user1/dgerman/tomcat/jakarta-tomcat-4.0.4/webapps/CompanyB/WEB-INF/classes
burrowww.cs.indiana.edu% ls -ld *
-rw-r--r--   1 dgerman  faculty      1044 Oct 19 22:30 Nine.java
-rw-r--r--   1 dgerman  faculty      1350 Oct 19 21:24 Three.class
-rw-r--r--   1 dgerman  faculty      1119 Oct 19 21:24 Three.java
-rw-r--r--   1 dgerman  faculty       418 Oct 20 11:19 one.html
-rw-r--r--   1 dgerman  faculty       296 Oct 20 11:05 one.xml
-rw-r--r--   1 dgerman  faculty       674 Oct 20 11:08 one.xslt
burrowww.cs.indiana.edu% cat one.xml
<?xml version="1.0" encoding="UTF-8"?>
<?xml-stylesheet type="text/xsl" href="discussionForumHome.xslt"?>
<discussionForumHome>
  <messageBoard id="1" name="Java Programming"/>
  <messageBoard id="2" name="XML Programming"/>
  <messageBoard id="3" name="XSLT Questions"/>
</discussionForumHome>

burrowww.cs.indiana.edu% cat one.xslt
<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
  <xsl:output method="html"/> <xsl:template match="/">
    <html>
      <head>
        <title>Discussion Forum Home Page</title>
      </head>
      <body>
        <h1>Discussion Forum Home Page</h1>
        <h3>Please select a message board to view:</h3>
        <ul>
          <xsl:apply-templates select="discussionForumHome/messageBoard"/>
        </ul>
      </body>
    </html>
  </xsl:template>

  <xsl:template match="messageBoard">
    <li><a href="viewForum?id={@id}"><xsl:value-of select="@name"/></a></li>
  </xsl:template>
</xsl:stylesheet>

burrowww.cs.indiana.edu%

So when this works CompanyB says: 'CompanyA could you please give this over the network?'

So Company A says: 'Yo, this will only take one moment!'

Here's what CompanyA immediately puts up:

burrowww.cs.indiana.edu% pwd
/nfs/paca/home/user1/dgerman/apache/apache_1.3.26/cgi-bin/CompanyA
burrowww.cs.indiana.edu% ls -ld *
-rwx------   1 dgerman  faculty       891 Oct 19 22:18 DOMReport.pl
-rwx------   1 dgerman  faculty      1454 Oct 19 19:36 addBook.pl
-rwx------   1 dgerman  faculty      1055 Oct 19 22:08 catalog.pl
-rwx------   1 dgerman  faculty       325 Oct 20 11:39 one
-rwx------   1 dgerman  faculty      1055 Oct 19 21:53 report.pl
-rwx------   1 dgerman  faculty       692 Oct 19 22:32 two
burrowww.cs.indiana.edu% cat one
#!/usr/bin/perl

print qq{
<?xml version="1.0" encoding="UTF-8"?>
<?xml-stylesheet type="text/xsl" href="discussionForumHome.xslt"?>
<discussionForumHome>
  <messageBoard id="1" name="Java Programming"/>
  <messageBoard id="2" name="XML Programming"/>
  <messageBoard id="3" name="XSLT Questions"/>
</discussionForumHome>}; 
burrowww.cs.indiana.edu% ./one

<?xml version="1.0" encoding="UTF-8"?>
<?xml-stylesheet type="text/xsl" href="discussionForumHome.xslt"?>
<discussionForumHome>
  <messageBoard id="1" name="Java Programming"/>
  <messageBoard id="2" name="XML Programming"/>
  <messageBoard id="3" name="XSLT Questions"/>
</discussionForumHome>burrowww.cs.indiana.edu%

Meanwhile CompanyB's waiting to test things out and when they do:

burrowww.cs.indiana.edu% pwd
/nfs/paca/home/user1/dgerman/tomcat/jakarta-tomcat-4.0.4/webapps/CompanyB/WEB-INF/classes
burrowww.cs.indiana.edu% ls -ld *.html
No match
burrowww.cs.indiana.edu% java org.apache.xalan.xslt.Process \
  -IN http://burrowww.cs.indiana.edu:10400/cgi-bin/CompanyA/one \
  -OUT alpha.html \
  -XSL one.xslt

burrowww.cs.indiana.edu% cat alpha.html
<html>
<head>
<META http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Discussion Forum Home Page</title>
</head>
<body>
<h1>Discussion Forum Home Page</h1>
<h3>Please select a message board to view:</h3>
<ul>
<li>
<a href="viewForum?id=1">Java Programming</a>
</li>
<li>
<a href="viewForum?id=2">XML Programming</a>
</li>
<li>
<a href="viewForum?id=3">XSLT Questions</a>
</li>
</ul>
</body>
</html>
burrowww.cs.indiana.edu%

Things seem to be working very well thus far.

So CompanyB says: 'We are going to test your other script, OK?'

And here's how this goes:

burrowww.cs.indiana.edu% pwd
/nfs/paca/home/user1/dgerman/tomcat/jakarta-tomcat-4.0.4/webapps/CompanyB/WEB-INF/classes
burrowww.cs.indiana.edu% ls 
Nine.java  Three.class  Three.java  one.xml  one.xslt  testing.xslt
burrowww.cs.indiana.edu% cat testing.xslt
<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
  <xsl:output method="html"/> 
  <xsl:template match="/">
    <html>
      <head>
        <title>Company B representing Company A Home Page</title>
      </head>
      <body>
        <h1>Discussion Forum Home Page</h1>
        <h3>Please select a message board to view:</h3>
        <ul>
          <xsl:apply-templates select="document/book"/>
        </ul>
      </body>
    </html>
  </xsl:template>

  <xsl:template match="book">
    <li> I can see a book! </li> 
  </xsl:template>

</xsl:stylesheet>

burrowww.cs.indiana.edu% java org.apache.xalan.xslt.Process \
  -IN http://burrowww.cs.indiana.edu:10400/cgi-bin/CompanyA/DOMReport.pl \
  -XSL testing.xslt \
  -OUT testing.html

burrowww.cs.indiana.edu% cat testing.html
<html>
<head>
<META http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Company B representing Company A Home Page</title>
</head>
<body>
<h1>Discussion Forum Home Page</h1>
<h3>Please select a message board to view:</h3>
<ul>
<li> I can see a book! </li>
<li> I can see a book! </li>
</ul>
</body>
</html>
burrowww.cs.indiana.edu%

You see how we are getting closer to wrapping things up.

burrowww.cs.indiana.edu% pwd
/nfs/paca/home/user1/dgerman/tomcat/jakarta-tomcat-4.0.4/webapps/CompanyB/WEB-INF/classes
burrowww.cs.indiana.edu% ls -l
total 10
-rw-r--r--   1 dgerman  faculty      1044 Oct 19 22:30 Nine.java
-rw-r--r--   1 dgerman  faculty      1350 Oct 19 21:24 Three.class
-rw-r--r--   1 dgerman  faculty      1119 Oct 19 21:24 Three.java
-rw-r--r--   1 dgerman  faculty       296 Oct 20 11:05 one.xml
-rw-r--r--   1 dgerman  faculty       674 Oct 20 11:08 one.xslt
-rw-r--r--   1 dgerman  faculty       324 Oct 20 12:02 testing.html
-rw-r--r--   1 dgerman  faculty       624 Oct 20 12:00 testing.xslt
burrowww.cs.indiana.edu% mkdir ../xslt
burrowww.cs.indiana.edu% cp testing.xslt ../xslt
burrowww.cs.indiana.edu% cat One.java
import java.io.*;
import java.net.*; 
import javax.servlet.*; 
import javax.servlet.http.*; 
import javax.xml.transform.*; 
import javax.xml.transform.dom.*; 
import javax.xml.transform.stream.*;

public class One extends HttpServlet {
    public void service(HttpServletRequest req, 
                        HttpServletResponse res) throws ServletException, 
                                                        IOException {

        res.setContentType("text/html"); 
    
        PrintWriter out = res.getWriter(); 

        out.println("How are you?"); 

    }
}
burrowww.cs.indiana.edu% javac One.java
burrowww.cs.indiana.edu%

Now the final servlet:

burrowww.cs.indiana.edu% pwd
/nfs/paca/home/user1/dgerman/tomcat/jakarta-tomcat-4.0.4/webapps/CompanyB/WEB-INF/classes
burrowww.cs.indiana.edu% ls -ld One.java
-rw-r--r--   1 dgerman  faculty      1391 Oct 20 19:59 One.java
burrowww.cs.indiana.edu% cat One.java
import java.io.*;
import java.net.*; 
import javax.servlet.*; 
import javax.servlet.http.*; 

import javax.xml.parsers.*; 

import javax.xml.transform.*; 
import javax.xml.transform.dom.*; 
import javax.xml.transform.stream.*;

public class One extends HttpServlet {

    private Templates stylesheet; 

    public void init() throws UnavailableException {
        try {

            URL xsltURL = getServletContext().getResource("/WEB-INF/xslt/testing.xslt"); 
            String xsltSystemID = xsltURL.toExternalForm(); 
            TransformerFactory transfact = TransformerFactory.newInstance(); 
            this.stylesheet = transfact.newTemplates(new StreamSource(xsltSystemID)); 

        } catch (Exception e) { } 

    }

    public void service(HttpServletRequest req, 
                        HttpServletResponse res) throws ServletException, 
                                                        IOException {

        res.setContentType("text/html"); 

        try {

            Transformer trans = stylesheet.newTransformer(); 
            res.setContentType("text/html"); 
            PrintWriter writer = res.getWriter(); 
            trans.transform(new StreamSource("http://burrowww.cs.indiana.edu:10400/cgi-bin/CompanyA/DOMReport.pl"), 
                            new StreamResult(writer)); 

        } catch (Exception e) {
            PrintWriter out = res.getWriter(); 
            out.println("Error: " + e.getMessage()); 
            out.close(); 
        }
    }
}
burrowww.cs.indiana.edu% pwd
/nfs/paca/home/user1/dgerman/tomcat/jakarta-tomcat-4.0.4/webapps/CompanyB/WEB-INF/classes
burrowww.cs.indiana.edu% cd ../xslt
burrowww.cs.indiana.edu% ls -l
total 2
-rw-r--r--   1 dgerman  faculty       638 Oct 20 20:02 testing.xslt
burrowww.cs.indiana.edu% cat testing.xslt 
<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
  <xsl:output method="html"/> 
  <xsl:template match="/">
    <html>
      <head>
        <title>Company B representing Company A Home Page</title>
      </head>
      <body>
        <h1>Welcome to Company B BDP </h1>
        <h3>BDP means Book Distribution Page, as indicated below:</h3>
        <ul>
          <xsl:apply-templates select="document/book"/>
        </ul>
      </body>
    </html>
  </xsl:template>

  <xsl:template match="book">
    <li> I can see a book! </li> 
  </xsl:template>

</xsl:stylesheet>

burrowww.cs.indiana.edu%

And there's a key element to all of this (for the servlet to compile):

burrowww.cs.indiana.edu% pwd
/nfs/paca/home/user1/dgerman/tomcat/jakarta-tomcat-4.0.4/webapps/CompanyB/WEB-INF/xslt
burrowww.cs.indiana.edu% cd ../lib
burrowww.cs.indiana.edu% ls -l
total 1024
-rw-r--r--   1 dgerman  faculty   1037500 Oct 20 19:55 everything.jar
burrowww.cs.indiana.edu%

For the meaning of everything don't forget to check the notes for next week.

Last updated: Apr 17, 2003 by Adrian German for A348/A548