<?php
/*
* This file is part of the Symfony package.
*
* (c) Fabien Potencier <fabien@symfony.com>
*
* For the full copyright and license information, please view the LICENSE
* file that was distributed with this source code.
*/
namespace Symfony\Component\HttpKernel\HttpCache;
use Symfony\Component\HttpFoundation\Response;
/**
* ResponseCacheStrategy knows how to compute the Response cache HTTP header
* based on the different response cache headers.
*
* This implementation changes the main response TTL to the smallest TTL received
* or force validation if one of the surrogates has validation cache strategy.
*
* @author Fabien Potencier <fabien@symfony.com>
*/
class ResponseCacheStrategy implements ResponseCacheStrategyInterface
{
/**
* Cache-Control headers that are sent to the final response if they appear in ANY of the responses.
*/
private const OVERRIDE_DIRECTIVES = ['private', 'no-cache', 'no-store', 'no-transform', 'must-revalidate', 'proxy-revalidate'];
/**
* Cache-Control headers that are sent to the final response if they appear in ALL of the responses.
*/
private const INHERIT_DIRECTIVES = ['public', 'immutable'];
private int $embeddedResponses = 0;
private bool $isNotCacheableResponseEmbedded = false;
private int $age = 0;
private array $flagDirectives = [
'no-cache' => null,
'no-store' => null,
'no-transform' => null,
'must-revalidate' => null,
'proxy-revalidate' => null,
'public' => null,
'private' => null,
'immutable' => null,
];
private array $ageDirectives = [
'max-age' => null,
's-maxage' => null,
'expires' => null,
];
/**
* {@inheritdoc}
*/
public function add(Response $response)
{
++$this->embeddedResponses;
foreach (self::OVERRIDE_DIRECTIVES as $directive) {
if ($response->headers->hasCacheControlDirective($directive)) {
$this->flagDirectives[$directive] = true;
}
}
foreach (self::INHERIT_DIRECTIVES as $directive) {
if (false !== $this->flagDirectives[$directive]) {
$this->flagDirectives[$directive] = $response->headers->hasCacheControlDirective($directive);
}
}
$age = $response->getAge();
$this->age = max($this->age, $age);
if ($this->willMakeFinalResponseUncacheable($response)) {
$this->isNotCacheableResponseEmbedded = true;
return;
}
$isHeuristicallyCacheable = $response->headers->hasCacheControlDirective('public');
$maxAge = $response->headers->hasCacheControlDirective('max-age') ? (int) $response->headers->getCacheControlDirective('max-age') : null;
$this->storeRelativeAgeDirective('max-age', $maxAge, $age, $isHeuristicallyCacheable);
$sharedMaxAge = $response->headers->hasCacheControlDirective('s-maxage') ? (int) $response->headers->getCacheControlDirective('s-maxage') : $maxAge;
$this->storeRelativeAgeDirective('s-maxage', $sharedMaxAge, $age, $isHeuristicallyCacheable);
$expires = $response->getExpires();
$expires = null !== $expires ? (int) $expires->format('U') - (int) $response->getDate()->format('U') : null;
$this->storeRelativeAgeDirective('expires', $expires >= 0 ? $expires : null, 0, $isHeuristicallyCacheable);
}
/**
* {@inheritdoc}
*/
public function update(Response $response)
{
// if we have no embedded Response, do nothing
if (0 === $this->embeddedResponses) {
return;
}
// Remove validation related headers of the master response,
// because some of the response content comes from at least
// one embedded response (which likely has a different caching strategy).
$response->setEtag(null);
$response->setLastModified(null);
$this->add($response);
$response->headers->set('Age', $this->age);
if ($this->isNotCacheableResponseEmbedded) {
if ($this->flagDirectives['no-store']) {
$response->headers->set('Cache-Control', 'no-cache, no-store, must-revalidate');
} else {
$response->headers->set('Cache-Control', 'no-cache, must-revalidate');
}
return;
}
$flags = array_filter($this->flagDirectives);
if (isset($flags['must-revalidate'])) {
$flags['no-cache'] = true;
}
$response->headers->set('Cache-Control', implode(', ', array_keys($flags)));
$maxAge = null;
if (is_numeric($this->ageDirectives['max-age'])) {
$maxAge = $this->ageDirectives['max-age'] + $this->age;
$response->headers->addCacheControlDirective('max-age', $maxAge);
}
if (is_numeric($this->ageDirectives['s-maxage'])) {
$sMaxage = $this->ageDirectives['s-maxage'] + $this->age;
if ($maxAge !== $sMaxage) {
$response->headers->addCacheControlDirective('s-maxage', $sMaxage);
}
}
if (is_numeric($this->ageDirectives['expires'])) {
$date = clone $response->getDate();
$date->modify('+'.($this->ageDirectives['expires'] + $this->age).' seconds');
$response->setExpires($date);
}
}
/**
* RFC2616, Section 13.4.
*
* @see https://www.w3.org/Protocols/rfc2616/rfc2616-sec13.html#sec13.4
*/
private function willMakeFinalResponseUncacheable(Response $response): bool
{
// RFC2616: A response received with a status code of 200, 203, 300, 301 or 410
// MAY be stored by a cache […] unless a cache-control directive prohibits caching.
if ($response->headers->hasCacheControlDirective('no-cache')
|| $response->headers->getCacheControlDirective('no-store')
) {
return true;
}
// Last-Modified and Etag headers cannot be merged, they render the response uncacheable
// by default (except if the response also has max-age etc.).
if (\in_array($response->getStatusCode(), [200, 203, 300, 301, 410])
&& null === $response->getLastModified()
&& null === $response->getEtag()
) {
return false;
}
// RFC2616: A response received with any other status code (e.g. status codes 302 and 307)
// MUST NOT be returned in a reply to a subsequent request unless there are
// cache-control directives or another header(s) that explicitly allow it.
$cacheControl = ['max-age', 's-maxage', 'must-revalidate', 'proxy-revalidate', 'public', 'private'];
foreach ($cacheControl as $key) {
if ($response->headers->hasCacheControlDirective($key)) {
return false;
}
}
if ($response->headers->has('Expires')) {
return false;
}
return true;
}
/**
* Store lowest max-age/s-maxage/expires for the final response.
*
* The response might have been stored in cache a while ago. To keep things comparable,
* we have to subtract the age so that the value is normalized for an age of 0.
*
* If the value is lower than the currently stored value, we update the value, to keep a rolling
* minimal value of each instruction.
*
* If the value is NULL and the isHeuristicallyCacheable parameter is false, the directive will
* not be set on the final response. In this case, not all responses had the directive set and no
* value can be found that satisfies the requirements of all responses. The directive will be dropped
* from the final response.
*
* If the isHeuristicallyCacheable parameter is true, however, the current response has been marked
* as cacheable in a public (shared) cache, but did not provide an explicit lifetime that would serve
* as an upper bound. In this case, we can proceed and possibly keep the directive on the final response.
*/
private function storeRelativeAgeDirective(string $directive, ?int $value, int $age, bool $isHeuristicallyCacheable)
{
if (null === $value) {
if ($isHeuristicallyCacheable) {
/*
* See https://datatracker.ietf.org/doc/html/rfc7234#section-4.2.2
* This particular response does not require maximum lifetime; heuristics might be applied.
* Other responses, however, might have more stringent requirements on maximum lifetime.
* So, return early here so that the final response can have the more limiting value set.
*/
return;
}
$this->ageDirectives[$directive] = false;
}
if (false !== $this->ageDirectives[$directive]) {
$value -= $age;
$this->ageDirectives[$directive] = null !== $this->ageDirectives[$directive] ? min($this->ageDirectives[$directive], $value) : $value;
}
}
}
NFC Pay was founded with a vision to transform the way people handle transactions. Our journey is defined by a commitment to innovation, security, and convenience. We strive to deliver seamless, user-friendly payment solutions that make everyday transactions effortless and secure. Our mission is to empower you to pay with ease and confidence, anytime, anywhere.
Simplifying Payments, One Tap at a Time.
Reinventing Your Wallet for Modern Convenience.
Smart Payments for a Effortless Lifestyle.
Experience the Ease of Tap and Pay.
Innovative Solutions for Your Daily Transactions.
FAQ Section
Frequently Asked Questions About NFC Pay
Here are answers to some common questions about NFC Pay. We aim to provide clear and concise information to help you understand how our platform works and how it can benefit you. If you have any further inquiries, please don’t hesitate to contact our support team.
How do I register for NFC Pay?
Download the app and sign up using your email or phone number, then complete the verification process.
Is my payment information secure?
Yes, we use advanced encryption and security protocols to protect your payment details.
Can I add multiple cards to my NFC Pay wallet?
Absolutely, you can link multiple debit or credit cards to your wallet.
How do I transfer money to another user?
Go to the transfer section, select the recipient, enter the amount, and authorize the transfer.
What should I do if I forget my PIN?
Use the “Forgot PIN” feature in the app to reset it following the provided instructions.
How can I activate my merchant account?
Sign up for a merchant account through the app and follow the setup instructions to start accepting payments.
Can I track my payment status?
Yes, you can view and track your payment status in the account dashboard
In the digital age, privacy concerns have become increasingly paramount, prompting the European Union to enact the General Data Protection Regulation (GDPR) in 2018. Among its many provisions, GDPR sets strict guidelines for the collection and processing of personal data, including the use of cookies on websites. Privacy Policy
