Signature::generatePolicy() - Code Metrics - Inspection of "Merge develop branch (simpler string casting)" - eddturtle/direct-upload - Measure and Improve Code Quality continuously with Scrutinizer

Completed

Push — master ( 8c79df...2723f8 )

by Edd

created 2016-11-14 19:56 UTC

Signature::generatePolicy() A

↳ Parent: Signature

Complexity

Conditions	1
Paths	1

Size

Total Lines	19
Code Lines	15

Duplication

Lines	0
Ratio	0 %

Importance

Changes

Metric	Value
dl	0
loc	19
rs	9.4285
c	0
b	0
f	0
cc	1
eloc	15
nc	1
nop	0

<?php

namespace EddTurtle\DirectUpload;

/**
 * Class Signature
 *
 * Build an AWS Signature, ready for direct upload. This will support AWS's signature v4 so should be
 * accepted by all regions.
 *
 * @package EddTurtle\DirectUpload
 */
class Signature
{

    CONST ALGORITHM = "AWS4-HMAC-SHA256";
    CONST SERVICE = "s3";
    CONST REQUEST_TYPE = "aws4_request";

    /**
     * Default options, these can be overwritten within the constructor.
     *
     * @var array
     */
    protected $options = [

        // If the upload is a success, this is the http code we get back from S3.
        // By default this will be a 201 Created.
        'success_status' => 201,

        // If the file should be private/public-read/public-write.
        // This is file specific, not bucket. More info: http://amzn.to/1SSOgwO
        'acl' => 'private',

        // The file's name on s3, can be set with JS by changing the input[name="key"].
        // ${filename} will just mean the original filename of the file being uploaded.
        'default_filename' => '${filename}',

        // The maximum file size of an upload in MB. Will refuse with a EntityTooLarge
        // and 400 Bad Request if you exceed this limit.
        'max_file_size' => 500,

        // Request expiration time, specified in relative time format or in seconds.
        // minimum of 1 (+1 second), maximum of 604800 (+7 days)
        'expires' => '+6 hours',

        // Server will check that the filename starts with this prefix and fail
        // with a AccessDenied 403 if not.
        'valid_prefix' => '',

        // Strictly only allow a single content type, blank will allow all. Will fail
        // with a AccessDenied 403 is this condition is not met.
        'content_type' => '',

        // Any additional inputs to add to the form. This is an array of name => value
        // pairs e.g. ['Content-Disposition' => 'attachment']
        'additional_inputs' => []

    ];

    private $key;
    private $secret;

    private $bucket;
    private $region;

    private $time = null;

    private $credentials = null;
    private $base64Policy = null;
    private $signature = null;

    /**
     * Signature constructor.
     *
     * @param string $key     the AWS API Key to use.
     * @param string $secret  the AWS API Secret to use.
     * @param string $bucket  the bucket to upload the file into.
     * @param string $region  the s3 region this bucket is within. More info: http://amzn.to/1FtPG6r
     * @param array  $options any additional options, like acl and success status.
     */
    public function __construct($key, $secret, $bucket, $region = "us-east-1", $options = [])
    {
        $this->setAwsCredentials($key, $secret);
        $this->populateTime();

        $this->bucket = $bucket;
        $this->region = new Region($region);

        $this->setOptions($options);
    }

    /**
     * Set the AWS Credentials
     *
     * @param string $key    the AWS API Key to use.
     * @param string $secret the AWS API Secret to use.
     */
    protected function setAwsCredentials($key, $secret)
    {
        // Key
        if (empty($key) || $key === "YOUR_S3_KEY") {
            throw new \InvalidArgumentException("Invalid AWS Key");
        }
        $this->key = $key;

        // Secret
        if (empty($secret) || $secret === "YOUR_S3_SECRET") {
            throw new \InvalidArgumentException("Invalid AWS Secret");
        }
        $this->secret = $secret;
    }

    /**
     * Build the form url for sending files, this will include the bucket and the region name.
     *
     * @return string the s3 bucket's url.
     */
    public function getFormUrl()
    {
        $region = (string)$this->region;

        // Only the us-east-1 region is exempt from needing the region in the url.
        if ($region !== "us-east-1") {
            $middle = "-" . $region;
        } else {
            $middle = "";
        }

        return "//" . urlencode($this->bucket) . "." . self::SERVICE . $middle . ".amazonaws.com";
    }

    /**
     * Get all options.
     *
     * @return array
     */
    public function getOptions()
    {
        return $this->options;
    }

    /**
     * Set/overwrite any default options.
     *
     * @param array $options any options to override.
     */
    public function setOptions($options)
    {
        $this->options = $options + $this->options;
        $this->options['acl'] = new Acl($this->options['acl']);

        // Return HTTP code must be a string
        $this->options['success_status'] = (string)$this->options['success_status'];
    }

    /**
     * Get an AWS Signature V4 generated.
     *
     * @return string the aws v4 signature.
     */
    public function getSignature()
    {
        if (is_null($this->signature)) {
            $this->generateScope();
            $this->generatePolicy();
            $this->generateSignature();
        }
        return $this->signature;
    }

    /**
     * Generate the necessary hidden inputs to go within the form. These inputs should match what's being send in
     * the policy.
     *
     * @param bool $addKey whether to add the 'key' input (filename), defaults to yes.
     *
     * @return array of the form inputs.
     */
    public function getFormInputs($addKey = true)
    {
        $this->getSignature();

        $inputs = [
            'Content-Type' => $this->options['content_type'],
            'acl' => $this->options['acl'],
            'success_action_status' => $this->options['success_status'],
            'policy' => $this->base64Policy,
            'X-amz-credential' => $this->credentials,
            'X-amz-algorithm' => self::ALGORITHM,
            'X-amz-date' => $this->getFullDateFormat(),
            'X-amz-signature' => $this->signature
        ];

        $inputs = array_merge($inputs, $this->options['additional_inputs']);

        if ($addKey) {
            // Note: The Key (filename) will need to be populated with JS on upload
            // if anything other than the filename is wanted.
            $inputs['key'] = $this->options['valid_prefix'] . $this->options['default_filename'];
        }

        return $inputs;
    }

    /**
     * Based on getFormInputs(), this will build up the html to go within the form.
     *
     * @param bool $addKey whether to add the 'key' input (filename), defaults to yes.
     *
     * @return string html of hidden form inputs.
     */
    public function getFormInputsAsHtml($addKey = true)
    {
        $inputs = [];
        foreach ($this->getFormInputs($addKey) as $name => $value) {
            $inputs[] = '<input type="hidden" name="' . $name . '" value="' . $value . '" />';
        }
        return implode(PHP_EOL, $inputs);
    }


    // Where the magic begins ;)

    /**
     * Step 1: Generate the Scope
     */
    protected function generateScope()
    {
        $scope = [
            $this->key,
            $this->getShortDateFormat(),
            $this->region,
            self::SERVICE,
            self::REQUEST_TYPE
        ];
        $this->credentials = implode('/', $scope);
    }

    /**
     * Step 2: Generate a Base64 Policy
     */
    protected function generatePolicy()
    {
        $policy = [
            'expiration' => $this->getExpirationDate(),
            'conditions' => [
                ['bucket' => $this->bucket],
                ['acl' => (string)$this->options['acl']],
                ['starts-with', '$key', $this->options['valid_prefix']],
                $this->getPolicyContentTypeArray(),
                ['content-length-range', 0, $this->mbToBytes($this->options['max_file_size'])],
                ['success_action_status' => $this->options['success_status']],
                ['x-amz-credential' => $this->credentials],
                ['x-amz-algorithm' => self::ALGORITHM],
                ['x-amz-date' => $this->getFullDateFormat()]
            ]
        ];
        $policy = $this->addAdditionalInputs($policy);
        $this->base64Policy = base64_encode(json_encode($policy));
    }

    private function getPolicyContentTypeArray()
    {
        $contentTypePrefix = (empty($this->options['content_type']) ? 'starts-with' : 'eq');
        return [
            $contentTypePrefix,
            '$Content-Type',
            $this->options['content_type']
        ];
    }

    private function addAdditionalInputs($policy)

    {
        foreach ($this->options['additional_inputs'] as $name => $value) {
            $policy['conditions'][] = ['starts-with', '$' . $name, $value];
        }
        return $policy;
    }

    /**
     * Step 3: Generate and sign the Signature (v4)
     */
    protected function generateSignature()
    {
        $signatureData = [
            $this->getShortDateFormat(),
            (string)$this->region,
            self::SERVICE,
            self::REQUEST_TYPE
        ];

        // Iterates over the data (defined in the array above), hashing it each time.
        $initial = 'AWS4' . $this->secret;
        $signingKey = array_reduce($signatureData, function($key, $data) {
            return $this->keyHash($data, $key);
        }, $initial);

        // Finally, use the signing key to hash the policy.
        $this->signature = $this->keyHash($this->base64Policy, $signingKey, false);
    }


    // Helper functions

    private function keyHash($date, $key, $raw = true)
    {
        return hash_hmac('sha256', $date, $key, $raw);
    }

    private function populateTime()
    {
        if (is_null($this->time)) {
            $this->time = time();
        }
    }

    private function mbToBytes($megaByte)
    {
        if (is_numeric($megaByte)) {
            return $megaByte * pow(1024, 2);
        }
        return 0;
    }


    // Dates

    private function getShortDateFormat()
    {
        return gmdate("Ymd", $this->time);
    }

    private function getFullDateFormat()
    {
        return gmdate("Ymd\THis\Z", $this->time);
    }

    private function getExpirationDate()
    {
        // Note: using \DateTime::ISO8601 doesn't work :(

        $exp = strtotime($this->options['expires'], $this->time);
        $diff = $exp - $this->time;

        if (!($diff >= 1 && $diff <= 604800)) {
            throw new \InvalidArgumentException("Expiry must be between 1 and 604800");
        }

        return gmdate('Y-m-d\TG:i:s\Z', $exp);
    }


}


1			<?php
2
3			namespace EddTurtle\DirectUpload;
4
5			/**
6			* Class Signature
7			*
8			* Build an AWS Signature, ready for direct upload. This will support AWS's signature v4 so should be
9			* accepted by all regions.
10			*
11			* @package EddTurtle\DirectUpload
12			*/
13			class Signature
14			{
15
16			CONST ALGORITHM = "AWS4-HMAC-SHA256";
17			CONST SERVICE = "s3";
18			CONST REQUEST_TYPE = "aws4_request";
19
20			/**
21			* Default options, these can be overwritten within the constructor.
22			*
23			* @var array
24			*/
25			protected $options = [
26
27			// If the upload is a success, this is the http code we get back from S3.
28			// By default this will be a 201 Created.
29			'success_status' => 201,
30
31			// If the file should be private/public-read/public-write.
32			// This is file specific, not bucket. More info: http://amzn.to/1SSOgwO
33			'acl' => 'private',
34
35			// The file's name on s3, can be set with JS by changing the input[name="key"].
36			// ${filename} will just mean the original filename of the file being uploaded.
37			'default_filename' => '${filename}',
38
39			// The maximum file size of an upload in MB. Will refuse with a EntityTooLarge
40			// and 400 Bad Request if you exceed this limit.
41			'max_file_size' => 500,
42
43			// Request expiration time, specified in relative time format or in seconds.
44			// minimum of 1 (+1 second), maximum of 604800 (+7 days)
45			'expires' => '+6 hours',
46
47			// Server will check that the filename starts with this prefix and fail
48			// with a AccessDenied 403 if not.
49			'valid_prefix' => '',
50
51			// Strictly only allow a single content type, blank will allow all. Will fail
52			// with a AccessDenied 403 is this condition is not met.
53			'content_type' => '',
54
55			// Any additional inputs to add to the form. This is an array of name => value
56			// pairs e.g. ['Content-Disposition' => 'attachment']
57			'additional_inputs' => []
58
59			];
60
61			private $key;
62			private $secret;
63
64			private $bucket;
65			private $region;
66
67			private $time = null;
68
69			private $credentials = null;
70			private $base64Policy = null;
71			private $signature = null;
72
73			/**
74			* Signature constructor.
75			*
76			* @param string $key the AWS API Key to use.
77			* @param string $secret the AWS API Secret to use.
78			* @param string $bucket the bucket to upload the file into.
79			* @param string $region the s3 region this bucket is within. More info: http://amzn.to/1FtPG6r
80			* @param array $options any additional options, like acl and success status.
81			*/
82			public function __construct($key, $secret, $bucket, $region = "us-east-1", $options = [])
83			{
84			$this->setAwsCredentials($key, $secret);
85			$this->populateTime();
86
87			$this->bucket = $bucket;
88			$this->region = new Region($region);
89
90			$this->setOptions($options);
91			}
92
93			/**
94			* Set the AWS Credentials
95			*
96			* @param string $key the AWS API Key to use.
97			* @param string $secret the AWS API Secret to use.
98			*/
99			protected function setAwsCredentials($key, $secret)
100			{
101			// Key
102			if (empty($key) \|\| $key === "YOUR_S3_KEY") {
103			throw new \InvalidArgumentException("Invalid AWS Key");
104			}
105			$this->key = $key;
106
107			// Secret
108			if (empty($secret) \|\| $secret === "YOUR_S3_SECRET") {
109			throw new \InvalidArgumentException("Invalid AWS Secret");
110			}
111			$this->secret = $secret;
112			}
113
114			/**
115			* Build the form url for sending files, this will include the bucket and the region name.
116			*
117			* @return string the s3 bucket's url.
118			*/
119			public function getFormUrl()
120			{
121			$region = (string)$this->region;
122
123			// Only the us-east-1 region is exempt from needing the region in the url.
124			if ($region !== "us-east-1") {
125			$middle = "-" . $region;
126			} else {
127			$middle = "";
128			}
129
130			return "//" . urlencode($this->bucket) . "." . self::SERVICE . $middle . ".amazonaws.com";
131			}
132
133			/**
134			* Get all options.
135			*
136			* @return array
137			*/
138			public function getOptions()
139			{
140			return $this->options;
141			}
142
143			/**
144			* Set/overwrite any default options.
145			*
146			* @param array $options any options to override.
147			*/
148			public function setOptions($options)
149			{
150			$this->options = $options + $this->options;
151			$this->options['acl'] = new Acl($this->options['acl']);
152
153			// Return HTTP code must be a string
154			$this->options['success_status'] = (string)$this->options['success_status'];
155			}
156
157			/**
158			* Get an AWS Signature V4 generated.
159			*
160			* @return string the aws v4 signature.
161			*/
162			public function getSignature()
163			{
164			if (is_null($this->signature)) {
165			$this->generateScope();
166			$this->generatePolicy();
167			$this->generateSignature();
168			}
169			return $this->signature;
170			}
171
172			/**
173			* Generate the necessary hidden inputs to go within the form. These inputs should match what's being send in
174			* the policy.
175			*
176			* @param bool $addKey whether to add the 'key' input (filename), defaults to yes.
177			*
178			* @return array of the form inputs.
179			*/
180			public function getFormInputs($addKey = true)
181			{
182			$this->getSignature();
183
184			$inputs = [
185			'Content-Type' => $this->options['content_type'],
186			'acl' => $this->options['acl'],
187			'success_action_status' => $this->options['success_status'],
188			'policy' => $this->base64Policy,
189			'X-amz-credential' => $this->credentials,
190			'X-amz-algorithm' => self::ALGORITHM,
191			'X-amz-date' => $this->getFullDateFormat(),
192			'X-amz-signature' => $this->signature
193			];
194
195			$inputs = array_merge($inputs, $this->options['additional_inputs']);
196
197			if ($addKey) {
198			// Note: The Key (filename) will need to be populated with JS on upload
199			// if anything other than the filename is wanted.
200			$inputs['key'] = $this->options['valid_prefix'] . $this->options['default_filename'];
201			}
202
203			return $inputs;
204			}
205
206			/**
207			* Based on getFormInputs(), this will build up the html to go within the form.
208			*
209			* @param bool $addKey whether to add the 'key' input (filename), defaults to yes.
210			*
211			* @return string html of hidden form inputs.
212			*/
213			public function getFormInputsAsHtml($addKey = true)
214			{
215			$inputs = [];
216			foreach ($this->getFormInputs($addKey) as $name => $value) {
217			$inputs[] = '<input type="hidden" name="' . $name . '" value="' . $value . '" />';
218			}
219			return implode(PHP_EOL, $inputs);
220			}
221
222
223			// Where the magic begins ;)
224
225			/**
226			* Step 1: Generate the Scope
227			*/
228			protected function generateScope()
229			{
230			$scope = [
231			$this->key,
232			$this->getShortDateFormat(),
233			$this->region,
234			self::SERVICE,
235			self::REQUEST_TYPE
236			];
237			$this->credentials = implode('/', $scope);
238			}
239
240			/**
241			* Step 2: Generate a Base64 Policy
242			*/
243			protected function generatePolicy()
244			{
245			$policy = [
246			'expiration' => $this->getExpirationDate(),
247			'conditions' => [
248			['bucket' => $this->bucket],
249			['acl' => (string)$this->options['acl']],
250			['starts-with', '$key', $this->options['valid_prefix']],
251			$this->getPolicyContentTypeArray(),
252			['content-length-range', 0, $this->mbToBytes($this->options['max_file_size'])],
253			['success_action_status' => $this->options['success_status']],
254			['x-amz-credential' => $this->credentials],
255			['x-amz-algorithm' => self::ALGORITHM],
256			['x-amz-date' => $this->getFullDateFormat()]
257			]
258			];
259			$policy = $this->addAdditionalInputs($policy);
260			$this->base64Policy = base64_encode(json_encode($policy));
261			}
262
263			private function getPolicyContentTypeArray()
264			{
265			$contentTypePrefix = (empty($this->options['content_type']) ? 'starts-with' : 'eq');
266			return [
267			$contentTypePrefix,
268			'$Content-Type',
269			$this->options['content_type']
270			];
271			}
272
273			private function addAdditionalInputs($policy)
			0 ignored issues – show Documentation introduced 2016-11-14 19:58 UTC by Report Bug Copy Issue Report The return type could not be reliably inferred; please add a `@return` annotation. Our type inference engine in quite powerful, but sometimes the code does not provide enough clues to go by. In these cases we request you to add a `@return` annotation as described here. Loading history...
274			{
275			foreach ($this->options['additional_inputs'] as $name => $value) {
276			$policy['conditions'][] = ['starts-with', '$' . $name, $value];
277			}
278			return $policy;
279			}
280
281			/**
282			* Step 3: Generate and sign the Signature (v4)
283			*/
284			protected function generateSignature()
285			{
286			$signatureData = [
287			$this->getShortDateFormat(),
288			(string)$this->region,
289			self::SERVICE,
290			self::REQUEST_TYPE
291			];
292
293			// Iterates over the data (defined in the array above), hashing it each time.
294			$initial = 'AWS4' . $this->secret;
295			$signingKey = array_reduce($signatureData, function($key, $data) {
296			return $this->keyHash($data, $key);
297			}, $initial);
298
299			// Finally, use the signing key to hash the policy.
300			$this->signature = $this->keyHash($this->base64Policy, $signingKey, false);
301			}
302
303
304			// Helper functions
305
306			private function keyHash($date, $key, $raw = true)
307			{
308			return hash_hmac('sha256', $date, $key, $raw);
309			}
310
311			private function populateTime()
312			{
313			if (is_null($this->time)) {
314			$this->time = time();
315			}
316			}
317
318			private function mbToBytes($megaByte)
319			{
320			if (is_numeric($megaByte)) {
321			return $megaByte * pow(1024, 2);
322			}
323			return 0;
324			}
325
326
327			// Dates
328
329			private function getShortDateFormat()
330			{
331			return gmdate("Ymd", $this->time);
332			}
333
334			private function getFullDateFormat()
335			{
336			return gmdate("Ymd\THis\Z", $this->time);
337			}
338
339			private function getExpirationDate()
340			{
341			// Note: using \DateTime::ISO8601 doesn't work :(
342
343			$exp = strtotime($this->options['expires'], $this->time);
344			$diff = $exp - $this->time;
345
346			if (!($diff >= 1 && $diff <= 604800)) {
347			throw new \InvalidArgumentException("Expiry must be between 1 and 604800");
348			}
349
350			return gmdate('Y-m-d\TG:i:s\Z', $exp);
351			}
352
353
354			}
355

eddturtle / direct-upload

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