FluentDirectorExtension.php

<?php

namespace TractorCow\Fluent\Extension;

use Exception;
use SilverStripe\Control\HTTPRequest;
use SilverStripe\Core\Config\Configurable;
use SilverStripe\Core\Extension;
use SilverStripe\Core\Injector\Injector;
use TractorCow\Fluent\Middleware\InitStateMiddleware;
use TractorCow\Fluent\Model\Locale;

/**
 * Fluent extension for {@link \SilverStripe\Control\Director} to apply routing rules for locales
 */
class FluentDirectorExtension extends Extension
{
    use Configurable;

    /**
     * Determine if the site should detect the browser locale for new users. Turn this off to disable 302 redirects
     * on the home page.
     *
     * @config
     * @var bool
     */
    private static $detect_locale = false;

    /**
     * Determine if the locale should be remembered across multiple sessions via cookies. If this is left on then
     * visitors to the home page will be redirected to the locale they last viewed. This may interefere with some
     * applications and can be turned off to prevent unexpected redirects.
     *
     * @config
     * @var bool
     */
    private static $remember_locale = false;

    /**
     * Request parameter to store the locale in
     *
     * @config
     * @var string
     */
    private static $query_param = 'l';

    /**
     * Allow the prefix for the default {@link Locale} (IsDefault = 1) to be disabled
     *
     * @config
     * @var bool
     */
    private static $disable_default_prefix = false;

    /**
     * Whether to force "domain mode"
     *
     * @config
     * @var bool
     */
    private static $force_domain = false;

    /**
     * Forces regeneration of all locale routes
     *
     * @param array &$rules
     */
    public function updateRules(&$rules)
    {
        $originalRules = $rules;
        $fluentRules = $this->getExplicitRoutes($rules);

        // Insert Fluent Rules before the default '$URLSegment//$Action/$ID/$OtherID'
        $rules = $this->insertRuleBefore($rules, '$URLSegment//$Action/$ID/$OtherID', $fluentRules);

        $request = Injector::inst()->get(HTTPRequest::class);
        if (!$request) {
            throw new Exception('No request found');
        }

        // Ensure InitStateMddleware is called here to set the correct defaultLocale
        Injector::inst()->create(InitStateMiddleware::class)->process($request, function () {
        });

        $defaultLocale = Locale::getDefault(true);
        if (!$defaultLocale) {
            return;
        }

        // If we do not wish to detect the locale automatically, fix the home page route
        // to the default locale for this domain.
        if (!static::config()->get('detect_locale')) {
            // Respect existing home controller
            $rules[''] = [
                'Controller' => $this->getRuleController($originalRules[''], $defaultLocale),
                static::config()->get('query_param') => $defaultLocale->Locale,
            ];
        }

        // If default locale doesn't have prefix, replace default route with
        // the default locale for this domain
        if (static::config()->get('disable_default_prefix')) {
            $rules['$URLSegment//$Action/$ID/$OtherID'] = [
                'Controller' => $this->getRuleController($originalRules['$URLSegment//$Action/$ID/$OtherID'], $defaultLocale),
                static::config()->get('query_param') => $defaultLocale->Locale
            ];
        }
    }

    /**
     * Generate an array of explicit routing rules for each locale
     *
     * @param array $originalRules
     * @return array
     */
    protected function getExplicitRoutes($originalRules)
    {
        $queryParam = static::config()->get('query_param');
        $rules = [];
        /** @var Locale $localeObj */
        foreach (Locale::getCached() as $localeObj) {
            $locale = $localeObj->getLocale();
            $url = $localeObj->getURLSegment();

            // apply encode so we could route urls that contain multi-byte charaters
            $url = urlencode($url);

            // Apply to nested page url
            $controller = $this->getRuleController($originalRules['$URLSegment//$Action/$ID/$OtherID'], $localeObj);
            $rules[$url . '/$URLSegment!//$Action/$ID/$OtherID'] = [
                'Controller' => $controller,
                $queryParam => $locale,
            ];

            // Home url for that locale
            $controller = $this->getRuleController($originalRules[''], $localeObj);
            $rules[$url] = [
                'Controller' => $controller,
                $queryParam => $locale,
            ];
        }
        return $rules;
    }

    /**
     * Get controller that fluent should inject
     * @param array|string $existingRule
     * @param Locale $localeObj
     * @return string Class name of controller to use
     */
    protected function getRuleController($existingRule, $localeObj)
    {
        $controller = isset($existingRule['Controller']) ? $existingRule['Controller'] : $existingRule;
        // Decorate Director class to override controllers for a specific locale
        $this->owner->extend('updateLocalePageController', $controller, $localeObj);
        return $controller;
    }

    /**
     * Inserts the given rule(s) before another rule
     * @param array $rules Array of rules to insert before
     * @param string $key Rule to insert the new rules before
     * @param array $rule New Rules to insert
     * @return array Resulting array of rules
     */
    protected function insertRuleBefore(array $rules, $key, array $rule)
    {
        $i = array_search($key, array_keys($rules));
        if ($i !== false) {
            return array_slice($rules, 0, $i, true) + $rule + array_slice($rules, $i, null, true);
        }

        return $rules;
    }
}