Difference between revisions of "API:EPrints/Storage"

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<!-- Pod2Wiki=_private_ -->{{API:Unstable}}<!-- Pod2Wiki=head_name -->
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==NAME==
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'''EPrints::Storage''' - store and retrieve objects in the storage engine
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==SYNOPSIS==
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  my $store = $repository-&gt;storage();
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  $store-&gt;store(
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    $fileobj,    # file object
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    "diddle.pdf",  # filename
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    $fh        # file handle
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  );
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==DESCRIPTION==
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This module is the storage control layer which uses [[API:EPrints/Plugin/Storage|EPrints::Plugin::Storage]] plugins to support various storage back-ends. It enables the storage, retrieval and deletion of data streams. The maximum size of a stream is dependent on the back-end storage mechanism.
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==METHODS==
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===$store = EPrints::Storage-&gt;new( $repository )===
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Create a new storage object for $repository. Should not be used directly, see [[API:EPrints/Session|EPrints::Session]].
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===$len = $store-&gt;store( $fileobj, CODEREF )===
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Read from and store all data from CODEREF for $fileobj. The '''filesize''' field in $fileobj must be set at the expected number of bytes to read from CODEREF.
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Returns undef if the file couldn't be stored, otherwise the number of bytes read.
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===$success = $store-&gt;retrieve( $fileobj, CALLBACK )===
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===$success = $store-&gt;delete( $fileobj )===
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Delete all object copies stored for $fileobj.
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===$ok = $store-&gt;delete_copy( $plugin, $fileobj )===
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Delete the copy of this file stored in $plugin.
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===$filename = $store-&gt;get_local_copy( $fileobj )===
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Return the name of a local copy of the file.
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Will retrieve and cache the remote object using {{API:PodLink|file=File/Temp|package_name=File::Temp|section=|text=File::Temp}} if necessary.
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Returns undef if retrieval failed.
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===$url = $store-&gt;get_remote_copy( $fileobj )===
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Returns a URL from which this file can be accessed.
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Returns undef if this file is not available via another service.
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===@plugins = $store-&gt;get_plugins( $fileobj )===
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Returns the [[API:EPrints/Plugin/Storage|EPrints::Plugin::Storage]] plugin(s) to use for $fileobj. If more than one plugin is returned they should be used in turn until one succeeds.
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===$ok = $store-&gt;copy( $plugin, $fileobj )===
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Copy the contents of $fileobj into another storage $plugin.
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Returns 1 on success, 0 on failure and -1 if a copy already exists in $plugin.
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===$ok = $storage-&gt;open_write( $fileobj )===
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Start a write session for $fileobj. $fileobj must have at least the "filesize" property set (which is the number of bytes that will be written).
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===$ok = $storage-&gt;write( $fileobj, $buffer )===
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Write $buffer to the storage plugin(s).
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===$ok = $storage-&gt;close_write( $fileobj );===
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Finish writing to the storage plugin(s) for $fileobj.
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<!-- Pod2Wiki=_postamble_ --><!-- Edit below this comment -->

Revision as of 12:08, 25 February 2010

EPrints 3 Reference: Directory Structure - Metadata Fields - Repository Configuration - XML Config Files - XML Export Format - EPrints data structure - Core API - Data Objects

API: Core API

Latest Source Code (3.4, 3.3) | Revision Log | Before editing this page please read Pod2Wiki


Warning The interface for this module has not been finalised and may change in the future.

NAME

EPrints::Storage - store and retrieve objects in the storage engine

User Comments


This should be inserted verbatum into the Wiki page.

SYNOPSIS

 my $store = $repository->storage();
 
 $store->store(
   $fileobj,    # file object
   "diddle.pdf",  # filename
   $fh        # file handle
 );

User Comments


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.

User Comments


METHODS

User Comments


$store = EPrints::Storage->new( $repository )

Create a new storage object for $repository. Should not be used directly, see EPrints::Session.

User Comments


$len = $store->store( $fileobj, CODEREF )

Read from and store all data from CODEREF for $fileobj. The filesize field in $fileobj must be set at the expected number of bytes to read from CODEREF.

Returns undef if the file couldn't be stored, otherwise the number of bytes read.

User Comments


$success = $store->retrieve( $fileobj, CALLBACK )

User Comments


$success = $store->delete( $fileobj )

Delete all object copies stored for $fileobj.

User Comments


$ok = $store->delete_copy( $plugin, $fileobj )

Delete the copy of this file stored in $plugin.

User Comments


$filename = $store->get_local_copy( $fileobj )

Return the name of a local copy of the file.

Will retrieve and cache the remote object using File::Temp if necessary.

Returns undef if retrieval failed.

User Comments


$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.

User Comments


@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.

User Comments


$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.

User Comments


$ok = $storage->open_write( $fileobj )

Start a write session for $fileobj. $fileobj must have at least the "filesize" property set (which is the number of bytes that will be written).

User Comments


$ok = $storage->write( $fileobj, $buffer )

Write $buffer to the storage plugin(s).

User Comments


$ok = $storage->close_write( $fileobj );

Finish writing to the storage plugin(s) for $fileobj.

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