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Simplifying PostObject to support all of the S3 POSTObject features m…
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…ore generically
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@mtdowling
mtdowling committed Mar 26, 2015
1 parent eddd5e7 commit 050b186
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216 changes: 63 additions & 153 deletions src/S3/PostObject.php
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Expand Up @@ -5,151 +5,49 @@

/**
* Encapsulates the logic for getting the data for an S3 object POST upload form
*
* @link http://docs.aws.amazon.com/AmazonS3/latest/API/RESTObjectPOST.html
*/
class PostObject
{
/** @var S3Client The S3 client being used to sign the policy */
private $client;

/** @var string The bucket name where the object will be posted */
private $bucket;

/** @var array The <form> tag attributes as an array */
private $formAttributes;

/** @var array The form's <input> elements as an array */
private $formInputs;

/** @var string The raw json policy */
private $jsonPolicy;

/**
* Constructs the PostObject
*
* The options array accepts the following keys:
*
* - acl: The access control setting to apply to the uploaded file. Accepts
* any of the CannedAcl constants.
* - Cache-Control: The Cache-Control HTTP header value to apply to the
* uploaded file
* - Content-Disposition: The Content-Disposition HTTP header value to
* apply to the uploaded file
* - Content-Encoding: The Content-Encoding HTTP header value to apply to
* the uploaded file.
* - Content-Type: The Content-Type HTTP header value to apply to the
* uploaded file. The default value is `application/octet-stream`.
* - Expires: The Expires HTTP header value to apply to the uploaded file
* - key: The location where the file should be uploaded to. The default
* value is `^${filename}` which will use the name of the uploaded file.
* - policy: A raw policy in JSON format. By default, the PostObject
* creates one for you.
* - policy_callback: A callback used to modify the policy before encoding
* and signing it. The method signature for the callback should accept an
* array of the policy data as the 1st argument, (optionally) the
* PostObject as the 2nd argument, and return the policy data with the
* desired modifications.
* - success_action_redirect: The URI for Amazon S3 to redirect to upon
* successful upload.
* - success_action_status: The status code for Amazon S3 to return upon
* successful upload.
* - ttd: The expiration time for the generated upload form data
* - x-amz-meta-*: Any custom meta tag that should be set to the object
* - x-amz-server-side-encryption: The server-side encryption mechanism to
* use
* - x-amz-storage-class: The storage setting to apply to the object
* - x-amz-storage-class: The storage setting to apply to the object
* - x-amz-server-side-encryption-customer-algorithm: The SSE-C algorithm
* - x-amz-server-side-encryption-customer-key: The SSE-C secret key
* - x-amz-server-side-encryption-customer-key-MD5: MD5 hash of the
* SSE-C customer secret key
* Constructs the PostObject.
*
* For the Cache-Control, Content-Disposition, Content-Encoding,
* Content-Type, Expires, and key options, to use a "starts-with" comparison
* instead of an equals comparison, prefix the value with a ^ (carat)
* character.
*
* @param S3Client $client Client used with the POST object
* @param string $bucket Bucket to use
* @param array $options Associative array of options
* @param S3Client $client Client used with the POST object
* @param string $bucket Bucket to use
* @param array $formInputs Associative array of form input fields.
* @param string|array $jsonPolicy JSON encoded POST policy document. The
* policy will be base64 encoded and applied
* to the form on your behalf.
*/
public function __construct(S3Client $client, $bucket, array $options = [])
{
public function __construct(
S3Client $client,
$bucket,
array $formInputs,
$jsonPolicy
) {
$this->client = $client;
$this->bucket = $bucket;
parent::__construct($options);
}

/**
* Prepares the POST object to be utilzed to build a POST form.
*
* @return PostObject
*/
public function prepareData()
{
// Validate required options
$options = Collection::fromConfig($this->data, [
'ttd' => '+1 hour',
'key' => '^${filename}',
]);

$ttd = $this->pluckTtd($options);

// If a policy or policy callback were provided, extract those from
// the options.
$rawJsonPolicy = $options['policy'];
$policyCallback = $options['policy_callback'];
unset($options['policy'], $options['policy_callback']);

// Setup policy document
$policy = [
'expiration' => gmdate('Y-m-d\TH:i:s\Z', $ttd),
'conditions' => [['bucket' => $this->bucket]]
];
if (is_array($jsonPolicy)) {
$jsonPolicy = json_encode($jsonPolicy);
}

// Setup basic form
$this->jsonPolicy = $jsonPolicy;
$this->formAttributes = [
'action' => $this->generateUrl($options),
'action' => $this->generateUri(),
'method' => 'POST',
'enctype' => 'multipart/form-data'
];

$this->formInputs = [
'AWSAccessKeyId' => $this->client->getCredentials()->getAccessKeyId()
];

// Add success action status
$status = (int) $options->get('success_action_status');

if ($status && in_array($status, [200, 201, 204])) {
$this->formInputs['success_action_status'] = (string) $status;
$policy['conditions'][] = [
'success_action_status' => (string) $status
];
unset($options['success_action_status']);
}

// Add other options
foreach ($options as $key => $value) {
$value = (string) $value;
if ($value[0] === '^') {
$value = substr($value, 1);
$this->formInputs[$key] = $value;
$value = preg_replace('/\$\{(\w*)\}/', '', $value);
$policy['conditions'][] = ['starts-with', '$' . $key, $value];
} else {
$this->formInputs[$key] = $value;
$policy['conditions'][] = [$key => $value];
}
}

// Handle the policy
$policy = is_callable($policyCallback)
? $policyCallback($policy, $this)
: $policy;
$this->jsonPolicy = $rawJsonPolicy ?: json_encode($policy);
$this->applyPolicy();

return $this;
$this->formInputs = $formInputs + ['key' => '${filename}'];
$this->formInputs['AWSAccessKeyId'] = $client->getCredentials()->getAccessKeyId();
$this->formInputs += $this->getPolicyAndSignature();
}

/**
Expand Down Expand Up @@ -182,6 +80,17 @@ public function getFormAttributes()
return $this->formAttributes;
}

/**
* Set a form attribute.
*
* @param string $attribute Form attribute to set.
* @param string $value Value to set.
*/
public function setFormAttribute($attribute, $value)
{
$this->formAttributes[$attribute] = $value;
}

/**
* Gets the form inputs as an array.
*
Expand All @@ -192,6 +101,17 @@ public function getFormInputs()
return $this->formInputs;
}

/**
* Set a form input.
*
* @param string $field Field name to set
* @param string $value Value to set.
*/
public function setFormInput($field, $value)
{
$this->formInputs[$field] = $value;
}

/**
* Gets the raw JSON policy.
*
Expand All @@ -202,45 +122,35 @@ public function getJsonPolicy()
return $this->jsonPolicy;
}

private function pluckTtd(Collection $options)
private function generateUri()
{
$ttd = $options['ttd'];
$ttd = is_numeric($ttd) ? (int) $ttd : strtotime($ttd);
unset($options['ttd']);
$uri = new Uri($this->client->getEndpoint());

return $ttd;
}

private function generateUrl()
{
$url = Url::fromString($this->client->getEndpoint());

if ($url->getScheme() === 'https' &&
strpos($this->bucket, '.') !== false
if ($uri->getScheme() === 'https'
&& strpos($this->bucket, '.') !== false
) {
// Use path-style URLs
$url->setPath($this->bucket);
$uri = $uri->withPath($this->bucket);
} else {
// Use virtual-style URLs
$url->setHost($this->bucket . '.' . $url->getHost());
$uri = $uri->withHost($this->bucket . '.' . $uri->getHost());
}

return $url;
return (string) $uri;
}

/**
* Handles the encoding, signing, and injecting of the policy
*/
protected function applyPolicy()
protected function getPolicyAndSignature()
{
$jsonPolicy64 = base64_encode($this->jsonPolicy);
$this->formInputs['policy'] = $jsonPolicy64;

$this->formInputs['signature'] = base64_encode(hash_hmac(
'sha1',
$jsonPolicy64,
$this->client->getCredentials()->getSecretKey(),
true
));

return [
'policy' => $jsonPolicy64,
'signature' => base64_encode(hash_hmac(
'sha1',
$jsonPolicy64,
$this->client->getCredentials()->getSecretKey(),
true
))
];
}
}

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