Merge pull request #1 from stefnadev/feature/pii-anonymizer

Add support for handling anonyimze some pii data

src/PII/Anonymizer/Anonymizer.php

@@ -0,0 +1,14 @@
+<?php declare(strict_types=1);
+
+namespace Stefna\Logger\PII\Anonymizer;
+
+interface Anonymizer
+{
+	public function support(string $key): bool;
+
+	/**
+	 * @param mixed $value
+	 * @return mixed
+	 */
+	public function process(string $key, $value);
+}

src/PII/Anonymizer/CardAnonymizer.php

@@ -0,0 +1,52 @@
+<?php declare(strict_types=1);
+
+namespace Stefna\Logger\PII\Anonymizer;
+
+use Stefna\Logger\PII\Exception\NotSupportedType;
+
+final class CardAnonymizer implements Anonymizer
+{
+	public const CARD_CCV = '_card_ccv';
+	public const CARD_HOLDER = '_card_holder';
+	public const CARD_NUMBER = '_card_number';
+
+	public function support(string $key): bool
+	{
+		return in_array($key, [
+			self::CARD_HOLDER,
+			self::CARD_NUMBER,
+			self::CARD_CCV,
+		]);
+	}
+
+	/**
+	 * @param mixed $value
+	 */
+	public function process(string $key, $value): ?string
+	{
+		if ($key === self::CARD_CCV) {
+			// remove value
+			return null;
+		}
+
+		if (!is_scalar($value)) {
+			return $value;
+		}
+
+		$value = (string)$value;
+		if ($key === self::CARD_NUMBER) {
+			return substr($value, 0, 2) . '**-****-****-' . substr($value, -4);
+		}
+
+		if ($key === self::CARD_HOLDER) {
+			$parts = explode(' ', $value);
+			$newValue = '';
+			foreach ($parts as $part) {
+				$newValue .= $part[0] . '**** ';
+			}
+			return trim($newValue);
+		}
+
+		throw NotSupportedType::key($key);
+	}
+}

src/PII/Anonymizer/PersonAnonymizer.php

@@ -0,0 +1,79 @@
+<?php declare(strict_types=1);
+
+namespace Stefna\Logger\PII\Anonymizer;
+
+use Stefna\Logger\PII\Exception\NotSupportedType;
+
+final class PersonAnonymizer implements Anonymizer
+{
+	public const NAME = '_name';
+	public const PHONE = '_phone';
+	public const EMAIL = '_email';
+	public const SSN = '_ssn';
+	public const DOB = '_date_of_birth';
+
+	/** @var array<string, string> */
+	private $aliasFields = [];
+
+	public function addAliasField(string $field, string $alias): void
+	{
+		$this->aliasFields[$alias] = $field;
+	}
+
+	public function support(string $key): bool
+	{
+		return in_array($key, [
+			self::NAME,
+			self::PHONE,
+			self::EMAIL,
+			self::SSN,
+			self::DOB,
+		], true) || array_key_exists($key, $this->aliasFields);
+	}
+
+	/**
+	 * @param mixed $value
+	 */
+	public function process(string $key, $value): ?string
+	{
+		if (array_key_exists($key, $this->aliasFields)) {
+			$key = $this->aliasFields[$key];
+		}
+
+		if (in_array($key, [self::SSN, self::DOB], true)) {
+			// remove value
+			return null;
+		}
+		if (!is_scalar($value)) {
+			return $value;
+		}
+
+		$value = (string)$value;
+		if ($key === self::EMAIL) {
+			$parts = explode('@', $value);
+			$domain = array_pop($parts);
+			$newValue = '';
+			foreach ($parts as $part) {
+				$newValue .= $part[0] . '****';
+			}
+			$newValue .= '@' . $domain;
+			return $newValue;
+		}
+		if ($key === self::PHONE) {
+			if (strlen($value) < 3) {
+				return '****';
+			}
+			return $value[0] . '****' . substr($value, -2);
+		}
+		if ($key === self::NAME) {
+			$parts = explode(' ', $value);
+			$newValue = '';
+			foreach ($parts as $part) {
+				$newValue .= $part[0] . '**** ';
+			}
+			return trim($newValue);
+		}
+
+		throw NotSupportedType::key($key);
+	}
+}

src/PII/Exception/NotSupportedType.php

@@ -0,0 +1,11 @@
+<?php declare(strict_types=1);
+
+namespace Stefna\Logger\PII\Exception;
+
+final class NotSupportedType extends \RuntimeException
+{
+	public static function key(string $key): self
+	{
+		return new self(sprintf('"%s" is not a valid key for anonymizer', $key));
+	}
+}

src/PII/Fields.php

@@ -0,0 +1,19 @@
+<?php declare(strict_types=1);
+
+namespace Stefna\Logger\PII;
+
+use Stefna\Logger\PII\Anonymizer\CardAnonymizer;
+use Stefna\Logger\PII\Anonymizer\PersonAnonymizer;
+
+interface Fields
+{
+	public const CARD_NUMBER = CardAnonymizer::CARD_NUMBER;
+	public const CARD_CCV = CardAnonymizer::CARD_CCV;
+	public const CARD_HOLDER = CardAnonymizer::CARD_HOLDER;
+
+	public const NAME = PersonAnonymizer::NAME;
+	public const PHONE = PersonAnonymizer::PHONE;
+	public const EMAIL = PersonAnonymizer::EMAIL;
+	public const SSN = PersonAnonymizer::SSN;
+	public const DOB = PersonAnonymizer::DOB;
+}

src/PII/Processor.php

@@ -0,0 +1,65 @@
+<?php declare(strict_types=1);
+
+namespace Stefna\Logger\PII;
+
+use Stefna\Logger\PII\Anonymizer\Anonymizer;
+use Stefna\Logger\PII\Anonymizer\CardAnonymizer;
+use Stefna\Logger\PII\Anonymizer\PersonAnonymizer;
+
+final class Processor
+{
+	/** @var Anonymizer[] */
+	private $anonymizers;
+
+	public function __construct(Anonymizer ...$anonymizers)
+	{
+		$this->anonymizers = $anonymizers;
+		if (!$this->anonymizers) {
+			$this->anonymizers[] = new CardAnonymizer();
+			$this->anonymizers[] = new PersonAnonymizer();
+		}
+	}
+
+	public function addAnonymizer(Anonymizer $anonymizer): void
+	{
+		$this->anonymizers[] = $anonymizer;
+	}
+
+	/**
+	 * @param array{context: array<string, mixed>} $record
+	 * @return array{context: array<string, mixed>}
+	 */
+	public function __invoke(array $record): array
+	{
+		$record['context'] = $this->processContext($record['context']);
+
+		return $record;
+	}
+
+	/**
+	 * @param array<string, mixed> $context
+	 * @return array<string, mixed>
+	 */
+	private function processContext(array $context): array
+	{
+		foreach ($context as $key => $value) {
+			if (is_array($value)) {
+				$context[$key] = $this->processContext($value);
+				continue;
+			}
+
+			foreach ($this->anonymizers as $anonymizer) {
+				if (!$anonymizer->support($key)) {
+					continue;
+				}
+				$value = $anonymizer->process($key, $value);
+				if ($value === null) {
+					unset($context[$key]);
+					continue 2;
+				}
+				$context[$key] = $value;
+			}
+		}
+		return $context;
+	}
+}

src/Processor/StripContextProcessor.php

@@ -0,0 +1,93 @@
+<?php declare(strict_types=1);
+
+namespace Stefna\Logger\Processor;
+
+final class StripContextProcessor
+{
+	private const DEFAULT_FIELDS = [
+		'%password%',
+	];
+
+	/** @var string[] */
+	private $fields = [];
+	/** @var array<array-key, array{field: string, type: string}> */
+	private $wildCardFields = [];
+
+	public function __construct(string ...$fields)
+	{
+		$fields = $fields + self::DEFAULT_FIELDS;
+		foreach ($fields as $field) {
+			$this->addField($field);
+		}
+	}
+
+	public function addField(string $field): void
+	{
+		$wildcardCount = substr_count($field, '%');
+		if ($wildcardCount) {
+			$wildcardField = [
+				'field' => strtolower(str_replace('%', '', $field)),
+				'type' => $wildcardCount === 2 ? 'containing' : 'beginning',
+			];
+			if ($wildcardCount === 1 && strpos($field, '%') === 0) {
+				$wildcardField['type'] = 'ending';
+			}
+
+			$this->wildCardFields[] = $wildcardField;
+		}
+		else {
+			$this->fields[] = $field;
+		}
+	}
+
+	/**
+	 * @param array{context: array<string, mixed>} $record
+	 * @return array{context: array<string, mixed>}
+	 */
+	public function __invoke(array $record): array
+	{
+		$record['context'] = $this->processContext($record['context']);
+
+		return $record;
+	}
+
+	/**
+	 * @param array<string, mixed> $context
+	 * @return array<string, mixed>
+	 */
+	private function processContext(array $context): array
+	{
+		foreach ($context as $key => $value) {
+			if (is_array($value)) {
+				$context[$key] = $this->processContext($value);
+				continue;
+			}
+
+			if (in_array($key, $this->fields, true)) {
+				unset($context[$key]);
+				continue;
+			}
+
+			$searchKey = strtolower($key);
+			foreach ($this->wildCardFields as $field) {
+				$pos = strpos($searchKey, $field['field']);
+				if ($field['type'] === 'beginning' && $pos === 0) {
+					unset($context[$key]);
+					continue 2;
+				}
+				if ($field['type'] === 'containing' && $pos !== false) {
+					unset($context[$key]);
+					continue 2;
+				}
+				if ($pos !== false &&
+					$field['type'] === 'ending' &&
+					substr($searchKey, -strlen($field['field'])) === $field['field']
+				) {
+					unset($context[$key]);
+					continue 2;
+				}
+			}
+		}
+		return $context;
+	}
+}

tests/Handler/CardAnonymizerTest.php

@@ -0,0 +1,42 @@
+<?php declare(strict_types=1);
+
+namespace Stefna\Logger\Handler;
+
+use PHPUnit\Framework\TestCase;
+use Stefna\Logger\PII\Anonymizer\CardAnonymizer;
+
+final class CardAnonymizerTest extends TestCase
+{
+	public function testCardNumber()
+	{
+		$anonymizer = new CardAnonymizer();
+
+		$cardNumber = '1111-1111-1111-1234';
+
+		$this->assertSame(
+			'11**-****-****-1234',
+			$anonymizer->process(CardAnonymizer::CARD_NUMBER, $cardNumber)
+		);
+	}
+
+	public function testCardCcv()
+	{
+		$anonymizer = new CardAnonymizer();
+
+		$cardCcv = '1234';
+
+		$this->assertNull($anonymizer->process(CardAnonymizer::CARD_CCV, $cardCcv));
+	}
+
+	public function testCardHolder()
+	{
+		$anonymizer = new CardAnonymizer();
+
+		$cardHolder = 'Test Sub Last';
+
+		$this->assertSame(
+			'T**** S**** L****',
+			$anonymizer->process(CardAnonymizer::CARD_HOLDER, $cardHolder)
+		);
+	}
+}