Arduino::Library

This gem encapsulates various rules about the library.properties file that contains meta-data about Arduino Libraries.

It also provides convenient shortcuts for downloading the Arduino-maintained database of published libraries in JSON format, searching for various libraries, choosing a version, and more.

It also provides validation functionality for the library.properties file for your custom libraries you would like to open source.

Installation

Add this line to your application's Gemfile:

gem 'arduino-library'

And then execute:

$ bundle

Or install it yourself as:

$ gem install arduino-library

Usage

Current version only contains Ruby-based API and is meant to be consumed by other projects (in particularly, check out Arli — a command-line tool and an Arduino Library Manager and installer). This project is invaluable if you are you using, for example, arduino-cmake project to build and upload your Arduino Code.

Configuration

The gem database can be configured to download the default database from a custom URL, keep a local cache in a custom file. It always downloads the index locally, and next time it's invoked, the local file is used (if and only if it's size is identical to the remote file).

You can change the configuration in two ways:

1. Set environment variables before invoking the gem
2. Configure the DefaultDatabase class variables

Environment Variables

• ARDUINO_CUSTOM_LIBRARY_PATH can be used to change local top-level path to the libraries folder.
• ARDUINO_LIBRARY_INDEX_PATH can be used to change the location of the cached index file.

Class Variables

require 'arduino/library'
Arduino::Library::DefaultDatabase.library_index_path =
Arduino::Library::DefaultDatabase.library_index_url  =
Arduino::Library::DefaultDatabase.library_path       =

# then reload the database:
Arduino::Library::DefaultDatabase.instance.setup

Default Values:

DEFAULT_ARDUINO_LIBRARY_INDEX_URL  =
   'http://downloads.arduino.cc/libraries/library_index.json.gz'

DEFAULT_ARDUINO_LIBRARY_PATH       =
    ENV['ARDUINO_CUSTOM_LIBRARY_PATH'] || (ENV['HOME'] + '/Documents/Arduino/Libraries')

DEFAULT_ARDUINO_LIBRARY_INDEX_PATH =
    ENV['ARDUINO_LIBRARY_INDEX_PATH'] ||
    (ENV['HOME'] + '/Documents/Arduino/Libraries/index.json.gz')

Using the top-level module

If you prefer not to have hard-coded dependencies on the Arduino::Library::* sub-classes and sub-modules, you can use the top level module, which proxies several shortcut methods.

You can access these methods in two different ways:

1. As class methods on Arduino::Library, for example Arduino::Library.db_default
2. By including the top-level module in your context, and using methods as instance methods in the current context, eg. #db_default

Below we'll focus on the second usage, but if you prefer to use the first syntax, it's there and available for you.

You can require the library for use in the DSL:

class Foo
  # this loads the library, and includes its methods in the current context
  require 'arduino/library/include
end

Using db_from

This method returns an instance of the Arduino::Library::Database from the provided source:

db_from('library_index.json').size 
# => 16
db_from('library_index.json.gz').size
# => 16
db_from('http://downloads.arduino.cc/libraries/library_index.json.gz').size 
# => 3653
# This required downloading a 400K gzipped file into a temp file, and reading from there.

Using db_default

This method downloads and returns the official Arduino-maintained index of Arduino libraries.

db_default.size
# => 3653

Using library_from

This method reads from a source that can be of many formats (see below) and returns an instantiated Arduino::Library::Model for this library. You can then get all library attributes via corresponding methods:

library_from('spec/fixtures/audio_zero.json').name 
# => 'AudioZero'
library_from('~/Documents/Arduino/Libraries/AudioZero/library.properties').name 
#=> 'AudioZero'
library_from('https://raw.githubusercontent.com/PaulStoffregen/DS1307RTC/master/library.properties').name
#=> 'DS1307RTC'

Using search

Method search is, perhaps, some of the most powerful functionality in this gem. It allows constructing very flexible and precise queries, to match any number of library attributes.

The method has the following signature:

search(database = db_default, **opts)

opts is a Hash that you can use to pass attributes with matchers. All matching results are returned as an array of models.

Examples

results = search(
  # direct string equality
  name:           'AudioZero',

  # regexp matching is fully supported 
  author:         /konstantin/i,              

 # array is matched if it's a subset or equality, or if library has '*'
  architectures:  [ 'avr' ],

  # or a proc for max flexibility
  version:        proc do |value|
    value.start_with?('1.')
  end
)

results.size 
#=> <whatever number of matches returned>

Note that multiple attributes must ALL match for the library to be included in the result set.

Arduino::Library::Database

Downloading the index of all libraries, and searching for a library.

You can load libraries from a local JSON file, or from a remote URL, eg:

require 'arduino/library'

database = Arduino::Library::Database.from(
  'http://downloads.arduino.cc/libraries/library_index.json.gz')

or, since the above link happens to be the default location of Arduino-maintained librarie index file, you can use the default method instead:

database = Arduino::Library::DefaultDatabase.instance

or, load the list from a local JSON file, that can be optionally gzipped (just like the URL):

database = Arduino::Library::Database.from('library_index.json.gz')

Once the library is initialized, the following operations are supported:

database.search(name: 'AudioZero', version: '1.0.1') do |audio_zero|
  audio_zero.website        #=> http://arduino.cc/en/Reference/Audio
  audio_zero.architectures  #=> [ 'samd' ] 
end

You can pass any of the attributes to #search, and the value can be a String (in which case only equality matches), or a regular expression, eg:

database.search(author: "Paul Stoffregen").size #=> 21
database.search(author: /stoffregen/i).size     #=> 33

You interate over multiple using either a block:

database.search(name: 'AudioZero') do |match|
  puts match.name # => 'AudioZero'
  puts match.version # => will print all versions of the library available
end

or, just grab the return value from #search, which is always an array.

all_versions = database.search(name: 'AudioZero')
# => [ Arduino::Library::Model<name: AudioZero, version: '1.0.1',... >, .. ]

Arduino::Library::Model

Use this class to operate on a single library.

Reading Library from an External Source using .from

You can use an intelligent class method .from that attempts to auto-detect the type of file or URL you are passing as an argument, and use an appropriate parser for each type.

For example, to read from a JSON file:

json_file = 'spec/fixtures/audio_zero.json'
model = Arduino::Library::Model.from(json_file)
model.name #=> 'AudioZero'

Or to read from the .properties file:

properties_file = 'spec/fixtures/audio_zero.properties'
model = Arduino::Library::Model.from(properties_file)
model.name #=> 'AudioZero'

Presenters

Presenters are there to convert to and from a particular format.

.properties Presenter

props = Arduino::Library::Presenters::Properties.new(model).present
File.open('/tmp/audio_zero.properties', 'w') do |f|
   f.write(props)
end

# this creates a file in the format:

# name=AudioZero
# version=1.0.1
# etc.

Development

After checking out the repo, run bin/setup to install dependencies. Then, run rake spec to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org.

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/kigster/arduino-library.

License

The gem is available as open source under the terms of the MIT License.