When Time Is Money, Recycle! - PHP

Tired of handcrafting configuration file manipulation tools for your Web application? Save yourself some time with patConfiguration, a PHP class designed to assist developers with reading, writing and maintaining application configuration files.

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By: Vikram Vaswani, (c) Melonfire

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January 29, 2003

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Here's another example, this one demonstrating how patConfiguration can be used in the context of a script accepting user input for application configuration. This script is divided into two parts: a form which displays the current configuration (if available) and allows the user to edit it, and a form processor, which accepts the new configuration and saves it to a file.

In addition to patConfiguration, this script also uses the patTemplate engine for the actual interface generation - you can read more about patTemplate at http://www.devshed.com/Server_Side/PHP/patTemplate/

Here's the template,

<patTemplate:tmpl name="form">
<html>
<head><basefont face="Arial"></head>
<body>
<h2>Configuration</h2>
<table 
border="0" cellspacing="5" cellpadding="5">
<form action="configure.php" method="post">
<tr>
<td>MySQL 
host name</td>
<td><input type="text" name="db_host" value="{DB_HOST}"></td> 
</tr>
<tr>
<td>MySQL user name</td>
<td><input type="text" 
name="db_user" value="{DB_USER}"></td> </tr>
<tr>
<td>MySQL user 
password</td>
<td><input type="text" name="db_pass" value="{DB_PASS}"></td> 
</tr>
<tr>
<td colspan="2" align="center"><input type="submit" name="submit"
value="Save 
Configuration"></td> </tr>
</form>
</table> 
</body>
</html>
</patTemplate:tmpl>

and here's the script that does all the work:

<?
// include classes
require("patConfiguration.php");
require("patTemplate.php");
// 
create patConfiguration object
$conf = new patConfiguration;
// set config file 
locations
$conf->setConfigDir("config");
// create patTemplate object
$template 
= new patTemplate;
// set template location 
$template->setBasedir("templates");
// 
add templates to the template engine
$template->readTemplatesFromFile("configuration.tmpl");
// 
form not yet submitted
if (!$_POST["submit"])
{
// check to see if config file 
exists
if (file_exists("config/config.xml"))
{
// parse it and display configuration 
values
$conf->parseConfigFile("config.xml");
$template->AddVar("form", "DB_HOST",
$conf->getConfigValue("db.host"));
$template->AddVar("form", 
"DB_USER",
$conf->getConfigValue("db.user"));
$template->AddVar("form", "DB_PASS",
$conf->getConfigValue("db.pass"));
}
// 
parse and display the template
$template->displayParsedTemplate("form");
}
else
{
// 
accept the submitted values
// and write them to a configuration file
$conf->setConfigValue("db.host", 
$_POST['db_host']);
$conf->setConfigValue("db.user", $_POST['db_user']);
$conf->setConfigValue("db.pass", 
$_POST['db_pass']);
$conf->writeConfigFile("config.xml", "xml", array("mode" 
=>
"pretty"));
}
?>

In this case, patConfiguration is used to read the application's database configuration from a file via the parseConfigFile() method and display the variable-value pairs contained within that file in an editable HTML form. The user may then modify these values and submit the form; patConfiguration will accept the new values and write them back to the configuration file via writeConfigFile().

This kind of application configuration is pretty common to most Web-based tools - and patConfiguration lets you build an interface around it quickly and efficiently, with maximum code reuse and minimal time wastage.

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