HomeMySQL Page 2 - Completing a Search Engine with MySQL and PHP 5
Listing the full source code of the original search application - MySQL
Building database-driven web sites is one of the most popular trends today in web site development. However, this approach implies that potential visitors must be provided with a straightforward mechanism that allows them to search through web site content. This three-part series walks you through the process of building an expandable search engine by using the combined functionality of MySQL and PHP 5.
As usual with many of my articles on PHP web development, before I proceed to implement the session mechanism for maintaining the value of a given search string across different web pages, I'd like to list all of the source files that comprise this search application as they were originally defined in the previous article of the series.
That being said, here are the signatures for the source files:
(definition of "form.htm" file)
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="Content-Type" content="text/html; charset=iso- 8859-1" /> <title>MySQL-based Search Engine</title> <link href="default.css" rel="stylesheet" type="text/css" media="screen" /> <script language="javascript" type="text/javascript"> window.onload=function(){ if(document.getElementById && document.getElementsByTagName && document.createElement){ var sfield=document.getElementsByTagName('form')[0].elements [0]; if(!sfield){return}; sfield.onfocus=function(){this.value=''}; sfield.onblur=function(){ if(!this.value){this.value='Enter your search term here'}; } } } </script> </head> <body> <h1>MySQL-based Search Engine</h1> <div class="maincontainer"> <form method="get" action="processform.php"> <input type="text" name="searchterm" title="Enter your search term here" value="Enter your search term here" class="searchbox" /> <input type="submit" name="search" title="Search Now! "value="Search" class="searchbutton" /> </form> </div> </body> </html>
<?php // define 'MySQL' class class MySQL{ private $conId; private $host; private $user; private $password; private $database; private $result; const OPTIONS=4; public function __construct($options=array()){ if(count($options)!=self::OPTIONS){ throw new Exception('Invalid number of connection parameters'); } foreach($options as $parameter=>$value){ if(!$value){ throw new Exception('Invalid parameter '.$parameter); } $this->{$parameter}=$value; } $this->connectDB(); } // connect to MySQL private function connectDB(){ if(!$this->conId=mysql_connect($this->host,$this- >user,$this->password)){ throw new Exception('Error connecting to the server'); } if(!mysql_select_db($this->database,$this->conId)){ throw new Exception('Error selecting database'); } } // run query public function query($query){ if(!$this->result=mysql_query($query,$this->conId)){ throw new Exception('Error performing query '.$query); } return new Result($this,$this->result,$query); } public function escapeString($value){ return mysql_escape_string($value); } } // define 'Result' class class Result { private $mysql; private $result; private $query; private $rowTemplate='default.tpl'; private $numRecs=4; public function __construct($mysql,$result,$query){ $this->mysql=$mysql; $this->result=$result; $this->query=$query; } // fetch row public function fetchRow(){ return mysql_fetch_assoc($this->result); } // count rows public function countRows(){ if(!$rows=mysql_num_rows($this->result)){ return false; } return $rows; } // count affected rows public function countAffectedRows(){ if(!$rows=mysql_affected_rows($this->mysql->conId)){ throw new Exception('Error counting affected rows'); } return $rows; } // get ID form last-inserted row public function getInsertID(){ if(!$id=mysql_insert_id($this->mysql->conId)){ throw new Exception('Error getting ID'); } return $id; } // seek row public function seekRow($row=0){ if(!is_int($row)||$row<0){ throw new Exception('Invalid result set offset'); } if(!mysql_data_seek($this->result,$row)){ throw new Exception('Error seeking data'); } } public function countFields(){ if(!$fields=mysql_num_fields($this->result)){ throw new Exception('Error counting fields.'); } return $fields; } public function fetchPagedRows($page){ $numPages=ceil($this->countRows()/$this->numRecs); if(empty($page)||$page>$numPages){ $page=1; } $result=$this->mysql->query($this->query.' LIMIT '.($page-1) *$this->numRecs.','.$this->numRecs); $output=''; while($row=$result->fetchRow()){ $rowTemplate=file_get_contents($this->rowTemplate); foreach($row as $key=>$value){ $rowTemplate=str_replace('{'.$key.'}',$value,$rowTemplate); } $output.=$rowTemplate; } $output.='<p>'; if($page>1){ $output.='<a href="'.$_SERVER['PHP_SELF'].'?&page='. ($page-1).'"><<</a> '; } for($i=1;$i<=$numPages;$i++){ $output.=$i!=$page?'<a href="'.$_SERVER['PHP_SELF'].'? page='.$i.'">'.$i.'</a> ':$i.' '; } if($page<$numPages){ $output.=' <a href="'.$_SERVER['PHP_SELF'].'?&page='. ($page+1).'">>></a>'; } $output.='</p>'; return $output; } } ?>
<?php class SessionHandler{ public function __construct(){ session_start(); } public function setVariable($value='default',$varname='default'){ $_SESSION[$varname]=$value; } public function getVariable($varname='default'){ if(!$_SESSION[$varname]){ return false; } return $_SESSION[$varname]; } public function destroy(){ session_start(); session_unset(); session_destroy(); } } ?>
As you can see, all the above source files perform well-differentiated tasks, in this way implementing the distinct application modules that comprise the search engine. These range from displaying a simple web form for entering diverse search terms to executing the search queries against one or more MySQL databases.
Besides, you should notice that I defined a template file called "default.tpl" which is used by the previous "Result" PHP class to format the results returned by a query. This record formatting process can be done directly from inside the class.
So far, so good right? At this stage I have shown you the complete signatures corresponding to all the source files that make up this MySQL-based search engine. So what is the next step?
Well, considering that all the database results returned by a specific query must be displayed on a separate web page, in the following section I'm going to define yet another PHP class. It will be tasked with building basic web documents, which makes it quite useful in conjunction with the rest of the source files that you saw earlier.
Want to see how this brand new PHP class will be built? Jump ahead and read the next few lines.
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