File::LibMagic (3)

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NAME

File::LibMagic - Determine MIME types of data or files using libmagic

VERSION

version 1.15

SYNOPSIS

  use File::LibMagic;

  my $magic = File::LibMagic->new();

  my $info = $magic->info_from_filename('path/to/file');
  # Prints a description like "ASCII text"
  print $info->{description};
  # Prints a MIME type like "text/plain"
  print $info->{mime_type};
  # Prints a character encoding like "us-ascii"
  print $info->{encoding};
  # Prints a MIME type with encoding like "text/plain; charset=us-ascii"
  print $info->{mime_with_encoding};

  my $file_content = read_file('path/to/file');
  $info = $magic->info_from_string($file_content);

  open my $fh, '<', 'path/to/file' or die $!;
  $info = $magic->info_from_handle($fh);

DESCRIPTION

The "File::LibMagic" is a simple perl interface to libmagic from the file package (version 4.x or 5.x). You will need both the library (libmagic.so) and the header file (magic.h) to build this Perl module.

Installing libmagic

On Debian/Ubuntu run:

    sudo apt-get install libmagic-dev

On Mac you can use homebrew (brew.sh/):

    brew install libmagic

Specifying lib and/or include directories

On some systems, you may need to pass additional lib and include directories to the Makefile.PL. You can do this with the `--lib` and `--include` parameters:

    perl Makefile.PL --lib /usr/local/lib --include /usr/local/include

You can pass these parameters multiple times to specify more than one location.

API

This module provides an object-oriented with the following methods:

File::LibMagic->new()

Creates a new File::LibMagic object.

Using the object oriented interface only opens the magic database once, which is probably most efficient for repeated uses.

Each "File::LibMagic" object loads the magic database independently of other "File::LibMagic" objects, so you may want to share a single object across many modules.

This method takes the following named parameters:

*

magic_file

This should be a string or an arrayref containing one or more magic files.

If a file you provide doesn't exist the constructor will throw an exception, but only with libmagic 4.17+.

If you don't set this parameter, the constructor will throw an exception if it can't find any magic files at all.

Note that even if you're using a custom file, you probably also want to use the standard file (/usr/share/misc/magic on my system, yours may vary).

*

follow_symlinks

If this is true, then calls to "$magic->info_from_filename" will follow symlinks to the real file.

*

uncompress

If this is true, then compressed files (such as gzip files) will be uncompressed, and the various "info_from_*" methods will return info about the uncompressed file.

$magic->info_from_filename('path/to/file')

This method returns info about the given file. The return value is a hash reference with four keys:

*

description

A textual description of the file content like ``

ASCII C

program text''.

*

mime_type

The

MIME

type without a character encoding, like ``text/x-c''.

*

encoding

Just the character encoding, like ``us-ascii''.

*

mime_with_encoding

The

MIME

type with a character encoding, like ``text/x-c; charset=us-ascii''. Note that if no encoding was found, this will be the same as the "mime_type" key.

$magic->info_from_string($string)

This method returns info about the given string. The string can be passed as a reference to save memory.

The return value is the same as that of "$mime->info_from_filename()".

$magic->info_from_handle($fh)

This method returns info about the given filehandle. It will read data starting from the handle's current position, and leave the handle at that same position after reading.

DISCOURAGED APIS

This module offers two different procedural APIs based on optional exports, the ``easy'' and ``complete'' interfaces. There is also an older still available. All of these APIs are discouraged, but will not be removed in the near future, nor will using them cause any warnings.

I strongly recommend you use the new

It's simpler than the complete interface, more efficient than the easy interface, and more featureful than the old

The Old

OO API

This uses the same constructor as the current

*

$magic->checktype_contents($data)

Returns the

MIME

type of the data given as the first argument. The data can be passed as a plain scalar or as a reference to a scalar.

This is the same value as would be returned by the "file" command with the "-i" switch.

*

$magic->checktype_filename($filename)

Returns the

MIME

type of the given file.

This is the same value as would be returned by the "file" command with the "-i" switch.

*

$magic->describe_contents($data)

Returns a description (as a string) of the data given as the first argument. The data can be passed as a plain scalar or as a reference to a scalar.

This is the same value as would be returned by the "file" command with no switches.

*

$magic->describe_filename($filename)

Returns a description (as a string) of the given file.

This is the same value as would be returned by the "file" command with no switches.

The easy interface

This interface is exported by:

  use File::LibMagic ':easy';

This interface exports two subroutines:

*

MagicBuffer($data)

Returns the description of a chunk of data, just like the "describe_contents" method.

*

MagicFile($filename)

Returns the description of a file, just like the "describe_filename" method.

The complete interface

This interface is exported by:

  use File::LibMagic ':complete';

This interface exports several subroutines:

*

magic_open($flags)

This subroutine opens creates a magic handle. See the libmagic man page for a description of all the flags. These are exported by the ":complete" import.

  my $handle = magic_open(MAGIC_MIME);

*

magic_load($handle, $filename)

This subroutine actually loads the magic file. The $filename argument is optional. There should be a sane default compiled into your "libmagic" library.

*

magic_buffer($handle, $data)

This returns information about a chunk of data as a string. What it returns depends on the flags you passed to "magic_open", a description, a

MIME

type, etc.

*

magic_file($handle, $filename)

This returns information about a file as a string. What it returns depends on the flags you passed to "magic_open", a description, a

MIME

type, etc.

*

magic_close($handle)

Closes the magic handle.

EXCEPTIONS

This module can throw an exception if your system runs out of memory when trying to call "magic_open" internally.

SUPPORT

Please submit bugs to the system at rt.cpan.org/NoAuth/Bugs.html?Dist=File-LibMagic or via email at bug-file-libmagic@rt.cpan.org.

BUGS

This module is totally dependent on the version of file on your system. It's possible that the tests will fail because of this. Please report these failures so I can make the tests smarter. Please make sure to report the version of file on your system as well!

DEPENDENCIES/PREREQUISITES

This module requires file 4.x or file 5x and the associated libmagic library and headers (darwinsys.com/file

RELATED MODULES

Andreas created File::LibMagic because he wanted to use libmagic (from file 4.x) File::MMagic only worked with file 3.x.

File::MimeInfo::Magic uses the magic file from freedesktop.org which is encoded in

and is thus not the fastest approach. See <mail.gnome.org/archives/nautilus-list/2003-December/msg00260.html> for a discussion of this issue.

File::Type uses a relatively small magic file, which is directly hacked into the module code. It is quite fast but the database is quite small relative to the file package.

AUTHORS

*

Andreas Fitzner

*

Michael Hendricks <michael@ndrix.org>

*

Dave Rolsky <autarch@urth.org>

CONTRIBUTORS

*

E. Choroba <choroba@matfyz.cz>

*

Mithun Ayachit <mayachit@amfam.com>

*

Olaf Alders <olaf@wundersolutions.com>

COPYRIGHT AND LICENSE

This software is copyright (c) 2015 by Andreas Fitzner, Michael Hendricks, and Dave Rolsky.

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.