# taglib-ruby

Ruby interface for the [TagLib C++ library][taglib], for reading and
writing meta-data (tags) of many audio formats.

In contrast to other libraries, this one wraps the full C++ API, not
only the minimal C API. This means that all tag data can be accessed,
e.g. cover art of ID3v2 or custom fields of Ogg Vorbis comments.

`taglib-ruby` currently supports the following:

* Reading/writing common tag data of all formats that TagLib supports
* Reading/writing ID3v1 and ID3v2 including ID3v2.4 and Unicode
* Reading/writing Ogg Vorbis comments
* Reading/writing MP4 tags (.m4a)
* Reading audio properties (e.g. bitrate) of the above formats

Contributions for more coverage of the library are very welcome.

[![Gem version][gem-img]][gem-link]
[![ci](https://github.com/robinst/taglib-ruby/workflows/ci/badge.svg)](https://github.com/robinst/taglib-ruby/actions?query=workflow%3Aci)

## Installation

Before you install the gem, make sure to have [taglib 1.11.1 or higher][taglib]
installed with header files (and a C++ compiler of course):

* Debian/Ubuntu: `sudo apt-get install libtag1-dev`
* Fedora/RHEL: `sudo dnf install taglib-devel`
* Brew: `brew install taglib`
* MacPorts: `sudo port install taglib`

Then do:

    gem install taglib-ruby

### MacOS

Depending on your brew setup, TagLib might be installed in different locations,
which makes it hard for taglib-ruby to find it. To get the library location, run:

    $ brew info taglib
    taglib: stable 1.12 (bottled), HEAD
    Audio metadata library
    https://taglib.org/
    /usr/local/Cellar/taglib/1.12 (122 files, 1.5MB) *
    ...

Note the line with the path at the end. Provide that using the `TAGLIB_DIR`
environment variable when installing, like this:

    TAGLIB_DIR=/usr/local/Cellar/taglib/1.12 gem install taglib-ruby

Another problem might be that `clang++` doesn't work with a specific version
of TagLib. In that case, try compiling taglib-ruby's C++ extensions with a
different compiler:

    TAGLIB_RUBY_CXX=g++-4.2 gem install taglib-ruby

## Usage

Complete API documentation can be found on
[rubydoc.info](http://rubydoc.info/gems/taglib-ruby/frames).

Begin with the `TagLib` namespace.

## Release Notes

See [CHANGELOG.md](CHANGELOG.md).

## Contributing

### Dependencies

Fedora:

    sudo dnf install taglib-devel ruby-devel gcc-c++ redhat-rpm-config swig

### Building

Install dependencies (uses bundler, install it via `gem install bundler`
if you don't have it):

    bundle install

Regenerate SWIG wrappers if you made changes in `.i` files (use version 3.0.7 of
SWIG - 3.0.8 through 3.0.12 will not work):

    rake swig

Force regeneration of all SWIG wrappers:

    touch ext/*/*.i
    rake swig

Compile extensions:

    rake clean compile

Run tests:

    rake test

Run irb with library:

    irb -Ilib -rtaglib

Build and install gem into system gems:

    rake install

Build a specific version of Taglib:

    PLATFORM=x86_64-linux TAGLIB_VERSION=1.11.1 rake vendor

The above command will automatically download Taglib 1.11.1, build it and
install it in `tmp/x86_64-linux/taglib-1.11.1`.

The `swig` and `compile` tasks can then be executed against that specific
version of Taglib by setting the `TAGLIB_DIR` environment variable to
`$PWD/tmp/x86_64-linux/taglib-1.11.1` (it is assumed that taglib headers are
located at `$TAGLIB_DIR/include` and taglib libraries at `$TAGLIB_DIR/lib`).

The `test` task can then be run for that version of Taglib by adding
`$PWD/tmp/x86_64-linux/taglib-1.11.1/lib` to the `LD_LIBRARY_PATH` environment
variable.

To do everything in one command:

    PLATFORM=x86_64-linux TAGLIB_VERSION=1.11.1 TAGLIB_DIR=$PWD/tmp/x86_64-linux/taglib-1.11.1 LD_LIBRARY_PATH=$PWD/tmp/x86_64-linux/taglib-1.11.1/lib rake vendor compile test

### Workflow

* Check out the latest `main` branch to make sure the feature hasn't been
  implemented or the bug hasn't been fixed yet.
* Check out the issue tracker to make sure someone hasn't already
  requested it and/or contributed it.
* Fork the project.
* Start a feature/bugfix branch from `main`.
* Commit and push until you are happy with your contribution.
* Make sure to add tests for it. This is important so that I don't break it
  in a future version unintentionally.
* Run `rubocop` locally to lint your changes and fix the issues. Please refer to
  [.rubocop.yml](.rubocop.yml) for the list of relaxed rules. Try to keep the
  liniting offenses to minimum. Preferably, first run `rubocop` on your fork to
  have a general idea of the existing linting offenses before writing new code.
* Please try not to mess with the Rakefile, version, or history. If you
  want to have your own version, or is otherwise necessary, that is
  fine, but please isolate to its own commit so I can cherry-pick around
  it.

## License

Copyright (c) 2010-2022 Robin Stocker and others, see Git history.

`taglib-ruby` is distributed under the MIT License, see
[LICENSE.txt](LICENSE.txt) for details.

In the binary gem for Windows, a compiled [TagLib][taglib] is bundled as
a DLL. TagLib is distributed under the GNU Lesser General Public License
version 2.1 (LGPL) and Mozilla Public License (MPL).

[taglib]: http://taglib.github.io/
[gem-img]: https://badge.fury.io/rb/taglib-ruby.svg
[gem-link]: https://rubygems.org/gems/taglib-ruby
