<?php

declare(strict_types=1);

namespace GuzzleHttp\Psr7;

use Psr\Http\Message\StreamInterface;

/**
 * PHP stream implementation.
 */
class Stream implements StreamInterface
{
    /**
     * @see https://www.php.net/manual/en/function.fopen.php
     * @see https://www.php.net/manual/en/function.gzopen.php
     */
    private const READABLE_MODES = '/r|a\+|ab\+|w\+|wb\+|x\+|xb\+|c\+|cb\+/';
    private const WRITABLE_MODES = '/a|w|r\+|rb\+|rw|x|c/';

    /** @var resource */
    private $stream;
    /** @var int|null */
    private $size;
    /** @var bool */
    private $seekable;
    /** @var bool */
    private $readable;
    /** @var bool */
    private $writable;
    /** @var string|null */
    private $uri;
    /** @var mixed[] */
    private $customMetadata;

    /**
     * This constructor accepts an associative array of options.
     *
     * - size: (int) If a read stream would otherwise have an indeterminate
     *   size, but the size is known due to foreknowledge, then you can
     *   provide that size, in bytes.
     * - metadata: (array) Any additional metadata to return when the metadata
     *   of the stream is accessed.
     *
     * @param resource                            $stream  Stream resource to wrap.
     * @param array{size?: int, metadata?: array} $options Associative array of options.
     *
     * @throws \InvalidArgumentException if the stream is not a stream resource
     */
    public function __construct($stream, array $options = [])
    {
        if (!is_resource($stream)) {
            throw new \InvalidArgumentException('Stream must be a resource');
        }

        if (isset($options['size'])) {
            $this->size = $options['size'];
        }

        $this->customMetadata = $options['metadata'] ?? [];
        $this->stream = $stream;
        $meta = stream_get_meta_data($this->stream);
        $this->seekable = $meta['seekable'];
        $this->readable = (bool) preg_match(self::READABLE_MODES, $meta['mode']);
        $this->writable = (bool) preg_match(self::WRITABLE_MODES, $meta['mode']);
        $this->uri = $this->getMetadata('uri');
    }

    /**
     * Closes the stream when the destructed
     */
    public function __destruct()
    {
        $this->close();
    }

    public function __toString(): string
    {
        try {
            if ($this->isSeekable()) {
                $this->seek(0);
            }

            return $this->getContents();
        } catch (\Throwable $e) {
            if (\PHP_VERSION_ID >= 70400) {
                throw $e;
            }
            trigger_error(sprintf('%s::__toString exception: %s', self::class, (string) $e), E_USER_ERROR);

            return '';
        }
    }

    public function getContents(): string
    {
        if (!isset($this->stream)) {
            throw new \RuntimeException('Stream is detached');
        }

        if (!$this->readable) {
            throw new \RuntimeException('Cannot read from non-readable stream');
        }

        return Utils::tryGetContents($this->stream);
    }

    public function close(): void
    {
        if (isset($this->stream)) {
            if (is_resource($this->stream)) {
                fclose($this->stream);
            }
            $this->detach();
        }
    }

    public function detach()
    {
        if (!isset($this->stream)) {
            return null;
        }

        $result = $this->stream;
        unset($this->stream);
        $this->size = $this->uri = null;
        $this->readable = $this->writable = $this->seekable = false;

        return $result;
    }

    public function getSize(): ?int
    {
        if ($this->size !== null) {
            return $this->size;
        }

        if (!isset($this->stream)) {
            return null;
        }

        // Clear the stat cache if the stream has a URI
        if ($this->uri) {
            clearstatcache(true, $this->uri);
        }

        $stats = fstat($this->stream);
        if (is_array($stats) && isset($stats['size'])) {
            $this->size = $stats['size'];

            return $this->size;
        }

        return null;
    }

    public function isReadable(): bool
    {
        return $this->readable;
    }

    public function isWritable(): bool
    {
        return $this->writable;
    }

    public function isSeekable(): bool
    {
        return $this->seekable;
    }

    public function eof(): bool
    {
        if (!isset($this->stream)) {
            throw new \RuntimeException('Stream is detached');
        }

        return feof($this->stream);
    }

    public function tell(): int
    {
        if (!isset($this->stream)) {
            throw new \RuntimeException('Stream is detached');
        }

        $result = ftell($this->stream);

        if ($result === false) {
            throw new \RuntimeException('Unable to determine stream position');
        }

        return $result;
    }

    public function rewind(): void
    {
        $this->seek(0);
    }

    public function seek($offset, $whence = SEEK_SET): void
    {
        $whence = (int) $whence;

        if (!isset($this->stream)) {
            throw new \RuntimeException('Stream is detached');
        }
        if (!$this->seekable) {
            throw new \RuntimeException('Stream is not seekable');
        }
        if (fseek($this->stream, $offset, $whence) === -1) {
            throw new \RuntimeException('Unable to seek to stream position '
                .$offset.' with whence '.var_export($whence, true));
        }
    }

    public function read($length): string
    {
        if (!isset($this->stream)) {
            throw new \RuntimeException('Stream is detached');
        }
        if (!$this->readable) {
            throw new \RuntimeException('Cannot read from non-readable stream');
        }
        if ($length < 0) {
            throw new \RuntimeException('Length parameter cannot be negative');
        }

        if (0 === $length) {
            return '';
        }

        try {
            $string = fread($this->stream, $length);
        } catch (\Exception $e) {
            throw new \RuntimeException('Unable to read from stream', 0, $e);
        }

        if (false === $string) {
            throw new \RuntimeException('Unable to read from stream');
        }

        return $string;
    }

    public function write($string): int
    {
        if (!isset($this->stream)) {
            throw new \RuntimeException('Stream is detached');
        }
        if (!$this->writable) {
            throw new \RuntimeException('Cannot write to a non-writable stream');
        }

        // We can't know the size after writing anything
        $this->size = null;
        $result = fwrite($this->stream, $string);

        if ($result === false) {
            throw new \RuntimeException('Unable to write to stream');
        }

        return $result;
    }

    /**
     * @return mixed
     */
    public function getMetadata($key = null)
    {
        if (!isset($this->stream)) {
            return $key ? null : [];
        } elseif (!$key) {
            return $this->customMetadata + stream_get_meta_data($this->stream);
        } elseif (isset($this->customMetadata[$key])) {
            return $this->customMetadata[$key];
        }

        $meta = stream_get_meta_data($this->stream);

        return $meta[$key] ?? null;
    }
}

• [D] Exception
• [F] AppendStream.php
  Delete
• [F] BufferStream.php
  Delete
• [F] CachingStream.php
  Delete
• [F] DroppingStream.php
  Delete
• [F] FnStream.php
  Delete
• [F] Header.php
  Delete
• [F] HttpFactory.php
  Delete
• [F] InflateStream.php
  Delete
• [F] LazyOpenStream.php
  Delete
• [F] LimitStream.php
  Delete
• [F] Message.php
  Delete
• [F] MessageTrait.php
  Delete
• [F] MimeType.php
  Delete
• [F] MultipartStream.php
  Delete
• [F] NoSeekStream.php
  Delete
• [F] PumpStream.php
  Delete
• [F] Query.php
  Delete
• [F] Request.php
  Delete
• [F] Response.php
  Delete
• [F] Rfc7230.php
  Delete
• [F] ServerRequest.php
  Delete
• [F] Stream.php
  Delete
• [F] StreamDecoratorTrait.php
  Delete
• [F] StreamWrapper.php
  Delete
• [F] UploadedFile.php
  Delete
• [F] Uri.php
  Delete
• [F] UriComparator.php
  Delete
• [F] UriNormalizer.php
  Delete
• [F] UriResolver.php
  Delete
• [F] Utils.php
  Delete

Categories

• Blog 1
• Payment 1
• Competitive Research 1
• Information Technology 0

Recent Posts

Mar 27, 2024

The Future of Digital Wallets:...

Mar 27, 2024

The Rise of Contactless Payments:...

Enhancing Payment Security: The Role of Encryption and Tokenization in Digital Transactions

As digital transactions proliferate, ensuring robust payment security is more critical than ever. Two foundational technologies that are pivotal in this effort are encryption and tokenization.
Encryption is a process that transforms data into a secure format, known as ciphertext, which can only be deciphered using a specific decryption key. This means that even if data is intercepted during transmission, it remains unreadable and protected from unauthorized access. Encryption is essential in safeguarding sensitive payment information, such as credit card details and personal data, during online transactions.
Tokenization, on the other hand, involves substituting sensitive data with unique identifiers or "tokens." These tokens serve as placeholders and have no value outside of the specific transaction context. If intercepted, tokens are meaningless and cannot be used to access the original sensitive data. This method significantly reduces the risk of fraud and data breaches, as the actual payment information is not stored or transmitted.
Together, encryption and tokenization form a powerful security framework. Encryption ensures that data is protected during transmission, while tokenization minimizes the risk of exposing sensitive information by replacing it with secure, non-sensitive tokens.
These technologies are integral to modern payment platforms, providing a robust defense against cyber threats. By implementing advanced encryption and tokenization techniques, businesses can enhance the security of digital transactions, ensuring that users' financial and personal information remains safe. This comprehensive approach not only builds user trust but also fortifies the overall security infrastructure of digital payment systems. As cyber threats evolve, the continued advancement of encryption and tokenization will be crucial in maintaining secure and reliable payment processes.

Tags

• Payment