Easy Application Configuration With patConfiguration - The Write Stuff (
Page 6 of 11 )
So that takes care of reading configuration
files - now how about writing them?
In the patConfiguration universe, creating a configuration file is a two-step
process: first add one or more entries (variable-value pairs) to the configuration
stack, and then write the stack to a file. patConfiguration comes with a setConfigValue()
method that takes care of the first step, and a writeConfigFile() method that
takes care of the second one. Consider the following example, which demonstrates:
<?
// include class
require("patConfiguration.php");
// create patConfiguration
object
$conf = new patConfiguration;
// set config file locations
$conf->setConfigDir("config");
//
set config values
$conf->setConfigValue("screen.width", 500);
$conf->setConfigValue("screen.height",
650);
// write file
$conf->writeConfigFile("config.xml", "xml");
?>
The setConfigValue() method accepts two primary parameters - variable name and
corresponding value - and a third optional parameter, which is the datatype of
the variable being set (if this third value is omitted, patConfiguration will
automatically determine the variable type). Valid type values include "string",
"integer", "boolean", "float" and "array" - I'll be discussing these again a little
further down.
Once the variable-value pairs have been created, the writeConfigFile() method
is called to actually write the configuration data to a file. In addition to the
file name, patConfiguration also allows you to specify the file format - "xml"
or "php" - together with a couple of miscellaneous options that adjust the behaviour
of the writeConfigFile() method.
Here's the output of the example above:
<?xml version="1.0" encoding="ISO-8859-1"?>
<configuration> <path name="screen"><configValue
name="height"
type="int">650</configValue><configValue name="width"
type="int">500</configValue> </path></configuration>
Having trouble reading it? Have patConfiguration indent it a little more neatly
with the additional "mode" parameter:
<?
// include class
require("patConfiguration.php");
// create patConfiguration
object
$conf = new patConfiguration;
// set config file locations
$conf->setConfigDir("config");
//
set config values
$conf->setConfigValue("screen.width", 500);
$conf->setConfigValue("screen.height",
650);
// write file
$conf->writeConfigFile("config.xml", "xml", array("mode"
=> "pretty"));
?>
Here's the revised output:
<?xml version="1.0" encoding="ISO-8859-1"?>
<configuration>
<path name="screen">
<configValue
name="height" type="int">650</configValue>
<configValue name="width" type="int">500</configValue>
</path>
</configuration>
You can set multiple configuration values at a time via the setConfigValues()
method, which accepts an array of variable-value pairs
<?
// include class
require("patConfiguration.php");
// create patConfiguration
object
$conf = new patConfiguration;
// set config file locations
$conf->setConfigDir("config");
//
create array of configuration values
$config = array(
"screen.height" => 650,
"screen.width"
=> 500
);
// add to configuration table
$conf->setConfigValues($config);
//
write file
$conf->writeConfigFile("a.xml", "xml");
?>
and clear a value using the clearConfigValue() method.
<?
// include class
require("patConfiguration.php");
// create patConfiguration
object
$conf = new patConfiguration;
// set and display value
$conf->setConfigValue("name",
"Superman");
echo $conf->getConfigValue("name");
// clear and check to see if
value exists
$conf->clearConfigValue("name"); echo $conf->getConfigValue("name");
?>
Note that if no path is provided to clearConfigValue(), the entire configuration
table is cleared.
