NAME

File::Metadata::Libextractor - Use libextractor to read file metadata

SYNOPSIS

use File::Metadata::Libextractor;

#| This program extracts all the information about a file
sub MAIN($file! where { .IO.f // die "file '$file' not found" })
{
  my File::Metadata::Libextractor $e .= new;
  my @info = $e.extract($file);
  for @info -> %record {
    for %record.kv -> $k, $v {
      say "$k: $v"
    }
    say '-' x 50;
  }
}

DESCRIPTION

File::Metadata::Libextractor provides an OO interface to libextractor in order to query files' metadata.

As the Libextractor site (https://www.gnu.org/software/libextractor) states, it is able to read information in the following file types:

• HTML

• MAN

• PS

• DVI

• OLE2 (DOC, XLS, PPT)

• OpenOffice (sxw)

• StarOffice (sdw)

• FLAC

• MP3 (ID3v1 and ID3v2)

• OGG

• WAV

• S3M (Scream Tracker 3)

• XM (eXtended Module)

• IT (Impulse Tracker)

• NSF(E) (NES music)

• SID (C64 music)

• EXIV2

• JPEG

• GIF

• PNG

• TIFF

• DEB

• RPM

• TAR(.GZ)

• LZH

• LHA

• RAR

• ZIP

• CAB

• 7-ZIP

• AR

• MTREE

• PAX

• CPIO

• ISO9660

• SHAR

• RAW

• XAR FLV

• REAL

• RIFF (AVI)

• MPEG

• QT

• ASF

Also, various additional MIME types are detected.

new(Bool :$in-process?)

Creates a File::Metadata::Libextractor object.

libextractor interfaces to several libraries in order to extract the metadata. To work safely it starts sub-processes to perform the actual extraction work.

This might cause problems in a concurrent envirnment with locks. A possible solution is to run the extraction process inside the program's own process. It's less secure, but it may avoid locking problems.

The optional argument $in-process allows the execution of the extraction job in the parent's process.

extract($file where .IO.f // fail "file '$file' not found" --> List)

Reads all the possible information from an existing file, or fails if the file doesn't exist. The output List is actually a List of Hashes. Each hash has the following keys:

• mime-type The file's mime-type

• plugin-name The name of the plugin the library used to find out the information

• plugin-type The plugin subtype used for the operation

• plugin-format The format of the plugin's output

• data-type The value returned by the plugin subtype

The possible values for plugin-format are:

• EXTRACTOR_METAFORMAT_UNKNOWN

• EXTRACTOR_METAFORMAT_UTF8

• EXTRACTOR_METAFORMAT_BINARY

• EXTRACTOR_METAFORMAT_C_STRING

The possible values for the plugin-type field are listed in File::Metadata::Libextractor::Constants, in the EXTRACTOR_MetaType enum (231 values as for v3.1.6).

Prerequisites

This module requires the libextractor library to be installed. It has been successfully tested on the following Linux distributions:

• Debian 9

• Debian sid

• Ubuntu 16.04

• Ubuntu 18.04

It doesn't work with the version of the library that comes with Ubuntu 14.04.

sudo apt-get install libextractor3

This module looks for a library called libextractor.so.3 .

Installation

To install it using zef (a module management tool):

$ zef install File::Metadata::Libextractor

Testing

To run the tests:

$ prove -e "raku -Ilib"

AUTHOR

Fernando Santagata nando.santagata@gmail.com

COPYRIGHT AND LICENSE

Copyright 2018 Fernando Santagata

This library is free software; you can redistribute it and/or modify it under the Artistic License 2.0.