Help:COAP-3180/week5

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Week 5 - COAP 3180

ATTENTION: Monday week 6 class is cancelled. Replacement has to be negociated..

Topics Covered

Homework and mid-term exam
  • Quick feedback
Termproject
  • Each student should now have a "must-have" and "nice-to-have" list of features
  • Demonstration of the Wordpress extension "Formidable"
Crashcourse on XML
  • XML - The formalism
  • XML - where is it used
  • XSLT - XML transformations
  • XPath - identify elements in a tree (used by XPath and XQuery)

Classroom activities

Monday

(1) Term project

  • Must have and nice to have features
  • Remark: There must an embedded "database", i.e. a data-collection / presentation module

(2) Wordpress

  • Fire up MoWes and enter wordpress as admin
  • Install "Formidable" if not already done so
    • Best method is to click on Plugins in the Dashboard
    • Else, use the "manual" method described by its developer.

(3) Produce XML output from an SQL query with php

  • copy this code to a mowes/web/ directoty
  • call it for example: mysql-to-xml.php
  • configure and test
<?php

/* Made by Daniel K. Schneider, TECFA Jan 2010. This is freeware
   Will connect to a MySQL database, execute an SQL statement and
   then return the result as valid XML. 
 */
error_reporting(E_ALL);

// ---------------------------  Configuration section

// Fill in according to your db settings (example is for a local and locked "play" WAMP server)
// Make sure to keep the ; and the ""
$host       = "localhost";
$user       = "root";
$pass       = "";
$database   = "exam";

// Replace by a query that matches your database
$SQL_query = "SELECT * FROM question,response_item WHERE question.id = response_item.id_question";

// Optional: add the name of XSLT file.
$xslt_file = ""; 
//$xslt_file = "mysql-result.xsl"; 

// -------------------------- no changes needed below

$DB_link = mysql_connect($host, $user, $pass) or die("Could not connect to host.");
mysql_select_db($database, $DB_link) or die ("Could not find or access the database.");
$result = mysql_query ($SQL_query, $DB_link) or die ("Data not found. Your SQL query didn't work... ");

// we produce XML
header("Content-type: text/xml");
$XML = "<?xml version=\"1.0\"?>\n";
if ($xslt_file) $XML .= "<?xml-stylesheet href=\"$xslt_file\" type=\"text/xsl\" ?>\n";

// root node
$XML .= "<result>\n";
// rows
while ($row = mysql_fetch_array($result, MYSQL_ASSOC)) {    
  $XML .= "\t<row>\n"; 
  $i = 0;
  // cells
  foreach ($row as $cell) {
    // Escaping illegal characters - not tested actually ;)
    $cell = str_replace("&", "&amp;", $cell);
    $cell = str_replace("<", "&lt;", $cell);
    $cell = str_replace(">", "&gt;", $cell);
    $cell = str_replace("\"", "&quot;", $cell);
    $col_name = mysql_field_name($result,$i);
    // creates the "<tag>contents</tag>" representing the column
    $XML .= "\t\t<" . $col_name . ">" . $cell . "</" . $col_name . ">\n";
    $i++;
  }
  $XML .= "\t</row>\n"; 
 }
$XML .= "</result>\n";

// output the whole XML string
echo $XML;
?>

Wednesday

(1) Editing an XML file

  • For fixing some contents in a raw XML file (that is just well-formed but not valid) you can use any programming editor
  • For XML that can be validated, use an XML editor.

(5) Create/adapt an XSLT file

  • Simple XSLT (adaptation of some code)
  • Filtering data with XSLT, e.g. creating rules that will do nothing
<?xml version="1.0"?>                
<xsl:stylesheet version="1.0"
                xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
 
  <xsl:output method="html"
	      doctype-public="-//W3C//DTD HTML 4.01 Transitional//EN"/>

  <xsl:template match="result">
    <html> <head> <title> Query results </title> </head>
      <body bgcolor="#ffffff">

	<h1>Query results</h1>

	<table border="2" cellspacing="1" cellpadding="6">
          <!-- Here you might insert a table heading row -->

	  <xsl:apply-templates select="row"/>
	</table>
	<hr />

      </body>
    </html>
  </xsl:template>
  
  <xsl:template match="row">
    <tr> <xsl:apply-templates/> </tr>
  </xsl:template>

  <!-- copy/paste the rule below and replace by custom rules for various columns of your output -->
  <xsl:template match="*">
    <td> <xsl:apply-templates/> </td>
  </xsl:template>

</xsl:stylesheet>

Homework 5

Objectives
  • Pull out data in XML format from a database. If you turned in homework 3, use its tables.
  • Produce an XSLT file that will display the data (any maybe do some filtering)
  • Associate the XSLT file with the XML
Steps
  • Copy file http://tecfa.unige.ch/guides/xml/examples/mysql-php-xml/mysql-to-xml-raw.php.txt to a web directory of your WAMP server (or a PHP/MySQL provider). Alternatively you may copy/paste it from here. Then call it something like mysql-to-xml.php (I.e. file must end with .php!!)
  • Change the values in the configuration section to make it work with one of your databases. You do not need to change anything else in this file.
  • Test this php script. In your browser, you should see some raw XML.
  • Then save the result as test.xml (for testing purposes). In your browser, right-click on mysql-to-xml.php and "save target as" test.xml.
  • Create an XSLT file that will render test.xml in HTML.

Test it with an XML editor and the test.xml file until you are pleased with the result. Remark: The XML file will be well-formed in principle, but you are likely to make XSLT syntax mistakes. Validate the XSLT file with the Exchanger light editor.

  • Once you are done copy this XSLT file to the directory of the php file.
  • Redit the configuration of the PHP file and specify the name of the XSLT file.

If the above is not clear, look at the files in this directory (it includes the test files)

XSLT - If things go wrong

Style-sheet error !

  • Validate the style-sheet in your XML editor
  • If it provides XSLT support, it will help you find the error spots

XHTML doesn’t display in Firefox !

  • Firefox wants a namespace declaration in the XHMTL produced, do it (see above).

HTML doesn’t seem to be right !

  • Transform the XML document within your XML editor and look at the HTML

In "Exchanger Lite", use Transform in the menu bar with the following parameters:

  • Transform->Execute Advanced XSLT
  • Input = current document
  • XSLT = Use Processing instructions
  • Output = to new file or to new document
  • You also may validate the output HTML with an HTML validator !

There is various unformatted text in the output

  • You forgot to write a rule for some XML element

HTML still doesn’t seem to be right !!

  • Use a XSLT debugger/tracer to understand how your XSLT executes

Submission Procedure and dates

You must upload the following files to the worldclassroom:

  • The *.xsl file
  • The *.sql file
  • The *.php file
  • This homework is due at start of Wed week 6
  • Each homework counts 10% in your global evaluation. The four best homeworks will be taken into account.

Evaluation

See the worldclassroom.

Tips for the homework

Links and teaching materials

Software
Online software
  • none
Teaching materials
Teaching materials (older slides)
Optional reading
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