New InputValidator::is_valid_rfc2616_token() method

This new method validates that an arbitrary input parameter can be considered valid for use as a "token" as per the RFC 2616 specification.

Includes tests.

Ref: https://datatracker.ietf.org/doc/html/rfc2616#section-2.2

src/Utility/InputValidator.php

@@ -109,4 +109,27 @@ public static function is_curl_handle($input) {
 
 		return false;
 	}
+
+	/**
+	 * Verify that a received input parameter is a valid "token name" according to the
+	 * specification in RFC 2616 (HTTP/1.1).
+	 *
+	 * The short version is: 1 or more ascii characters, CTRL chars and separators not allowed.
+	 * For the long version, see the specs in the RFC.
+	 *
+	 * @link https://datatracker.ietf.org/doc/html/rfc2616#section-2.2
+	 *
+	 * @since 2.1.0
+	 *
+	 * @param mixed $input Input parameter to verify.
+	 *
+	 * @return bool
+	 */
+	public static function is_valid_rfc2616_token($input) {
+		if (!is_int($input) && !is_string($input)) {
+			return false;
+		}
+
+		return (preg_match('@^[0-9A-Za-z!#$%&\'*+.^_`|~-]+$@', $input) === 1);
+	}
 }

tests/Utility/InputValidator/IsValidRfc2616TokenTest.php

@@ -0,0 +1,146 @@
+<?php
+
+namespace WpOrg\Requests\Tests\Utility\InputValidator;
+
+use WpOrg\Requests\Tests\TestCase;
+use WpOrg\Requests\Tests\TypeProviderHelper;
+use WpOrg\Requests\Utility\InputValidator;
+
+/**
+ * @covers \WpOrg\Requests\Utility\InputValidator::is_valid_rfc2616_token
+ */
+final class IsValidRfc2616TokenTest extends TestCase {
+
+	/**
+	 * Test whether a received input parameter is correctly identified as a valid RFC 2616 token.
+	 *
+	 * @dataProvider dataValidIntegers
+	 * @dataProvider dataValidStrings
+	 *
+	 * @param mixed $input Input parameter to verify.
+	 *
+	 * @return void
+	 */
+	public function testValid($input) {
+		$this->assertTrue(InputValidator::is_valid_rfc2616_token($input));
+	}
+
+	/**
+	 * Data Provider.
+	 *
+	 * @return array
+	 */
+	public static function dataValidIntegers() {
+		return TypeProviderHelper::getSelection(TypeProviderHelper::GROUP_INT);
+	}
+
+	/**
+	 * Data Provider.
+	 *
+	 * @return array
+	 */
+	public static function dataValidStrings() {
+		$all_valid_ascii = '!#$%&\'*+-.'; // Valid chars in ASCII 33-47 range.
+		// No valid chars in ASCII 58-64 range.
+		$all_valid_ascii .= '^_`'; // Valid chars in ASCII 91-96 range.
+		$all_valid_ascii .= '|~'; // Valid chars in ASCII 123-126 range.
+
+		for ($char = 48; $char <= 57; $char++) {
+			// Chars 0-9.
+			$all_valid_ascii .= chr($char);
+		}
+
+		for ($char = 65; $char <= 90; $char++) {
+			// Chars A-Z.
+			$all_valid_ascii .= chr($char);
+		}
+
+		for ($char = 97; $char <= 122; $char++) {
+			// Chars a-z.
+			$all_valid_ascii .= chr($char);
+		}
+
+		return [
+			'string containing only valid ascii characters / all valid ascii characters' => [
+				'input' => $all_valid_ascii,
+			],
+			'string with a typical cookie name' => [
+				'input' => 'requests-testcookie',
+			],
+		];
+	}
+
+	/**
+	 * Test whether a received input parameter is correctly identified as NOT a valid RFC 2616 token.
+	 *
+	 * @dataProvider dataInvalidTypes
+	 * @dataProvider dataInvalidValues
+	 *
+	 * @param mixed $input Input parameter to verify.
+	 *
+	 * @return void
+	 */
+	public function testInvalid($input) {
+		$this->assertFalse(InputValidator::is_valid_rfc2616_token($input));
+	}
+
+	/**
+	 * Data Provider for invalid data types.
+	 *
+	 * @return array
+	 */
+	public static function dataInvalidTypes() {
+		return TypeProviderHelper::getAllExcept(TypeProviderHelper::GROUP_INT, TypeProviderHelper::GROUP_STRING);
+	}
+
+	/**
+	 * Data Provider for valid data types containing invalid values.
+	 *
+	 * @return array
+	 */
+	public static function dataInvalidValues() {
+		$all_control = chr(127); // DEL.
+		for ($char = 0; $char <= 31; $char++) {
+			$all_control .= chr($char);
+		}
+
+		return [
+			'empty string' => [
+				'input' => '',
+			],
+			'string containing only control characters / all control characters' => [
+				'input' => $all_control,
+			],
+			'string containing control character at start' => [
+				'input' => chr(6) . 'some text',
+			],
+			'string containing control characters in text' => [
+				'input' => "some\ntext\rwith\tcontrol\echaracters\fin\vit",
+			],
+			'string containing control character at end' => [
+				'input' => 'some text' . chr(127),
+			],
+			'string containing only separator characters / all separator characters' => [
+				'input' => '()<>@,;:\\"/[]?={} 	',
+			],
+			'string containing separator character at start' => [
+				'input' => '=value',
+			],
+			'string containing separator characters in text' => [
+				'input' => 'words "with" spaces and quotes',
+			],
+			'string containing separator character at end' => [
+				'input' => 'punctuated;',
+			],
+			'string containing separator characters - leading and trailing whitespace' => [
+				'input' => '	words    ',
+			],
+			'string containing non-ascii characters - Iñtërnâtiônàlizætiøn' => [
+				'input' => 'Iñtërnâtiônàlizætiøn',
+			],
+			'string containing non-ascii characters - ௫' => [
+				'input' => '௫', // Tamil digit five.
+			],
+		];
+	}
+}