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DROLSKY / File-LibMagic-1.11 / README.md

NAME

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

VERSION

version 1.11

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 (http://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/include --include /usr/local/include

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

API

This module provides an object-oriented API 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 an optional argument containing one or more path to
the magic file. If the file doesn't exist this will throw an exception
(but only with libmagic 4.17+).

If you don't pass an argument, it will throw an exception if it can't
find any magic files at all.

You can pass an array reference to specify more than one file. 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).

$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.

DEPRECATED APIS

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

I strongly recommend you use the new OO API. It's simpler than the
complete interface, more efficient than the easy interface, and more
featureful than the old OO API.

The Old OO API

This API uses the same constructor as the current API.

  * $magic->checktype_contents($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 CPAN RT system at
http://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 (http://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 XML, and is thus not the fastest approach. See
http://mail.gnome.org/archives/nautilus-list/2003-December/msg00260.htm
l 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

  * 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.