Multitagger

Multitagger offers a unified API for automatic image tagging services. With Multitagger, you can start developing your image-recognizing app and have the comfort of changing your provider without rewriting the code, or even use multiple providers at once. See the blog post for background.

Multitagger currently supports five providers:

• Algorithmia Illustration Tagger
• Clarifai
• Google Cloud Vision
• Imagga
• Microsoft Cognitive Services

Installation

Add this line to your application’s Gemfile:

gem 'multitagger'

And then execute:

$ bundle

Or install it yourself as:

$ gem install multitagger

Usage

The simplest way to use Multitagger is to just do:

tags = Multitagger.tag(:google, "/path/to/your/image.jpg")

Where the first argument tells Multitagger to use Google Cloud Vision as the tagging service, and the second designates a local path to your image.

This will return an array of Multitagger::Tag structures, each of which has name (a string) and prob (a number from 0.0 to 1.0 representing the probability that this tag fits the image). See the file multitagger/tag.rb.

To use another provider, just replace the first argument. Multitagger.providers will tell you what providers are available.

You can also instantiate the tagging service and then call the tag method on that:

tagger = Multitagger.tagger(:google)
tags = tagger.tag("/path/to/your/image.jpg")

Configuration

Before you can use Multitagger, you must configure it. This is commonly done by putting your service’s credentials in config/multitagger.yml.

You need obtain the credentials (typically an API key, an app ID, a secret, or a combination of these, depending on the service) separately for each service you plan on using, by registering with the service.

You’ll find a sample multitagger.yml in the config/ directory in this repo; substitute the keys as needed.

If you need to put this file elsewhere, call this before invoking tagging:

Multitagger::Config.read("/path/to/your/multitagger.yml")

Alternatively, you can pass the configuration hash as a second argument to Multitagger.tagger.

Development

After checking out the repo, run bin/setup to install dependencies. 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/rebased/multitagger. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the Contributor Covenant code of conduct.

License

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