API:EPrints/Plugin/Convert: Difference between revisions

Latest revision as of 09:56, 22 January 2013

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

NAME

EPrints::Plugin::Convert - Convert EPrints::DataObj::Document into different formats

DESCRIPTION

This plugin and its dependents allow EPrints to convert documents from one format into another format. Convert plugins are also used by the full-text indexer to extract plain-text from documents.

Convert plugins may provide conversions from any number of formats to any number of other formats (or not even 'formats' per-se e.g. unpacking/packing archives). A single plugin may represent a particular software package (e.g. ImageMagick) or a common goal (e.g. textifying documents for indexing).

Using the root Convert plugin it is possible to query all loaded conversion plugins for available conversions from a given EPrints::DataObj::Document.

To allow for simpler local configuration Convert plugins should use SystemSettings to store the location of external programs.

SYNOPSIS

my $root = $repo->plugin( 'Convert' );

# Get the the available conversions for all plugins
my %available = $root->can_convert( $document );

# Get a conversion scheme for text/plain
my $txt_tool = $available{'text/plain'};

# Use the plugin to convert the document to text/plain
my $plugin = $txt_tool->{'plugin'};
$plugin->convert( $eprint, $document, 'text/plain' );

METHODS

new

new OPTIONS

Create a new plugin object using OPTIONS (should only be called by EPrints::Session).

render_name

$xhtml = $plugin->render_name

Return the name of this plugin as a chunk of XHTML.

is_visible

$plugin->is_visible( $level )

Returns whether this plugin is visible at level (currently 'all' or ).

can_convert

%types = $p->can_convert( $doc, [$type], [%params] )

Returns a hash of types that this plugin can convert the document $doc to. The key is the type. The value is a hash ref containing:

plugin

The object that can do the conversion.

encoding

The encoding this conversion generates (e.g. 'utf-8').

phraseid

A unique phrase id for this conversion.

preference

A value between 0 and 1 representing the 'quality' or confidence in this conversion.

export

@filelist = $p->export( $dir, $doc, $type )

Convert $doc to $type and export it to $dir. Returns a list of file names that resulted from the conversion. The main file (if there is one) is the first file name returned. Returns empty list on failure.

convert

$doc = $p->convert( $eprint, $doc, $type [, $epdata ] )

Convert $doc to format $type (as returned by can_convert). Stores the resulting $doc in $eprint, and returns the new document or undef on failure.

Optionally initialise the new document with $epdata. Specifying 'files' in $epdata will cause the converted file content to be discarded.

COPYRIGHT

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/.

@@ Line 28: / Line 28: @@
 <!-- Pod2Wiki=head_synopsis -->
 ==SYNOPSIS==
-<pre>  my $root = $session-&gt;plugin( 'Convert' );
+<source lang="perl">my $root = $repo->plugin( 'Convert' );
-  my %available = $root-&gt;can_convert( $document );
+# Get the the available conversions for all plugins
+my %available = $root->can_convert( $document );
-  # Convert a document to plain-text
-  my $txt_tool = $available{'text/plain'};
+# Get a conversion scheme for text/plain
-  my $plugin = $txt_tool-&gt;{ plugin };
+my $txt_tool = $available{'text/plain'};
-  $plugin-&gt;convert( $eprint, $document, 'text/plain' );</pre>
+# Use the plugin to convert the document to text/plain
+my $plugin = $txt_tool->{'plugin'};
+$plugin->convert( $eprint, $document, 'text/plain' );</source>
 <!-- Edit below this comment -->
@@ Line 49: / Line 52: @@
 </source>
-:Create a new plugin object using OPTIONS (should only be called by [[API:EPrints/Session|EPrints::Session]]).
+Create a new plugin object using OPTIONS (should only be called by [[API:EPrints/Session|EPrints::Session]]).
-:
 <!-- Edit below this comment -->
@@ Line 61: / Line 64: @@
 </source>
-:Return the name of this plugin as a chunk of XHTML.
+Return the name of this plugin as a chunk of XHTML.
-:
 <!-- Edit below this comment -->
@@ Line 73: / Line 76: @@
 </source>
-:Returns whether this plugin is visible at level (currently 'all' or '').
+Returns whether this plugin is visible at level (currently 'all' or '').
-:
 <!-- Edit below this comment -->
@@ Line 85: / Line 88: @@
 </source>
-:Returns a hash of types that this plugin can convert the document $doc to. The key is the type. The value is a hash ref containing:
+Returns a hash of types that this plugin can convert the document $doc to. The key is the type. The value is a hash ref containing:
-:
 * plugin
-::The object that can do the conversion.
+: The object that can do the conversion.
-::
 * encoding
-::The encoding this conversion generates (e.g. 'utf-8').
+: The encoding this conversion generates (e.g. 'utf-8').
-::
 * phraseid
-::A unique phrase id for this conversion.
+: A unique phrase id for this conversion.
-::
 * preference
-::A value between 0 and 1 representing the 'quality' or confidence in this conversion.
+: A value between 0 and 1 representing the 'quality' or confidence in this conversion.
-::
 <!-- Edit below this comment -->
@@ Line 109: / Line 112: @@
 </source>
-:Convert $doc to $type and export it to $dir. Returns a list of file names that resulted from the conversion. The main file (if there is one) is the first file name returned. Returns empty list on failure.
+Convert $doc to $type and export it to $dir. Returns a list of file names that resulted from the conversion. The main file (if there is one) is the first file name returned. Returns empty list on failure.
-:
 <!-- Edit below this comment -->
@@ Line 121: / Line 124: @@
 </source>
-:Convert $doc to format $type (as returned by can_convert). Stores the resulting $doc in $eprint, and returns the new document or undef on failure.
+Convert $doc to format $type (as returned by can_convert). Stores the resulting $doc in $eprint, and returns the new document or undef on failure.
-:
-:Optionally initialise the new document with $epdata. Specifying 'files' in $epdata will cause the converted file content to be discarded.
+Optionally initialise the new document with $epdata. Specifying 'files' in $epdata will cause the converted file content to be discarded.
-:
 <!-- Edit below this comment -->