Manipulate a configuration

In this example, we write a configuration file. Then we read the configuration from the file. Or we extract configuration parameters. We use a PHP configuration file, an INI configuration file, or an XML configuration file.

Components used in this example

• Zend_Config
• Zend_Config_Ini
• Zend_Config_Writer_Array
• Zend_Config_Writer_Ini
• Zend_Config_Writer_Xml
• Zend_Config_Xml

---

MyConfig MyConfigWriter MyHtml Entry point HTML | Try it | View source code

Implementation of the configuration

class MyConfig
{

Processing the configuration

• We get the name of the configuration writer and the parameter, from the GET request.
• We create a configuration.
• We write the configuration in a file.
• We read the content of the configuration file.
• Or we get the configuration as an object.
• Or we get the configuration of a section.
• Or we get the configuration of a parameter.
• If we catch an exception, we return the error message.

    public function process()
    {
        // We get the name of the configuration writer and the parameter, from the GET request.
        list($class, $view) = $this->_getParameters();

        try {
            $result = array();

            // We create a configuration.
            $config = $this->_createConfig();
            // We write the configuration in a file.
            $writer = new MyConfigWriter($class);
            $writer->write($config);

            switch ($view) {
                case 'Content':
                    // We read the content of the configuration file.
                    $result = $writer->read();
                    break;

                case 'Config':
                    // Or we get the configuration as an object.
                    $result = $writer->get();
                    break;

                case 'production':
                case 'staging':
                    // Or we get the configuration of a section.
                    $result = $writer->get($view);
                    break;

                default:
                    // Or we get the configuration of a parameter.
                    $result = $writer->getParameter($view);
            }

        } catch (Exception $e) {
            // If we catch an exception, we return the error message.
            $result = $e->getMessage();
        }

        return array($class, $view, $result);
    }

Extraction of the parameters from the GET request

    private function _getParameters()
    {
        $class = (isset($_GET['class']) and MyConfigWriter::isValid($_GET['class']))?
            $_GET['class'] : 'Zend_Config_Writer_Array';

        $view = isset($_GET['view'])? $_GET['view'] : 'Content';

        return array($class, $view);
    }

Creation of the configuration

    private function _createConfig()
    {
        $config = new Zend_Config(array(), true);

        $config->production = array();
        $config->production->webhost = 'www.example.com';
        $config->production->database = array();
        $config->production->database->adapter = 'pdo_mysql';
        $config->production->database->params = array();
        $config->production->database->params->host = 'db.example.com';
        $config->production->database->params->username = 'dbuser';
        $config->production->database->params->password = 'secret';
        $config->production->database->params->dbname = 'dbname';

        $config->staging    = array();
        $config->setExtend('staging', 'production');
        $config->staging->database = array();
        $config->staging->database->params = array();
        $config->staging->database->params->host = 'dev.example.com';
        $config->staging->database->params->username = 'devuser';
        $config->staging->database->params->password = 'devsecret';

        return $config;
    }

}

Implementation of the configuration writers

class MyConfigWriter
{
    public static $writers = array(
        'Zend_Config_Writer_Array' => 'Zend_Config',
        'Zend_Config_Writer_Ini' => 'Zend_Config_Ini',
        'Zend_Config_Writer_Xml' => 'Zend_Config_Xml',
    );

    private $_class;
    private $_file;

Creation of a temporary file to hold the configuration

    public function __construct($class)
    {
        $this->_file = tempnam('/tmp', 'zfex');
        $this->_class = $class;
    }

Deletion of the configuration file

    public function __destruct()
    {
        @unlink($this->_file);
    }

Validation of the class name of the writer

    public static function isValid($class)
    {
        return isset(self::$writers[$class]);
    }

Writing the configuration in the file

    public function write($config)
    {
        $writer = new $this->_class;
        $writer->write($this->_file, $config);
    }

Reading the configuration from the file

    public function read()
    {
        return file_get_contents($this->_file);
    }

Getting the configuration as an object

• We get the whole configuration from the file, or we get the configuration of the requested section

    public function get($section = null)
    {
        $class = self::$writers[$this->_class];

        // We get the whole configuration from the file, or
        // we get the configuration of the requested section

        if ($class == 'Zend_Config') {
            $mixed = require($this->_file);
            $config = new Zend_Config($mixed);
            isset($section) and $config = $config->$section;
        } else {
            $config = new $class($this->_file, $section);
        }

        return $config;
    }

Getting the configuration of a specific parameter

• We extract the section where the parameter belongs if any.
• We scan the hierarchy of properties that define the parameter.
• And we return the value of the parameter.

    public function getParameter($parameter)
    {
        $properties = explode('.', $parameter);

        $config = null;

        // We extract the section where the parameter belongs if any.
        if ($section = array_shift($properties) and $config = $this->get($section)) {
            // We scan the hierarchy of properties that define the parameter.
            foreach($properties as $property) {
                if (!isset($config->$property)) {
                    $config = null;
                    break;
                }

                // And we return the value of the parameter.
                $config = $config->$property;
            }
        }

        return $config;
    }

List of the configuration writers

    public static function getList()
    {
        return array_keys(self::$writers);
    }

}

Displaying items

class MyHtml
{

Displaying the title of the page based on the file name.

    public static function printTitle()
    {
        $basename = basename(__FILE__, '.php');
        $title = ucwords(str_replace('-' , ' ', $basename));
        $zfVersion = Zend_Version::VERSION;
        $phpVersion = phpversion();
        echo "ZfEx $title (ZF/$zfVersion PHP/$phpVersion)";
    }

Displaying the selected option

    public static function printSelected($value, $target)
    {
        $value == $target and print 'selected="selected"';
    }

Colorization of data

• We export the data as valid PHP code.
• We add the PHP tag, we colorize the code, we remove the PHP tag.
• We display the data.

    public static function colorize($mixed)
    {
        // We export the data as valid PHP code.
        $mixed = var_export($mixed, true);
        // We add the PHP tag, we colorize the code, we remove the PHP tag.
        $mixed = '<?' . "php $mixed";
        $mixed = highlight_string($mixed, true);
        $mixed = str_replace('&lt;?php&nbsp;', '', $mixed);
        // We display the data.
        echo "<pre>$mixed</pre>";
    }

}

Processing the configuration

• We process the configuration, and we get the class name of the writer, the parameter, and the configuration, to display in the form.

// We process the configuration, and we get the class name of the writer,
// the parameter, and the configuration, to display in the form.
$config = new MyConfig();
list($class, $view, $result) = $config->process();

<html xmlns="http://www.w3.org/1999/xhtml">
  <head>
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
    <title><?php MyHtml::printTitle();?></title>
    <style type="text/css">
      body, td {
          font-family: arial, sans-serif;
          font-size: 0.9em;
      }
    </style>
  </head>

  <body>

    <p>EXAMPLE <?php MyHtml::printTitle();?></p>
    <hr />

    <form name="form">

      <table>

        <tr>
          <td>Config Writer</td>
          <td>
            <select name="class">
              <?php foreach(MyConfigWriter::getList() as $name) :?>
                  <option <?php MyHtml::printSelected($class, $name);?>>
                    <?php echo $name;?>
                  </option>
              <?php endforeach;?>
            </select>
          </td>
        </tr>

        <tr>
          <td>View</td>
          <td>
            <select name="view">
              <option <?php MyHtml::printSelected($view, 'Content');?>>
                Content
              </option>
              <option <?php MyHtml::printSelected($view, 'Config');?>>
                Config
              </option>
              <optgroup label="Section">
                <option <?php MyHtml::printSelected($view, 'production');?>>
                  production
                </option>
                <option <?php MyHtml::printSelected($view, 'staging');?>>
                  staging
                </option>
              </optgroup>

              <optgroup label="Production Parameter">
                <option <?php MyHtml::printSelected($view, 'production.webhost');?>>
                  production.webhost
                </option>
                <option <?php MyHtml::printSelected($view, 'production.database');?>>
                  production.database
                </option>
                <option <?php MyHtml::printSelected($view, 'production.database.adapter');?>>
                  production.database.adapter
                </option>
                <option <?php MyHtml::printSelected($view, 'production.database.params');?>>
                  production.database.params
                </option>
                <option <?php MyHtml::printSelected($view, 'production.database.params.host');?>>
                  production.database.params.host
                </option>
                <option <?php MyHtml::printSelected($view, 'production.database.params.username');?>>
                  production.database.params.username
                </option>
                <option <?php MyHtml::printSelected($view, 'production.database.params.password');?>>
                  production.database.params.password
                </option>
                <option <?php MyHtml::printSelected($view, 'production.database.params.dbname');?>>
                  production.database.params.dbname
                </option>
              </optgroup>

              <optgroup label="Staging Parameter">
                <option <?php MyHtml::printSelected($view, 'staging.webhost');?>>
                  staging.webhost
                </option>
                <option <?php MyHtml::printSelected($view, 'staging.database');?>>
                  staging.database
                </option>
                <option <?php MyHtml::printSelected($view, 'staging.database.adapter');?>>
                  staging.database.adapter
                </option>
                <option <?php MyHtml::printSelected($view, 'staging.database.params');?>>
                  staging.database.params
                </option>
                <option <?php MyHtml::printSelected($view, 'staging.database.params.host');?>>
                  staging.database.params.host
                </option>
                <option <?php MyHtml::printSelected($view, 'staging.database.params.username');?>>
                  staging.database.params.username
                </option>
                <option <?php MyHtml::printSelected($view, 'staging.database.params.password');?>>
                  staging.database.params.password
                </option>
                <option <?php MyHtml::printSelected($view, 'staging.database.params.dbname');?>>
                  staging.database.params.dbname
                </option>
             </optgroup>
            </select>
          </td>
        </tr>

        <tr><td>&nbsp;</td></tr>

        <tr>
          <td></td>
          <td>
            <input type="submit" value="Submit" />
          </td>
        </tr>

      </table>
    </form>

    <hr />
    RESULT
    <?php MyHtml::colorize($result);?>

  </body>
</html>