<?php
namespace Aws\S3;
use Aws\CacheInterface;
use Aws\LruArrayCache;
use Aws\Result;
use Aws\S3\Exception\S3Exception;
use GuzzleHttp\Psr7;
use GuzzleHttp\Psr7\Stream;
use GuzzleHttp\Psr7\CachingStream;
use Psr\Http\Message\StreamInterface;
/**
* Amazon S3 stream wrapper to use "s3://<bucket>/<key>" files with PHP
* streams, supporting "r", "w", "a", "x".
*
* # Opening "r" (read only) streams:
*
* Read only streams are truly streaming by default and will not allow you to
* seek. This is because data read from the stream is not kept in memory or on
* the local filesystem. You can force a "r" stream to be seekable by setting
* the "seekable" stream context option true. This will allow true streaming of
* data from Amazon S3, but will maintain a buffer of previously read bytes in
* a 'php://temp' stream to allow seeking to previously read bytes from the
* stream.
*
* You may pass any GetObject parameters as 's3' stream context options. These
* options will affect how the data is downloaded from Amazon S3.
*
* # Opening "w" and "x" (write only) streams:
*
* Because Amazon S3 requires a Content-Length header, write only streams will
* maintain a 'php://temp' stream to buffer data written to the stream until
* the stream is flushed (usually by closing the stream with fclose).
*
* You may pass any PutObject parameters as 's3' stream context options. These
* options will affect how the data is uploaded to Amazon S3.
*
* When opening an "x" stream, the file must exist on Amazon S3 for the stream
* to open successfully.
*
* # Opening "a" (write only append) streams:
*
* Similar to "w" streams, opening append streams requires that the data be
* buffered in a "php://temp" stream. Append streams will attempt to download
* the contents of an object in Amazon S3, seek to the end of the object, then
* allow you to append to the contents of the object. The data will then be
* uploaded using a PutObject operation when the stream is flushed (usually
* with fclose).
*
* You may pass any GetObject and/or PutObject parameters as 's3' stream
* context options. These options will affect how the data is downloaded and
* uploaded from Amazon S3.
*
* Stream context options:
*
* - "seekable": Set to true to create a seekable "r" (read only) stream by
* using a php://temp stream buffer
* - For "unlink" only: Any option that can be passed to the DeleteObject
* operation
*/
class StreamWrapper
{
/** @var resource|null Stream context (this is set by PHP) */
public $context;
/** @var StreamInterface Underlying stream resource */
private $body;
/** @var int Size of the body that is opened */
private $size;
/** @var array Hash of opened stream parameters */
private $params = [];
/** @var string Mode in which the stream was opened */
private $mode;
/** @var \Iterator Iterator used with opendir() related calls */
private $objectIterator;
/** @var string The bucket that was opened when opendir() was called */
private $openedBucket;
/** @var string The prefix of the bucket that was opened with opendir() */
private $openedBucketPrefix;
/** @var string Opened bucket path */
private $openedPath;
/** @var CacheInterface Cache for object and dir lookups */
private $cache;
/** @var string The opened protocol (e.g., "s3") */
private $protocol = 's3';
/**
* Register the 's3://' stream wrapper
*
* @param S3Client $client Client to use with the stream wrapper
* @param string $protocol Protocol to register as.
* @param CacheInterface $cache Default cache for the protocol.
*/
public static function register(
S3Client $client,
$protocol = 's3',
CacheInterface $cache = null
) {
if (in_array($protocol, stream_get_wrappers())) {
stream_wrapper_unregister($protocol);
}
// Set the client passed in as the default stream context client
stream_wrapper_register($protocol, get_called_class(), STREAM_IS_URL);
$default = stream_context_get_options(stream_context_get_default());
$default[$protocol]['client'] = $client;
if ($cache) {
$default[$protocol]['cache'] = $cache;
} elseif (!isset($default[$protocol]['cache'])) {
// Set a default cache adapter.
$default[$protocol]['cache'] = new LruArrayCache();
}
stream_context_set_default($default);
}
public function stream_close()
{
$this->body = $this->cache = null;
}
public function stream_open($path, $mode, $options, &$opened_path)
{
$this->initProtocol($path);
$this->params = $this->getBucketKey($path);
$this->mode = rtrim($mode, 'bt');
if ($errors = $this->validate($path, $this->mode)) {
return $this->triggerError($errors);
}
return $this->boolCall(function() use ($path) {
switch ($this->mode) {
case 'r': return $this->openReadStream($path);
case 'a': return $this->openAppendStream($path);
default: return $this->openWriteStream($path);
}
});
}
public function stream_eof()
{
return $this->body->eof();
}
public function stream_flush()
{
if ($this->mode == 'r') {
return false;
}
if ($this->body->isSeekable()) {
$this->body->seek(0);
}
$params = $this->getOptions(true);
$params['Body'] = $this->body;
// Attempt to guess the ContentType of the upload based on the
// file extension of the key
if (!isset($params['ContentType']) &&
($type = Psr7\mimetype_from_filename($params['Key']))
) {
$params['ContentType'] = $type;
}
return $this->boolCall(function () use ($params) {
return (bool) $this->getClient()->putObject($params);
});
}
public function stream_read($count)
{
return $this->body->read($count);
}
public function stream_seek($offset, $whence = SEEK_SET)
{
return !$this->body->isSeekable()
? false
: $this->boolCall(function () use ($offset, $whence) {
$this->body->seek($offset, $whence);
return true;
});
}
public function stream_tell()
{
return $this->boolCall(function() { return $this->body->tell(); });
}
public function stream_write($data)
{
return $this->body->write($data);
}
public function unlink($path)
{
$this->initProtocol($path);
return $this->boolCall(function () use ($path) {
$this->clearCacheKey($path);
$this->getClient()->deleteObject($this->withPath($path));
return true;
});
}
public function stream_stat()
{
$stat = $this->getStatTemplate();
$stat[7] = $stat['size'] = $this->getSize();
$stat[2] = $stat['mode'] = $this->mode;
return $stat;
}
/**
* Provides information for is_dir, is_file, filesize, etc. Works on
* buckets, keys, and prefixes.
* @link http://www.php.net/manual/en/streamwrapper.url-stat.php
*/
public function url_stat($path, $flags)
{
$this->initProtocol($path);
// Some paths come through as S3:// for some reason.
$split = explode('://', $path);
$path = strtolower($split[0]) . '://' . $split[1];
// Check if this path is in the url_stat cache
if ($value = $this->getCacheStorage()->get($path)) {
return $value;
}
$stat = $this->createStat($path, $flags);
if (is_array($stat)) {
$this->getCacheStorage()->set($path, $stat);
}
return $stat;
}
/**
* Parse the protocol out of the given path.
*
* @param $path
*/
private function initProtocol($path)
{
$parts = explode('://', $path, 2);
$this->protocol = $parts[0] ?: 's3';
}
private function createStat($path, $flags)
{
$this->initProtocol($path);
$parts = $this->withPath($path);
if (!$parts['Key']) {
return $this->statDirectory($parts, $path, $flags);
}
return $this->boolCall(function () use ($parts, $path) {
try {
$result = $this->getClient()->headObject($parts);
if (substr($parts['Key'], -1, 1) == '/' &&
$result['ContentLength'] == 0
) {
// Return as if it is a bucket to account for console
// bucket objects (e.g., zero-byte object "foo/")
return $this->formatUrlStat($path);
} else {
// Attempt to stat and cache regular object
return $this->formatUrlStat($result->toArray());
}
} catch (S3Exception $e) {
// Maybe this isn't an actual key, but a prefix. Do a prefix
// listing of objects to determine.
$result = $this->getClient()->listObjects([
'Bucket' => $parts['Bucket'],
'Prefix' => rtrim($parts['Key'], '/') . '/',
'MaxKeys' => 1
]);
if (!$result['Contents'] && !$result['CommonPrefixes']) {
throw new \Exception("File or directory not found: $path");
}
return $this->formatUrlStat($path);
}
}, $flags);
}
private function statDirectory($parts, $path, $flags)
{
// Stat "directories": buckets, or "s3://"
if (!$parts['Bucket'] ||
$this->getClient()->doesBucketExist($parts['Bucket'])
) {
return $this->formatUrlStat($path);
}
return $this->triggerError("File or directory not found: $path", $flags);
}
/**
* Support for mkdir().
*
* @param string $path Directory which should be created.
* @param int $mode Permissions. 700-range permissions map to
* ACL_PUBLIC. 600-range permissions map to
* ACL_AUTH_READ. All other permissions map to
* ACL_PRIVATE. Expects octal form.
* @param int $options A bitwise mask of values, such as
* STREAM_MKDIR_RECURSIVE.
*
* @return bool
* @link http://www.php.net/manual/en/streamwrapper.mkdir.php
*/
public function mkdir($path, $mode, $options)
{
$this->initProtocol($path);
$params = $this->withPath($path);
$this->clearCacheKey($path);
if (!$params['Bucket']) {
return false;
}
if (!isset($params['ACL'])) {
$params['ACL'] = $this->determineAcl($mode);
}
return empty($params['Key'])
? $this->createBucket($path, $params)
: $this->createSubfolder($path, $params);
}
public function rmdir($path, $options)
{
$this->initProtocol($path);
$this->clearCacheKey($path);
$params = $this->withPath($path);
$client = $this->getClient();
if (!$params['Bucket']) {
return $this->triggerError('You must specify a bucket');
}
return $this->boolCall(function () use ($params, $path, $client) {
if (!$params['Key']) {
$client->deleteBucket(['Bucket' => $params['Bucket']]);
return true;
}
return $this->deleteSubfolder($path, $params);
});
}
/**
* Support for opendir().
*
* The opendir() method of the Amazon S3 stream wrapper supports a stream
* context option of "listFilter". listFilter must be a callable that
* accepts an associative array of object data and returns true if the
* object should be yielded when iterating the keys in a bucket.
*
* @param string $path The path to the directory
* (e.g. "s3://dir[</prefix>]")
* @param string $options Unused option variable
*
* @return bool true on success
* @see http://www.php.net/manual/en/function.opendir.php
*/
public function dir_opendir($path, $options)
{
$this->initProtocol($path);
$this->openedPath = $path;
$params = $this->withPath($path);
$delimiter = $this->getOption('delimiter');
/** @var callable $filterFn */
$filterFn = $this->getOption('listFilter');
$op = ['Bucket' => $params['Bucket']];
$this->openedBucket = $params['Bucket'];
if ($delimiter === null) {
$delimiter = '/';
}
if ($delimiter) {
$op['Delimiter'] = $delimiter;
}
if ($params['Key']) {
$params['Key'] = rtrim($params['Key'], $delimiter) . $delimiter;
$op['Prefix'] = $params['Key'];
}
$this->openedBucketPrefix = $params['Key'];
// Filter our "/" keys added by the console as directories, and ensure
// that if a filter function is provided that it passes the filter.
$this->objectIterator = \Aws\flatmap(
$this->getClient()->getPaginator('ListObjects', $op),
function (Result $result) use ($filterFn) {
$contentsAndPrefixes = $result->search('[Contents[], CommonPrefixes[]][]');
// Filter out dir place holder keys and use the filter fn.
return array_filter(
$contentsAndPrefixes,
function ($key) use ($filterFn) {
return (!$filterFn || call_user_func($filterFn, $key))
&& (!isset($key['Key']) || substr($key['Key'], -1, 1) !== '/');
}
);
}
);
return true;
}
/**
* Close the directory listing handles
*
* @return bool true on success
*/
public function dir_closedir()
{
$this->objectIterator = null;
gc_collect_cycles();
return true;
}
/**
* This method is called in response to rewinddir()
*
* @return boolean true on success
*/
public function dir_rewinddir()
{
$this->boolCall(function() {
$this->objectIterator = null;
$this->dir_opendir($this->openedPath, null);
return true;
});
}
/**
* This method is called in response to readdir()
*
* @return string Should return a string representing the next filename, or
* false if there is no next file.
* @link http://www.php.net/manual/en/function.readdir.php
*/
public function dir_readdir()
{
// Skip empty result keys
if (!$this->objectIterator->valid()) {
return false;
}
// First we need to create a cache key. This key is the full path to
// then object in s3: protocol://bucket/key.
// Next we need to create a result value. The result value is the
// current value of the iterator without the opened bucket prefix to
// emulate how readdir() works on directories.
// The cache key and result value will depend on if this is a prefix
// or a key.
$cur = $this->objectIterator->current();
if (isset($cur['Prefix'])) {
// Include "directories". Be sure to strip a trailing "/"
// on prefixes.
$result = rtrim($cur['Prefix'], '/');
$key = $this->formatKey($result);
$stat = $this->formatUrlStat($key);
} else {
$result = $cur['Key'];
$key = $this->formatKey($cur['Key']);
$stat = $this->formatUrlStat($cur);
}
// Cache the object data for quick url_stat lookups used with
// RecursiveDirectoryIterator.
$this->getCacheStorage()->set($key, $stat);
$this->objectIterator->next();
// Remove the prefix from the result to emulate other stream wrappers.
return $this->openedBucketPrefix
? substr($result, strlen($this->openedBucketPrefix))
: $result;
}
private function formatKey($key)
{
$protocol = explode('://', $this->openedPath)[0];
return "{$protocol}://{$this->openedBucket}/{$key}";
}
/**
* Called in response to rename() to rename a file or directory. Currently
* only supports renaming objects.
*
* @param string $path_from the path to the file to rename
* @param string $path_to the new path to the file
*
* @return bool true if file was successfully renamed
* @link http://www.php.net/manual/en/function.rename.php
*/
public function rename($path_from, $path_to)
{
// PHP will not allow rename across wrapper types, so we can safely
// assume $path_from and $path_to have the same protocol
$this->initProtocol($path_from);
$partsFrom = $this->withPath($path_from);
$partsTo = $this->withPath($path_to);
$this->clearCacheKey($path_from);
$this->clearCacheKey($path_to);
if (!$partsFrom['Key'] || !$partsTo['Key']) {
return $this->triggerError('The Amazon S3 stream wrapper only '
. 'supports copying objects');
}
return $this->boolCall(function () use ($partsFrom, $partsTo) {
$options = $this->getOptions(true);
// Copy the object and allow overriding default parameters if
// desired, but by default copy metadata
$this->getClient()->copy(
$partsFrom['Bucket'],
$partsFrom['Key'],
$partsTo['Bucket'],
$partsTo['Key'],
isset($options['acl']) ? $options['acl'] : 'private',
$options
);
// Delete the original object
$this->getClient()->deleteObject([
'Bucket' => $partsFrom['Bucket'],
'Key' => $partsFrom['Key']
] + $options);
return true;
});
}
public function stream_cast($cast_as)
{
return false;
}
/**
* Validates the provided stream arguments for fopen and returns an array
* of errors.
*/
private function validate($path, $mode)
{
$errors = [];
if (!$this->getOption('Key')) {
$errors[] = 'Cannot open a bucket. You must specify a path in the '
. 'form of s3://bucket/key';
}
if (!in_array($mode, ['r', 'w', 'a', 'x'])) {
$errors[] = "Mode not supported: {$mode}. "
. "Use one 'r', 'w', 'a', or 'x'.";
}
// When using mode "x" validate if the file exists before attempting
// to read
if ($mode == 'x' &&
$this->getClient()->doesObjectExist(
$this->getOption('Bucket'),
$this->getOption('Key'),
$this->getOptions(true)
)
) {
$errors[] = "{$path} already exists on Amazon S3";
}
return $errors;
}
/**
* Get the stream context options available to the current stream
*
* @param bool $removeContextData Set to true to remove contextual kvp's
* like 'client' from the result.
*
* @return array
*/
private function getOptions($removeContextData = false)
{
// Context is not set when doing things like stat
if ($this->context === null) {
$options = [];
} else {
$options = stream_context_get_options($this->context);
$options = isset($options[$this->protocol])
? $options[$this->protocol]
: [];
}
$default = stream_context_get_options(stream_context_get_default());
$default = isset($default[$this->protocol])
? $default[$this->protocol]
: [];
$result = $this->params + $options + $default;
if ($removeContextData) {
unset($result['client'], $result['seekable'], $result['cache']);
}
return $result;
}
/**
* Get a specific stream context option
*
* @param string $name Name of the option to retrieve
*
* @return mixed|null
*/
private function getOption($name)
{
$options = $this->getOptions();
return isset($options[$name]) ? $options[$name] : null;
}
/**
* Gets the client from the stream context
*
* @return S3Client
* @throws \RuntimeException if no client has been configured
*/
private function getClient()
{
if (!$client = $this->getOption('client')) {
throw new \RuntimeException('No client in stream context');
}
return $client;
}
private function getBucketKey($path)
{
// Remove the protocol
$parts = explode('://', $path);
// Get the bucket, key
$parts = explode('/', $parts[1], 2);
return [
'Bucket' => $parts[0],
'Key' => isset($parts[1]) ? $parts[1] : null
];
}
/**
* Get the bucket and key from the passed path (e.g. s3://bucket/key)
*
* @param string $path Path passed to the stream wrapper
*
* @return array Hash of 'Bucket', 'Key', and custom params from the context
*/
private function withPath($path)
{
$params = $this->getOptions(true);
return $this->getBucketKey($path) + $params;
}
private function openReadStream()
{
$client = $this->getClient();
$command = $client->getCommand('GetObject', $this->getOptions(true));
$command['@http']['stream'] = true;
$result = $client->execute($command);
$this->size = $result['ContentLength'];
$this->body = $result['Body'];
// Wrap the body in a caching entity body if seeking is allowed
if ($this->getOption('seekable') && !$this->body->isSeekable()) {
$this->body = new CachingStream($this->body);
}
return true;
}
private function openWriteStream()
{
$this->body = new Stream(fopen('php://temp', 'r+'));
return true;
}
private function openAppendStream()
{
try {
// Get the body of the object and seek to the end of the stream
$client = $this->getClient();
$this->body = $client->getObject($this->getOptions(true))['Body'];
$this->body->seek(0, SEEK_END);
return true;
} catch (S3Exception $e) {
// The object does not exist, so use a simple write stream
return $this->openWriteStream();
}
}
/**
* Trigger one or more errors
*
* @param string|array $errors Errors to trigger
* @param mixed $flags If set to STREAM_URL_STAT_QUIET, then no
* error or exception occurs
*
* @return bool Returns false
* @throws \RuntimeException if throw_errors is true
*/
private function triggerError($errors, $flags = null)
{
// This is triggered with things like file_exists()
if ($flags & STREAM_URL_STAT_QUIET) {
return $flags & STREAM_URL_STAT_LINK
// This is triggered for things like is_link()
? $this->formatUrlStat(false)
: false;
}
// This is triggered when doing things like lstat() or stat()
trigger_error(implode("\n", (array) $errors), E_USER_WARNING);
return false;
}
/**
* Prepare a url_stat result array
*
* @param string|array $result Data to add
*
* @return array Returns the modified url_stat result
*/
private function formatUrlStat($result = null)
{
$stat = $this->getStatTemplate();
switch (gettype($result)) {
case 'NULL':
case 'string':
// Directory with 0777 access - see "man 2 stat".
$stat['mode'] = $stat[2] = 0040777;
break;
case 'array':
// Regular file with 0777 access - see "man 2 stat".
$stat['mode'] = $stat[2] = 0100777;
// Pluck the content-length if available.
if (isset($result['ContentLength'])) {
$stat['size'] = $stat[7] = $result['ContentLength'];
} elseif (isset($result['Size'])) {
$stat['size'] = $stat[7] = $result['Size'];
}
if (isset($result['LastModified'])) {
// ListObjects or HeadObject result
$stat['mtime'] = $stat[9] = $stat['ctime'] = $stat[10]
= strtotime($result['LastModified']);
}
}
return $stat;
}
/**
* Creates a bucket for the given parameters.
*
* @param string $path Stream wrapper path
* @param array $params A result of StreamWrapper::withPath()
*
* @return bool Returns true on success or false on failure
*/
private function createBucket($path, array $params)
{
if ($this->getClient()->doesBucketExist($params['Bucket'])) {
return $this->triggerError("Bucket already exists: {$path}");
}
return $this->boolCall(function () use ($params, $path) {
$this->getClient()->createBucket($params);
$this->clearCacheKey($path);
return true;
});
}
/**
* Creates a pseudo-folder by creating an empty "/" suffixed key
*
* @param string $path Stream wrapper path
* @param array $params A result of StreamWrapper::withPath()
*
* @return bool
*/
private function createSubfolder($path, array $params)
{
// Ensure the path ends in "/" and the body is empty.
$params['Key'] = rtrim($params['Key'], '/') . '/';
$params['Body'] = '';
// Fail if this pseudo directory key already exists
if ($this->getClient()->doesObjectExist(
$params['Bucket'],
$params['Key'])
) {
return $this->triggerError("Subfolder already exists: {$path}");
}
return $this->boolCall(function () use ($params, $path) {
$this->getClient()->putObject($params);
$this->clearCacheKey($path);
return true;
});
}
/**
* Deletes a nested subfolder if it is empty.
*
* @param string $path Path that is being deleted (e.g., 's3://a/b/c')
* @param array $params A result of StreamWrapper::withPath()
*
* @return bool
*/
private function deleteSubfolder($path, $params)
{
// Use a key that adds a trailing slash if needed.
$prefix = rtrim($params['Key'], '/') . '/';
$result = $this->getClient()->listObjects([
'Bucket' => $params['Bucket'],
'Prefix' => $prefix,
'MaxKeys' => 1
]);
// Check if the bucket contains keys other than the placeholder
if ($contents = $result['Contents']) {
return (count($contents) > 1 || $contents[0]['Key'] != $prefix)
? $this->triggerError('Subfolder is not empty')
: $this->unlink(rtrim($path, '/') . '/');
}
return $result['CommonPrefixes']
? $this->triggerError('Subfolder contains nested folders')
: true;
}
/**
* Determine the most appropriate ACL based on a file mode.
*
* @param int $mode File mode
*
* @return string
*/
private function determineAcl($mode)
{
switch (substr(decoct($mode), 0, 1)) {
case '7': return 'public-read';
case '6': return 'authenticated-read';
default: return 'private';
}
}
/**
* Gets a URL stat template with default values
*
* @return array
*/
private function getStatTemplate()
{
return [
0 => 0, 'dev' => 0,
1 => 0, 'ino' => 0,
2 => 0, 'mode' => 0,
3 => 0, 'nlink' => 0,
4 => 0, 'uid' => 0,
5 => 0, 'gid' => 0,
6 => -1, 'rdev' => -1,
7 => 0, 'size' => 0,
8 => 0, 'atime' => 0,
9 => 0, 'mtime' => 0,
10 => 0, 'ctime' => 0,
11 => -1, 'blksize' => -1,
12 => -1, 'blocks' => -1,
];
}
/**
* Invokes a callable and triggers an error if an exception occurs while
* calling the function.
*
* @param callable $fn
* @param int $flags
*
* @return bool
*/
private function boolCall(callable $fn, $flags = null)
{
try {
return $fn();
} catch (\Exception $e) {
return $this->triggerError($e->getMessage(), $flags);
}
}
/**
* @return LruArrayCache
*/
private function getCacheStorage()
{
if (!$this->cache) {
$this->cache = $this->getOption('cache') ?: new LruArrayCache();
}
return $this->cache;
}
/**
* Clears a specific stat cache value from the stat cache and LRU cache.
*
* @param string $key S3 path (s3://bucket/key).
*/
private function clearCacheKey($key)
{
clearstatcache(true, $key);
$this->getCacheStorage()->remove($key);
}
/**
* Returns the size of the opened object body.
*
* @return int|null
*/
private function getSize()
{
$size = $this->body->getSize();
return $size !== null ? $size : $this->size;
}
}
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