Added EncryptionTrait and CipherInterface with tests

lib/CipherInterface.php

@@ -0,0 +1,24 @@
+<?php
+
+namespace Aol\Transformers;
+
+interface CipherInterface
+{
+	/**
+	 * Encrypt the given text.
+	 *
+	 * @param string $plain_text The text to encrypt.
+	 *
+	 * @return string The encrypted text.
+	 */
+	function encrypt($plain_text);
+
+	/**
+	 * Decrypt the given text.
+	 *
+	 * @param string $encrypted_text The text to decrypt.
+	 *
+	 * @return string The decrypted text.
+	 */
+	function decrypt($encrypted_text);
+}

lib/Utilities/EncryptionTrait.php

@@ -0,0 +1,73 @@
+<?php
+namespace Aol\Transformers\Utilities;
+
+use Aol\Transformers\CipherInterface;
+
+trait EncryptionTrait
+{
+	/** @var \Aol\Transformers\CipherInterface */
+	private $cipher;
+
+	/**
+	 * This trait requires the define method.
+	 *
+	 * @see \Aol\Transformers\Transformer
+	 */
+	abstract public function define(
+		$app_name,
+		$ext_name,
+		callable $app_func = null,
+		callable $ext_func = null,
+		$app_args = [],
+		$ext_args = []
+	);
+
+	public function setCipher(CipherInterface $cipher)
+	{
+		$this->cipher = $cipher;
+	}
+
+	protected function encrypt($plain_string)
+	{
+		return $this->getCipher()->encrypt($plain_string);
+	}
+
+	protected function decrypt($encrypted_string)
+	{
+		return $this->getCipher()->decrypt($encrypted_string);
+	}
+
+	protected function defineEncrypted($app_name, $ext_name)
+	{
+		$to_app = function ($encrypted_string) {
+			return $this->decrypt($encrypted_string);
+		};
+		$to_ext = function ($plain_string) {
+			return $this->encrypt($plain_string);
+		};
+		$this->define($app_name, $ext_name, $to_app, $to_ext);
+	}
+
+	protected function defineSerializedEncrypted($app_name, $ext_name)
+	{
+		$to_app = function ($encrypted_string) {
+			return unserialize($this->decrypt($encrypted_string));
+		};
+		$to_ext = function ($plain_string) {
+			return $this->encrypt(serialize($plain_string));
+		};
+		$this->define($app_name, $ext_name, $to_app, $to_ext);
+	}
+
+	private function getCipher()
+	{
+		if (empty($this->cipher)) {
+			throw new \RuntimeException(
+				'You must supply a cipher before using encryption. '
+				. 'See ' . get_class()
+			);
+		}
+
+		return $this->cipher;
+	}
+}

tests/Utilities/EncryptionTest.php

@@ -0,0 +1,84 @@
+<?php
+
+namespace Aol\Transformers\Tests\Utilities;
+
+use Aol\Transformers\CipherInterface;
+use Aol\Transformers\Transformer;
+use Aol\Transformers\Utilities\EncryptionTrait;
+
+class EncryptionTest extends \PHPUnit_Framework_TestCase
+{
+	/** @var EncryptionTransformer */
+	private $transformer;
+
+	public function testEncryptedToApp()
+	{
+		$this->assertSame(
+			'abc',
+			$this->transformer->toApp('YWJj', 'ext_encrypted')
+		);
+	}
+
+	public function testEncryptedToExt()
+	{
+		$this->assertSame(
+			'YWJj',
+			$this->transformer->toExt('abc', 'app_encrypted')
+		);
+	}
+
+	public function testSerializedEncryptedToApp()
+	{
+		$this->assertSame(
+			'abc',
+			$this->transformer->toApp('czozOiJhYmMiOw==', 'ext_serialized_encrypted')
+		);
+	}
+
+	public function testSerializedEncryptedToExt()
+	{
+		$this->assertSame(
+			'czozOiJhYmMiOw==',
+			$this->transformer->toExt('abc', 'app_serialized_encrypted')
+		);
+	}
+
+	/**
+	 * @expectedException \RuntimeException
+	 * @expectedExceptionMessage You must supply a cipher before using encryption. See Aol\Transformers\Tests\Utilities\EncryptionTransformer
+	 */
+	public function testEncryptionWithoutCipherShouldThrowException()
+	{
+		(new EncryptionTransformer())->toApp('123', 'ext_encrypted');
+	}
+
+	protected function setUp()
+	{
+		$this->transformer = new EncryptionTransformer;
+		$this->transformer->setCipher(new EncryptionCipher);
+	}
+}
+
+class EncryptionTransformer extends Transformer
+{
+	use EncryptionTrait;
+
+	protected function definitions()
+	{
+		$this->defineEncrypted('app_encrypted', 'ext_encrypted');
+		$this->defineSerializedEncrypted('app_serialized_encrypted', 'ext_serialized_encrypted');
+	}
+}
+
+class EncryptionCipher implements CipherInterface
+{
+	function encrypt($plain_text)
+	{
+		return base64_encode($plain_text);
+	}
+
+	function decrypt($encrypted_text)
+	{
+		return base64_decode($encrypted_text);
+	}
+}