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

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

  <-- copy/paste this rule 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 it
  • Then save the result as test.xml (for testing purposes). In your browser, right-click on the 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.
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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