getPreferredLanguage example

        if (null !== $parentRequest = $this->requestStack->getParentRequest()) {
            $this->setRouterContext($parentRequest);
        }
    }

    private function setLocale(Request $request): void
    {
        if ($locale = $request->attributes->get('_locale')) {
            $request->setLocale($locale);
        } elseif ($this->useAcceptLanguageHeader) {
            if ($preferredLanguage = $request->getPreferredLanguage($this->enabledLocales)) {
                $request->setLocale($preferredLanguage);
            }
            $request->attributes->set('_vary_by_language', true);
        }
    }

    private function setRouterContext(Request $request): void
    {
        $this->router?->getContext()->setParameter('_locale', $request->getLocale());
    }

    

        if (null !== $parentRequest = $this->requestStack->getParentRequest()) {
            $this->setRouterContext($parentRequest);
        }
    }

    private function setLocale(Request $request): void
    {
        if ($locale = $request->attributes->get('_locale')) {
            $request->setLocale($locale);
        } elseif ($this->useAcceptLanguageHeader) {
            if ($preferredLanguage = $request->getPreferredLanguage($this->enabledLocales)) {
                $request->setLocale($preferredLanguage);
            }
            $request->attributes->set('_vary_by_language', true);
        }
    }

    private function setRouterContext(Request $request): void
    {
        $this->router?->getContext()->setParameter('_locale', $request->getLocale());
    }

    

$request->query->remove('foo');
        $this->assertSame('body', $request->get('foo'));

        $request->request->remove('foo');
        $this->assertNull($request->get('foo'));
    }

    public function testGetPreferredLanguage()
    {
        $request = new Request();
        $this->assertNull($request->getPreferredLanguage());
        $this->assertNull($request->getPreferredLanguage([]));
        $this->assertEquals('fr', $request->getPreferredLanguage(['fr']));
        $this->assertEquals('fr', $request->getPreferredLanguage(['fr', 'en']));
        $this->assertEquals('en', $request->getPreferredLanguage(['en', 'fr']));
        $this->assertEquals('fr-ch', $request->getPreferredLanguage(['fr-ch', 'fr-fr']));

        $request = new Request();
        $request->headers->set('Accept-language', 'zh, en-us; q=0.8, en; q=0.6');
        $this->assertEquals('en', $request->getPreferredLanguage(['en', 'en-us']));

        $request = new Request();