Base62x::_getCompressionFootprintAndSanitizePayload() - Code Metrics - Inspection of "fix: scrutinizer hints" - mauriziofonte/php-base62x - Measure and Improve Code Quality continuously with Scrutinizer

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by Maurizio

created 2021-09-24 08:10 UTC

_getCompressionFootprintAndSanitizePayload() D

↳ Parent: Base62x

Complexity

Conditions	18
Paths	30

Size

Total Lines	55
Code Lines	33

Duplication

Lines	0
Ratio	0 %

Importance

Changes	1
Bugs	0	Features	0

Metric	Value
eloc	33
c	1
b	0
f	0
dl	0
loc	55
rs	4.8666
cc	18
nc	30
nop	1

How to fix Long Method Complexity

<?php

namespace Mfonte\Base62x;

use Exception;
use Mfonte\Base62x\Exception\InvalidParam;
use Mfonte\Base62x\Exception\CryptException;
use Mfonte\Base62x\Exception\DecodeException;
use Mfonte\Base62x\Exception\EncodeException;
use Mfonte\Base62x\Encoding\Base62x as Encoder;
use Mfonte\Base62x\Encryption\Crypt as Crypter;
use Mfonte\Base62x\Compression\Gzip\GzipCompression as GzipCompressor;
use Mfonte\Base62x\Compression\Huffman\HuffmanCoding as HuffmanCompressor;

class Base62x
{
    const MODE_ENCODE = 1;
    const MODE_DECODE = 2;

    protected $_validCompressionAlgorithms = ['gzip' => ['zlib', 'deflate', 'gzip'], 'huffman'];

    /**
     * The mode: encode or decode.
     *
     * @var int
     */
    protected $mode;

    /**
     * The payload to be encoded or decoded.
     *
     * @var mixed
     */
    protected $payload;

    /**
     * Wheter the payload needs to be compressed prior of encoding. Defaults to null.
     *
     * @var string
     */
    protected $compressAlgorithm = null;

    /**
     * The compression mode related to the compression algo. Defaults to null.
     *
     * @var string
     */
    protected $compressEncoding = null;

    /**
     * The encryption method (algorithm) to be used in case of password-protected encoding.
     * This variable *must* be a valid method supported in openssl_get_cipher_methods().
     *
     * @var string
     */
    protected $cryptMethod;

    /**
     * The encrypt/decrypt key (password) to be used to protect/unprotect the encoding.
     *
     * @var mixed
     */
    protected $cryptKey;

    /**
     * Wheter the payload needs to be decompressed after the decoding. Defaults to false.
     *
     * @var string
     */
    protected $decompressAlgorithm = null;

    /**
     * The compression mode related to the compression algo. Defaults to null.
     *
     * @var string
     */
    protected $decompressEncoding = null;

    /**
     * @param mixed $payload
     *
     * @return \Mfonte\Base62x\Base62x
     */
    public static function encode($payload): self
    {
        return new self(self::MODE_ENCODE, $payload);
    }

    /**
     * @param mixed $payload
     *
     * @return \Mfonte\Base62x\Base62x
     */
    public static function decode($payload): self
    {
        return new self(self::MODE_DECODE, $payload);
    }

    public function __construct($mode, $payload)
    {
        $this->mode = $mode;

        if (empty($payload)) {
            throw new InvalidParam('payload', __FUNCTION__, __CLASS__, 'The payload cannot be empty');
        } elseif (\is_resource($payload)) {
            throw new InvalidParam('payload', __FUNCTION__, __CLASS__, 'The payload cannot be a resource');
        } elseif (\is_object($payload)) {
            throw new InvalidParam('payload', __FUNCTION__, __CLASS__, 'The payload cannot be an object');
        } elseif (\is_array($payload)) {
            // if the payload is an array, perform here and now the translation to a serialized string
            $payload = serialize($payload);
        }

        $this->payload = $payload;
    }

    /**
     * Sets the compression type and encoding.
     *
     * @param string $algo     A valid compression algorithm as seen on $_validCompressionAlgorithms
     * @param string $encoding A valid compression encoding as seen on $_validCompressionAlgorithms
     *
     * @return \Mfonte\Base62x\Base62x
     */
    public function compress($algo = 'gzip', $encoding = 'gzip'): self
    {
        // sanity check for bad $algo
        if (
            !\array_key_exists($algo, $this->_validCompressionAlgorithms) &&
            !\in_array($algo, $this->_validCompressionAlgorithms, true)
        ) {
            throw new InvalidParam('algo', __FUNCTION__, __CLASS__);
        }

        // sanity check for bad $encoding
        if (
            \array_key_exists($algo, $this->_validCompressionAlgorithms) &&
            \is_array($this->_validCompressionAlgorithms[$algo]) &&
            !\in_array($encoding, $this->_validCompressionAlgorithms[$algo], true)
        ) {
            throw new InvalidParam('encoding', __FUNCTION__, __CLASS__);
        }

        // make sure we nullify the $encoding if we don't have one
        if (
            !\array_key_exists($algo, $this->_validCompressionAlgorithms) ||
            !\is_array($this->_validCompressionAlgorithms[$algo])
        ) {
            $encoding = null;
        }

        $this->compressAlgorithm = $algo;
        $this->compressEncoding = $encoding;

        return $this;
    }

    /**
     * As the decompression is done automagically via the "magic string" at the beginning of the
     * encoded payload, this method is pointless.
     * It is present only as a reference.
     *
     * @return \Mfonte\Base62x\Base62x
     */
    public function decompress(): self
    {
        return $this;
    }

    /**
     * Sets the encryption key (password) and method (algorithm).
     *
     * @param string $key    A password for your encoded base62x output string
     * @param string $method A valid openssl cypher method as supported in your environment (openssl_get_cipher_methods)
     *
     * @return \Mfonte\Base62x\Base62x
     */
    public function encrypt(string $key, string $method = 'aes-128-ctr'): self
    {
        if (!\function_exists('openssl_get_cipher_methods')) {
            throw new CryptException('openssl_get_cipher_methods unsupported in your PHP installation');
        }
        if (!\in_array(mb_strtolower($method), openssl_get_cipher_methods(), true)) {
            throw new CryptException('Encryption method "'.$method.'" is either unsupported in your PHP installation or not a valid encryption algorithm.');
        }

        $this->cryptMethod = mb_strtolower($method);
        $this->cryptKey = $key;

        return $this;
    }

    /**
     * Sets the encryption key (password) and method (algorithm).
     *
     * @see self::encrypt
     */
    public function decrypt(string $key, string $method = 'aes-128-ctr'): self
    {
        return $this->encrypt($key, $method);
    }

    /**
     * Gets the encoded or decoded mixed variable originally passed as $payload to instance.
     *
     * @return mixed
     */
    public function get()
    {
        $retval = null;
        switch ($this->mode) {
            case self::MODE_ENCODE:
                $retval = $this->_encode($this->payload);
            break;

            case self::MODE_DECODE:
                $retval = $this->_decode($this->payload);

                // decoded payload can be a serialized array: if so, we return the original representation
                if ($this->_isSerializedString($retval) && ($unserialized = @unserialize($retval)) !== false) {
                    $retval = $unserialized;
                }
            break;
        }

        return $retval;
    }

    /**
     * Performs the actual Base62x encoding.
     */
    private function _encode(string $payload): string
    {
        if ($this->cryptKey && $this->cryptMethod) {
            $payload = $this->_performEncryption($payload);
        }
        if ($this->compressAlgorithm) {
            $payload = $this->_performCompress($payload);
        }

        $encoded = Encoder::encode($payload);
        if (empty($encoded)) {
            throw new EncodeException();
        }

        return $encoded;
    }

    /**
     * Performs the actual Base62x decoding.
     */
    private function _decode(string $payload): string
    {
        $decoded = Encoder::decode($payload);
        if (empty($decoded)) {
            throw new DecodeException();
        }

        // remove the magic string for Compression
        $data = $this->_getCompressionFootprintAndSanitizePayload($decoded);

        if ($data['compression_algo']) {
            $decoded = $this->_performUncompress($data['payload'], $data['compression_algo'], $data['compression_encoding']);
        }

        // eventually perform decryption
        if ($this->cryptKey && $this->cryptMethod) {
            $decoded = $this->_performDecryption($decoded);
        }

        return $decoded;
    }

    /**
     * Performs the actual compress before chaining it into the Base62x encoder.
     */
    private function _performCompress(string $payload): string
    {
        $compressed = null;
        switch ($this->compressAlgorithm) {
            case 'gzip':
                $compressed = GzipCompressor::encode($payload, $this->compressEncoding);
            break;
            case 'huffman':
                $compressed = HuffmanCompressor::encode($payload, HuffmanCompressor::createCodeTree($payload));
            break;
        }

        if (empty($compressed)) {
            throw new EncodeException();
        }

        // create the compression footprint, to avoid the decompress() on Base62x::decode()
        $footprint = $this->_createCompressionFootprint();

        return $footprint.$compressed;
    }

    /**
     * Decompresses the payload, that was prior compressed using one of the available compression types.
     */
    private function _performUncompress(string $compressed_payload, string $compression_algo, ?string $compression_encoding): string
    {
        switch ($compression_algo) {
            case 'gzip':
                $payload = GzipCompressor::decode($compressed_payload, $compression_encoding);
            break;
            case 'huffman':
                $payload = HuffmanCompressor::decode($compressed_payload);
            break;
            default:
                $payload = '';
        }

        return (string) $payload;
    }

    /**
     * Performs the actual encryption before chaining it into the Base62x encoder.
     */
    private function _performEncryption(string $payload): ?string
    {
        try {
            $crypt = new Crypter([
                'key' => $this->cryptKey,
                'method' => $this->cryptMethod,
            ]);

            return $crypt->cipher($payload)->encrypt();
        } catch (Exception $ex) {
            throw new CryptException('Cannot encrypt the payload: '.$ex->getMessage());
        }
    }

    /**
     * Decrypts the payload, that was prior encrypted using the on-board encrypter.
     */
    private function _performDecryption(string $payload): string
    {
        if (empty($this->cryptKey)) {
            throw new CryptException('Cannot decrypt the payload without a valid cryptKey');
        }
        if (empty($this->cryptMethod)) {
            throw new CryptException('Cannot decrypt the payload without a valid cryptMethod');
        }

        try {
            $crypt = new Crypter([
                'key' => $this->cryptKey,
                'method' => $this->cryptMethod,
            ]);

            $decrypted = $crypt->cipher($payload)->decrypt();
            if ($decrypted === false) {
                throw new CryptException('Cannot decrypt the payload: result from cipher()->decrypt() is false');
            }

            return $decrypted;
        } catch (Exception $ex) {
            throw new CryptException('Cannot decrypt the payload: '.$ex->getMessage());
        }
    }

    /**
     * Prepares a "magic string" that will be appendend at beginning of the compressed payload,
     * prior of chaining it into the Base62x encoder.
     * Doing so, the decode method will automagically uncompress the encoded payload, so the subsequent "decode"
     * can understand which compression algo+encoding was originally used.
     */
    private function _createCompressionFootprint(): string
    {
        return '[MFB62X.COMPRESS.'.base64_encode(implode(',', [$this->compressAlgorithm, $this->compressEncoding])).']';
    }

    /**
     * Gets the decoded Base26x string, and checks if it needs decompression,
     * by analyzing its "compression footprint" placed at the very beginning of the payload.
     */
    private function _getCompressionFootprintAndSanitizePayload(string $payload): array
    {
        $compression_algo = $compression_encoding = null;
        $pos_start = mb_strpos($payload, '[MFB62X.COMPRESS.');
        $pos_end = mb_strpos($payload, ']');

        if ($pos_start === 0 && $pos_end > 0) {
            $footprint = mb_substr($payload, 0, $pos_end + 1);
            $compression_footprint = str_replace(['[', 'MFB62X.COMPRESS.', ']'], '', $footprint);

            $compression_params = @base64_decode($compression_footprint, true);
            if ($compression_params && \count(explode(',', $compression_params)) === 2) {
                $compression_params = explode(',', $compression_params);
                $compression_algo = $compression_params[0];
                $compression_encoding = $compression_params[1];
            }

            // clean the payload, removing the compression footprint
            $payload = mb_substr($payload, $pos_end + 1);
        }

        // some sanity checks to avoid tampering with the payload and cause bad behaviour or worse
        // sanity check for bad $algo
        if (
            $compression_algo &&
            !\array_key_exists($compression_algo, $this->_validCompressionAlgorithms) &&
            !\in_array($compression_algo, $this->_validCompressionAlgorithms, true)
        ) {
            throw new DecodeException();
        }

        // sanity check for bad $encoding
        if (
            $compression_algo &&
            $compression_encoding &&
            \array_key_exists($compression_algo, $this->_validCompressionAlgorithms) &&
            \is_array($this->_validCompressionAlgorithms[$compression_algo]) &&
            !\in_array($compression_encoding, $this->_validCompressionAlgorithms[$compression_algo], true)
        ) {
            throw new DecodeException();
        }

        // make sure we nullify the $encoding if we don't have one
        if (
            $compression_algo &&
            (!\array_key_exists($compression_algo, $this->_validCompressionAlgorithms) ||
            !\is_array($this->_validCompressionAlgorithms[$compression_algo]))
        ) {
            $compression_encoding = null;
        }

        return [
            'payload' => $payload,
            'compression_algo' => $compression_algo,
            'compression_encoding' => ($compression_encoding && mb_strlen($compression_encoding) > 0) ? $compression_encoding : null,
        ];
    }

    /**
     * Checks whether the $data argument is a serialized string, i.e. an array serialized with native PHP's serialize().
     *
     * @param mixed $data   (should always be a string)
     * @param bool  $strict Whether to perform a strict analysis or not
     */
    private function _isSerializedString($data, $strict = true): bool
    {
        // If it isn't a string, it isn't serialized.
        if (!\is_string($data)) {
            return false;
        }
        $data = trim($data);
        if ($data == 'N;') {
            return true;
        }
        if (mb_strlen($data) < 4) {
            return false;
        }
        if ($data[1] !== ':') {
            return false;
        }
        if ($strict) {
            $lastc = mb_substr($data, -1);
            if ($lastc !== ';' && $lastc !== '}') {
                return false;
            }
        } else {
            $semicolon = mb_strpos($data, ';');
            $brace = mb_strpos($data, '}');
            // Either ; or } must exist.
            if ($semicolon === false && $brace === false) {
                return false;
            }
            // But neither must be in the first X characters.
            if ($semicolon !== false && $semicolon < 3) {
                return false;
            }
            if ($brace !== false && $brace < 4) {
                return false;
            }
        }
        $token = $data[0];
        switch ($token) {
            case 's':
                if ($strict) {
                    if (mb_substr($data, -2, 1) !== '"') {
                        return false;
                    }
                } elseif (mb_strpos($data, '"') === false) {
                    return false;
                }
                // Or else fall through.
                // no break
            case 'a':
            case 'O':
                return (bool) preg_match("/^{$token}:[0-9]+:/s", $data);
            case 'b':
            case 'i':
            case 'd':
                $end = $strict ? '$' : '';

                return (bool) preg_match("/^{$token}:[0-9.E+-]+;$end/", $data);
        }

        return false;
    }
}

1			<?php
2
3			namespace Mfonte\Base62x;
4
5			use Exception;
6			use Mfonte\Base62x\Exception\InvalidParam;
7			use Mfonte\Base62x\Exception\CryptException;
8			use Mfonte\Base62x\Exception\DecodeException;
9			use Mfonte\Base62x\Exception\EncodeException;
10			use Mfonte\Base62x\Encoding\Base62x as Encoder;
11			use Mfonte\Base62x\Encryption\Crypt as Crypter;
12			use Mfonte\Base62x\Compression\Gzip\GzipCompression as GzipCompressor;
13			use Mfonte\Base62x\Compression\Huffman\HuffmanCoding as HuffmanCompressor;
14
15			class Base62x
16			{
17			const MODE_ENCODE = 1;
18			const MODE_DECODE = 2;
19
20			protected $_validCompressionAlgorithms = ['gzip' => ['zlib', 'deflate', 'gzip'], 'huffman'];
21
22			/**
23			* The mode: encode or decode.
24			*
25			* @var int
26			*/
27			protected $mode;
28
29			/**
30			* The payload to be encoded or decoded.
31			*
32			* @var mixed
33			*/
34			protected $payload;
35
36			/**
37			* Wheter the payload needs to be compressed prior of encoding. Defaults to null.
38			*
39			* @var string
40			*/
41			protected $compressAlgorithm = null;
42
43			/**
44			* The compression mode related to the compression algo. Defaults to null.
45			*
46			* @var string
47			*/
48			protected $compressEncoding = null;
49
50			/**
51			* The encryption method (algorithm) to be used in case of password-protected encoding.
52			* This variable must be a valid method supported in openssl_get_cipher_methods().
53			*
54			* @var string
55			*/
56			protected $cryptMethod;
57
58			/**
59			* The encrypt/decrypt key (password) to be used to protect/unprotect the encoding.
60			*
61			* @var mixed
62			*/
63			protected $cryptKey;
64
65			/**
66			* Wheter the payload needs to be decompressed after the decoding. Defaults to false.
67			*
68			* @var string
69			*/
70			protected $decompressAlgorithm = null;
71
72			/**
73			* The compression mode related to the compression algo. Defaults to null.
74			*
75			* @var string
76			*/
77			protected $decompressEncoding = null;
78
79			/**
80			* @param mixed $payload
81			*
82			* @return \Mfonte\Base62x\Base62x
83			*/
84			public static function encode($payload): self
85			{
86			return new self(self::MODE_ENCODE, $payload);
87			}
88
89			/**
90			* @param mixed $payload
91			*
92			* @return \Mfonte\Base62x\Base62x
93			*/
94			public static function decode($payload): self
95			{
96			return new self(self::MODE_DECODE, $payload);
97			}
98
99			public function __construct($mode, $payload)
100			{
101			$this->mode = $mode;
102
103			if (empty($payload)) {
104			throw new InvalidParam('payload', __FUNCTION__, __CLASS__, 'The payload cannot be empty');
105			} elseif (\is_resource($payload)) {
106			throw new InvalidParam('payload', __FUNCTION__, __CLASS__, 'The payload cannot be a resource');
107			} elseif (\is_object($payload)) {
108			throw new InvalidParam('payload', __FUNCTION__, __CLASS__, 'The payload cannot be an object');
109			} elseif (\is_array($payload)) {
110			// if the payload is an array, perform here and now the translation to a serialized string
111			$payload = serialize($payload);
112			}
113
114			$this->payload = $payload;
115			}
116
117			/**
118			* Sets the compression type and encoding.
119			*
120			* @param string $algo A valid compression algorithm as seen on $_validCompressionAlgorithms
121			* @param string $encoding A valid compression encoding as seen on $_validCompressionAlgorithms
122			*
123			* @return \Mfonte\Base62x\Base62x
124			*/
125			public function compress($algo = 'gzip', $encoding = 'gzip'): self
126			{
127			// sanity check for bad $algo
128			if (
129			!\array_key_exists($algo, $this->_validCompressionAlgorithms) &&
130			!\in_array($algo, $this->_validCompressionAlgorithms, true)
131			) {
132			throw new InvalidParam('algo', __FUNCTION__, __CLASS__);
133			}
134
135			// sanity check for bad $encoding
136			if (
137			\array_key_exists($algo, $this->_validCompressionAlgorithms) &&
138			\is_array($this->_validCompressionAlgorithms[$algo]) &&
139			!\in_array($encoding, $this->_validCompressionAlgorithms[$algo], true)
140			) {
141			throw new InvalidParam('encoding', __FUNCTION__, __CLASS__);
142			}
143
144			// make sure we nullify the $encoding if we don't have one
145			if (
146			!\array_key_exists($algo, $this->_validCompressionAlgorithms) \|\|
147			!\is_array($this->_validCompressionAlgorithms[$algo])
148			) {
149			$encoding = null;
150			}
151
152			$this->compressAlgorithm = $algo;
153			$this->compressEncoding = $encoding;
154
155			return $this;
156			}
157
158			/**
159			* As the decompression is done automagically via the "magic string" at the beginning of the
160			* encoded payload, this method is pointless.
161			* It is present only as a reference.
162			*
163			* @return \Mfonte\Base62x\Base62x
164			*/
165			public function decompress(): self
166			{
167			return $this;
168			}
169
170			/**
171			* Sets the encryption key (password) and method (algorithm).
172			*
173			* @param string $key A password for your encoded base62x output string
174			* @param string $method A valid openssl cypher method as supported in your environment (openssl_get_cipher_methods)
175			*
176			* @return \Mfonte\Base62x\Base62x
177			*/
178			public function encrypt(string $key, string $method = 'aes-128-ctr'): self
179			{
180			if (!\function_exists('openssl_get_cipher_methods')) {
181			throw new CryptException('openssl_get_cipher_methods unsupported in your PHP installation');
182			}
183			if (!\in_array(mb_strtolower($method), openssl_get_cipher_methods(), true)) {
184			throw new CryptException('Encryption method "'.$method.'" is either unsupported in your PHP installation or not a valid encryption algorithm.');
185			}
186
187			$this->cryptMethod = mb_strtolower($method);
188			$this->cryptKey = $key;
189
190			return $this;
191			}
192
193			/**
194			* Sets the encryption key (password) and method (algorithm).
195			*
196			* @see self::encrypt
197			*/
198			public function decrypt(string $key, string $method = 'aes-128-ctr'): self
199			{
200			return $this->encrypt($key, $method);
201			}
202
203			/**
204			* Gets the encoded or decoded mixed variable originally passed as $payload to instance.
205			*
206			* @return mixed
207			*/
208			public function get()
209			{
210			$retval = null;
211			switch ($this->mode) {
212			case self::MODE_ENCODE:
213			$retval = $this->_encode($this->payload);
214			break;
215
216			case self::MODE_DECODE:
217			$retval = $this->_decode($this->payload);
218
219			// decoded payload can be a serialized array: if so, we return the original representation
220			if ($this->_isSerializedString($retval) && ($unserialized = @unserialize($retval)) !== false) {
221			$retval = $unserialized;
222			}
223			break;
224			}
225
226			return $retval;
227			}
228
229			/**
230			* Performs the actual Base62x encoding.
231			*/
232			private function _encode(string $payload): string
233			{
234			if ($this->cryptKey && $this->cryptMethod) {
235			$payload = $this->_performEncryption($payload);
236			}
237			if ($this->compressAlgorithm) {
238			$payload = $this->_performCompress($payload);
239			}
240
241			$encoded = Encoder::encode($payload);
242			if (empty($encoded)) {
243			throw new EncodeException();
244			}
245
246			return $encoded;
247			}
248
249			/**
250			* Performs the actual Base62x decoding.
251			*/
252			private function _decode(string $payload): string
253			{
254			$decoded = Encoder::decode($payload);
255			if (empty($decoded)) {
256			throw new DecodeException();
257			}
258
259			// remove the magic string for Compression
260			$data = $this->_getCompressionFootprintAndSanitizePayload($decoded);
261
262			if ($data['compression_algo']) {
263			$decoded = $this->_performUncompress($data['payload'], $data['compression_algo'], $data['compression_encoding']);
264			}
265
266			// eventually perform decryption
267			if ($this->cryptKey && $this->cryptMethod) {
268			$decoded = $this->_performDecryption($decoded);
269			}
270
271			return $decoded;
272			}
273
274			/**
275			* Performs the actual compress before chaining it into the Base62x encoder.
276			*/
277			private function _performCompress(string $payload): string
278			{
279			$compressed = null;
280			switch ($this->compressAlgorithm) {
281			case 'gzip':
282			$compressed = GzipCompressor::encode($payload, $this->compressEncoding);
283			break;
284			case 'huffman':
285			$compressed = HuffmanCompressor::encode($payload, HuffmanCompressor::createCodeTree($payload));
286			break;
287			}
288
289			if (empty($compressed)) {
290			throw new EncodeException();
291			}
292
293			// create the compression footprint, to avoid the decompress() on Base62x::decode()
294			$footprint = $this->_createCompressionFootprint();
295
296			return $footprint.$compressed;
297			}
298
299			/**
300			* Decompresses the payload, that was prior compressed using one of the available compression types.
301			*/
302			private function _performUncompress(string $compressed_payload, string $compression_algo, ?string $compression_encoding): string
303			{
304			switch ($compression_algo) {
305			case 'gzip':
306			$payload = GzipCompressor::decode($compressed_payload, $compression_encoding);
307			break;
308			case 'huffman':
309			$payload = HuffmanCompressor::decode($compressed_payload);
310			break;
311			default:
312			$payload = '';
313			}
314
315			return (string) $payload;
316			}
317
318			/**
319			* Performs the actual encryption before chaining it into the Base62x encoder.
320			*/
321			private function _performEncryption(string $payload): ?string
322			{
323			try {
324			$crypt = new Crypter([
325			'key' => $this->cryptKey,
326			'method' => $this->cryptMethod,
327			]);
328
329			return $crypt->cipher($payload)->encrypt();
330			} catch (Exception $ex) {
331			throw new CryptException('Cannot encrypt the payload: '.$ex->getMessage());
332			}
333			}
334
335			/**
336			* Decrypts the payload, that was prior encrypted using the on-board encrypter.
337			*/
338			private function _performDecryption(string $payload): string
339			{
340			if (empty($this->cryptKey)) {
341			throw new CryptException('Cannot decrypt the payload without a valid cryptKey');
342			}
343			if (empty($this->cryptMethod)) {
344			throw new CryptException('Cannot decrypt the payload without a valid cryptMethod');
345			}
346
347			try {
348			$crypt = new Crypter([
349			'key' => $this->cryptKey,
350			'method' => $this->cryptMethod,
351			]);
352
353			$decrypted = $crypt->cipher($payload)->decrypt();
354			if ($decrypted === false) {
355			throw new CryptException('Cannot decrypt the payload: result from cipher()->decrypt() is false');
356			}
357
358			return $decrypted;
359			} catch (Exception $ex) {
360			throw new CryptException('Cannot decrypt the payload: '.$ex->getMessage());
361			}
362			}
363
364			/**
365			* Prepares a "magic string" that will be appendend at beginning of the compressed payload,
366			* prior of chaining it into the Base62x encoder.
367			* Doing so, the decode method will automagically uncompress the encoded payload, so the subsequent "decode"
368			* can understand which compression algo+encoding was originally used.
369			*/
370			private function _createCompressionFootprint(): string
371			{
372			return '[MFB62X.COMPRESS.'.base64_encode(implode(',', [$this->compressAlgorithm, $this->compressEncoding])).']';
373			}
374
375			/**
376			* Gets the decoded Base26x string, and checks if it needs decompression,
377			* by analyzing its "compression footprint" placed at the very beginning of the payload.
378			*/
379			private function _getCompressionFootprintAndSanitizePayload(string $payload): array
380			{
381			$compression_algo = $compression_encoding = null;
382			$pos_start = mb_strpos($payload, '[MFB62X.COMPRESS.');
383			$pos_end = mb_strpos($payload, ']');
384
385			if ($pos_start === 0 && $pos_end > 0) {
386			$footprint = mb_substr($payload, 0, $pos_end + 1);
387			$compression_footprint = str_replace(['[', 'MFB62X.COMPRESS.', ']'], '', $footprint);
388
389			$compression_params = @base64_decode($compression_footprint, true);
390			if ($compression_params && \count(explode(',', $compression_params)) === 2) {
391			$compression_params = explode(',', $compression_params);
392			$compression_algo = $compression_params[0];
393			$compression_encoding = $compression_params[1];
394			}
395
396			// clean the payload, removing the compression footprint
397			$payload = mb_substr($payload, $pos_end + 1);
398			}
399
400			// some sanity checks to avoid tampering with the payload and cause bad behaviour or worse
401			// sanity check for bad $algo
402			if (
403			$compression_algo &&
404			!\array_key_exists($compression_algo, $this->_validCompressionAlgorithms) &&
405			!\in_array($compression_algo, $this->_validCompressionAlgorithms, true)
406			) {
407			throw new DecodeException();
408			}
409
410			// sanity check for bad $encoding
411			if (
412			$compression_algo &&
413			$compression_encoding &&
414			\array_key_exists($compression_algo, $this->_validCompressionAlgorithms) &&
415			\is_array($this->_validCompressionAlgorithms[$compression_algo]) &&
416			!\in_array($compression_encoding, $this->_validCompressionAlgorithms[$compression_algo], true)
417			) {
418			throw new DecodeException();
419			}
420
421			// make sure we nullify the $encoding if we don't have one
422			if (
423			$compression_algo &&
424			(!\array_key_exists($compression_algo, $this->_validCompressionAlgorithms) \|\|
425			!\is_array($this->_validCompressionAlgorithms[$compression_algo]))
426			) {
427			$compression_encoding = null;
428			}
429
430			return [
431			'payload' => $payload,
432			'compression_algo' => $compression_algo,
433			'compression_encoding' => ($compression_encoding && mb_strlen($compression_encoding) > 0) ? $compression_encoding : null,
434			];
435			}
436
437			/**
438			* Checks whether the $data argument is a serialized string, i.e. an array serialized with native PHP's serialize().
439			*
440			* @param mixed $data (should always be a string)
441			* @param bool $strict Whether to perform a strict analysis or not
442			*/
443			private function _isSerializedString($data, $strict = true): bool
444			{
445			// If it isn't a string, it isn't serialized.
446			if (!\is_string($data)) {
447			return false;
448			}
449			$data = trim($data);
450			if ($data == 'N;') {
451			return true;
452			}
453			if (mb_strlen($data) < 4) {
454			return false;
455			}
456			if ($data[1] !== ':') {
457			return false;
458			}
459			if ($strict) {
460			$lastc = mb_substr($data, -1);
461			if ($lastc !== ';' && $lastc !== '}') {
462			return false;
463			}
464			} else {
465			$semicolon = mb_strpos($data, ';');
466			$brace = mb_strpos($data, '}');
467			// Either ; or } must exist.
468			if ($semicolon === false && $brace === false) {
469			return false;
470			}
471			// But neither must be in the first X characters.
472			if ($semicolon !== false && $semicolon < 3) {
473			return false;
474			}
475			if ($brace !== false && $brace < 4) {
476			return false;
477			}
478			}
479			$token = $data[0];
480			switch ($token) {
481			case 's':
482			if ($strict) {
483			if (mb_substr($data, -2, 1) !== '"') {
484			return false;
485			}
486			} elseif (mb_strpos($data, '"') === false) {
487			return false;
488			}
489			// Or else fall through.
490			// no break
491			case 'a':
492			case 'O':
493			return (bool) preg_match("/^{$token}:[0-9]+:/s", $data);
494			case 'b':
495			case 'i':
496			case 'd':
497			$end = $strict ? '$' : '';
498
499			return (bool) preg_match("/^{$token}:[0-9.E+-]+;$end/", $data);
500			}
501
502			return false;
503			}
504			}

mauriziofonte / php-base62x

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_getCompressionFootprintAndSanitizePayload() D

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