OmniAuth Line

LINE Login v2.1 (OAuth 2.0 / OpenID Connect) strategy for OmniAuth.

See the LINE Login docs for details: https://developers.line.biz/en/docs/line-login/integrate-line-login/

Using This Strategy

First start by adding this gem to your Gemfile:

gem 'omniauth-line'

Next, tell OmniAuth about this provider. For a Rails app, your config/initializers/omniauth.rb file should look like this:

Rails.application.config.middleware.use OmniAuth::Builder do
  provider :line, ENV['LINE_CHANNEL_ID'], ENV['LINE_CHANNEL_SECRET']
end

Register your callback URL (e.g. https://your.app/auth/line/callback) under "LINE Login > Callback URL" in the LINE Developers console, or the authorization request will fail with "Invalid redirect_uri value".

Scopes and email

The default scope is profile openid. To receive the user's email address, apply for the "OpenID Connect email" permission in the LINE Developers console and request the email scope:

provider :line, ENV['LINE_CHANNEL_ID'], ENV['LINE_CHANNEL_SECRET'],
         scope: 'profile openid email'

LINE only exposes the email inside the ID token, never through the profile API; the strategy decodes it via LINE's verify endpoint. When the email scope is not granted, info[:email] is nil.

Authentication Hash

An example auth hash available in request.env['omniauth.auth']:

{
  provider: "line",
  uid: "U1234567890abcdef1234567890abcdef",
  info: {
    name: "yamada tarou",
    image: "https://profile.line-scdn.net/xxxxx",
    description: nil,            # the user's status message, may be nil
    email: "user@example.com"    # nil unless the email scope is granted
  },
  credentials: {
    token: "a1b2c3d4...",        # OAuth 2.0 access token
    refresh_token: "e5f6g7h8...",
    expires_at: 1789266388,
    expires: true
  },
  extra: {
    id_token: "eyJ0eXAiOiJKV1Qi..."  # OpenID Connect ID token (JWT), issued with the openid scope
  }
}

Development

bundle install
bundle exec rake   # runs the specs with a minimum-coverage gate

The test suite stubs all HTTP with WebMock; no LINE credentials are needed. CI runs the suite on Ruby 3.1 through 3.4.