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[mediawiki.git] / includes / libs / filebackend / SwiftFileBackend.php

<?php
/**
 * OpenStack Swift based file backend.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 * http://www.gnu.org/copyleft/gpl.html
 *
 * @file
 * @ingroup FileBackend
 * @author Russ Nelson
 */

namespace Wikimedia\FileBackend;

use Exception;
use LockManager;
use MapCacheLRU;
use MediaWiki\Json\FormatJson;
use MediaWiki\Utils\MWTimestamp;
use Psr\Log\LoggerInterface;
use Shellbox\Command\BoxedCommand;
use StatusValue;
use stdClass;
use Wikimedia\AtEase\AtEase;
use Wikimedia\FileBackend\FileIteration\SwiftFileBackendDirList;
use Wikimedia\FileBackend\FileIteration\SwiftFileBackendFileList;
use Wikimedia\FileBackend\FileOpHandle\SwiftFileOpHandle;
use Wikimedia\Http\MultiHttpClient;
use Wikimedia\ObjectCache\BagOStuff;
use Wikimedia\ObjectCache\EmptyBagOStuff;
use Wikimedia\ObjectCache\WANObjectCache;
use Wikimedia\RequestTimeout\TimeoutException;

/**
 * @brief Class for an OpenStack Swift (or Ceph RGW) based file backend.
 *
 * StatusValue messages should avoid mentioning the Swift account name.
 * Likewise, error suppression should be used to avoid path disclosure.
 *
 * @ingroup FileBackend
 * @since 1.19
 */
class SwiftFileBackend extends FileBackendStore {
        private const DEFAULT_HTTP_OPTIONS = [ 'httpVersion' => 'v1.1' ];
        private const AUTH_FAILURE_ERROR = 'Could not connect due to prior authentication failure';

        /** @var MultiHttpClient */
        protected $http;
        /** @var int TTL in seconds */
        protected $authTTL;
        /** @var string Authentication base URL (without version) */
        protected $swiftAuthUrl;
        /** @var string Override of storage base URL */
        protected $swiftStorageUrl;
        /** @var string Swift user (account:user) to authenticate as */
        protected $swiftUser;
        /** @var string Secret key for user */
        protected $swiftKey;
        /** @var string Shared secret value for making temp URLs */
        protected $swiftTempUrlKey;
        /** @var bool */
        protected $canShellboxGetTempUrl;
        /** @var string|null */
        protected $shellboxIpRange;
        /** @var string S3 access key (RADOS Gateway) */
        protected $rgwS3AccessKey;
        /** @var string S3 authentication key (RADOS Gateway) */
        protected $rgwS3SecretKey;
        /** @var array Additional users (account:user) with read permissions on public containers */
        protected $readUsers;
        /** @var array Additional users (account:user) with write permissions on public containers */
        protected $writeUsers;
        /** @var array Additional users (account:user) with read permissions on private containers */
        protected $secureReadUsers;
        /** @var array Additional users (account:user) with write permissions on private containers */
        protected $secureWriteUsers;

        /** @var BagOStuff */
        protected $srvCache;

        /** @var MapCacheLRU Container stat cache */
        protected $containerStatCache;

        /** @var array|null */
        protected $authCreds;
        /** @var int|null UNIX timestamp */
        protected $authErrorTimestamp = null;

        /** @var bool Whether the server is an Ceph RGW */
        protected $isRGW = false;

        /**
         * @see FileBackendStore::__construct()
         * @param array $config Params include:
         *   - swiftAuthUrl       : Swift authentication server URL
         *   - swiftUser          : Swift user used by MediaWiki (account:username)
         *   - swiftKey           : Swift authentication key for the above user
         *   - swiftAuthTTL       : Swift authentication TTL (seconds)
         *   - swiftTempUrlKey    : Swift "X-Account-Meta-Temp-URL-Key" value on the account.
         *                          Do not set this until it has been set in the backend.
         *   - canShellboxGetTempUrl : Set this to true to generate a TempURL allowing Shellbox to
         *                          directly fetch files from Swift. swiftTempUrlKey should be set.
         *   - shellboxIpRange    : An IP range string to use when generating TempURLs for Shellbox.
         *                          Specifying this will improve security by preventing exfiltrated
         *                          TempURLs from being usable outside the server.
         *   - swiftStorageUrl    : Swift storage URL (overrides that of the authentication response).
         *                          This is useful to set if a TLS proxy is in use.
         *   - shardViaHashLevels : Map of container names to sharding config with:
         *                             - base   : base of hash characters, 16 or 36
         *                             - levels : the number of hash levels (and digits)
         *                             - repeat : hash subdirectories are prefixed with all the
         *                                        parent hash directory names (e.g. "a/ab/abc")
         *   - cacheAuthInfo      : Whether to cache authentication tokens in APC, etc.
         *                          If those are not available, then the main cache will be used.
         *                          This is probably insecure in shared hosting environments.
         *   - rgwS3AccessKey     : Rados Gateway S3 "access key" value on the account.
         *                          Do not set this until it has been set in the backend.
         *                          This is used for generating expiring pre-authenticated URLs.
         *                          Only use this when using rgw and to work around
         *                          http://tracker.newdream.net/issues/3454.
         *   - rgwS3SecretKey     : Rados Gateway S3 "secret key" value on the account.
         *                          Do not set this until it has been set in the backend.
         *                          This is used for generating expiring pre-authenticated URLs.
         *                          Only use this when using rgw and to work around
         *                          http://tracker.newdream.net/issues/3454.
         *   - readUsers           : Swift users with read access to public containers (account:username)
         *   - writeUsers          : Swift users with write access to public containers (account:username)
         *   - secureReadUsers     : Swift users with read access to private containers (account:username)
         *   - secureWriteUsers    : Swift users with write access to private containers (account:username)
         *   - connTimeout         : The HTTP connect timeout to use when connecting to Swift, in
         *                           seconds.
         *   - reqTimeout          : The HTTP request timeout to use when communicating with Swift, in
         *                           seconds.
         */
        public function __construct( array $config ) {
                parent::__construct( $config );
                // Required settings
                $this->swiftAuthUrl = $config['swiftAuthUrl'];
                $this->swiftUser = $config['swiftUser'];
                $this->swiftKey = $config['swiftKey'];
                // Optional settings
                $this->authTTL = $config['swiftAuthTTL'] ?? 15 * 60; // some sensible number
                $this->swiftTempUrlKey = $config['swiftTempUrlKey'] ?? '';
                $this->canShellboxGetTempUrl = $config['canShellboxGetTempUrl'] ?? false;
                $this->shellboxIpRange = $config['shellboxIpRange'] ?? null;
                $this->swiftStorageUrl = $config['swiftStorageUrl'] ?? null;
                $this->shardViaHashLevels = $config['shardViaHashLevels'] ?? '';
                $this->rgwS3AccessKey = $config['rgwS3AccessKey'] ?? '';
                $this->rgwS3SecretKey = $config['rgwS3SecretKey'] ?? '';

                // HTTP helper client
                $httpOptions = [];
                foreach ( [ 'connTimeout', 'reqTimeout' ] as $optionName ) {
                        if ( isset( $config[$optionName] ) ) {
                                $httpOptions[$optionName] = $config[$optionName];
                        }
                }
                $this->http = new MultiHttpClient( $httpOptions );
                $this->http->setLogger( $this->logger );

                // Cache container information to mask latency
                if ( isset( $config['wanCache'] ) && $config['wanCache'] instanceof WANObjectCache ) {
                        $this->memCache = $config['wanCache'];
                }
                // Process cache for container info
                $this->containerStatCache = new MapCacheLRU( 300 );
                // Cache auth token information to avoid RTTs
                if ( !empty( $config['cacheAuthInfo'] ) && isset( $config['srvCache'] ) ) {
                        $this->srvCache = $config['srvCache'];
                } else {
                        $this->srvCache = new EmptyBagOStuff();
                }
                $this->readUsers = $config['readUsers'] ?? [];
                $this->writeUsers = $config['writeUsers'] ?? [];
                $this->secureReadUsers = $config['secureReadUsers'] ?? [];
                $this->secureWriteUsers = $config['secureWriteUsers'] ?? [];
                // Per https://docs.openstack.org/swift/latest/overview_large_objects.html
                // we need to split objects if they are larger than 5 GB. Support for
                // splitting objects has not yet been implemented by this class
                // so limit max file size to 5GiB.
                $this->maxFileSize = 5 * 1024 * 1024 * 1024;
        }

        public function setLogger( LoggerInterface $logger ) {
                parent::setLogger( $logger );
                $this->http->setLogger( $logger );
        }

        public function getFeatures() {
                return (
                        self::ATTR_UNICODE_PATHS |
                        self::ATTR_HEADERS |
                        self::ATTR_METADATA
                );
        }

        protected function resolveContainerPath( $container, $relStoragePath ) {
                if ( !mb_check_encoding( $relStoragePath, 'UTF-8' ) ) {
                        return null; // not UTF-8, makes it hard to use CF and the swift HTTP API
                } elseif ( strlen( rawurlencode( $relStoragePath ) ) > 1024 ) {
                        return null; // too long for Swift
                }

                return $relStoragePath;
        }

        public function isPathUsableInternal( $storagePath ) {
                [ $container, $rel ] = $this->resolveStoragePathReal( $storagePath );
                if ( $rel === null ) {
                        return false; // invalid
                }

                return is_array( $this->getContainerStat( $container ) );
        }

        /**
         * Filter/normalize a header map to only include mutable "content-"/"x-content-" headers
         *
         * Mutable headers can be changed via HTTP POST even if the file content is the same
         *
         * @see https://docs.openstack.org/api-ref/object-store
         * @param string[] $headers Map of (header => value) for a swift object
         * @return string[] Map of (header => value) for Content-* headers mutable via POST
         */
        protected function extractMutableContentHeaders( array $headers ) {
                $contentHeaders = [];
                // Normalize casing, and strip out illegal headers
                foreach ( $headers as $name => $value ) {
                        $name = strtolower( $name );
                        if ( $name === 'x-delete-at' && is_numeric( $value ) ) {
                                // Expects a Unix Epoch date
                                $contentHeaders[$name] = $value;
                        } elseif ( $name === 'x-delete-after' && is_numeric( $value ) ) {
                                // Expects number of minutes time to live.
                                $contentHeaders[$name] = $value;
                        } elseif ( preg_match( '/^(x-)?content-(?!length$)/', $name ) ) {
                                // Only allow content-* and x-content-* headers (but not content-length)
                                $contentHeaders[$name] = $value;
                        } elseif ( $name === 'content-type' && strlen( $value ) ) {
                                // This header can be set to a value but not unset
                                $contentHeaders[$name] = $value;
                        }
                }
                // By default, Swift has annoyingly low maximum header value limits
                if ( isset( $contentHeaders['content-disposition'] ) ) {
                        $maxLength = 255;
                        // @note: assume FileBackend::makeContentDisposition() already used
                        $offset = $maxLength - strlen( $contentHeaders['content-disposition'] );
                        if ( $offset < 0 ) {
                                $pos = strrpos( $contentHeaders['content-disposition'], ';', $offset );
                                $contentHeaders['content-disposition'] = $pos === false
                                        ? ''
                                        : trim( substr( $contentHeaders['content-disposition'], 0, $pos ) );
                        }
                }

                return $contentHeaders;
        }

        /**
         * @see https://docs.openstack.org/api-ref/object-store
         * @param string[] $headers Map of (header => value) for a swift object
         * @return string[] Map of (metadata header name => metadata value)
         */
        protected function extractMetadataHeaders( array $headers ) {
                $metadataHeaders = [];
                foreach ( $headers as $name => $value ) {
                        $name = strtolower( $name );
                        if ( strpos( $name, 'x-object-meta-' ) === 0 ) {
                                $metadataHeaders[$name] = $value;
                        }
                }

                return $metadataHeaders;
        }

        /**
         * @see https://docs.openstack.org/api-ref/object-store
         * @param string[] $headers Map of (header => value) for a swift object
         * @return string[] Map of (metadata key name => metadata value)
         */
        protected function getMetadataFromHeaders( array $headers ) {
                $prefixLen = strlen( 'x-object-meta-' );

                $metadata = [];
                foreach ( $this->extractMetadataHeaders( $headers ) as $name => $value ) {
                        $metadata[substr( $name, $prefixLen )] = $value;
                }

                return $metadata;
        }

        protected function doCreateInternal( array $params ) {
                $status = $this->newStatus();

                [ $dstCont, $dstRel ] = $this->resolveStoragePathReal( $params['dst'] );
                if ( $dstRel === null ) {
                        $status->fatal( 'backend-fail-invalidpath', $params['dst'] );

                        return $status;
                }

                // Headers that are not strictly a function of the file content
                $mutableHeaders = $this->extractMutableContentHeaders( $params['headers'] ?? [] );
                // Make sure that the "content-type" header is set to something sensible
                $mutableHeaders['content-type']
                        ??= $this->getContentType( $params['dst'], $params['content'], null );

                $reqs = [ [
                        'method' => 'PUT',
                        'container' => $dstCont,
                        'relPath' => $dstRel,
                        'headers' => array_merge(
                                $mutableHeaders,
                                [
                                        'etag' => md5( $params['content'] ),
                                        'content-length' => strlen( $params['content'] ),
                                        'x-object-meta-sha1base36' =>
                                                \Wikimedia\base_convert( sha1( $params['content'] ), 16, 36, 31 )
                                ]
                        ),
                        'body' => $params['content']
                ] ];

                $method = __METHOD__;
                $handler = function ( array $request, StatusValue $status ) use ( $method, $params ) {
                        [ $rcode, $rdesc, , $rbody, $rerr ] = $request['response'];
                        if ( $rcode === 201 || $rcode === 202 ) {
                                // good
                        } elseif ( $rcode === 412 ) {
                                $status->fatal( 'backend-fail-contenttype', $params['dst'] );
                        } else {
                                $this->onError( $status, $method, $params, $rerr, $rcode, $rdesc, $rbody );
                        }

                        return SwiftFileOpHandle::CONTINUE_IF_OK;
                };

                $opHandle = new SwiftFileOpHandle( $this, $handler, $reqs );
                if ( !empty( $params['async'] ) ) { // deferred
                        $status->value = $opHandle;
                } else { // actually write the object in Swift
                        $status->merge( current( $this->executeOpHandlesInternal( [ $opHandle ] ) ) );
                }

                return $status;
        }

        protected function doStoreInternal( array $params ) {
                $status = $this->newStatus();

                [ $dstCont, $dstRel ] = $this->resolveStoragePathReal( $params['dst'] );
                if ( $dstRel === null ) {
                        $status->fatal( 'backend-fail-invalidpath', $params['dst'] );

                        return $status;
                }

                // Open a handle to the source file so that it can be streamed. The size and hash
                // will be computed using the handle. In the off chance that the source file changes
                // during this operation, the PUT will fail due to an ETag mismatch and be aborted.
                AtEase::suppressWarnings();
                $srcHandle = fopen( $params['src'], 'rb' );
                AtEase::restoreWarnings();
                if ( $srcHandle === false ) { // source doesn't exist?
                        $status->fatal( 'backend-fail-notexists', $params['src'] );

                        return $status;
                }

                // Compute the MD5 and SHA-1 hashes in one pass
                $srcSize = fstat( $srcHandle )['size'];
                $md5Context = hash_init( 'md5' );
                $sha1Context = hash_init( 'sha1' );
                $hashDigestSize = 0;
                while ( !feof( $srcHandle ) ) {
                        $buffer = (string)fread( $srcHandle, 131_072 ); // 128 KiB
                        hash_update( $md5Context, $buffer );
                        hash_update( $sha1Context, $buffer );
                        $hashDigestSize += strlen( $buffer );
                }
                // Reset the handle back to the beginning so that it can be streamed
                rewind( $srcHandle );

                if ( $hashDigestSize !== $srcSize ) {
                        $status->fatal( 'backend-fail-hash', $params['src'] );

                        return $status;
                }

                // Headers that are not strictly a function of the file content
                $mutableHeaders = $this->extractMutableContentHeaders( $params['headers'] ?? [] );
                // Make sure that the "content-type" header is set to something sensible
                $mutableHeaders['content-type']
                        ??= $this->getContentType( $params['dst'], null, $params['src'] );

                $reqs = [ [
                        'method' => 'PUT',
                        'container' => $dstCont,
                        'relPath' => $dstRel,
                        'headers' => array_merge(
                                $mutableHeaders,
                                [
                                        'content-length' => $srcSize,
                                        'etag' => hash_final( $md5Context ),
                                        'x-object-meta-sha1base36' =>
                                                \Wikimedia\base_convert( hash_final( $sha1Context ), 16, 36, 31 )
                                ]
                        ),
                        'body' => $srcHandle // resource
                ] ];

                $method = __METHOD__;
                $handler = function ( array $request, StatusValue $status ) use ( $method, $params ) {
                        [ $rcode, $rdesc, , $rbody, $rerr ] = $request['response'];
                        if ( $rcode === 201 || $rcode === 202 ) {
                                // good
                        } elseif ( $rcode === 412 ) {
                                $status->fatal( 'backend-fail-contenttype', $params['dst'] );
                        } else {
                                $this->onError( $status, $method, $params, $rerr, $rcode, $rdesc, $rbody );
                        }

                        return SwiftFileOpHandle::CONTINUE_IF_OK;
                };

                $opHandle = new SwiftFileOpHandle( $this, $handler, $reqs );
                $opHandle->resourcesToClose[] = $srcHandle;

                if ( !empty( $params['async'] ) ) { // deferred
                        $status->value = $opHandle;
                } else { // actually write the object in Swift
                        $status->merge( current( $this->executeOpHandlesInternal( [ $opHandle ] ) ) );
                }

                return $status;
        }

        protected function doCopyInternal( array $params ) {
                $status = $this->newStatus();

                [ $srcCont, $srcRel ] = $this->resolveStoragePathReal( $params['src'] );
                if ( $srcRel === null ) {
                        $status->fatal( 'backend-fail-invalidpath', $params['src'] );

                        return $status;
                }

                [ $dstCont, $dstRel ] = $this->resolveStoragePathReal( $params['dst'] );
                if ( $dstRel === null ) {
                        $status->fatal( 'backend-fail-invalidpath', $params['dst'] );

                        return $status;
                }

                $reqs = [ [
                        'method' => 'PUT',
                        'container' => $dstCont,
                        'relPath' => $dstRel,
                        'headers' => array_merge(
                                $this->extractMutableContentHeaders( $params['headers'] ?? [] ),
                                [
                                        'x-copy-from' => '/' . rawurlencode( $srcCont ) . '/' .
                                                str_replace( "%2F", "/", rawurlencode( $srcRel ) )
                                ]
                        )
                ] ];

                $method = __METHOD__;
                $handler = function ( array $request, StatusValue $status ) use ( $method, $params ) {
                        [ $rcode, $rdesc, , $rbody, $rerr ] = $request['response'];
                        if ( $rcode === 201 ) {
                                // good
                        } elseif ( $rcode === 404 ) {
                                if ( empty( $params['ignoreMissingSource'] ) ) {
                                        $status->fatal( 'backend-fail-copy', $params['src'], $params['dst'] );
                                }
                        } else {
                                $this->onError( $status, $method, $params, $rerr, $rcode, $rdesc, $rbody );
                        }

                        return SwiftFileOpHandle::CONTINUE_IF_OK;
                };

                $opHandle = new SwiftFileOpHandle( $this, $handler, $reqs );
                if ( !empty( $params['async'] ) ) { // deferred
                        $status->value = $opHandle;
                } else { // actually write the object in Swift
                        $status->merge( current( $this->executeOpHandlesInternal( [ $opHandle ] ) ) );
                }

                return $status;
        }

        protected function doMoveInternal( array $params ) {
                $status = $this->newStatus();

                [ $srcCont, $srcRel ] = $this->resolveStoragePathReal( $params['src'] );
                if ( $srcRel === null ) {
                        $status->fatal( 'backend-fail-invalidpath', $params['src'] );

                        return $status;
                }

                [ $dstCont, $dstRel ] = $this->resolveStoragePathReal( $params['dst'] );
                if ( $dstRel === null ) {
                        $status->fatal( 'backend-fail-invalidpath', $params['dst'] );

                        return $status;
                }

                $reqs = [ [
                        'method' => 'PUT',
                        'container' => $dstCont,
                        'relPath' => $dstRel,
                        'headers' => array_merge(
                                $this->extractMutableContentHeaders( $params['headers'] ?? [] ),
                                [
                                        'x-copy-from' => '/' . rawurlencode( $srcCont ) . '/' .
                                                str_replace( "%2F", "/", rawurlencode( $srcRel ) )
                                ]
                        )
                ] ];
                if ( "{$srcCont}/{$srcRel}" !== "{$dstCont}/{$dstRel}" ) {
                        $reqs[] = [
                                'method' => 'DELETE',
                                'container' => $srcCont,
                                'relPath' => $srcRel,
                                'headers' => []
                        ];
                }

                $method = __METHOD__;
                $handler = function ( array $request, StatusValue $status ) use ( $method, $params ) {
                        [ $rcode, $rdesc, , $rbody, $rerr ] = $request['response'];
                        if ( $request['method'] === 'PUT' && $rcode === 201 ) {
                                // good
                        } elseif ( $request['method'] === 'DELETE' && $rcode === 204 ) {
                                // good
                        } elseif ( $rcode === 404 ) {
                                if ( empty( $params['ignoreMissingSource'] ) ) {
                                        $status->fatal( 'backend-fail-move', $params['src'], $params['dst'] );
                                } else {
                                        // Leave Status as OK but skip the DELETE request
                                        return SwiftFileOpHandle::CONTINUE_NO;
                                }
                        } else {
                                $this->onError( $status, $method, $params, $rerr, $rcode, $rdesc, $rbody );
                        }

                        return SwiftFileOpHandle::CONTINUE_IF_OK;
                };

                $opHandle = new SwiftFileOpHandle( $this, $handler, $reqs );
                if ( !empty( $params['async'] ) ) { // deferred
                        $status->value = $opHandle;
                } else { // actually move the object in Swift
                        $status->merge( current( $this->executeOpHandlesInternal( [ $opHandle ] ) ) );
                }

                return $status;
        }

        protected function doDeleteInternal( array $params ) {
                $status = $this->newStatus();

                [ $srcCont, $srcRel ] = $this->resolveStoragePathReal( $params['src'] );
                if ( $srcRel === null ) {
                        $status->fatal( 'backend-fail-invalidpath', $params['src'] );

                        return $status;
                }

                $reqs = [ [
                        'method' => 'DELETE',
                        'container' => $srcCont,
                        'relPath' => $srcRel,
                        'headers' => []
                ] ];

                $method = __METHOD__;
                $handler = function ( array $request, StatusValue $status ) use ( $method, $params ) {
                        [ $rcode, $rdesc, , $rbody, $rerr ] = $request['response'];
                        if ( $rcode === 204 ) {
                                // good
                        } elseif ( $rcode === 404 ) {
                                if ( empty( $params['ignoreMissingSource'] ) ) {
                                        $status->fatal( 'backend-fail-delete', $params['src'] );
                                }
                        } else {
                                $this->onError( $status, $method, $params, $rerr, $rcode, $rdesc, $rbody );
                        }

                        return SwiftFileOpHandle::CONTINUE_IF_OK;
                };

                $opHandle = new SwiftFileOpHandle( $this, $handler, $reqs );
                if ( !empty( $params['async'] ) ) { // deferred
                        $status->value = $opHandle;
                } else { // actually delete the object in Swift
                        $status->merge( current( $this->executeOpHandlesInternal( [ $opHandle ] ) ) );
                }

                return $status;
        }

        protected function doDescribeInternal( array $params ) {
                $status = $this->newStatus();

                [ $srcCont, $srcRel ] = $this->resolveStoragePathReal( $params['src'] );
                if ( $srcRel === null ) {
                        $status->fatal( 'backend-fail-invalidpath', $params['src'] );

                        return $status;
                }

                // Fetch the old object headers/metadata...this should be in stat cache by now
                $stat = $this->getFileStat( [ 'src' => $params['src'], 'latest' => 1 ] );
                if ( $stat && !isset( $stat['xattr'] ) ) { // older cache entry
                        $stat = $this->doGetFileStat( [ 'src' => $params['src'], 'latest' => 1 ] );
                }
                if ( !$stat ) {
                        $status->fatal( 'backend-fail-describe', $params['src'] );

                        return $status;
                }

                // Swift object POST clears any prior headers, so merge the new and old headers here.
                // Also, during, POST, libcurl adds "Content-Type: application/x-www-form-urlencoded"
                // if "Content-Type" is not set, which would clobber the header value for the object.
                $oldMetadataHeaders = [];
                foreach ( $stat['xattr']['metadata'] as $name => $value ) {
                        $oldMetadataHeaders["x-object-meta-$name"] = $value;
                }
                $newContentHeaders = $this->extractMutableContentHeaders( $params['headers'] ?? [] );
                $oldContentHeaders = $stat['xattr']['headers'];

                $reqs = [ [
                        'method' => 'POST',
                        'container' => $srcCont,
                        'relPath' => $srcRel,
                        'headers' => $oldMetadataHeaders + $newContentHeaders + $oldContentHeaders
                ] ];

                $method = __METHOD__;
                $handler = function ( array $request, StatusValue $status ) use ( $method, $params ) {
                        [ $rcode, $rdesc, , $rbody, $rerr ] = $request['response'];
                        if ( $rcode === 202 ) {
                                // good
                        } elseif ( $rcode === 404 ) {
                                $status->fatal( 'backend-fail-describe', $params['src'] );
                        } else {
                                $this->onError( $status, $method, $params, $rerr, $rcode, $rdesc, $rbody );
                        }
                };

                $opHandle = new SwiftFileOpHandle( $this, $handler, $reqs );
                if ( !empty( $params['async'] ) ) { // deferred
                        $status->value = $opHandle;
                } else { // actually change the object in Swift
                        $status->merge( current( $this->executeOpHandlesInternal( [ $opHandle ] ) ) );
                }

                return $status;
        }

        /**
         * @inheritDoc
         */
        protected function doPrepareInternal( $fullCont, $dir, array $params ) {
                $status = $this->newStatus();

                // (a) Check if container already exists
                $stat = $this->getContainerStat( $fullCont );
                if ( is_array( $stat ) ) {
                        return $status; // already there
                } elseif ( $stat === self::RES_ERROR ) {
                        $status->fatal( 'backend-fail-internal', $this->name );
                        $this->logger->error( __METHOD__ . ': cannot get container stat' );
                } else {
                        // (b) Create container as needed with proper ACLs
                        $params['op'] = 'prepare';
                        $status->merge( $this->createContainer( $fullCont, $params ) );
                }

                return $status;
        }

        protected function doSecureInternal( $fullCont, $dir, array $params ) {
                $status = $this->newStatus();
                if ( empty( $params['noAccess'] ) ) {
                        return $status; // nothing to do
                }

                $stat = $this->getContainerStat( $fullCont );
                if ( is_array( $stat ) ) {
                        $readUsers = array_merge( $this->secureReadUsers, [ $this->swiftUser ] );
                        $writeUsers = array_merge( $this->secureWriteUsers, [ $this->swiftUser ] );
                        // Make container private to end-users...
                        $status->merge( $this->setContainerAccess(
                                $fullCont,
                                $readUsers,
                                $writeUsers
                        ) );
                } elseif ( $stat === self::RES_ABSENT ) {
                        $status->fatal( 'backend-fail-usable', $params['dir'] );
                } else {
                        $status->fatal( 'backend-fail-internal', $this->name );
                        $this->logger->error( __METHOD__ . ': cannot get container stat' );
                }

                return $status;
        }

        protected function doPublishInternal( $fullCont, $dir, array $params ) {
                $status = $this->newStatus();
                if ( empty( $params['access'] ) ) {
                        return $status; // nothing to do
                }

                $stat = $this->getContainerStat( $fullCont );
                if ( is_array( $stat ) ) {
                        $readUsers = array_merge( $this->readUsers, [ $this->swiftUser, '.r:*' ] );
                        if ( !empty( $params['listing'] ) ) {
                                array_push( $readUsers, '.rlistings' );
                        }
                        $writeUsers = array_merge( $this->writeUsers, [ $this->swiftUser ] );

                        // Make container public to end-users...
                        $status->merge( $this->setContainerAccess(
                                $fullCont,
                                $readUsers,
                                $writeUsers
                        ) );
                } elseif ( $stat === self::RES_ABSENT ) {
                        $status->fatal( 'backend-fail-usable', $params['dir'] );
                } else {
                        $status->fatal( 'backend-fail-internal', $this->name );
                        $this->logger->error( __METHOD__ . ': cannot get container stat' );
                }

                return $status;
        }

        protected function doCleanInternal( $fullCont, $dir, array $params ) {
                $status = $this->newStatus();

                // Only containers themselves can be removed, all else is virtual
                if ( $dir != '' ) {
                        return $status; // nothing to do
                }

                // (a) Check the container
                $stat = $this->getContainerStat( $fullCont, true );
                if ( $stat === self::RES_ABSENT ) {
                        return $status; // ok, nothing to do
                } elseif ( $stat === self::RES_ERROR ) {
                        $status->fatal( 'backend-fail-internal', $this->name );
                        $this->logger->error( __METHOD__ . ': cannot get container stat' );
                } elseif ( is_array( $stat ) && $stat['count'] == 0 ) {
                        // (b) Delete the container if empty
                        $params['op'] = 'clean';
                        $status->merge( $this->deleteContainer( $fullCont, $params ) );
                }

                return $status;
        }

        protected function doGetFileStat( array $params ) {
                $params = [ 'srcs' => [ $params['src'] ], 'concurrency' => 1 ] + $params;
                unset( $params['src'] );
                $stats = $this->doGetFileStatMulti( $params );

                return reset( $stats );
        }

        /**
         * Convert dates like "Tue, 03 Jan 2012 22:01:04 GMT"/"2013-05-11T07:37:27.678360Z".
         * Dates might also come in like "2013-05-11T07:37:27.678360" from Swift listings,
         * missing the timezone suffix (though Ceph RGW does not appear to have this bug).
         *
         * @param string $ts
         * @param int $format Output format (TS_* constant)
         * @return string
         * @throws FileBackendError
         */
        protected function convertSwiftDate( $ts, $format = TS_MW ) {
                try {
                        $timestamp = new MWTimestamp( $ts );

                        return $timestamp->getTimestamp( $format );
                } catch ( TimeoutException $e ) {
                        throw $e;
                } catch ( Exception $e ) {
                        throw new FileBackendError( $e->getMessage() );
                }
        }

        /**
         * Fill in any missing object metadata and save it to Swift
         *
         * @param array $objHdrs Object response headers
         * @param string $path Storage path to object
         * @return array New headers
         */
        protected function addMissingHashMetadata( array $objHdrs, $path ) {
                if ( isset( $objHdrs['x-object-meta-sha1base36'] ) ) {
                        return $objHdrs; // nothing to do
                }

                /** @noinspection PhpUnusedLocalVariableInspection */
                $ps = $this->scopedProfileSection( __METHOD__ . "-{$this->name}" );
                $this->logger->error( __METHOD__ . ": {path} was not stored with SHA-1 metadata.",
                        [ 'path' => $path ] );

                $objHdrs['x-object-meta-sha1base36'] = false;

                // Find prior custom HTTP headers
                $postHeaders = $this->extractMutableContentHeaders( $objHdrs );
                // Find prior metadata headers
                $postHeaders += $this->extractMetadataHeaders( $objHdrs );

                $status = $this->newStatus();
                /** @noinspection PhpUnusedLocalVariableInspection */
                $scopeLockS = $this->getScopedFileLocks( [ $path ], LockManager::LOCK_UW, $status );
                if ( $status->isOK() ) {
                        $tmpFile = $this->getLocalCopy( [ 'src' => $path, 'latest' => 1 ] );
                        if ( $tmpFile ) {
                                $hash = $tmpFile->getSha1Base36();
                                if ( $hash !== false ) {
                                        $objHdrs['x-object-meta-sha1base36'] = $hash;
                                        // Merge new SHA1 header into the old ones
                                        $postHeaders['x-object-meta-sha1base36'] = $hash;
                                        [ $srcCont, $srcRel ] = $this->resolveStoragePathReal( $path );
                                        [ $rcode ] = $this->requestWithAuth( [
                                                'method' => 'POST',
                                                'container' => $srcCont,
                                                'relPath' => $srcRel,
                                                'headers' => $postHeaders
                                        ] );
                                        if ( $rcode >= 200 && $rcode <= 299 ) {
                                                $this->deleteFileCache( $path );

                                                return $objHdrs; // success
                                        }
                                }
                        }
                }

                $this->logger->error( __METHOD__ . ': unable to set SHA-1 metadata for {path}',
                        [ 'path' => $path ] );

                return $objHdrs; // failed
        }

        protected function doGetFileContentsMulti( array $params ) {
                $ep = array_diff_key( $params, [ 'srcs' => 1 ] ); // for error logging
                // Blindly create tmp files and stream to them, catching any exception
                // if the file does not exist. Do not waste time doing file stats here.
                $reqs = []; // (path => op)

                // Initial dummy values to preserve path order
                $contents = array_fill_keys( $params['srcs'], self::RES_ERROR );
                foreach ( $params['srcs'] as $path ) { // each path in this concurrent batch
                        [ $srcCont, $srcRel ] = $this->resolveStoragePathReal( $path );
                        if ( $srcRel === null ) {
                                continue; // invalid storage path
                        }
                        // Create a new temporary memory file...
                        $handle = fopen( 'php://temp', 'wb' );
                        if ( $handle ) {
                                $reqs[$path] = [
                                        'method'  => 'GET',
                                        'container' => $srcCont,
                                        'relPath' => $srcRel,
                                        'headers' => $this->headersFromParams( $params ),
                                        'stream'  => $handle,
                                ];
                        }
                }

                $reqs = $this->requestMultiWithAuth(
                        $reqs,
                        [ 'maxConnsPerHost' => $params['concurrency'] ]
                );
                foreach ( $reqs as $path => $op ) {
                        [ $rcode, $rdesc, $rhdrs, $rbody, $rerr ] = $op['response'];
                        if ( $rcode >= 200 && $rcode <= 299 ) {
                                rewind( $op['stream'] ); // start from the beginning
                                $content = (string)stream_get_contents( $op['stream'] );
                                $size = strlen( $content );
                                // Make sure that stream finished
                                if ( $size === (int)$rhdrs['content-length'] ) {
                                        $contents[$path] = $content;
                                } else {
                                        $contents[$path] = self::RES_ERROR;
                                        $rerr = "Got {$size}/{$rhdrs['content-length']} bytes";
                                        $this->onError( null, __METHOD__,
                                                [ 'src' => $path ] + $ep, $rerr, $rcode, $rdesc );
                                }
                        } elseif ( $rcode === 404 ) {
                                $contents[$path] = self::RES_ABSENT;
                        } else {
                                $contents[$path] = self::RES_ERROR;
                                $this->onError( null, __METHOD__,
                                        [ 'src' => $path ] + $ep, $rerr, $rcode, $rdesc, $rbody );
                        }
                        fclose( $op['stream'] ); // close open handle
                }

                return $contents;
        }

        protected function doDirectoryExists( $fullCont, $dir, array $params ) {
                $prefix = ( $dir == '' ) ? null : "{$dir}/";
                $status = $this->objectListing( $fullCont, 'names', 1, null, $prefix );
                if ( $status->isOK() ) {
                        return ( count( $status->value ) ) > 0;
                }

                return self::RES_ERROR;
        }

        /**
         * @see FileBackendStore::getDirectoryListInternal()
         * @param string $fullCont
         * @param string $dir
         * @param array $params
         * @return SwiftFileBackendDirList
         */
        public function getDirectoryListInternal( $fullCont, $dir, array $params ) {
                return new SwiftFileBackendDirList( $this, $fullCont, $dir, $params );
        }

        /**
         * @see FileBackendStore::getFileListInternal()
         * @param string $fullCont
         * @param string $dir
         * @param array $params
         * @return SwiftFileBackendFileList
         */
        public function getFileListInternal( $fullCont, $dir, array $params ) {
                return new SwiftFileBackendFileList( $this, $fullCont, $dir, $params );
        }

        /**
         * Do not call this function outside of SwiftFileBackendFileList
         *
         * @param string $fullCont Resolved container name
         * @param string $dir Resolved storage directory with no trailing slash
         * @param string|null &$after Resolved container relative path used for continuation paging
         * @param int $limit Max number of items to list
         * @param array $params Parameters for {@link getDirectoryList()}
         * @return string[] List of resolved container relative directories directly under $dir
         * @throws FileBackendError
         */
        public function getDirListPageInternal( $fullCont, $dir, &$after, $limit, array $params ) {
                $dirs = [];
                if ( $after === INF ) {
                        return $dirs; // nothing more
                }

                /** @noinspection PhpUnusedLocalVariableInspection */
                $ps = $this->scopedProfileSection( __METHOD__ . "-{$this->name}" );

                $prefix = ( $dir == '' ) ? null : "{$dir}/";
                // Non-recursive: only list dirs right under $dir
                if ( !empty( $params['topOnly'] ) ) {
                        $status = $this->objectListing( $fullCont, 'names', $limit, $after, $prefix, '/' );
                        if ( !$status->isOK() ) {
                                throw new FileBackendError( "Iterator page I/O error." );
                        }
                        $objects = $status->value;
                        // @phan-suppress-next-line PhanTypeSuspiciousNonTraversableForeach
                        foreach ( $objects as $object ) { // files and directories
                                if ( substr( $object, -1 ) === '/' ) {
                                        $dirs[] = $object; // directories end in '/'
                                }
                        }
                } else {
                        // Recursive: list all dirs under $dir and its subdirs
                        $getParentDir = static function ( $path ) {
                                return ( $path !== null && strpos( $path, '/' ) !== false ) ? dirname( $path ) : false;
                        };

                        // Get directory from last item of prior page
                        $lastDir = $getParentDir( $after ); // must be first page
                        $status = $this->objectListing( $fullCont, 'names', $limit, $after, $prefix );

                        if ( !$status->isOK() ) {
                                throw new FileBackendError( "Iterator page I/O error." );
                        }

                        $objects = $status->value;

                        // @phan-suppress-next-line PhanTypeSuspiciousNonTraversableForeach
                        foreach ( $objects as $object ) { // files
                                $objectDir = $getParentDir( $object ); // directory of object

                                if ( $objectDir !== false && $objectDir !== $dir ) {
                                        // Swift stores paths in UTF-8, using binary sorting.
                                        // See function "create_container_table" in common/db.py.
                                        // If a directory is not "greater" than the last one,
                                        // then it was already listed by the calling iterator.
                                        if ( strcmp( $objectDir, $lastDir ) > 0 ) {
                                                $pDir = $objectDir;
                                                do { // add dir and all its parent dirs
                                                        $dirs[] = "{$pDir}/";
                                                        $pDir = $getParentDir( $pDir );
                                                } while ( $pDir !== false
                                                        && strcmp( $pDir, $lastDir ) > 0 // not done already
                                                        && strlen( $pDir ) > strlen( $dir ) // within $dir
                                                );
                                        }
                                        $lastDir = $objectDir;
                                }
                        }
                }
                // Page on the unfiltered directory listing (what is returned may be filtered)
                if ( count( $objects ) < $limit ) {
                        $after = INF; // avoid a second RTT
                } else {
                        $after = end( $objects ); // update last item
                }

                return $dirs;
        }

        /**
         * Do not call this function outside of SwiftFileBackendFileList
         *
         * @param string $fullCont Resolved container name
         * @param string $dir Resolved storage directory with no trailing slash
         * @param string|null &$after Resolved container relative path of file to list items after
         * @param int $limit Max number of items to list
         * @param array $params Parameters for {@link getFileList()}
         * @return array[] List of (name, stat map or null) tuples under $dir
         * @throws FileBackendError
         */
        public function getFileListPageInternal( $fullCont, $dir, &$after, $limit, array $params ) {
                $files = []; // list of (path, stat map or null) entries
                if ( $after === INF ) {
                        return $files; // nothing more
                }

                /** @noinspection PhpUnusedLocalVariableInspection */
                $ps = $this->scopedProfileSection( __METHOD__ . "-{$this->name}" );

                $prefix = ( $dir == '' ) ? null : "{$dir}/";
                // $objects will contain a list of unfiltered names or stdClass items
                // Non-recursive: only list files right under $dir
                if ( !empty( $params['topOnly'] ) ) {
                        if ( !empty( $params['adviseStat'] ) ) {
                                $status = $this->objectListing( $fullCont, 'info', $limit, $after, $prefix, '/' );
                        } else {
                                $status = $this->objectListing( $fullCont, 'names', $limit, $after, $prefix, '/' );
                        }
                } else {
                        // Recursive: list all files under $dir and its subdirs
                        if ( !empty( $params['adviseStat'] ) ) {
                                $status = $this->objectListing( $fullCont, 'info', $limit, $after, $prefix );
                        } else {
                                $status = $this->objectListing( $fullCont, 'names', $limit, $after, $prefix );
                        }
                }

                // Reformat this list into a list of (name, stat map or null) entries
                if ( !$status->isOK() ) {
                        throw new FileBackendError( "Iterator page I/O error." );
                }

                $objects = $status->value;
                $files = $this->buildFileObjectListing( $objects );

                // Page on the unfiltered object listing (what is returned may be filtered)
                if ( count( $objects ) < $limit ) {
                        $after = INF; // avoid a second RTT
                } else {
                        $after = end( $objects ); // update last item
                        $after = is_object( $after ) ? $after->name : $after;
                }

                return $files;
        }

        /**
         * Build a list of file objects, filtering out any directories
         * and extracting any stat info if provided in $objects
         *
         * @param stdClass[]|string[] $objects List of stdClass items or object names
         * @return array[] List of (name, stat map or null) entries
         */
        private function buildFileObjectListing( array $objects ) {
                $names = [];
                foreach ( $objects as $object ) {
                        if ( is_object( $object ) ) {
                                if ( isset( $object->subdir ) || !isset( $object->name ) ) {
                                        continue; // virtual directory entry; ignore
                                }
                                $stat = [
                                        // Convert various random Swift dates to TS_MW
                                        'mtime'  => $this->convertSwiftDate( $object->last_modified, TS_MW ),
                                        'size'   => (int)$object->bytes,
                                        'sha1'   => null,
                                        // Note: manifest ETags are not an MD5 of the file
                                        'md5'    => ctype_xdigit( $object->hash ) ? $object->hash : null,
                                        'latest' => false // eventually consistent
                                ];
                                $names[] = [ $object->name, $stat ];
                        } elseif ( substr( $object, -1 ) !== '/' ) {
                                // Omit directories, which end in '/' in listings
                                $names[] = [ $object, null ];
                        }
                }

                return $names;
        }

        /**
         * Do not call this function outside of SwiftFileBackendFileList
         *
         * @param string $path Storage path
         * @param array $val Stat value
         */
        public function loadListingStatInternal( $path, array $val ) {
                $this->cheapCache->setField( $path, 'stat', $val );
        }

        protected function doGetFileXAttributes( array $params ) {
                $stat = $this->getFileStat( $params );
                // Stat entries filled by file listings don't include metadata/headers
                if ( is_array( $stat ) && !isset( $stat['xattr'] ) ) {
                        $this->clearCache( [ $params['src'] ] );
                        $stat = $this->getFileStat( $params );
                }

                if ( is_array( $stat ) ) {
                        return $stat['xattr'];
                }

                return $stat === self::RES_ERROR ? self::RES_ERROR : self::RES_ABSENT;
        }

        protected function doGetFileSha1base36( array $params ) {
                // Avoid using stat entries from file listings, which never include the SHA-1 hash.
                // Also, recompute the hash if it's not part of the metadata headers for some reason.
                $params['requireSHA1'] = true;

                $stat = $this->getFileStat( $params );
                if ( is_array( $stat ) ) {
                        return $stat['sha1'];
                }

                return $stat === self::RES_ERROR ? self::RES_ERROR : self::RES_ABSENT;
        }

        protected function doStreamFile( array $params ) {
                $status = $this->newStatus();

                $flags = !empty( $params['headless'] ) ? HTTPFileStreamer::STREAM_HEADLESS : 0;

                [ $srcCont, $srcRel ] = $this->resolveStoragePathReal( $params['src'] );
                if ( $srcRel === null ) {
                        HTTPFileStreamer::send404Message( $params['src'], $flags );
                        $status->fatal( 'backend-fail-invalidpath', $params['src'] );

                        return $status;
                }

                if ( !is_array( $this->getContainerStat( $srcCont ) ) ) {
                        HTTPFileStreamer::send404Message( $params['src'], $flags );
                        $status->fatal( 'backend-fail-stream', $params['src'] );

                        return $status;
                }

                // If "headers" is set, we only want to send them if the file is there.
                // Do not bother checking if the file exists if headers are not set though.
                if ( $params['headers'] && !$this->fileExists( $params ) ) {
                        HTTPFileStreamer::send404Message( $params['src'], $flags );
                        $status->fatal( 'backend-fail-stream', $params['src'] );

                        return $status;
                }

                // Send the requested additional headers
                if ( empty( $params['headless'] ) ) {
                        foreach ( $params['headers'] as $header ) {
                                $this->header( $header );
                        }
                }

                if ( empty( $params['allowOB'] ) ) {
                        // Cancel output buffering and gzipping if set
                        $this->resetOutputBuffer();
                }

                $handle = fopen( 'php://output', 'wb' );
                [ $rcode, $rdesc, , $rbody, $rerr ] = $this->requestWithAuth( [
                        'method' => 'GET',
                        'container' => $srcCont,
                        'relPath' => $srcRel,
                        'headers' => $this->headersFromParams( $params ) + $params['options'],
                        'stream' => $handle,
                        'flags'  => [ 'relayResponseHeaders' => empty( $params['headless'] ) ]
                ] );

                if ( $rcode >= 200 && $rcode <= 299 ) {
                        // good
                } elseif ( $rcode === 404 ) {
                        $status->fatal( 'backend-fail-stream', $params['src'] );
                        // Per T43113, nasty things can happen if bad cache entries get
                        // stuck in cache. It's also possible that this error can come up
                        // with simple race conditions. Clear out the stat cache to be safe.
                        $this->clearCache( [ $params['src'] ] );
                        $this->deleteFileCache( $params['src'] );
                } else {
                        $this->onError( $status, __METHOD__, $params, $rerr, $rcode, $rdesc, $rbody );
                }

                return $status;
        }

        protected function doGetLocalCopyMulti( array $params ) {
                $ep = array_diff_key( $params, [ 'srcs' => 1 ] ); // for error logging
                // Blindly create tmp files and stream to them, catching any exception
                // if the file does not exist. Do not waste time doing file stats here.
                $reqs = []; // (path => op)

                // Initial dummy values to preserve path order
                $tmpFiles = array_fill_keys( $params['srcs'], self::RES_ERROR );
                foreach ( $params['srcs'] as $path ) { // each path in this concurrent batch
                        [ $srcCont, $srcRel ] = $this->resolveStoragePathReal( $path );
                        if ( $srcRel === null ) {
                                continue; // invalid storage path
                        }
                        // Get source file extension
                        $ext = FileBackend::extensionFromPath( $path );
                        // Create a new temporary file...
                        $tmpFile = $this->tmpFileFactory->newTempFSFile( 'localcopy_', $ext );
                        $handle = $tmpFile ? fopen( $tmpFile->getPath(), 'wb' ) : false;
                        if ( $handle ) {
                                $reqs[$path] = [
                                        'method'  => 'GET',
                                        'container' => $srcCont,
                                        'relPath' => $srcRel,
                                        'headers' => $this->headersFromParams( $params ),
                                        'stream'  => $handle,
                                ];
                                $tmpFiles[$path] = $tmpFile;
                        }
                }

                // Ceph RADOS Gateway is in use (strong consistency) or X-Newest will be used
                $latest = ( $this->isRGW || !empty( $params['latest'] ) );

                $reqs = $this->requestMultiWithAuth(
                        $reqs,
                        [ 'maxConnsPerHost' => $params['concurrency'] ]
                );
                foreach ( $reqs as $path => $op ) {
                        [ $rcode, $rdesc, $rhdrs, $rbody, $rerr ] = $op['response'];
                        fclose( $op['stream'] ); // close open handle
                        if ( $rcode >= 200 && $rcode <= 299 ) {
                                /** @var TempFSFile $tmpFile */
                                $tmpFile = $tmpFiles[$path];
                                // Make sure that the stream finished and fully wrote to disk
                                $size = $tmpFile->getSize();
                                if ( $size !== (int)$rhdrs['content-length'] ) {
                                        $tmpFiles[$path] = self::RES_ERROR;
                                        $rerr = "Got {$size}/{$rhdrs['content-length']} bytes";
                                        $this->onError( null, __METHOD__,
                                                [ 'src' => $path ] + $ep, $rerr, $rcode, $rdesc );
                                }
                                // Set the file stat process cache in passing
                                $stat = $this->getStatFromHeaders( $rhdrs );
                                $stat['latest'] = $latest;
                                $this->cheapCache->setField( $path, 'stat', $stat );
                        } elseif ( $rcode === 404 ) {
                                $tmpFiles[$path] = self::RES_ABSENT;
                                $this->cheapCache->setField(
                                        $path,
                                        'stat',
                                        $latest ? self::ABSENT_LATEST : self::ABSENT_NORMAL
                                );
                        } else {
                                $tmpFiles[$path] = self::RES_ERROR;
                                $this->onError( null, __METHOD__,
                                        [ 'src' => $path ] + $ep, $rerr, $rcode, $rdesc, $rbody );
                        }
                }

                return $tmpFiles;
        }

        public function addShellboxInputFile( BoxedCommand $command, string $boxedName,
                array $params
        ) {
                if ( $this->canShellboxGetTempUrl ) {
                        $urlParams = [ 'src' => $params['src'] ];
                        if ( $this->shellboxIpRange !== null ) {
                                $urlParams['ipRange'] = $this->shellboxIpRange;
                        }
                        $url = $this->getFileHttpUrl( $urlParams );
                        if ( $url ) {
                                $command->inputFileFromUrl( $boxedName, $url );
                                return $this->newStatus();
                        }
                }
                return parent::addShellboxInputFile( $command, $boxedName, $params );
        }

        public function getFileHttpUrl( array $params ) {
                if ( $this->swiftTempUrlKey == '' &&
                        ( $this->rgwS3AccessKey == '' || $this->rgwS3SecretKey != '' )
                ) {
                        $this->logger->debug( "Can't get Swift file URL: no key available" );
                        return self::TEMPURL_ERROR;
                }

                [ $srcCont, $srcRel ] = $this->resolveStoragePathReal( $params['src'] );
                if ( $srcRel === null ) {
                        $this->logger->debug( "Can't get Swift file URL: can't resolve path" );
                        return self::TEMPURL_ERROR; // invalid path
                }

                $auth = $this->getAuthentication();
                if ( !$auth ) {
                        $this->logger->debug( "Can't get Swift file URL: authentication failed" );
                        return self::TEMPURL_ERROR;
                }

                $method = $params['method'] ?? 'GET';
                $ttl = $params['ttl'] ?? 86400;
                $expires = time() + $ttl;

                if ( $this->swiftTempUrlKey != '' ) {
                        $url = $this->storageUrl( $auth, $srcCont, $srcRel );
                        // Swift wants the signature based on the unencoded object name
                        $contPath = parse_url( $this->storageUrl( $auth, $srcCont ), PHP_URL_PATH );
                        $messageParts = [
                                $method,
                                $expires,
                                "{$contPath}/{$srcRel}"
                        ];
                        $query = [
                                'temp_url_expires' => $expires,
                        ];
                        if ( isset( $params['ipRange'] ) ) {
                                array_unshift( $messageParts, "ip={$params['ipRange']}" );
                                $query['temp_url_ip_range'] = $params['ipRange'];
                        }

                        $signature = hash_hmac( 'sha1',
                                implode( "\n", $messageParts ),
                                $this->swiftTempUrlKey
                        );
                        $query = [ 'temp_url_sig' => $signature ] + $query;

                        return $url . '?' . http_build_query( $query );
                } else { // give S3 API URL for rgw
                        // Path for signature starts with the bucket
                        $spath = '/' . rawurlencode( $srcCont ) . '/' .
                                str_replace( '%2F', '/', rawurlencode( $srcRel ) );
                        // Calculate the hash
                        $signature = base64_encode( hash_hmac(
                                'sha1',
                                "{$method}\n\n\n{$expires}\n{$spath}",
                                $this->rgwS3SecretKey,
                                true // raw
                        ) );
                        // See https://s3.amazonaws.com/doc/s3-developer-guide/RESTAuthentication.html.
                        // Note: adding a newline for empty CanonicalizedAmzHeaders does not work.
                        // Note: S3 API is the rgw default; remove the /swift/ URL bit.
                        return str_replace( '/swift/v1', '', $this->storageUrl( $auth ) . $spath ) .
                                '?' .
                                http_build_query( [
                                        'Signature' => $signature,
                                        'Expires' => $expires,
                                        'AWSAccessKeyId' => $this->rgwS3AccessKey
                                ] );
                }
        }

        protected function directoriesAreVirtual() {
                return true;
        }

        /**
         * Get headers to send to Swift when reading a file based
         * on a FileBackend params array, e.g. that of getLocalCopy().
         * $params is currently only checked for a 'latest' flag.
         *
         * @param array $params
         * @return array
         */
        protected function headersFromParams( array $params ) {
                $hdrs = [];
                if ( !empty( $params['latest'] ) ) {
                        $hdrs['x-newest'] = 'true';
                }

                return $hdrs;
        }

        protected function doExecuteOpHandlesInternal( array $fileOpHandles ) {
                /** @var SwiftFileOpHandle[] $fileOpHandles */
                '@phan-var SwiftFileOpHandle[] $fileOpHandles';

                /** @var StatusValue[] $statuses */
                $statuses = [];

                // Split the HTTP requests into stages that can be done concurrently
                $httpReqsByStage = []; // map of (stage => index => HTTP request)
                foreach ( $fileOpHandles as $index => $fileOpHandle ) {
                        $reqs = $fileOpHandle->httpOp;
                        foreach ( $reqs as $stage => $req ) {
                                $httpReqsByStage[$stage][$index] = $req;
                        }
                        $statuses[$index] = $this->newStatus();
                }

                // Run all requests for the first stage, then the next, and so on
                $reqCount = count( $httpReqsByStage );
                for ( $stage = 0; $stage < $reqCount; ++$stage ) {
                        $httpReqs = $this->requestMultiWithAuth( $httpReqsByStage[$stage] );
                        foreach ( $httpReqs as $index => $httpReq ) {
                                /** @var SwiftFileOpHandle $fileOpHandle */
                                $fileOpHandle = $fileOpHandles[$index];
                                // Run the callback for each request of this operation
                                $status = $statuses[$index];
                                ( $fileOpHandle->callback )( $httpReq, $status );
                                // On failure, abort all remaining requests for this operation. This is used
                                // in "move" operations to abort the DELETE request if the PUT request fails.
                                if (
                                        !$status->isOK() ||
                                        $fileOpHandle->state === $fileOpHandle::CONTINUE_NO
                                ) {
                                        $stages = count( $fileOpHandle->httpOp );
                                        for ( $s = ( $stage + 1 ); $s < $stages; ++$s ) {
                                                unset( $httpReqsByStage[$s][$index] );
                                        }
                                }
                        }
                }

                return $statuses;
        }

        /**
         * Set read/write permissions for a Swift container.
         *
         * @see http://docs.openstack.org/developer/swift/misc.html#acls
         *
         * In general, we don't allow listings to end-users. It's not useful, isn't well-defined
         * (lists are truncated to 10000 item with no way to page), and is just a performance risk.
         *
         * @param string $container Resolved Swift container
         * @param array $readUsers List of the possible criteria for a request to have
         * access to read a container. Each item is one of the following formats:
         *   - account:user        : Grants access if the request is by the given user
         *   - ".r:<regex>"        : Grants access if the request is from a referrer host that
         *                           matches the expression and the request is not for a listing.
         *                           Setting this to '*' effectively makes a container public.
         *   -".rlistings:<regex>" : Grants access if the request is from a referrer host that
         *                           matches the expression and the request is for a listing.
         * @param array $writeUsers A list of the possible criteria for a request to have
         * access to write to a container. Each item is of the following format:
         *   - account:user       : Grants access if the request is by the given user
         * @return StatusValue Good status without value for success, fatal otherwise.
         */
        protected function setContainerAccess( $container, array $readUsers, array $writeUsers ) {
                $status = $this->newStatus();

                [ $rcode, , , , ] = $this->requestWithAuth( [
                        'method' => 'POST',
                        'container' => $container,
                        'headers' => [
                                'x-container-read' => implode( ',', $readUsers ),
                                'x-container-write' => implode( ',', $writeUsers )
                        ]
                ] );

                if ( $rcode != 204 && $rcode !== 202 ) {
                        $status->fatal( 'backend-fail-internal', $this->name );
                        $this->logger->error( __METHOD__ . ': unexpected rcode value ({rcode})',
                                [ 'rcode' => $rcode ] );
                }

                return $status;
        }

        /**
         * Get a Swift container stat map, possibly from process cache.
         * Use $reCache if the file count or byte count is needed.
         *
         * @param string $container Container name
         * @param bool $bypassCache Bypass all caches and load from Swift
         * @return array|false|null False on 404, null on failure
         */
        protected function getContainerStat( $container, $bypassCache = false ) {
                /** @noinspection PhpUnusedLocalVariableInspection */
                $ps = $this->scopedProfileSection( __METHOD__ . "-{$this->name}" );

                if ( $bypassCache ) { // purge cache
                        $this->containerStatCache->clear( $container );
                } elseif ( !$this->containerStatCache->hasField( $container, 'stat' ) ) {
                        $this->primeContainerCache( [ $container ] ); // check persistent cache
                }
                if ( !$this->containerStatCache->hasField( $container, 'stat' ) ) {
                        [ $rcode, $rdesc, $rhdrs, $rbody, $rerr ] = $this->requestWithAuth( [
                                'method' => 'HEAD',
                                'container' => $container
                        ] );

                        if ( $rcode === 204 ) {
                                $stat = [
                                        'count' => $rhdrs['x-container-object-count'],
                                        'bytes' => $rhdrs['x-container-bytes-used']
                                ];
                                if ( $bypassCache ) {
                                        return $stat;
                                } else {
                                        $this->containerStatCache->setField( $container, 'stat', $stat ); // cache it
                                        $this->setContainerCache( $container, $stat ); // update persistent cache
                                }
                        } elseif ( $rcode === 404 ) {
                                return self::RES_ABSENT;
                        } else {
                                $this->onError( null, __METHOD__,
                                        [ 'cont' => $container ], $rerr, $rcode, $rdesc, $rbody );

                                return self::RES_ERROR;
                        }
                }

                return $this->containerStatCache->getField( $container, 'stat' );
        }

        /**
         * Create a Swift container
         *
         * @param string $container Container name
         * @param array $params
         * @return StatusValue Good status without value for success, fatal otherwise.
         */
        protected function createContainer( $container, array $params ) {
                $status = $this->newStatus();

                // @see SwiftFileBackend::setContainerAccess()
                if ( empty( $params['noAccess'] ) ) {
                        // public
                        $readUsers = array_merge( $this->readUsers, [ '.r:*', $this->swiftUser ] );
                        if ( empty( $params['noListing'] ) ) {
                                array_push( $readUsers, '.rlistings' );
                        }
                        $writeUsers = array_merge( $this->writeUsers, [ $this->swiftUser ] );
                } else {
                        // private
                        $readUsers = array_merge( $this->secureReadUsers, [ $this->swiftUser ] );
                        $writeUsers = array_merge( $this->secureWriteUsers, [ $this->swiftUser ] );
                }

                [ $rcode, $rdesc, , $rbody, $rerr ] = $this->requestWithAuth( [
                        'method' => 'PUT',
                        'container' => $container,
                        'headers' => [
                                'x-container-read' => implode( ',', $readUsers ),
                                'x-container-write' => implode( ',', $writeUsers )
                        ]
                ] );

                if ( $rcode === 201 ) { // new
                        // good
                } elseif ( $rcode === 202 ) { // already there
                        // this shouldn't really happen, but is OK
                } else {
                        $this->onError( $status, __METHOD__, $params, $rerr, $rcode, $rdesc, $rbody );
                }

                return $status;
        }

        /**
         * Delete a Swift container
         *
         * @param string $container Container name
         * @param array $params
         * @return StatusValue
         */
        protected function deleteContainer( $container, array $params ) {
                $status = $this->newStatus();

                [ $rcode, $rdesc, , $rbody, $rerr ] = $this->requestWithAuth( [
                        'method' => 'DELETE',
                        'container' => $container
                ] );

                if ( $rcode >= 200 && $rcode <= 299 ) { // deleted
                        $this->containerStatCache->clear( $container ); // purge
                } elseif ( $rcode === 404 ) { // not there
                        // this shouldn't really happen, but is OK
                } elseif ( $rcode === 409 ) { // not empty
                        $this->onError( $status, __METHOD__, $params, $rerr, $rcode, $rdesc ); // race?
                } else {
                        $this->onError( $status, __METHOD__, $params, $rerr, $rcode, $rdesc, $rbody );
                }

                return $status;
        }

        /**
         * Get a list of objects under a container.
         * Either just the names or a list of stdClass objects with details can be returned.
         *
         * @param string $fullCont
         * @param string $type ('info' for a list of object detail maps, 'names' for names only)
         * @param int $limit
         * @param string|null $after
         * @param string|null $prefix
         * @param string|null $delim
         * @return StatusValue With the list as value
         */
        private function objectListing(
                $fullCont, $type, $limit, $after = null, $prefix = null, $delim = null
        ) {
                $status = $this->newStatus();

                $query = [ 'limit' => $limit ];
                if ( $type === 'info' ) {
                        $query['format'] = 'json';
                }
                if ( $after !== null ) {
                        $query['marker'] = $after;
                }
                if ( $prefix !== null ) {
                        $query['prefix'] = $prefix;
                }
                if ( $delim !== null ) {
                        $query['delimiter'] = $delim;
                }

                [ $rcode, $rdesc, , $rbody, $rerr ] = $this->requestWithAuth( [
                        'method' => 'GET',
                        'container' => $fullCont,
                        'query' => $query,
                ] );

                $params = [ 'cont' => $fullCont, 'prefix' => $prefix, 'delim' => $delim ];
                if ( $rcode === 200 ) { // good
                        if ( $type === 'info' ) {
                                $status->value = FormatJson::decode( trim( $rbody ) );
                        } else {
                                $status->value = explode( "\n", trim( $rbody ) );
                        }
                } elseif ( $rcode === 204 ) {
                        $status->value = []; // empty container
                } elseif ( $rcode === 404 ) {
                        $status->value = []; // no container
                } else {
                        $this->onError( $status, __METHOD__, $params, $rerr, $rcode, $rdesc, $rbody );
                }

                return $status;
        }

        protected function doPrimeContainerCache( array $containerInfo ) {
                foreach ( $containerInfo as $container => $info ) {
                        $this->containerStatCache->setField( $container, 'stat', $info );
                }
        }

        protected function doGetFileStatMulti( array $params ) {
                $stats = [];

                $reqs = []; // (path => op)
                // (a) Check the containers of the paths...
                foreach ( $params['srcs'] as $path ) {
                        [ $srcCont, $srcRel ] = $this->resolveStoragePathReal( $path );
                        if ( $srcRel === null ) {
                                // invalid storage path
                                $stats[$path] = self::RES_ERROR;
                                continue;
                        }

                        $cstat = $this->getContainerStat( $srcCont );
                        if ( $cstat === self::RES_ABSENT ) {
                                $stats[$path] = self::RES_ABSENT;
                                continue; // ok, nothing to do
                        } elseif ( $cstat === self::RES_ERROR ) {
                                $stats[$path] = self::RES_ERROR;
                                continue;
                        }

                        $reqs[$path] = [
                                'method'  => 'HEAD',
                                'container' => $srcCont,
                                'relPath' => $srcRel,
                                'headers' => $this->headersFromParams( $params )
                        ];
                }

                // (b) Check the files themselves...
                $reqs = $this->requestMultiWithAuth(
                        $reqs,
                        [ 'maxConnsPerHost' => $params['concurrency'] ]
                );
                foreach ( $reqs as $path => $op ) {
                        [ $rcode, $rdesc, $rhdrs, $rbody, $rerr ] = $op['response'];
                        if ( $rcode === 200 || $rcode === 204 ) {
                                // Update the object if it is missing some headers
                                if ( !empty( $params['requireSHA1'] ) ) {
                                        $rhdrs = $this->addMissingHashMetadata( $rhdrs, $path );
                                }
                                // Load the stat map from the headers
                                $stat = $this->getStatFromHeaders( $rhdrs );
                                if ( $this->isRGW ) {
                                        $stat['latest'] = true; // strong consistency
                                }
                        } elseif ( $rcode === 404 ) {
                                $stat = self::RES_ABSENT;
                        } else {
                                $stat = self::RES_ERROR;
                                $this->onError( null, __METHOD__, $params, $rerr, $rcode, $rdesc, $rbody );
                        }
                        $stats[$path] = $stat;
                }

                return $stats;
        }

        /**
         * @param array $rhdrs
         * @return array
         */
        protected function getStatFromHeaders( array $rhdrs ) {
                // Fetch all of the custom metadata headers
                $metadata = $this->getMetadataFromHeaders( $rhdrs );
                // Fetch all of the custom raw HTTP headers
                $headers = $this->extractMutableContentHeaders( $rhdrs );

                return [
                        // Convert various random Swift dates to TS_MW
                        'mtime' => $this->convertSwiftDate( $rhdrs['last-modified'], TS_MW ),
                        // Empty objects actually return no content-length header in Ceph
                        'size'  => isset( $rhdrs['content-length'] ) ? (int)$rhdrs['content-length'] : 0,
                        'sha1'  => $metadata['sha1base36'] ?? null,
                        // Note: manifest ETags are not an MD5 of the file
                        'md5'   => ctype_xdigit( $rhdrs['etag'] ) ? $rhdrs['etag'] : null,
                        'xattr' => [ 'metadata' => $metadata, 'headers' => $headers ]
                ];
        }

        /**
         * Get the cached auth token.
         *
         * @return array|null Credential map
         */
        protected function getAuthentication() {
                if ( $this->authErrorTimestamp !== null ) {
                        $interval = time() - $this->authErrorTimestamp;
                        if ( $interval < 60 ) {
                                $this->logger->debug(
                                        'rejecting request since auth failure occurred {interval} seconds ago',
                                        [ 'interval' => $interval ]
                                );
                                return null;
                        } else { // actually retry this time
                                $this->authErrorTimestamp = null;
                        }
                }
                // Authenticate with proxy and get a session key...
                if ( !$this->authCreds ) {
                        $cacheKey = $this->getCredsCacheKey( $this->swiftUser );
                        $creds = $this->srvCache->get( $cacheKey ); // credentials
                        // Try to use the credential cache
                        if ( isset( $creds['auth_token'] )
                                && isset( $creds['storage_url'] )
                                && isset( $creds['expiry_time'] )
                                && $creds['expiry_time'] > time()
                        ) {
                                $this->setAuthCreds( $creds );
                        } else { // cache miss
                                $this->refreshAuthentication();
                        }
                }

                return $this->authCreds;
        }

        /**
         * Update the auth credentials
         *
         * @param array|null $creds
         */
        private function setAuthCreds( ?array $creds ) {
                $this->logger->debug( 'Using auth token with expiry_time={expiry_time}',
                        [
                                'expiry_time' => isset( $creds['expiry_time'] )
                                        ? gmdate( 'c', $creds['expiry_time'] ) : 'null'
                        ]
                );
                $this->authCreds = $creds;
                // Ceph RGW does not use <account> in URLs (OpenStack Swift uses "/v1/<account>")
                if ( $creds && str_ends_with( $creds['storage_url'], '/v1' ) ) {
                        $this->isRGW = true; // take advantage of strong consistency in Ceph
                }
        }

        /**
         * Fetch the auth token from the server, without caching.
         *
         * @return array|null Credential map
         */
        private function refreshAuthentication() {
                [ $rcode, , $rhdrs, $rbody, ] = $this->http->run( [
                        'method' => 'GET',
                        'url' => "{$this->swiftAuthUrl}/v1.0",
                        'headers' => [
                                'x-auth-user' => $this->swiftUser,
                                'x-auth-key' => $this->swiftKey
                        ]
                ], self::DEFAULT_HTTP_OPTIONS );

                if ( $rcode >= 200 && $rcode <= 299 ) { // OK
                        if ( isset( $rhdrs['x-auth-token-expires'] ) ) {
                                $ttl = intval( $rhdrs['x-auth-token-expires'] );
                        } else {
                                $ttl = $this->authTTL;
                        }
                        $expiryTime = time() + $ttl;
                        $creds = [
                                'auth_token' => $rhdrs['x-auth-token'],
                                'storage_url' => $this->swiftStorageUrl ?? $rhdrs['x-storage-url'],
                                'expiry_time' => $expiryTime,
                        ];
                        $this->srvCache->set( $this->getCredsCacheKey( $this->swiftUser ), $creds, $expiryTime );
                } elseif ( $rcode === 401 ) {
                        $this->onError( null, __METHOD__, [], "Authentication failed.", $rcode );
                        $this->authErrorTimestamp = time();
                        $creds = null;
                } else {
                        $this->onError( null, __METHOD__, [], "HTTP return code: $rcode", $rcode, $rbody );
                        $this->authErrorTimestamp = time();
                        $creds = null;
                }
                $this->setAuthCreds( $creds );
                return $creds;
        }

        /**
         * @param array $creds From getAuthentication()
         * @param string|null $container
         * @param string|null $object
         * @return string
         */
        protected function storageUrl( array $creds, $container = null, $object = null ) {
                $parts = [ $creds['storage_url'] ];
                if ( strlen( $container ?? '' ) ) {
                        $parts[] = rawurlencode( $container );
                }
                if ( strlen( $object ?? '' ) ) {
                        $parts[] = str_replace( "%2F", "/", rawurlencode( $object ) );
                }

                return implode( '/', $parts );
        }

        /**
         * @param array $creds From getAuthentication()
         * @return array
         */
        protected function authTokenHeaders( array $creds ) {
                return [ 'x-auth-token' => $creds['auth_token'] ];
        }

        /**
         * Get the cache key for a container
         *
         * @param string $username
         * @return string
         */
        private function getCredsCacheKey( $username ) {
                return 'swiftcredentials:' . md5( $username . ':' . $this->swiftAuthUrl );
        }

        /**
         * Perform an authenticated HTTP request
         *
         * @param array $req The request data, including:
         *   - container: The name of the container (required)
         *   - relPath: The relative path under the container. If this is omitted,
         *     the request will refer to the container itself.
         *   - headers: An array of request headers to send, in addition to the
         *     auth headers.
         *   - Other keys to be passed through to MultiHttpClient::run()
         * @param array $options Options to pass through to MultiHttpClient, in
         *   addition to the default options DEFAULT_HTTP_OPTIONS
         * @return array The response array from MultiHttpClient::run()
         */
        private function requestWithAuth( array $req, array $options = [] ) {
                return $this->requestMultiWithAuth( [ $req ], $options )[0]['response'];
        }

        /**
         * Perform a batch of authenticated HTTP requests
         *
         * @param array $reqs An array of request data arrays. See self::requestWithAuth()
         * @param array $options Options to pass through to MultiHttpClient, in
         *    addition to the default options DEFAULT_HTTP_OPTIONS
         * @return array The request array with responses populated, as returned by
         *   MultiHttpClient::runMulti()
         */
        private function requestMultiWithAuth( array $reqs, $options = [] ) {
                $remainingTries = 2;
                $auth = $this->getAuthentication();
                while ( true ) {
                        if ( !$auth ) {
                                foreach ( $reqs as &$req ) {
                                        if ( !isset( $req['response'] ) ) {
                                                $req['response'] = $this->getAuthFailureResponse();
                                        }
                                }
                                break;
                        }
                        foreach ( $reqs as &$req ) {
                                '@phan-var array $req'; // Not array[]
                                if ( isset( $req['response'] ) ) {
                                        // Request was attempted before
                                        // Retry only if it gave a 401 response code
                                        if ( $req['response']['code'] !== 401 ) {
                                                continue;
                                        }
                                }
                                $req['headers'] = $this->authTokenHeaders( $auth ) + ( $req['headers'] ?? [] );
                                $req['url'] = $this->storageUrl( $auth, $req['container'], $req['relPath'] ?? null );
                        }
                        unset( $req );
                        $reqs = $this->http->runMulti( $reqs, $options + self::DEFAULT_HTTP_OPTIONS );
                        if ( --$remainingTries > 0 ) {
                                // Retry if any request failed with 401 "not authorized"
                                foreach ( $reqs as $req ) {
                                        if ( $req['response']['code'] === 401 ) {
                                                $auth = $this->refreshAuthentication();
                                                continue 2;
                                        }
                                }
                        }
                        break;
                }
                return $reqs;
        }

        /**
         * Get a synthetic response to return from requestWithAuth() or requestMultiWithAuth()
         * if the request could not be issued due to failure of a prior authentication request.
         * This failure should not be logged as an HTTP error since the original failure would
         * have been logged.
         *
         * @return array
         */
        private function getAuthFailureResponse() {
                return [
                        'code' => 0,
                        0 => 0,
                        'reason' => '',
                        1 => '',
                        'headers' => [],
                        2 => [],
                        'body' => '',
                        3 => '',
                        'error' => self::AUTH_FAILURE_ERROR,
                        4 => self::AUTH_FAILURE_ERROR
                ];
        }

        /**
         * Determine whether an HTTP response was generated by getAuthFailureResponse()
         *
         * @param int $code
         * @param string $error
         * @return bool
         */
        private function isAuthFailureResponse( $code, $error ) {
                return $code === 0 && $error === self::AUTH_FAILURE_ERROR;
        }

        /**
         * Log an unexpected exception for this backend.
         * This also sets the StatusValue object to have a fatal error.
         *
         * @param StatusValue|null $status To add fatal errors to
         * @param string $func
         * @param array $params
         * @param string $err Error string
         * @param int $code HTTP status
         * @param string $desc HTTP StatusValue description
         * @param string $body HTTP body
         */
        public function onError( $status, $func, array $params, $err = '', $code = 0, $desc = '', $body = '' ) {
                if ( $this->isAuthFailureResponse( $code, $err ) ) {
                        if ( $status instanceof StatusValue ) {
                                $status->fatal( 'backend-fail-connect', $this->name );
                        }
                        // Already logged
                        return;
                }
                if ( $status instanceof StatusValue ) {
                        $status->fatal( 'backend-fail-internal', $this->name );
                }
                $msg = "HTTP {code} ({desc}) in '{func}' (given '{req_params}')";
                $msgParams = [
                        'code'   => $code,
                        'desc'   => $desc,
                        'func'   => $func,
                        'req_params' => FormatJson::encode( $params ),
                ];
                if ( $err ) {
                        $msg .= ': {err}';
                        $msgParams['err'] = $err;
                }
                if ( $code == 502 ) {
                        $msg .= ' ({truncatedBody})';
                        $msgParams['truncatedBody'] = substr( strip_tags( $body ), 0, 100 );
                }
                $this->logger->error( $msg, $msgParams );
        }
}

/** @deprecated class alias since 1.43 */
class_alias( SwiftFileBackend::class, 'SwiftFileBackend' );