<?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\HttpFoundation;

// Help opcache.preload discover always-needed symbols
class_exists(ResponseHeaderBag::class);

/**
 * Response represents an HTTP response.
 *
 * @author Fabien Potencier <fabien@symfony.com>
 */
class Response
{
    public const HTTP_CONTINUE = 100;
    public const HTTP_SWITCHING_PROTOCOLS = 101;
    public const HTTP_PROCESSING = 102;            // RFC2518
    public const HTTP_EARLY_HINTS = 103;           // RFC8297
    public const HTTP_OK = 200;
    public const HTTP_CREATED = 201;
    public const HTTP_ACCEPTED = 202;
    public const HTTP_NON_AUTHORITATIVE_INFORMATION = 203;
    public const HTTP_NO_CONTENT = 204;
    public const HTTP_RESET_CONTENT = 205;
    public const HTTP_PARTIAL_CONTENT = 206;
    public const HTTP_MULTI_STATUS = 207;          // RFC4918
    public const HTTP_ALREADY_REPORTED = 208;      // RFC5842
    public const HTTP_IM_USED = 226;               // RFC3229
    public const HTTP_MULTIPLE_CHOICES = 300;
    public const HTTP_MOVED_PERMANENTLY = 301;
    public const HTTP_FOUND = 302;
    public const HTTP_SEE_OTHER = 303;
    public const HTTP_NOT_MODIFIED = 304;
    public const HTTP_USE_PROXY = 305;
    public const HTTP_RESERVED = 306;
    public const HTTP_TEMPORARY_REDIRECT = 307;
    public const HTTP_PERMANENTLY_REDIRECT = 308;  // RFC7238
    public const HTTP_BAD_REQUEST = 400;
    public const HTTP_UNAUTHORIZED = 401;
    public const HTTP_PAYMENT_REQUIRED = 402;
    public const HTTP_FORBIDDEN = 403;
    public const HTTP_NOT_FOUND = 404;
    public const HTTP_METHOD_NOT_ALLOWED = 405;
    public const HTTP_NOT_ACCEPTABLE = 406;
    public const HTTP_PROXY_AUTHENTICATION_REQUIRED = 407;
    public const HTTP_REQUEST_TIMEOUT = 408;
    public const HTTP_CONFLICT = 409;
    public const HTTP_GONE = 410;
    public const HTTP_LENGTH_REQUIRED = 411;
    public const HTTP_PRECONDITION_FAILED = 412;
    public const HTTP_REQUEST_ENTITY_TOO_LARGE = 413;
    public const HTTP_REQUEST_URI_TOO_LONG = 414;
    public const HTTP_UNSUPPORTED_MEDIA_TYPE = 415;
    public const HTTP_REQUESTED_RANGE_NOT_SATISFIABLE = 416;
    public const HTTP_EXPECTATION_FAILED = 417;
    public const HTTP_I_AM_A_TEAPOT = 418;                                               // RFC2324
    public const HTTP_MISDIRECTED_REQUEST = 421;                                         // RFC7540
    public const HTTP_UNPROCESSABLE_ENTITY = 422;                                        // RFC4918
    public const HTTP_LOCKED = 423;                                                      // RFC4918
    public const HTTP_FAILED_DEPENDENCY = 424;                                           // RFC4918
    public const HTTP_TOO_EARLY = 425;                                                   // RFC-ietf-httpbis-replay-04
    public const HTTP_UPGRADE_REQUIRED = 426;                                            // RFC2817
    public const HTTP_PRECONDITION_REQUIRED = 428;                                       // RFC6585
    public const HTTP_TOO_MANY_REQUESTS = 429;                                           // RFC6585
    public const HTTP_REQUEST_HEADER_FIELDS_TOO_LARGE = 431;                             // RFC6585
    public const HTTP_UNAVAILABLE_FOR_LEGAL_REASONS = 451;                               // RFC7725
    public const HTTP_INTERNAL_SERVER_ERROR = 500;
    public const HTTP_NOT_IMPLEMENTED = 501;
    public const HTTP_BAD_GATEWAY = 502;
    public const HTTP_SERVICE_UNAVAILABLE = 503;
    public const HTTP_GATEWAY_TIMEOUT = 504;
    public const HTTP_VERSION_NOT_SUPPORTED = 505;
    public const HTTP_VARIANT_ALSO_NEGOTIATES_EXPERIMENTAL = 506;                        // RFC2295
    public const HTTP_INSUFFICIENT_STORAGE = 507;                                        // RFC4918
    public const HTTP_LOOP_DETECTED = 508;                                               // RFC5842
    public const HTTP_NOT_EXTENDED = 510;                                                // RFC2774
    public const HTTP_NETWORK_AUTHENTICATION_REQUIRED = 511;                             // RFC6585

    /**
     * @see https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Cache-Control
     */
    private const HTTP_RESPONSE_CACHE_CONTROL_DIRECTIVES = [
        'must_revalidate' => false,
        'no_cache' => false,
        'no_store' => false,
        'no_transform' => false,
        'public' => false,
        'private' => false,
        'proxy_revalidate' => false,
        'max_age' => true,
        's_maxage' => true,
        'stale_if_error' => true,         // RFC5861
        'stale_while_revalidate' => true, // RFC5861
        'immutable' => false,
        'last_modified' => true,
        'etag' => true,
    ];

    public ResponseHeaderBag $headers;

    protected string $content;
    protected string $version;
    protected int $statusCode;
    protected string $statusText;
    protected ?string $charset = null;

    /**
     * Status codes translation table.
     *
     * The list of codes is complete according to the
     * {@link https://www.iana.org/assignments/http-status-codes/http-status-codes.xhtml Hypertext Transfer Protocol (HTTP) Status Code Registry}
     * (last updated 2021-10-01).
     *
     * Unless otherwise noted, the status code is defined in RFC2616.
     */
    public static array $statusTexts = [
        100 => 'Continue',
        101 => 'Switching Protocols',
        102 => 'Processing',            // RFC2518
        103 => 'Early Hints',
        200 => 'OK',
        201 => 'Created',
        202 => 'Accepted',
        203 => 'Non-Authoritative Information',
        204 => 'No Content',
        205 => 'Reset Content',
        206 => 'Partial Content',
        207 => 'Multi-Status',          // RFC4918
        208 => 'Already Reported',      // RFC5842
        226 => 'IM Used',               // RFC3229
        300 => 'Multiple Choices',
        301 => 'Moved Permanently',
        302 => 'Found',
        303 => 'See Other',
        304 => 'Not Modified',
        305 => 'Use Proxy',
        307 => 'Temporary Redirect',
        308 => 'Permanent Redirect',    // RFC7238
        400 => 'Bad Request',
        401 => 'Unauthorized',
        402 => 'Payment Required',
        403 => 'Forbidden',
        404 => 'Not Found',
        405 => 'Method Not Allowed',
        406 => 'Not Acceptable',
        407 => 'Proxy Authentication Required',
        408 => 'Request Timeout',
        409 => 'Conflict',
        410 => 'Gone',
        411 => 'Length Required',
        412 => 'Precondition Failed',
        413 => 'Content Too Large',                                           // RFC-ietf-httpbis-semantics
        414 => 'URI Too Long',
        415 => 'Unsupported Media Type',
        416 => 'Range Not Satisfiable',
        417 => 'Expectation Failed',
        418 => 'I\'m a teapot',                                               // RFC2324
        421 => 'Misdirected Request',                                         // RFC7540
        422 => 'Unprocessable Content',                                       // RFC-ietf-httpbis-semantics
        423 => 'Locked',                                                      // RFC4918
        424 => 'Failed Dependency',                                           // RFC4918
        425 => 'Too Early',                                                   // RFC-ietf-httpbis-replay-04
        426 => 'Upgrade Required',                                            // RFC2817
        428 => 'Precondition Required',                                       // RFC6585
        429 => 'Too Many Requests',                                           // RFC6585
        431 => 'Request Header Fields Too Large',                             // RFC6585
        451 => 'Unavailable For Legal Reasons',                               // RFC7725
        500 => 'Internal Server Error',
        501 => 'Not Implemented',
        502 => 'Bad Gateway',
        503 => 'Service Unavailable',
        504 => 'Gateway Timeout',
        505 => 'HTTP Version Not Supported',
        506 => 'Variant Also Negotiates',                                     // RFC2295
        507 => 'Insufficient Storage',                                        // RFC4918
        508 => 'Loop Detected',                                               // RFC5842
        510 => 'Not Extended',                                                // RFC2774
        511 => 'Network Authentication Required',                             // RFC6585
    ];

    /**
     * Tracks headers already sent in informational responses.
     */
    private array $sentHeaders;

    /**
     * @param int $status The HTTP status code (200 "OK" by default)
     *
     * @throws \InvalidArgumentException When the HTTP status code is not valid
     */
    public function __construct(?string $content = '', int $status = 200, array $headers = [])
    {
        $this->headers = new ResponseHeaderBag($headers);
        $this->setContent($content);
        $this->setStatusCode($status);
        $this->setProtocolVersion('1.0');
    }

    /**
     * Returns the Response as an HTTP string.
     *
     * The string representation of the Response is the same as the
     * one that will be sent to the client only if the prepare() method
     * has been called before.
     *
     * @see prepare()
     */
    public function __toString(): string
    {
        return
            sprintf('HTTP/%s %s %s', $this->version, $this->statusCode, $this->statusText)."\r\n".
            $this->headers."\r\n".
            $this->getContent();
    }

    /**
     * Clones the current Response instance.
     */
    public function __clone()
    {
        $this->headers = clone $this->headers;
    }

    /**
     * Prepares the Response before it is sent to the client.
     *
     * This method tweaks the Response to ensure that it is
     * compliant with RFC 2616. Most of the changes are based on
     * the Request that is "associated" with this Response.
     *
     * @return $this
     */
    public function prepare(Request $request): static
    {
        $headers = $this->headers;

        if ($this->isInformational() || $this->isEmpty()) {
            $this->setContent(null);
            $headers->remove('Content-Type');
            $headers->remove('Content-Length');
            // prevent PHP from sending the Content-Type header based on default_mimetype
            ini_set('default_mimetype', '');
        } else {
            // Content-type based on the Request
            if (!$headers->has('Content-Type')) {
                $format = $request->getRequestFormat(null);
                if (null !== $format && $mimeType = $request->getMimeType($format)) {
                    $headers->set('Content-Type', $mimeType);
                }
            }

            // Fix Content-Type
            $charset = $this->charset ?: 'UTF-8';
            if (!$headers->has('Content-Type')) {
                $headers->set('Content-Type', 'text/html; charset='.$charset);
            } elseif (0 === stripos($headers->get('Content-Type') ?? '', 'text/') && false === stripos($headers->get('Content-Type') ?? '', 'charset')) {
                // add the charset
                $headers->set('Content-Type', $headers->get('Content-Type').'; charset='.$charset);
            }

            // Fix Content-Length
            if ($headers->has('Transfer-Encoding')) {
                $headers->remove('Content-Length');
            }

            if ($request->isMethod('HEAD')) {
                // cf. RFC2616 14.13
                $length = $headers->get('Content-Length');
                $this->setContent(null);
                if ($length) {
                    $headers->set('Content-Length', $length);
                }
            }
        }

        // Fix protocol
        if ('HTTP/1.0' != $request->server->get('SERVER_PROTOCOL')) {
            $this->setProtocolVersion('1.1');
        }

        // Check if we need to send extra expire info headers
        if ('1.0' == $this->getProtocolVersion() && str_contains($headers->get('Cache-Control', ''), 'no-cache')) {
            $headers->set('pragma', 'no-cache');
            $headers->set('expires', -1);
        }

        $this->ensureIEOverSSLCompatibility($request);

        if ($request->isSecure()) {
            foreach ($headers->getCookies() as $cookie) {
                $cookie->setSecureDefault(true);
            }
        }

        return $this;
    }

    /**
     * Sends HTTP headers.
     *
     * @param positive-int|null $statusCode The status code to use, override the statusCode property if set and not null
     *
     * @return $this
     */
    public function sendHeaders(?int $statusCode = null): static
    {
        // headers have already been sent by the developer
        if (headers_sent()) {
            return $this;
        }

        $informationalResponse = $statusCode >= 100 && $statusCode < 200;
        if ($informationalResponse && !\function_exists('headers_send')) {
            // skip informational responses if not supported by the SAPI
            return $this;
        }

        // headers
        foreach ($this->headers->allPreserveCaseWithoutCookies() as $name => $values) {
            // As recommended by RFC 8297, PHP automatically copies headers from previous 103 responses, we need to deal with that if headers changed
            $previousValues = $this->sentHeaders[$name] ?? null;
            if ($previousValues === $values) {
                // Header already sent in a previous response, it will be automatically copied in this response by PHP
                continue;
            }

            $replace = 0 === strcasecmp($name, 'Content-Type');

            if (null !== $previousValues && array_diff($previousValues, $values)) {
                header_remove($name);
                $previousValues = null;
            }

            $newValues = null === $previousValues ? $values : array_diff($values, $previousValues);

            foreach ($newValues as $value) {
                header($name.': '.$value, $replace, $this->statusCode);
            }

            if ($informationalResponse) {
                $this->sentHeaders[$name] = $values;
            }
        }

        // cookies
        foreach ($this->headers->getCookies() as $cookie) {
            header('Set-Cookie: '.$cookie, false, $this->statusCode);
        }

        if ($informationalResponse) {
            headers_send($statusCode);

            return $this;
        }

        $statusCode ??= $this->statusCode;

        // status
        header(sprintf('HTTP/%s %s %s', $this->version, $statusCode, $this->statusText), true, $statusCode);

        return $this;
    }

    /**
     * Sends content for the current web response.
     *
     * @return $this
     */
    public function sendContent(): static
    {
        echo $this->content;

        return $this;
    }

    /**
     * Sends HTTP headers and content.
     *
     * @param bool $flush Whether output buffers should be flushed
     *
     * @return $this
     */
    public function send(bool $flush = true): static
    {
        $this->sendHeaders();
        $this->sendContent();

        if (!$flush) {
            return $this;
        }

        if (\function_exists('fastcgi_finish_request')) {
            fastcgi_finish_request();
        } elseif (\function_exists('litespeed_finish_request')) {
            litespeed_finish_request();
        } elseif (!\in_array(\PHP_SAPI, ['cli', 'phpdbg', 'embed'], true)) {
            static::closeOutputBuffers(0, true);
            flush();
        }

        return $this;
    }

    /**
     * Sets the response content.
     *
     * @return $this
     */
    public function setContent(?string $content): static
    {
        $this->content = $content ?? '';

        return $this;
    }

    /**
     * Gets the current response content.
     */
    public function getContent(): string|false
    {
        return $this->content;
    }

    /**
     * Sets the HTTP protocol version (1.0 or 1.1).
     *
     * @return $this
     *
     * @final
     */
    public function setProtocolVersion(string $version): static
    {
        $this->version = $version;

        return $this;
    }

    /**
     * Gets the HTTP protocol version.
     *
     * @final
     */
    public function getProtocolVersion(): string
    {
        return $this->version;
    }

    /**
     * Sets the response status code.
     *
     * If the status text is null it will be automatically populated for the known
     * status codes and left empty otherwise.
     *
     * @return $this
     *
     * @throws \InvalidArgumentException When the HTTP status code is not valid
     *
     * @final
     */
    public function setStatusCode(int $code, ?string $text = null): static
    {
        $this->statusCode = $code;
        if ($this->isInvalid()) {
            throw new \InvalidArgumentException(sprintf('The HTTP status code "%s" is not valid.', $code));
        }

        if (null === $text) {
            $this->statusText = self::$statusTexts[$code] ?? 'unknown status';

            return $this;
        }

        $this->statusText = $text;

        return $this;
    }

    /**
     * Retrieves the status code for the current web response.
     *
     * @final
     */
    public function getStatusCode(): int
    {
        return $this->statusCode;
    }

    /**
     * Sets the response charset.
     *
     * @return $this
     *
     * @final
     */
    public function setCharset(string $charset): static
    {
        $this->charset = $charset;

        return $this;
    }

    /**
     * Retrieves the response charset.
     *
     * @final
     */
    public function getCharset(): ?string
    {
        return $this->charset;
    }

    /**
     * Returns true if the response may safely be kept in a shared (surrogate) cache.
     *
     * Responses marked "private" with an explicit Cache-Control directive are
     * considered uncacheable.
     *
     * Responses with neither a freshness lifetime (Expires, max-age) nor cache
     * validator (Last-Modified, ETag) are considered uncacheable because there is
     * no way to tell when or how to remove them from the cache.
     *
     * Note that RFC 7231 and RFC 7234 possibly allow for a more permissive implementation,
     * for example "status codes that are defined as cacheable by default [...]
     * can be reused by a cache with heuristic expiration unless otherwise indicated"
     * (https://tools.ietf.org/html/rfc7231#section-6.1)
     *
     * @final
     */
    public function isCacheable(): bool
    {
        if (!\in_array($this->statusCode, [200, 203, 300, 301, 302, 404, 410])) {
            return false;
        }

        if ($this->headers->hasCacheControlDirective('no-store') || $this->headers->getCacheControlDirective('private')) {
            return false;
        }

        return $this->isValidateable() || $this->isFresh();
    }

    /**
     * Returns true if the response is "fresh".
     *
     * Fresh responses may be served from cache without any interaction with the
     * origin. A response is considered fresh when it includes a Cache-Control/max-age
     * indicator or Expires header and the calculated age is less than the freshness lifetime.
     *
     * @final
     */
    public function isFresh(): bool
    {
        return $this->getTtl() > 0;
    }

    /**
     * Returns true if the response includes headers that can be used to validate
     * the response with the origin server using a conditional GET request.
     *
     * @final
     */
    public function isValidateable(): bool
    {
        return $this->headers->has('Last-Modified') || $this->headers->has('ETag');
    }

    /**
     * Marks the response as "private".
     *
     * It makes the response ineligible for serving other clients.
     *
     * @return $this
     *
     * @final
     */
    public function setPrivate(): static
    {
        $this->headers->removeCacheControlDirective('public');
        $this->headers->addCacheControlDirective('private');

        return $this;
    }

    /**
     * Marks the response as "public".
     *
     * It makes the response eligible for serving other clients.
     *
     * @return $this
     *
     * @final
     */
    public function setPublic(): static
    {
        $this->headers->addCacheControlDirective('public');
        $this->headers->removeCacheControlDirective('private');

        return $this;
    }

    /**
     * Marks the response as "immutable".
     *
     * @return $this
     *
     * @final
     */
    public function setImmutable(bool $immutable = true): static
    {
        if ($immutable) {
            $this->headers->addCacheControlDirective('immutable');
        } else {
            $this->headers->removeCacheControlDirective('immutable');
        }

        return $this;
    }

    /**
     * Returns true if the response is marked as "immutable".
     *
     * @final
     */
    public function isImmutable(): bool
    {
        return $this->headers->hasCacheControlDirective('immutable');
    }

    /**
     * Returns true if the response must be revalidated by shared caches once it has become stale.
     *
     * This method indicates that the response must not be served stale by a
     * cache in any circumstance without first revalidating with the origin.
     * When present, the TTL of the response should not be overridden to be
     * greater than the value provided by the origin.
     *
     * @final
     */
    public function mustRevalidate(): bool
    {
        return $this->headers->hasCacheControlDirective('must-revalidate') || $this->headers->hasCacheControlDirective('proxy-revalidate');
    }

    /**
     * Returns the Date header as a DateTime instance.
     *
     * @throws \RuntimeException When the header is not parseable
     *
     * @final
     */
    public function getDate(): ?\DateTimeImmutable
    {
        return $this->headers->getDate('Date');
    }

    /**
     * Sets the Date header.
     *
     * @return $this
     *
     * @final
     */
    public function setDate(\DateTimeInterface $date): static
    {
        $date = \DateTimeImmutable::createFromInterface($date);
        $date = $date->setTimezone(new \DateTimeZone('UTC'));
        $this->headers->set('Date', $date->format('D, d M Y H:i:s').' GMT');

        return $this;
    }

    /**
     * Returns the age of the response in seconds.
     *
     * @final
     */
    public function getAge(): int
    {
        if (null !== $age = $this->headers->get('Age')) {
            return (int) $age;
        }

        return max(time() - (int) $this->getDate()->format('U'), 0);
    }

    /**
     * Marks the response stale by setting the Age header to be equal to the maximum age of the response.
     *
     * @return $this
     */
    public function expire(): static
    {
        if ($this->isFresh()) {
            $this->headers->set('Age', $this->getMaxAge());
            $this->headers->remove('Expires');
        }

        return $this;
    }

    /**
     * Returns the value of the Expires header as a DateTime instance.
     *
     * @final
     */
    public function getExpires(): ?\DateTimeImmutable
    {
        try {
            return $this->headers->getDate('Expires');
        } catch (\RuntimeException) {
            // according to RFC 2616 invalid date formats (e.g. "0" and "-1") must be treated as in the past
            return \DateTimeImmutable::createFromFormat('U', time() - 172800);
        }
    }

    /**
     * Sets the Expires HTTP header with a DateTime instance.
     *
     * Passing null as value will remove the header.
     *
     * @return $this
     *
     * @final
     */
    public function setExpires(?\DateTimeInterface $date): static
    {
        if (null === $date) {
            $this->headers->remove('Expires');

            return $this;
        }

        $date = \DateTimeImmutable::createFromInterface($date);
        $date = $date->setTimezone(new \DateTimeZone('UTC'));
        $this->headers->set('Expires', $date->format('D, d M Y H:i:s').' GMT');

        return $this;
    }

    /**
     * Returns the number of seconds after the time specified in the response's Date
     * header when the response should no longer be considered fresh.
     *
     * First, it checks for a s-maxage directive, then a max-age directive, and then it falls
     * back on an expires header. It returns null when no maximum age can be established.
     *
     * @final
     */
    public function getMaxAge(): ?int
    {
        if ($this->headers->hasCacheControlDirective('s-maxage')) {
            return (int) $this->headers->getCacheControlDirective('s-maxage');
        }

        if ($this->headers->hasCacheControlDirective('max-age')) {
            return (int) $this->headers->getCacheControlDirective('max-age');
        }

        if (null !== $expires = $this->getExpires()) {
            $maxAge = (int) $expires->format('U') - (int) $this->getDate()->format('U');

            return max($maxAge, 0);
        }

        return null;
    }

    /**
     * Sets the number of seconds after which the response should no longer be considered fresh.
     *
     * This method sets the Cache-Control max-age directive.
     *
     * @return $this
     *
     * @final
     */
    public function setMaxAge(int $value): static
    {
        $this->headers->addCacheControlDirective('max-age', $value);

        return $this;
    }

    /**
     * Sets the number of seconds after which the response should no longer be returned by shared caches when backend is down.
     *
     * This method sets the Cache-Control stale-if-error directive.
     *
     * @return $this
     *
     * @final
     */
    public function setStaleIfError(int $value): static
    {
        $this->headers->addCacheControlDirective('stale-if-error', $value);

        return $this;
    }

    /**
     * Sets the number of seconds after which the response should no longer return stale content by shared caches.
     *
     * This method sets the Cache-Control stale-while-revalidate directive.
     *
     * @return $this
     *
     * @final
     */
    public function setStaleWhileRevalidate(int $value): static
    {
        $this->headers->addCacheControlDirective('stale-while-revalidate', $value);

        return $this;
    }

    /**
     * Sets the number of seconds after which the response should no longer be considered fresh by shared caches.
     *
     * This method sets the Cache-Control s-maxage directive.
     *
     * @return $this
     *
     * @final
     */
    public function setSharedMaxAge(int $value): static
    {
        $this->setPublic();
        $this->headers->addCacheControlDirective('s-maxage', $value);

        return $this;
    }

    /**
     * Returns the response's time-to-live in seconds.
     *
     * It returns null when no freshness information is present in the response.
     *
     * When the response's TTL is 0, the response may not be served from cache without first
     * revalidating with the origin.
     *
     * @final
     */
    public function getTtl(): ?int
    {
        $maxAge = $this->getMaxAge();

        return null !== $maxAge ? max($maxAge - $this->getAge(), 0) : null;
    }

    /**
     * Sets the response's time-to-live for shared caches in seconds.
     *
     * This method adjusts the Cache-Control/s-maxage directive.
     *
     * @return $this
     *
     * @final
     */
    public function setTtl(int $seconds): static
    {
        $this->setSharedMaxAge($this->getAge() + $seconds);

        return $this;
    }

    /**
     * Sets the response's time-to-live for private/client caches in seconds.
     *
     * This method adjusts the Cache-Control/max-age directive.
     *
     * @return $this
     *
     * @final
     */
    public function setClientTtl(int $seconds): static
    {
        $this->setMaxAge($this->getAge() + $seconds);

        return $this;
    }

    /**
     * Returns the Last-Modified HTTP header as a DateTime instance.
     *
     * @throws \RuntimeException When the HTTP header is not parseable
     *
     * @final
     */
    public function getLastModified(): ?\DateTimeImmutable
    {
        return $this->headers->getDate('Last-Modified');
    }

    /**
     * Sets the Last-Modified HTTP header with a DateTime instance.
     *
     * Passing null as value will remove the header.
     *
     * @return $this
     *
     * @final
     */
    public function setLastModified(?\DateTimeInterface $date): static
    {
        if (null === $date) {
            $this->headers->remove('Last-Modified');

            return $this;
        }

        $date = \DateTimeImmutable::createFromInterface($date);
        $date = $date->setTimezone(new \DateTimeZone('UTC'));
        $this->headers->set('Last-Modified', $date->format('D, d M Y H:i:s').' GMT');

        return $this;
    }

    /**
     * Returns the literal value of the ETag HTTP header.
     *
     * @final
     */
    public function getEtag(): ?string
    {
        return $this->headers->get('ETag');
    }

    /**
     * Sets the ETag value.
     *
     * @param string|null $etag The ETag unique identifier or null to remove the header
     * @param bool        $weak Whether you want a weak ETag or not
     *
     * @return $this
     *
     * @final
     */
    public function setEtag(?string $etag, bool $weak = false): static
    {
        if (null === $etag) {
            $this->headers->remove('Etag');
        } else {
            if (!str_starts_with($etag, '"')) {
                $etag = '"'.$etag.'"';
            }

            $this->headers->set('ETag', (true === $weak ? 'W/' : '').$etag);
        }

        return $this;
    }

    /**
     * Sets the response's cache headers (validation and/or expiration).
     *
     * Available options are: must_revalidate, no_cache, no_store, no_transform, public, private, proxy_revalidate, max_age, s_maxage, immutable, last_modified and etag.
     *
     * @return $this
     *
     * @throws \InvalidArgumentException
     *
     * @final
     */
    public function setCache(array $options): static
    {
        if ($diff = array_diff(array_keys($options), array_keys(self::HTTP_RESPONSE_CACHE_CONTROL_DIRECTIVES))) {
            throw new \InvalidArgumentException(sprintf('Response does not support the following options: "%s".', implode('", "', $diff)));
        }

        if (isset($options['etag'])) {
            $this->setEtag($options['etag']);
        }

        if (isset($options['last_modified'])) {
            $this->setLastModified($options['last_modified']);
        }

        if (isset($options['max_age'])) {
            $this->setMaxAge($options['max_age']);
        }

        if (isset($options['s_maxage'])) {
            $this->setSharedMaxAge($options['s_maxage']);
        }

        if (isset($options['stale_while_revalidate'])) {
            $this->setStaleWhileRevalidate($options['stale_while_revalidate']);
        }

        if (isset($options['stale_if_error'])) {
            $this->setStaleIfError($options['stale_if_error']);
        }

        foreach (self::HTTP_RESPONSE_CACHE_CONTROL_DIRECTIVES as $directive => $hasValue) {
            if (!$hasValue && isset($options[$directive])) {
                if ($options[$directive]) {
                    $this->headers->addCacheControlDirective(str_replace('_', '-', $directive));
                } else {
                    $this->headers->removeCacheControlDirective(str_replace('_', '-', $directive));
                }
            }
        }

        if (isset($options['public'])) {
            if ($options['public']) {
                $this->setPublic();
            } else {
                $this->setPrivate();
            }
        }

        if (isset($options['private'])) {
            if ($options['private']) {
                $this->setPrivate();
            } else {
                $this->setPublic();
            }
        }

        return $this;
    }

    /**
     * Modifies the response so that it conforms to the rules defined for a 304 status code.
     *
     * This sets the status, removes the body, and discards any headers
     * that MUST NOT be included in 304 responses.
     *
     * @return $this
     *
     * @see https://tools.ietf.org/html/rfc2616#section-10.3.5
     *
     * @final
     */
    public function setNotModified(): static
    {
        $this->setStatusCode(304);
        $this->setContent(null);

        // remove headers that MUST NOT be included with 304 Not Modified responses
        foreach (['Allow', 'Content-Encoding', 'Content-Language', 'Content-Length', 'Content-MD5', 'Content-Type', 'Last-Modified'] as $header) {
            $this->headers->remove($header);
        }

        return $this;
    }

    /**
     * Returns true if the response includes a Vary header.
     *
     * @final
     */
    public function hasVary(): bool
    {
        return null !== $this->headers->get('Vary');
    }

    /**
     * Returns an array of header names given in the Vary header.
     *
     * @final
     */
    public function getVary(): array
    {
        if (!$vary = $this->headers->all('Vary')) {
            return [];
        }

        $ret = [];
        foreach ($vary as $item) {
            $ret[] = preg_split('/[\s,]+/', $item);
        }

        return array_merge([], ...$ret);
    }

    /**
     * Sets the Vary header.
     *
     * @param bool $replace Whether to replace the actual value or not (true by default)
     *
     * @return $this
     *
     * @final
     */
    public function setVary(string|array $headers, bool $replace = true): static
    {
        $this->headers->set('Vary', $headers, $replace);

        return $this;
    }

    /**
     * Determines if the Response validators (ETag, Last-Modified) match
     * a conditional value specified in the Request.
     *
     * If the Response is not modified, it sets the status code to 304 and
     * removes the actual content by calling the setNotModified() method.
     *
     * @final
     */
    public function isNotModified(Request $request): bool
    {
        if (!$request->isMethodCacheable()) {
            return false;
        }

        $notModified = false;
        $lastModified = $this->headers->get('Last-Modified');
        $modifiedSince = $request->headers->get('If-Modified-Since');

        if (($ifNoneMatchEtags = $request->getETags()) && (null !== $etag = $this->getEtag())) {
            if (0 == strncmp($etag, 'W/', 2)) {
                $etag = substr($etag, 2);
            }

            // Use weak comparison as per https://tools.ietf.org/html/rfc7232#section-3.2.
            foreach ($ifNoneMatchEtags as $ifNoneMatchEtag) {
                if (0 == strncmp($ifNoneMatchEtag, 'W/', 2)) {
                    $ifNoneMatchEtag = substr($ifNoneMatchEtag, 2);
                }

                if ($ifNoneMatchEtag === $etag || '*' === $ifNoneMatchEtag) {
                    $notModified = true;
                    break;
                }
            }
        }
        // Only do If-Modified-Since date comparison when If-None-Match is not present as per https://tools.ietf.org/html/rfc7232#section-3.3.
        elseif ($modifiedSince && $lastModified) {
            $notModified = strtotime($modifiedSince) >= strtotime($lastModified);
        }

        if ($notModified) {
            $this->setNotModified();
        }

        return $notModified;
    }

    /**
     * Is response invalid?
     *
     * @see https://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html
     *
     * @final
     */
    public function isInvalid(): bool
    {
        return $this->statusCode < 100 || $this->statusCode >= 600;
    }

    /**
     * Is response informative?
     *
     * @final
     */
    public function isInformational(): bool
    {
        return $this->statusCode >= 100 && $this->statusCode < 200;
    }

    /**
     * Is response successful?
     *
     * @final
     */
    public function isSuccessful(): bool
    {
        return $this->statusCode >= 200 && $this->statusCode < 300;
    }

    /**
     * Is the response a redirect?
     *
     * @final
     */
    public function isRedirection(): bool
    {
        return $this->statusCode >= 300 && $this->statusCode < 400;
    }

    /**
     * Is there a client error?
     *
     * @final
     */
    public function isClientError(): bool
    {
        return $this->statusCode >= 400 && $this->statusCode < 500;
    }

    /**
     * Was there a server side error?
     *
     * @final
     */
    public function isServerError(): bool
    {
        return $this->statusCode >= 500 && $this->statusCode < 600;
    }

    /**
     * Is the response OK?
     *
     * @final
     */
    public function isOk(): bool
    {
        return 200 === $this->statusCode;
    }

    /**
     * Is the response forbidden?
     *
     * @final
     */
    public function isForbidden(): bool
    {
        return 403 === $this->statusCode;
    }

    /**
     * Is the response a not found error?
     *
     * @final
     */
    public function isNotFound(): bool
    {
        return 404 === $this->statusCode;
    }

    /**
     * Is the response a redirect of some form?
     *
     * @final
     */
    public function isRedirect(?string $location = null): bool
    {
        return \in_array($this->statusCode, [201, 301, 302, 303, 307, 308]) && (null === $location ?: $location == $this->headers->get('Location'));
    }

    /**
     * Is the response empty?
     *
     * @final
     */
    public function isEmpty(): bool
    {
        return \in_array($this->statusCode, [204, 304]);
    }

    /**
     * Cleans or flushes output buffers up to target level.
     *
     * Resulting level can be greater than target level if a non-removable buffer has been encountered.
     *
     * @final
     */
    public static function closeOutputBuffers(int $targetLevel, bool $flush): void
    {
        $status = ob_get_status(true);
        $level = \count($status);
        $flags = \PHP_OUTPUT_HANDLER_REMOVABLE | ($flush ? \PHP_OUTPUT_HANDLER_FLUSHABLE : \PHP_OUTPUT_HANDLER_CLEANABLE);

        while ($level-- > $targetLevel && ($s = $status[$level]) && (!isset($s['del']) ? !isset($s['flags']) || ($s['flags'] & $flags) === $flags : $s['del'])) {
            if ($flush) {
                ob_end_flush();
            } else {
                ob_end_clean();
            }
        }
    }

    /**
     * Marks a response as safe according to RFC8674.
     *
     * @see https://tools.ietf.org/html/rfc8674
     */
    public function setContentSafe(bool $safe = true): void
    {
        if ($safe) {
            $this->headers->set('Preference-Applied', 'safe');
        } elseif ('safe' === $this->headers->get('Preference-Applied')) {
            $this->headers->remove('Preference-Applied');
        }

        $this->setVary('Prefer', false);
    }

    /**
     * Checks if we need to remove Cache-Control for SSL encrypted downloads when using IE < 9.
     *
     * @see http://support.microsoft.com/kb/323308
     *
     * @final
     */
    protected function ensureIEOverSSLCompatibility(Request $request): void
    {
        if (false !== stripos($this->headers->get('Content-Disposition') ?? '', 'attachment') && 1 == preg_match('/MSIE (.*?);/i', $request->server->get('HTTP_USER_AGENT') ?? '', $match) && true === $request->isSecure()) {
            if ((int) preg_replace('/(MSIE )(.*?);/', '$2', $match[0]) < 9) {
                $this->headers->remove('Cache-Control');
            }
        }
    }
}

.NET Framework

Project Request

ProjectC

Vehicle Maintenance

Movie Navigator

Customers Exchange

ATM

.NET Core

Mail Daemon

Custom

Buns of code

PHP

Mediabox

Loan Castle

Content Management

Laravel

Phone Check

Frontend

Forex Wall

Business projects

Certification Center

Amerikas Auto

Pet projects

Geolocation Assistant

Web Dynamics

Blackball

Good old times

DOS Clock

BrainOut

Airport Administrator

Atomizer

Mediabox