silverstripe-testsession/code/TestSessionStubCodeWriter.php

<?php
/**
 * Writes PHP to a file which can be included in SilverStripe runs on existence.
 * The generated file is included in page execution through {@link TestSessionRequestFilter}.
 */
class TestSessionStubCodeWriter {

	/**
	 * @var boolean Add debug statements to the generated PHP about
	 * the generator's origin code location.
	 */
	protected $debug = false;

	/**
	 * @var String Absolute path to a PHP file, essentially the "name" of the stub.
	 */
	protected $filePath;

	public function __construct($filePath = null) {
		$this->filePath = $filePath ? $filePath : BASE_PATH . '/testSessionStubCode.php';
	}

	/**
	 * Writes arbitrary PHP code to {@link $filePath} for later inclusion.
	 * Creates the file if it doesn't exist.
	 * Adds debug information about the origin of this code if {@link $debug} is set.
	 * 
	 * @param String $php Block of PHP code (without preceding <?php)
	 * @param boolean $eval Sanity check on code.
	 */
	public function write($php, $eval = true) {
		$trace = $this->debug ? debug_backtrace() : null;
		$path = $this->getFilePath();
		$header = '';

		// Create file incl. header if it doesn't exist
		if(!file_exists($this->getFilePath())) {
			touch($this->getFilePath());
			if($this->debug) {
				$header .= "<?php\n// Generated by " . $trace[1]['class'] . " on " . date('Y-m-d H:i:s') . "\n\n";
			} else {
				$header .= "<?php\n";
			}
		} 

		// Add content
		if($this->debug) {
			$header .= "// Added by " . $trace[1]['class'] . '::' . $trace[1]['function'] . "\n";
		}
		file_put_contents($path, $header . $php . "\n", FILE_APPEND);
	}

	public function reset() {
		if(file_exists($this->getFilePath())) {
			unlink($this->getFilePath());
		}
	}

	public function getFilePath() {
		return $this->filePath;
	}

	public function getDebug() {
		return $this->debug;
	}

	public function setDebug($debug) {
		$this->debug = $debug;

		return $this;
	}

}