This gem contains the Square strategy for OmniAuth.
Square uses the OAuth2 flow, you can read about it here: http://connect.squareup.com
So let's say you're using Rails, you need to add the strategy to your Gemfile
:
gem 'omniauth-square', '~> 2.0.0'
You can pull it in directly from github (if you really want to) e.g.:
gem 'omniauth-square', :git => 'https://github.com/dja/omniauth-square.git'
Once these are in, you need to add the following to your config/initializers/devise.rb
(NOTE: A full enumeration of Square Permissions can be found here.):
config.omniauth :square, "your_app_id", "your_app_oauth_secret", {:scope => "ITEMS_READ,ITEMS_WRITE"}
Sandbox Example:
config.omniauth :square, "your_app_id", "your_app_oauth_secret", {:scope => "ITEMS_READ,ITEMS_WRITE", :client_options => {:connect_site => 'https://connect.squareupsandbox.com', :site => 'https://squareupsandbox.com'}}
You will obviously have to put in your key and secret, which you get when you register your app with Square (they call them Application Key and Secret Key).
Now just follow the README at: https://github.com/intridea/omniauth