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A Decidim module to add strong authentication to Decidim as a way to authenticate and authorize the users.

The gem has been developed by Mainio Tech.

The development has been sponsored by the City of Helsinki.

The Population Register Centre (VRK) or the maintainers are not related to this gem in any way, nor do they provide technical support for it. Please contact the gem maintainers in case you find any issues with it.


Please refer to the omniauth-suomifi documentation in order to learn more about the preparation and getting started with


Add this line to your application's Gemfile:

gem "decidim-suomifi"

And then execute:

$ bundle
$ bundle exec rails decidim_suomifi:install:migrations
$ bundle exec rails db:migrate

After installation, you can add the initializer running the following command:

$ bundle exec rails generate decidim:suomifi:install

You need to set the following configuration options inside the initializer:

  • :scope_of_data - The scope of data for
    • Default: :medium_extensive
    • :limited - Limited scope (name and personal identity number)
    • :medium_extensive - Medium extensive scope (limted + address information)
    • :extensive - Extensive scope (medium extensive + Finnish citizenship information)
  • :sp_entity_id - The service provider entity ID, i.e. your applications entity ID used to identify the service at the SAML identity provider.
    • Set this to the same ID that you use for the metadata sent to
    • Default: depends on the application's URL, e.g.
  • :certificate_file - Path to the local certificate included in the metadata sent to
  • :private_key_file - Path to the local private key (corresponding to the certificate). Will be used to decrypt messages coming from

Optionally you can also configure the module with the following options:

  • :auto_email_domain - Defines the auto-email domain in case the user's domain is not stored at In case this is not set (default), emails will not be auto-generated and users will need to enter them manually in case does not report them.
    • The auto-generated email format is similar to the following string: The email will always have the suomifi- prefix and the domain part is defined by the configuration option.
    • In case this is not defined, the organization's host will be used as the default.
  • :use_suomifi_email - Defines whether the emails stored in should be used for the user accounts if they are available. Note that not all people have an email address stored in the database and not everyone keeps it up to date. Another problem with this is that some people may have an old or incorrectly written email address stored in that may cause wrong email addresses to be used for the use accounts.

For more information about these options and possible other options, please refer to the omniauth-suomifi documentation.

Note that you will also need to generate a private key and a corresponding certificate and configure them inside the generated initializer. For the testing environment you can create a self signed certificate e.g. with the following command:

$ mkdir config/cert
$ cd config/cert
$ openssl req -x509 -sha256 -nodes -days 3650 -newkey rsa:2048 \
  -keyout suomifi.key -out suomifi.crt

For the production environment you will need an actual certificate signed by a trusted CA. The self signed certificate can be used for the test environment.

The install generator will also enable the authentication method for OmniAuth by default by adding these lines your config/secrets.yml:

default: &default
  # ...
    # ...
      enabled: false
      icon: icon-globe
  # ...
    # ...
      enabled: true
      mode: test
      icon: icon-globe

This will enable the authentication for the development environment only. In case you want to enable it for other environments as well, apply the OmniAuth configuration keys accordingly to other environments as well.

The development environment is hooking into the testing endpoints by default which is defined by the mode: test option in the OmniAuth configuration. For environments that you want to hook into the production environment, you can omit this configuration option completely.

The example configuration will set the icon-globe icon for the the authentication button from the Decidim's own iconset. In case you want to have a better and more formal styling for the sign in button, you will need to customize the sign in / sign up views.


After the installation steps, you will need to enable the authorization from Decidim's system management panel. After enabled, you can start using it.

This gem also provides a sign in method which will automatically authorize the user accounts. In case the users already have an account, they can still authorize themselves using the authorization.


For some specific needs, you may need to store extra metadata for the authorization or add new authorization configuration options for the authorization.

This can be achieved by applying the following configuration to the module inside the initializer described above:

# config/initializers/suomifi.rb

Decidim::Suomifi.configure do |config|
  # ... keep the default configuration as is ...
  # Add this extra configuration:
  config.workflow_configurator = lambda do |workflow|
    # When expiration is set to 0 minutes, it will never expire.
    workflow.expires_in = 0.minutes
    workflow.action_authorizer = "CustomSuomifiActionAuthorizer"
    workflow.options do |options|
      options.attribute :custom_option, type: :string, required: false
  config.metadata_collector_class = CustomSuomifiMetadataCollector

For the workflow configuration options, please refer to the decidim-verifications documentation.

For the custom metadata collector, please extend the default class as follows:

# frozen_string_literal: true

class CustomSuomifiMetadataCollector < Decidim::Suomifi::Verification::MetadataCollector
  def metadata
    base = super

    base.tap do |data|
      # You can access the SAML attributes using the `saml_attributes` accessor:
      postal_code = saml_attributes[:permanent_domestic_address_postal_code]

      # Or you can access the base attributes already defined through the
      # default metadata collector:
      postal_code = base[:postal_code]

      unless postal_code.blank?
        # This will actually add the data to the user's authorization metadata
        # hash.
        data[:extra] = "Custom data for: #{postal_code}"


See Decidim.


To run the tests run the following in the gem development path:

$ bundle
$ DATABASE_USERNAME=<username> DATABASE_PASSWORD=<password> bundle exec rake test_app
$ DATABASE_USERNAME=<username> DATABASE_PASSWORD=<password> bundle exec rspec

Note that the database user has to have rights to create and drop a database in order to create the dummy test app database.

In case you are using rbenv and have the rbenv-vars plugin installed for it, you can add these environment variables to the root directory of the project in a file named .rbenv-vars. In this case, you can omit defining these in the commands shown above.

Test code coverage

If you want to generate the code coverage report for the tests, you can use the SIMPLECOV=1 environment variable in the rspec command as follows:

$ SIMPLECOV=1 bundle exec rspec

This will generate a folder named coverage in the project root which contains the code coverage report.


If you would like to see this module in your own language, you can help with its translation at Crowdin: