[stable24] Add support for different encodings

composer.json

@@ -6,7 +6,9 @@
         "christophwurst/nextcloud": "dev-master",
         "jakub-onderka/php-parallel-lint": "^1.0.0",
         "nextcloud/coding-standard": "^1.0.0",
-        "psalm/phar": "^4.3"
+        "psalm/phar": "^4.3",
+        "phpunit/phpunit": "^9.5",
+        "ext-mbstring": "*"
     },
     "license": "AGPLv3",
     "authors": [
@@ -22,6 +24,7 @@
       "lint": "find . -name \\*.php -not -path './vendor/*' -print0 | xargs -0 -n1 php -l",
       "cs:check": "php-cs-fixer fix --dry-run --diff",
       "cs:fix": "php-cs-fixer fix",
-      "psalm": "psalm.phar"
+      "psalm": "psalm.phar",
+      "test:unit": "phpunit -c tests/phpunit.xml"
     }
 }

lib/Service/ApiService.php

@@ -50,17 +50,20 @@ class ApiService {
 	protected $documentService;
 	protected $logger;
 	private $imageService;
+	private $encodingService;
 
 	public function __construct(IRequest $request,
 								SessionService $sessionService,
 								DocumentService $documentService,
 								ImageService $imageService,
+								EncodingService $encodingService,
 								ILogger $logger) {
 		$this->request = $request;
 		$this->sessionService = $sessionService;
 		$this->documentService = $documentService;
 		$this->logger = $logger;
 		$this->imageService = $imageService;
+		$this->encodingService = $encodingService;
 	}
 
 	public function create($fileId = null, $filePath = null, $token = null, $guestName = null, bool $forceRecreate = false): DataResponse {
@@ -105,6 +108,11 @@ public function create($fileId = null, $filePath = null, $token = null, $guestNa
 		try {
 			$baseFile = $this->documentService->getBaseFile($document->getId());
 			$content = $baseFile->getContent();
+
+			$content = $this->encodingService->encodeToUtf8($content);
+			if (!$content) {
+				$this->logger->log(ILogger::WARN, 'Failed to encode file to UTF8. File ID: ' . $file->getId());
+			}
 		} catch (NotFoundException $e) {
 			$this->logger->logException($e, ['level' => ILogger::INFO]);
 			$content = null;

lib/Service/EncodingService.php

@@ -0,0 +1,81 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * @copyright Copyright (c) 2022 Raul Ferreira Fuentes <[email protected]>
+ *
+ * @author Raul Ferreira Fuentes <[email protected]>
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+namespace OCA\Text\Service;
+
+class EncodingService {
+	public const COMMON_ENCODINGS = [ 'UTF-8', 'GB2312', 'GBK', 'BIG-5', 'SJIS-win', 'EUC-JP', 'Windows-1252', 'ISO-8859-15', 'ISO-8859-1', 'ASCII'];
+
+	public const UTF_BOMs = [
+		'UTF-32BE' => "\x00\x00\xfe\xff",
+		'UTF-32LE' => "\xff\xfe\x00\x00",
+		'UTF-16BE' => "\xfe\xff",
+		'UTF-16LE' => "\xff\xfe",
+		'UTF-8' => "\xef\xbb\xbf"
+	];
+
+	public function encodeToUtf8(string $string): ?string {
+		$encoding = $this->detectEncoding($string);
+		if (!$encoding) {
+			return null;
+		}
+
+		return mb_convert_encoding($string, 'UTF-8', $encoding);
+	}
+
+	public function detectEncoding(string $string): ?string {
+		$bomDetect = $this->detectUtfBom($string);
+		if ($bomDetect) {
+			return $bomDetect;
+		}
+
+		foreach ($this->getEncodings() as $encoding) {
+			if (mb_check_encoding($string, $encoding)) {
+				return $encoding;
+			}
+		}
+
+		return mb_detect_encoding($string, $this->getEncodings(), true) ?: null;
+	}
+
+	private function detectUtfBom(string $string): ?string {
+		foreach (self::UTF_BOMs as $encoding => $utfBom) {
+			$bom = substr($string, 0, strlen($utfBom));
+			if ($bom === $utfBom) {
+				return $encoding;
+			}
+		}
+
+		return null;
+	}
+
+	/**
+	 * @return string[]
+	 */
+	private function getEncodings(): array {
+		$mbOrder = mb_detect_order() ?: [];
+		return array_merge($mbOrder, self::COMMON_ENCODINGS);
+	}
+}

tests/data/iso-8859-15.txt

@@ -0,0 +1,6 @@
+Todos os seres humanos nascem livres e iguais em dignidade e em direitos. Dotados de raz�o e de consci�ncia, devem agir uns para com os outros em esp�rito de fraternidade. 
+
+Alle menneske er f�dde til fridom og med same menneskeverd og menneskerettar. Dei har f�tt fornuft og samvit og skal leve med kvarandre som br�r.
+
+Tous les �tres humains naissent libres et �gaux en dignit� et en droits. Ils sont dou�s de raison et de conscience et doivent agir les uns envers les autres dans un esprit de fraternit�. 
+

tests/data/iso-8859-5.txt

@@ -0,0 +1,12 @@
+������ 1
+��� ���� ��������� ���������� � ������� � ����� ����������� � ������. ��� �������� ������� � �������� � ������ ��������� � ��������� ���� ����� � ���� ��������.
+
+������ 2
+������ ������� ������ �������� ����� ������� � ����� ���������, ���������������� ��������� �����������, ��� ������ �� �� �� ���� ��������, ���-�� � ��������� ����, ����� ����, ����, �����, �������, ������������ ��� ���� ���������, ������������� ��� ����������� �������������, ��������������, ���������� ��� ����� ���������.
+
+����� ����, �� ������ ����������� �������� �������� �� ������ �������������, ��������� ��� �������������� ������� ������ ��� ����������, � ������� ������� �����������, ���������� �� ����, �������� �� ��� ���������� �����������, ����������, ������������������� ��� ���-���� ����� ������������ � ����� ������������.
+
+������ 3
+������ ������� ����� ����� �� �����, �� ������� � �� ������ ������������������.
+
+

tests/unit/Service/EncodingServiceTest.php

@@ -0,0 +1,76 @@
+<?php
+
+namespace OCA\Text\Service;
+
+use Test\TestCase;
+
+class LabelServiceTest extends TestCase {
+	private $encodingService;
+
+	protected function setUp(): void {
+		parent::setUp();
+		$this->encodingService = new EncodingService();
+	}
+
+	/**
+	 * Attempt to decode the file using the default decoding order.
+	 * For files with encodings not included in the COMMON_ENCODINGS array encoding to UTF-8 will fail.
+	 * We then do the conversion again after setting the mb_detect_order value: all conversions should succeed.
+	 * @dataProvider dataFileEncodings
+	 */
+	public function testEncoding(string $file, string $encoding) {
+		$utf8String = $this->encodingService->encodeToUtf8(file_get_contents($file));
+
+		// If encoding is not part of the default encodings we can expect it to fail
+		// It might still succeed because encoding detection is not precise.
+		if ($utf8String || $this->isSupportedEncoding($encoding)) {
+			$this->assertNotNull($utf8String);
+			$this->assertNotFalse(mb_detect_encoding($utf8String, 'UTF-8', true));
+		}
+
+		$originalOrder = mb_detect_order();
+		$this->assertNotFalse(mb_detect_order($encoding));
+
+		$utf8String = $this->encodingService->encodeToUtf8(file_get_contents($file));
+		$this->assertNotNull($utf8String);
+		$this->assertNotFalse(mb_detect_encoding($utf8String, 'UTF-8', true));
+
+		mb_detect_order($originalOrder);
+	}
+
+	/**
+	 * If the encoding is in the list of common encodings we should be able to detect an encoding (it might not be the
+	 * correct encoding due to detection inaccuracies). If not, add the encoding to mb_detect_order.
+	 * @dataProvider dataFileEncodings
+	 */
+	public function testDetection(string $file, string $encoding) {
+		$detectedEncoding = $this->encodingService->detectEncoding(file_get_contents($file));
+		if ($this->isSupportedEncoding($encoding)) {
+			$this->assertNotNull($detectedEncoding);
+		}
+
+		$originalOrder = mb_detect_order();
+		$this->assertNotFalse(mb_detect_order($encoding));
+
+		$detectedEncoding = $this->encodingService->detectEncoding(file_get_contents($file));
+		$this->assertEquals($encoding, $detectedEncoding);
+
+		mb_detect_order($originalOrder);
+	}
+
+
+	public function dataFileEncodings(): array {
+		return [
+			['./tests/data/iso-8859-15.txt', 'ISO-8859-15'],
+			['./tests/data/big5.txt', 'BIG-5'],
+			['./tests/data/cp936.txt', 'CP936'],
+			['./tests/data/utf-16.txt', 'UTF-16LE'],
+			['./tests/data/iso-8859-5.txt', 'ISO-8859-5'],
+		];
+	}
+
+	private function isSupportedEncoding(string $encoding): bool {
+		return in_array($encoding, EncodingService::COMMON_ENCODINGS, true)
+			|| isset(EncodingService::UTF_BOMs[$encoding]);
+	}
+}