Add implementation of HTTP Media Type

- Add charset extraction from DOMDocument
- TESTS!

src/Content/Text/HTML.php

@@ -23,6 +23,7 @@ namespace Friendica\Content\Text;
 
 use DOMDocument;
 use DOMXPath;
+use Friendica\Protocol\HTTP\MediaType;
 use Friendica\Content\Widget\ContactBlock;
 use Friendica\Core\Hook;
 use Friendica\Core\Renderer;
@@ -1055,4 +1056,30 @@ class HTML
 
 		return $result !== false && $result->length > 0;
 	}
+
+	/**
+	 * @param DOMDocument $doc
+	 * @return string|null Lowercase charset
+	 */
+	public static function extractCharset(DOMDocument $doc): ?string
+	{
+		$xpath = new DOMXPath($doc);
+
+		$expression = "string(//meta[@charset]/@charset)";
+		if ($charset = $xpath->evaluate($expression)) {
+			return strtolower($charset);
+		}
+
+		try {
+			// This expression looks for a meta tag with the http-equiv attribute set to "content-type" ignoring case
+			// whose content attribute contains a "charset" string and returns its value
+			$expression = "string(//meta[@http-equiv][translate(@http-equiv, 'ABCDEFGHIJKLMNOPQRSTUVWXYZ', 'abcdefghijklmnopqrstuvwxyz') = 'content-type'][contains(translate(@content, 'ABCDEFGHIJKLMNOPQRSTUVWXYZ', 'abcdefghijklmnopqrstuvwxyz'), 'charset')]/@content)";
+			$mediaType = MediaType::fromContentType($xpath->evaluate($expression));
+			if (isset($mediaType->parameters['charset'])) {
+				return strtolower($mediaType->parameters['charset']);
+			}
+		} catch(\InvalidArgumentException $e) {}
+
+		return null;
+	}
 }

src/Protocol/HTTP/MediaType.php

@@ -0,0 +1,237 @@
+<?php
+/**
+ * @copyright Copyright (C) 2010-2023, the Friendica project
+ *
+ * @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 <https://www.gnu.org/licenses/>.
+ *
+ */
+
+namespace Friendica\Protocol\HTTP;
+
+/**
+ * @see https://httpwg.org/specs/rfc9110.html#media.type
+ *
+ * @property-read string $type
+ * @property-read string $subType
+ * @property-read string $parameters
+ */
+final class MediaType
+{
+	const DQUOTE = '"';
+	const DIGIT  = '0-9';
+	const ALPHA  = 'a-zA-Z';
+
+	// @see https://www.charset.org/charsets/us-ascii
+	const VCHAR = "\\x21-\\x7E";
+
+	const SYMBOL_NO_DELIM = "!#$%&'*+-.^_`|~";
+
+	const OBSTEXT = "\\x80-\\xFF";
+
+	const QDTEXT = "\t \\x21\\x23-\\x5B\\x5D-\\x7E" . self::OBSTEXT;
+
+	/**
+	 * @var string
+	 */
+	private $type;
+
+	/**
+	 * @var @string
+	 */
+	private $subType;
+
+	/**
+	 * @var string[]
+	 */
+	private $parameters;
+
+	public function __construct(string $type, string $subType, array $parameters = [])
+	{
+		if (!self::isToken($type)) {
+			throw new \InvalidArgumentException("Type isn't a valid token: " . $type);
+		}
+
+		if (!self::isToken($subType)) {
+			throw new \InvalidArgumentException("Subtype isn't a valid token: " . $subType);
+		}
+
+		foreach ($parameters as $key => $value) {
+			if (!self::isToken($key)) {
+				throw new \InvalidArgumentException("Parameter key isn't a valid token: " . $key);
+			}
+
+			if (!self::isToken($value) && !self::isQuotableString($value)) {
+				throw new \InvalidArgumentException("Parameter value isn't a valid token or a quotable string: " . $value);
+			}
+		}
+
+		$this->type       = $type;
+		$this->subType    = $subType;
+		$this->parameters = $parameters;
+	}
+
+	public function __get(string $name)
+	{
+		if (!isset($this->$name)) {
+			throw new \InvalidArgumentException('Unknown property ' . $name);
+		}
+
+		return $this->$name;
+	}
+
+	public static function fromContentType(string $contentType): self
+	{
+		if (!$contentType) {
+			throw new \InvalidArgumentException('Provided string is empty');
+		}
+
+		$parts         = explode(';', $contentType);
+		$mimeTypeParts = explode('/', trim(array_shift($parts)));
+		if (count($mimeTypeParts) !== 2) {
+			throw new \InvalidArgumentException('Provided string doesn\'t look like a MIME type: ' . $contentType);
+		}
+
+		list($type, $subType) = $mimeTypeParts;
+
+		$parameters = [];
+		foreach ($parts as $parameterString) {
+			if (!trim($parameterString)) {
+				continue;
+			}
+
+			$parameterParts = explode('=', trim($parameterString));
+
+			if (count($parameterParts) < 2) {
+				throw new \InvalidArgumentException('Parameter lacks a value: ' . $parameterString);
+			}
+
+			if (count($parameterParts) > 2) {
+				throw new \InvalidArgumentException('Parameter has too many values: ' . $parameterString);
+			}
+
+			list($key, $value) = $parameterParts;
+
+			if (!self::isToken($value) && !self::isQuotedString($value)) {
+				throw new \InvalidArgumentException("Parameter value isn't a valid token or a quoted string: \"" . $value . '"');
+			}
+
+			if (self::isQuotedString($value)) {
+				$value = self::extractQuotedStringValue($value);
+			}
+
+			// Parameter keys are case-insensitive, values are not
+			$parameters[strtolower($key)] = $value;
+		}
+
+		return new self($type, $subType, $parameters);
+	}
+
+	public function __toString(): string
+	{
+		$parameters = $this->parameters;
+
+		array_walk($parameters, function (&$value, $key) {
+			$value = '; ' . $key . '=' . (self::isToken($value) ? $value : '"' . addcslashes($value, '"\\') . '"');
+		});
+
+		return $this->type . '/' . $this->subType . implode($parameters);
+	}
+
+	/**
+	 * token          = 1*tchar
+	 * tchar          = "!" / "#" / "$" / "%" / "&" / "'" / "*"
+	 *                / "+" / "-" / "." / "^" / "_" / "`" / "|" / "~"
+	 *                / DIGIT / ALPHA
+	 *                ; any VCHAR, except delimiters
+	 *
+	 * @see https://httpwg.org/specs/rfc9110.html#tokens
+	 *
+	 * @param string $string
+	 * @return false|int
+	 */
+	private static function isToken(string $string)
+	{
+		$symbol = preg_quote(self::SYMBOL_NO_DELIM, '/');
+		$digit  = self::DIGIT;
+		$alpha  = self::ALPHA;
+
+		$pattern = "/^[$symbol$digit$alpha]+$/";
+
+		return preg_match($pattern, $string);
+	}
+
+	/**
+	 * quoted-string  = DQUOTE *( qdtext / quoted-pair ) DQUOTE
+	 * qdtext         = HTAB / SP / %x21 / %x23-5B / %x5D-7E / obs-text
+	 *
+	 * @see https://httpwg.org/specs/rfc9110.html#quoted.strings
+	 *
+	 * @param string $string
+	 * @return bool
+	 */
+	private static function isQuotedString(string $string): bool
+	{
+		$dquote = self::DQUOTE;
+
+		$vchar = self::VCHAR;
+
+		$obsText = self::OBSTEXT;
+
+		$qdtext = '[' . self::QDTEXT . ']';
+
+		$quotedPair = "\\\\[\t $vchar$obsText]";
+
+		$pattern = "/^$dquote(?:$qdtext|$quotedPair)*$dquote$/";
+
+		return preg_match($pattern, $string);
+	}
+
+	/**
+	 * Is the string an extracted quoted string value?
+	 *
+	 * @param string $string
+	 * @return bool
+	 */
+	private static function isQuotableString(string $string): bool
+	{
+		$vchar = self::VCHAR;
+
+		$obsText = self::OBSTEXT;
+
+		$qdtext = '[' . self::QDTEXT . ']';
+
+		$quotedSingle = "[\t $vchar$obsText]";
+
+		$pattern = "/^(?:$qdtext|$quotedSingle)*$/";
+
+		return preg_match($pattern, $string);
+	}
+
+	/**
+	 * Extracts the value from a quoted-string, removing quoted pairs
+	 *
+	 * @param string $value
+	 * @return string
+	 */
+	private static function extractQuotedStringValue(string $value): string
+	{
+		return preg_replace_callback('/^"(.*)"$/', function ($matches) {
+			$vchar   = self::VCHAR;
+			$obsText = self::OBSTEXT;
+			return preg_replace("/\\\\([\t $vchar$obsText])/", '$1', $matches[1]);
+		}, $value);
+	}
+}

tests/src/Protocol/HTTP/MediaTypeTest.php

@@ -0,0 +1,150 @@
+<?php
+/**
+ * @copyright Copyright (C) 2010-2023, the Friendica project
+ *
+ * @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 <https://www.gnu.org/licenses/>.
+ *
+ */
+
+namespace Friendica\Test\src\Protocol\HTTP;
+
+use Friendica\Protocol\HTTP\MediaType;
+
+class MediaTypeTest extends \PHPUnit\Framework\TestCase
+{
+	public function dataValid(): array
+	{
+		return [
+			'HTML UTF-8' => [
+				'expected'     => new MediaType('text', 'html', ['charset' => 'utf-8']),
+				'content-type' => 'text/html; charset=utf-8',
+			],
+			'HTML Northern Europe' => [
+				'expected'     => new MediaType('text', 'html', ['charset' => 'ISO-8859-4']),
+				'content-type' => 'text/html; charset=ISO-8859-4',
+			],
+			'multipart/form-data' => [
+				'expected'     => new MediaType('multipart', 'form-data', ['boundary' => '---------------------------974767299852498929531610575']),
+				'content-type' => 'multipart/form-data; boundary=---------------------------974767299852498929531610575',
+			],
+			'Multiple parameters' => [
+				'expected'     => new MediaType('application', 'octet-stream', ['charset' => 'ISO-8859-4', 'another' => 'parameter']),
+				'content-type' => 'application/octet-stream; charset=ISO-8859-4 ; another=parameter',
+			],
+			'No parameters' => [
+				'expected'     => new MediaType('application', 'vnd.adobe.air-application-installer-package+zip'),
+				'content-type' => 'application/vnd.adobe.air-application-installer-package+zip',
+			],
+			'No parameters colon' => [
+				'expected'     => new MediaType('application', 'vnd.adobe.air-application-installer-package+zip'),
+				'content-type' => 'application/vnd.adobe.air-application-installer-package+zip;',
+			],
+			'No parameters space colon' => [
+				'expected'     => new MediaType('application', 'vnd.adobe.air-application-installer-package+zip'),
+				'content-type' => 'application/vnd.adobe.air-application-installer-package+zip ;',
+			],
+			'No parameters space colon space' => [
+				'expected'     => new MediaType('application', 'vnd.adobe.air-application-installer-package+zip'),
+				'content-type' => 'application/vnd.adobe.air-application-installer-package+zip ; ',
+			],
+			'Parameter quoted string' => [
+				'expected'     => new MediaType('text', 'html', ['parameter' => 'Quoted string with a space and a "double-quote"']),
+				'content-type' => 'text/html; parameter="Quoted string with a space and a \"double-quote\""',
+			]
+		];
+	}
+
+	/**
+	 * @dataProvider dataValid
+	 *
+	 * @param MediaType $expected
+	 * @param string    $contentType
+	 * @return void
+	 */
+	public function testValid(MediaType $expected, string $contentType)
+	{
+		$this->assertEquals($expected, MediaType::fromContentType($contentType));
+	}
+
+	public function dataInvalid(): array
+	{
+		return [
+			'no slash'                  => ['application'],
+			'two slashes'               => ['application/octet/stream'],
+			'parameter no value'        => ['application/octet-stream ; parameter'],
+			'parameter too many values' => ['application/octet-stream ; parameter=value1=value2'],
+			'type non token'            => ['appli"cation/octet-stream'],
+			'subtype non token'         => ['application/octet\-stream'],
+			'parameter name non token'  => ['application/octet-stream; para"meter=value'],
+			'parameter value invalid'   => ['application/octet-stream; parameter="value"value'],
+		];
+	}
+
+	/**
+	 * @dataProvider dataInvalid
+	 *
+	 * @param string $contentType
+	 * @return void
+	 */
+	public function testInvalid(string $contentType)
+	{
+		$this->expectException(\InvalidArgumentException::class);
+
+		MediaType::fromContentType($contentType);
+	}
+
+	public function dataToString(): array
+	{
+		return [
+			'HTML UTF-8' => [
+				'content-type' => 'text/html; charset=utf-8',
+				'mediaType'    => new MediaType('text', 'html', ['charset' => 'utf-8']),
+			],
+			'HTML Northern Europe' => [
+				'expected'  => 'text/html; charset=ISO-8859-4',
+				'mediaType' => new MediaType('text', 'html', ['charset' => 'ISO-8859-4']),
+			],
+			'multipart/form-data' => [
+				'expected'  => 'multipart/form-data; boundary=---------------------------974767299852498929531610575',
+				'mediaType' => new MediaType('multipart', 'form-data', ['boundary' => '---------------------------974767299852498929531610575']),
+			],
+			'Multiple parameters' => [
+				'expected'  => 'application/octet-stream; charset=ISO-8859-4; another=parameter',
+				'mediaType' => new MediaType('application', 'octet-stream', ['charset' => 'ISO-8859-4', 'another' => 'parameter']),
+			],
+			'No parameters' => [
+				'expected'  => 'application/vnd.adobe.air-application-installer-package+zip',
+				'mediaType' => new MediaType('application', 'vnd.adobe.air-application-installer-package+zip'),
+			],
+			'Parameter quoted string' => [
+				'expected'  => 'text/html; parameter="Quoted string with a space and a \"double-quote\""',
+				'mediaType' => new MediaType('text', 'html', ['parameter' => 'Quoted string with a space and a "double-quote"']),
+			],
+		];
+	}
+
+	/**
+	 * @dataProvider dataToString
+	 *
+	 * @param string    $expected
+	 * @param MediaType $mediaType
+	 * @return void
+	 */
+	public function testToString(string $expected, MediaType $mediaType)
+	{
+		$this->assertEquals($expected, $mediaType->__toString());
+	}
+}