Precondition for a good understanding: knowledge of a higher programming language (e.g. C, Java, Perl, Pascal, Basic,... ) basic knowledge of html

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1 Some Remarks about Dynamic Webpages Matthias K. Krause Hochschule für Telekommunikation, Leipzig University of Applied Sciences Deutsche Telekom Precondition for a good understanding: knowledge of a higher programming language (e.g. C, Java, Perl, Pascal, Basic,... ) basic knowledge of html Books and articles: Christoph Reeg: Datenbank, mysql und PHP, a nice German tutorial (PHP and mysql) Stefan Münz: Selfhtml, the best tutorial around HTML, Javascipt,..., but in German PHP Manual:

de Precondition for a good understanding: knowledge of a higher programming language (e.g. C, Java, Perl, Pascal, Basic,.

2 Why dynamic webpages should be used? Let s have a look on a static page! How does the source of this page look like? We see a static page, as exists in the file system of a webserver (suffix: htm oder html). <html> <head> <title> Freunde </title> </head> <body> <h2> Meine Freunde </h2> <table border="1"> <tr><th>name</th><th>handy-nummer</th></tr> <tr><td>tino</td><td> </td></tr> <tr><td>...</td> <td>...</td> </tr> </table> </body> </html> Look at the differences to a dynamically generated page! <html> <head> <title> Freunde </title> </head> <body> <h2> Meine Freunde </h2> <table border="1"> <tr><th>name</th><th>handy-nummer</th></tr> <?php Datenbankverbindung herstellen, und die Inhalte, durch Tags separiert, ausgeben?> </table> </body> </html> Which technologies can be used for the generation of dynamic webpages?

<html> <head> <title> Freunde </title> </head> <body> <h2> Meine Freunde </h2> <table border="1"> <tr><th>name</th><th>handy-nummer</th></tr> <tr><td>tino</td><td>0170-1234567</td></tr> <tr><td>.

3 Technologies for the generation of dynamic webpages these are (except ASP) OS independent technologies CGI (Common Gateway Interface) an interface standard for serverside scripting, the standard output of the scripts produces the html, sended to the client PHP scripting language, commonly embedded in HTML, runs on the server Servlets and Java Server Pages (JSP) modern Java technologies, comparable to CGI and PHP Active Serverpages (ASP) Microsoft technologie, runs only on Microsoft systems An often used and freely distributed combination of operations system an tools is called by the acronym LAMP or (less free) WAMP: Linux or Windows the operations system Apache an open source webserver MySQL a relational database management system PHP (PHP: Hypertext Preprocessor) a serverside scripting language

comparable to CGI and PHP Active Serverpages (ASP) Microsoft technologie, runs only on Microsoft systems An often used and freely distributed combination of operations system an tools is called by

4 Using a textfile for data Programming in PHP The file Freunde.php (on the server): 1 <html> 2 <head> <title> Freunde </ title > </head> 3 <body> <h2> Meine Freunde </h2> 4 5 < script language= php > 6 print < li >Tino: \n ; 7 print < li >Eva: \n ; 8 </ script > 9 10 <?php print?> < li >...:...\ n ; </body> 15 </html> The data, received by the browser: <html> <head> <title> Freunde </title> </head> <body> <h2> Meine Freunde </h2> <li>tino: <li>eva: <li>...:... </body> </html> Disadvantage: What have we to do for insertion of a new entry?

$170 1234567\n ; 7 print < li >Eva:0$

5 But we don t want to deal nor with a php neither with an html source, but with a simple text file (Freunde.csv)! The file Freunde2.php 1 <html> 2 <head> <title> Freunde </ title > </head> 3 <body> <h2> Meine Freunde </h2> 4 5 < script language= php > 6 $fname= Freunde.csv ; 7 $fp=fopen($fname, r ) 8 or die ( Error found. ); 9 $line = fgets( $fp, 1024 ); 10 while (! feof ($fp )){ 11 print < li > $line \n ; 12 $line = fgets( $fp, 1024 ); 13 } 14 fclose ($fp ); 15 </ script > </body> 18 </html> The file Freunde.csv (csv... character separated values) Tino: Eva: :... Disadvantage: The form of the output! To do: Making a table!

$feof ($fp )){ 11 print < li > $line \n ; 12 $line = fgets( $fp, 1024 ); 13 } 14 fclose ($fp ); 15 </ script > 16 17 </body> 18 </html> The file Freunde.csv (csv.$

6 The file Freunde3.php: 1 <html> 2 <head> <title> Freunde </ title > </head> 3 4 <body> <h2> Meine Freunde </h2> <table border= 1 > 5 <tr><th>name</th><th>handy</th></tr> 6 7 < script language= php > 8 $fname= Freunde.csv ; 9 $fp=fopen($fname, r ) or die ( Error found. ); 10 $line = fgets( $fp, 1024 ); 11 while (! feof ($fp )){ 12 print <tr> ; 13 //////////////////////////////////////////////////////////// 14 list ($name,$handy) = split( :, $line ); 15 print <td>$name</td><td>$handy</td> ; 16 //////////////////////////////////////////////////////////// 17 print <tr>\n ; 18 $line = fgets( $fp, 1024 ); 19 } 20 fclose ($fp ); 21 </ script > 22 </table> 23 </body> 24 </html> Disadvantage: The textfile Freunde.csv has to be edited directly. To do: Possibility of insertion of new data with the browser.... we use a html form... <h2> Ein neuer Freund </h2> <form action="addfreund.php" method="get"> <p>name: <input name="name" type="text" size="30" maxlength="30"></p> <p>handy: <input name="handy" type="text" size="30" maxlength="40"></p> <p> <input type="submit" value="freund eintragen"></p> </form>...

csv ; 9 $fp=fopen($fname, r ) or die ( Error found. ); 10 $line = fgets( $fp, 1024 ); 11 while (!

7 ... on the server must exist a reactionscript addfreund.php realising the new entry! (In chap. 8 of the PHP-manual is explained how to get the form parameters!) < script language= php > 3 // Option register globals muss auf on gesetzt sein fuer Nutzung von $name... 4 // sonst erfolgt der Zugriff ueber $HTTP GET VARS[ name ]: 5 // $name = $HTTP GET VARS[ name ]; 6 if ($name and $handy) { 7 print eingetragen : Name: $name, Handy Nummer: $handy \n ; 8 $fname= Freunde.csv ; 9 $fp=fopen($fname, a ) or die( Error found. ); 10 fputs ($fp, $name : $handy \n ); 11 fclose ($fp ); 12 } 13 </ script > Important: The file Freunde.csv on the webserver must be writable by the webserver process, it means, by everybody (in the case, that it is owned by another user, e.g. by you)!!! The three parts reaction on form parameter, display of the current data and generation of a form can of course be placed in the same script/page. Nassi Shneiderman diagram (structogram, structure chart) of the script, producing the whole page (Freunde4.php)

$.. 4 // sonst erfolgt der Zugriff ueber $HTTP GET VARS[ name ]: 5 // $name = $HTTP GET VARS[ name ]; 6 if ($name and $handy) { 7 print eingetragen : Name: $name, Handy Nummer: $handy \n ; 8 $fname=$

8 (Freunde4.php) Inserting the new values into the file: 1 <html> 2 <head> <title> Freunde </ title > </head> 3 <body> 4 < script language= php > 5 if ($name and $handy) { 6 print eingetragen : Name: $name, Handy Nummer: $handy \n ; 7 $fname= Freunde.csv ; 8 $fp=fopen($fname, a ) or die( Error found. ); 9 fputs ($fp, $name : $handy \n ); 10 fclose ($fp ); 11 } 12 </ script > Printing the data here is just for didactical and protocol reasons, in the real world this part might be silent or print into a logfile! Reading and output of all data: <h2> Meine Freunde </h2> <table border= 1 > <tr><th>name</th><th>handy</th></tr> < script language= php > 17 $fname= Freunde.csv ; 18 $fp=fopen($fname, r ) or die ( Error found. ); 19 $line = fgets( $fp, 1024 ); 20 while (! feof ($fp )){ 21 print <tr> ; 22 list ($name,$handy) = split( :, $line ); 23 print <td>$name</td><td>$handy</td> ; 24 print <tr>\n ; 25 $line = fgets( $fp, 1024 ); 26 } 27 fclose ($fp ); 28 </ script > 29 </table> Generating the form for data input: <h2> Ein neuer Freund </h2> <form action= Freunde4.php method= get > 32 <p>name: <input name= name type= text size= 30 maxlength= 30 ></p> 33 <p>handy: <input name= handy type= text size= 30 maxlength= 40 ></p> 34 <p> <input type= submit value= Freund eintragen ></p> 35 </form> 36 </body> 37 </html>

$Handy Nummer: $handy \n ; 7 $fname= Freunde.csv ; 8 $fp=fopen($fname, a ) or die( Error found.$

9 Using a database

10 Using the database-api of PHP (disadvantage of this version: the functionnames contain the name of the database server) mysql_connect(...) mysql_select_db(...) mysql_query(...) e.g. for queries (SELECT * FROM table) and INSERT/UPDATE/DELETE-Statements <table border= 1 > 3 <tr><th>name</th><th>handy</th></tr> 4 5 < script language= php > 6 7 mysql connect ( localhost,, ); 8 mysql select db ( mytestdb ); 9 $result = mysql query ( SELECT name, handy FROM freunde ); while ( $row = mysql fetch array ( $result )) { 12 print <tr><td>.$row[ name ]. </td><td>.$row[ handy ]. </td></tr>\n ; 13 } 14 </ script > 15 </table> Making the same database connection with Java as to be done inside a servlet in a pure object oriented manner. 1 import java. sql. ; 2 import java. util. ; 3 4 public class DBSimple { String username = root ; 8 String password = ; 9 String url = jdbc:mysql:// localhost /mytestdb ; Connection con; 12 Statement stmt; String querystring = SELECT name, handy FROM freunde; ; try { 17 Class.forName( org.gjt.mm.mysql.driver );

$handy FROM freunde ); 10 11 while ( $row = mysql fetch array ( $result )) { 12 print <tr><td>.$row[ name ]. </td><td>.$row[ handy ]. </td></tr>\n ; 13 } 14 </ script > 15 </table> 16.$

11 con = DriverManager.getConnection(url, username, password); 21 stmt = con.createstatement(); stmt. execute( use mysql; ); 24 ResultSet rs = stmt.executequery(querystring ); System.out. println ( <html >... ); while ( rs. next ()) { 29 String name = rs. getstring (1); 30 String handy = rs. getstring (2); 31 System.out. println 32 ( <tr><td> + name + </td><td> + handy + </td></tr>\n ); 33 } System.out. println ( <html >... ); stmt. close (); 38 con. close (); 39 } 40 catch(exception ex) { 41 System.out. println ( Message: + ex.getmessage ()); 42 } } The servlet may generate the whole dynamic page by printing it on its output! Thank you very much for your attention and much fun with the preparation of your dynamic webpages ;-) generated with dvipdfm

out. println ( <html >... ); 36 37 stmt. close (); 38 con. close (); 39 } 40 catch(exception ex) { 41 System.out. println ( Message: + ex.getmessage ()); 42 } 43.

7 Web Databases. Access to Web Databases: Servlets, Applets. Java Server Pages PHP, PEAR. Languages: Java, PHP, Python,...

7 Web Databases. Access to Web Databases: Servlets, Applets. Java Server Pages PHP, PEAR. Languages: Java, PHP, Python,... 7 Web Databases Access to Web Databases: Servlets, Applets Java Server Pages PHP, PEAR Languages: Java, PHP, Python,... Prof. Dr. Dietmar Seipel 837 7.1 Access to Web Databases by Servlets Java Servlets