Flight\Routing\RouteCompiler

Complexity

Total Complexity

40

Size/Duplication

Total Lines	266
Duplicated Lines	0 %

Importance

Changes	4
Bugs	0	Features	0

7 Methods

Rating	Name	Duplication	Size	Complexity
A	compile()	0	25	6
A	filterVariableName()	0	17	3
B	interpolate()	0	32	8
B	generateUri()	0	30	7
A	prepareSegment()	0	9	2
B	sanitizeRequirement()	0	21	8
A	compilePattern()	0	25	6

<?php

declare(strict_types=1);

/*
 * This file is part of Flight Routing.
 *
 * PHP version 7.1 and above required
 *
 * @author    Divine Niiquaye Ibok <divineibok@gmail.com>
 * @copyright 2019 Biurad Group (https://biurad.com/)
 * @license   https://opensource.org/licenses/BSD-3-Clause License
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */

namespace Flight\Routing;

use Flight\Routing\{GeneratedUri, Route};

This use statement conflicts with another class in this namespace, Flight\Routing\GeneratedUri. Consider defining an alias.

This use statement conflicts with another class in this namespace, Flight\Routing\Route. Consider defining an alias.

use Flight\Routing\Exceptions\{UriHandlerException, UrlGenerationException};
use Flight\Routing\Interfaces\RouteCompilerInterface;

/**
 * RouteCompiler compiles Route instances to regex.
 *
 * provides ability to match and generate uris based on given parameters.
 *
 * @final This class is final and recommended not to be extended unless special cases
 *
 * @author Divine Niiquaye Ibok <divineibok@gmail.com>
 */
class RouteCompiler implements RouteCompilerInterface
{
    private const DEFAULT_SEGMENT = '[^\/]+';

    /**
     * This string defines the characters that are automatically considered separators in front of
     * optional placeholders (with default and no static text following). Such a single separator
     * can be left out together with the optional placeholder from matching and generating URLs.
     */
    private const PATTERN_REPLACES = ['/' => '\\/', '/[' => '\/?(?:', '[' => '(?:', ']' => ')?', '.' => '\.'];

    private const SEGMENT_REPLACES = ['/' => '\\/', '.' => '\.'];

    /**
     * This regex is used to match a certain rule of pattern to be used for routing.
     *
     * List of string patterns that regex matches:
     * - /{var} - A required variable pattern
     * - /[{var}] - An optional variable pattern
     * - /foo[/{var}] - A path with an optional sub variable pattern
     * - /foo[/{var}[.{format}]] - A path with optional nested variables
     * - /{var:[a-z]+} - A required variable with lowercase rule
     * - /{var=foo} - A required variable with default value
     * - /{var}[.{format:(html|php)=html}] - A required variable with an optional variable, a rule & default
     */
    private const COMPILER_REGEX = '~\\{(\\w+)(?:\\:([^{}=]+(?:\\{[\\w,^{}]+)?))?(?:\\=((?2)))?\\}~i';

    /**
     * A matching requirement helper, to ease matching route pattern when found.
     */
    private const SEGMENT_TYPES = [
        'int' => '\d+',
        'lower' => '[a-z]+',
        'upper' => '[A-Z]+',
        'alpha' => '[A-Za-z]+',
        'alnum' => '[A-Za-z0-9]+',
        'year' => '[12][0-9]{3}',
        'month' => '0[1-9]|1[012]+',
        'day' => '0[1-9]|[12][0-9]|3[01]+',
        'uuid' => '0-9a-fA-F]{8}\-[0-9a-fA-F]{4}\-[0-9a-fA-F]{4}\-[0-9a-fA-F]{4}\-[0-9a-fA-F]{12}',
    ];

    /**
     * A helper in reversing route pattern to URI.
     */
    private const URI_FIXERS = [
        '[]' => '',
        '[/]' => '',
        '[' => '',
        ']' => '',
        '://' => '://',
        '//' => '/',
        '/..' => '/%2E%2E',
        '/.' => '/%2E',
    ];

    /**
     * The maximum supported length of a PCRE subpattern name
     * http://pcre.org/current/doc/html/pcre2pattern.html#SEC16.
     *
     * @internal
     */
    private const VARIABLE_MAXIMUM_LENGTH = 32;

    /**
     * {@inheritdoc}
     */
    public function compile(Route $route): array
    {
        $hostVariables = $hostsRegex = [];
        $requirements = $route->get('patterns');

        // Strip supported browser prefix of $routePath ...
        $routePath = \rtrim($routePath = $route->get('path'), Route::URL_PREFIX_SLASHES[$routePath[-1]] ?? '/');

        if (!empty($routePath) && '/' === $routePath[0]) {
            $routePath = \substr($routePath, 1);
        }

        foreach ($route->get('domain') as $host) {
            [$hostRegex, $hostVariable] = self::compilePattern($host, false, $requirements);

            $hostVariables += $hostVariable;
            $hostsRegex[] = $hostRegex;
        }

        if (\str_contains($routePath, '{')) {
            [$pathRegex, $pathVariables] = self::compilePattern('/' . $routePath, false, $requirements);
            $variables = empty($hostVariables) ? $pathVariables : $hostVariables += $pathVariables;
        }

        return [$pathRegex ?? '/' . $routePath, $hostsRegex, $variables ?? $hostVariables];
    }

    /**
     * {@inheritdoc}
     */
    public function generateUri(Route $route, array $parameters, array $defaults = []): GeneratedUri
    {
        [$pathRegex, $pathVariables] = self::compilePattern(\ltrim($route->get('path'), '/'), true);

        $pathRegex = '/' . \stripslashes(\str_replace('?', '', $pathRegex));
        $createUri = new GeneratedUri(self::interpolate($pathRegex, $parameters, $defaults, $pathVariables));

        foreach ($route->get('domain') as $host) {
            $compiledHost = self::compilePattern($host, true);

            if (!empty($compiledHost)) {
                [$hostRegex, $hostVariables] = $compiledHost;

                break;
            }
        }

        if (!empty($schemes = $route->get('schemes'))) {
            $createUri->withScheme(\in_array('https', $schemes, true) ? 'https' : \end($schemes) ?? 'http');

            if (!isset($hostRegex)) {
                $createUri->withHost($_SERVER['HTTP_HOST'] ?? '');
            }
        }

        if (isset($hostRegex)) {
            $createUri->withHost(self::interpolate($hostRegex, $parameters, $defaults, $hostVariables));

The variable $hostVariables does not seem to be defined for all execution paths leading up to this point.

        }

        return $createUri;
    }

    /**
     * Check for mandatory parameters then interpolate $uriRoute with given $parameters.
     *
     * @param array<int|string,mixed> $parameters
     */
    private static function interpolate(string $uriRoute, array $parameters, array $defaults, array $allowed): string
    {
        \preg_match_all('#(?:\[)?\<(\w+).*?\>(?:\])?#', $uriRoute, $paramVars, \PREG_SET_ORDER);

        foreach ($paramVars as $offset => [$type, $var]) {
            if ('[' === $type[0]) {
                $defaults[$var] = null;

                continue;
            }

            if (isset($parameters[$offset])) {
                $defaults[$var] = $parameters[$offset];
                unset($parameters[$offset]);
            }
        }

        // Fetch and merge all possible parameters + route defaults ...
        $parameters += $defaults;

        // all params must be given
        if ($diff = \array_diff_key($allowed, $parameters)) {
            throw new UrlGenerationException(\sprintf('Some mandatory parameters are missing ("%s") to generate a URL for route path "%s".', \implode('", "', \array_keys($diff)), $uriRoute));
        }

        $replaces = self::URI_FIXERS;

        foreach ($parameters as $key => $value) {
            $replaces["<{$key}>"] = (\is_array($value) || $value instanceof \Closure) ? '' : $value;
        }

        return \strtr($uriRoute, $replaces);
    }

    private static function sanitizeRequirement(string $key, ?string $regex): string
    {
        if (!empty($regex)) {
            if ('^' === $regex[0]) {
                $regex = \substr($regex, 1);
            } elseif (0 === \strpos($regex, '\\A')) {
                $regex = \substr($regex, 2);
            }

            if ('$' === $regex[-1]) {
                $regex = \substr($regex, 0, -1);
            } elseif (\strlen($regex) - 2 === \strpos($regex, '\\z')) {
                $regex = \substr($regex, 0, -2);
            }
        }

        if ('' === $regex) {
            throw new \InvalidArgumentException(\sprintf('Routing requirement for "%s" cannot be empty.', $key));
        }

        return null !== $regex ? \strtr($regex, self::SEGMENT_REPLACES) : self::DEFAULT_SEGMENT;
    }

    /**
     * @param array<string,string|string[]> $requirements
     *
     * @throws UriHandlerException if a variable name starts with a digit or
     *                             if it is too long to be successfully used as a PCRE subpattern or
     *                             if a variable is referenced more than once
     *
     * @return array<string,mixed>
     */
    private static function compilePattern(string $uriPattern, bool $reversed = false, array $requirements = []): array
    {
        $variables = $replaces = [];

        // correct [/ first occurrence]
        if (0 === \strpos($uriPattern, '[/')) {
            $uriPattern = '[' . \substr($uriPattern, 3);
        }

        // Match all variables enclosed in "{}" and iterate over them...
        \preg_match_all(self::COMPILER_REGEX, $uriPattern, $matches, \PREG_SET_ORDER | \PREG_UNMATCHED_AS_NULL);

        foreach ($matches as [$placeholder, $varName, $segment, $default]) {
            // Filter variable name to meet requirement
            self::filterVariableName($varName, $uriPattern);

            if (\array_key_exists($varName, $variables)) {
                throw new UriHandlerException(\sprintf('Route pattern "%s" cannot reference variable name "%s" more than once.', $uriPattern, $varName));
            }

            $variables[$varName] = $default;
            $replaces[$placeholder] = !$reversed ? '(?P<' . $varName . '>' . (self::SEGMENT_TYPES[$segment] ?? $segment ?? self::prepareSegment($varName, $requirements)) . ')' : "<$varName>";
        }

        return [\strtr($uriPattern, !$reversed ? self::PATTERN_REPLACES + $replaces : $replaces), $variables];
    }

    /**
     * Prevent variables with same name used more than once.
     */
    private static function filterVariableName(string $varName, string $pattern): void
    {
        // A PCRE subpattern name must start with a non-digit. Also a PHP variable cannot start with a digit so the
        // variable would not be usable as a Controller action argument.
        if (1 === \preg_match('/^\d/', $varName)) {
            throw new UriHandlerException(
                \sprintf('Variable name "%s" cannot start with a digit in route pattern "%s". Use a different name.', $varName, $pattern)
            );
        }

        if (\strlen($varName) > self::VARIABLE_MAXIMUM_LENGTH) {
            throw new UriHandlerException(
                \sprintf(
                    'Variable name "%s" cannot be longer than %s characters in route pattern "%s".',
                    $varName,
                    self::VARIABLE_MAXIMUM_LENGTH,
                    $pattern
                )
            );
        }
    }

    /**
     * Prepares segment pattern with given constrains.
     *
     * @param array<string,mixed> $requirements
     */
    private static function prepareSegment(string $name, array $requirements): string
    {
        $segment = $requirements[$name] ?? null;

        if (!\is_array($segment)) {
            return self::sanitizeRequirement($name, $segment);
        }

        return \implode('|', \array_map([__CLASS__, 'sanitizeRequirement'], $segment));
    }
}