API:EPrints/Storage
EPrints 3 Reference: Directory Structure - Metadata Fields - Repository Configuration - XML Config Files - XML Export Format - EPrints data structure - Core API - Data Objects
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The interface for this module has not been finalised and may change in the future. |
Contents
NAME
EPrints::Storage - store and retrieve objects in the storage engine
SYNOPSIS
my $store = $repository->storage();
$store->store(
$fileobj, # file object
"diddle.pdf", # filename
$fh # file handle
);
DESCRIPTION
This module is the storage control layer which uses EPrints::Plugin::Storage plugins to support various storage back-ends. It enables the storage, retrieval and deletion of data streams. The maximum size of a stream is dependent on the back-end storage mechanism.
METHODS
new
$store = EPrints::Storage->new( $repository )
Create a new storage object for $repository. Should not be used directly, see EPrints::Session.
store
$len = $store->store( $fileobj, CODEREF [, $offset ] )
Read from and store all data from CODEREF for $fileobj.
Behaviour is undefined if an attempt is made to write beyond $fileobj's filesize.
Returns undef if the file couldn't be stored, otherwise the number of bytes actually written.
The combination of methods open_write, write, and close_write can be used as an alternative to this method.
retrieve
$success = $store->retrieve( $fileobj, $offset, $n, CALLBACK )
Retrieve the contents of the $fileobj starting at $offset for $n bytes.
CALLBACK = $rc = &f( BUFFER )
delete
$success = $store->delete( $fileobj )
Delete all object copies stored for $fileobj.
delete_copy
$ok = $store->delete_copy( $plugin, $fileobj )
Delete the copy of this file stored in $plugin.
get_local_copy
$fh = $store->get_local_copy( $fileobj )
Return a local copy of the file. Potentially expensive if the file has to be retrieved.
Stringifying $fh will give the full path to the local file, which may be useful for calling external tools (see File::Temp).
Returns undef if retrieval failed.
get_remote_copy
$url = $store->get_remote_copy( $fileobj )
Returns a URL from which this file can be accessed.
Returns undef if this file is not available via another service.
get_plugins
@plugins = $store->get_plugins( $fileobj )
Returns the EPrints::Plugin::Storage plugin(s) to use for $fileobj. If more than one plugin is returned they should be used in turn until one succeeds.
copy
$ok = $store->copy( $plugin, $fileobj )
Copy the contents of $fileobj into another storage $plugin.
Returns 1 on success, 0 on failure and -1 if a copy already exists in $plugin.
open_write
$ok = $storage->open_write( $fileobj [, $offset ] )
Start a write session for $fileobj. $fileobj must have at least the "filesize" property set (which is the total number of bytes that will be written).
write
$ok = $storage->write( $fileobj, $buffer )
Write $buffer to the storage plugin(s), starting from the previously written data.
close_write
$ok = $storage->close_write( $fileobj );
Finish writing to the storage plugin(s) for $fileobj.
COPYRIGHT
Copyright 2000-2011 University of Southampton.
This file is part of EPrints http://www.eprints.org/.
EPrints is free software: you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.
EPrints 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 Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License along with EPrints. If not, see http://www.gnu.org/licenses/.
