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Decidim::Verifications

Decidim offers several methods for allowing participants to get authorization to perform certain privileged actions. This module implements several of those methods and also offers a way for installation to implement their custom verification methods.

There are several use cases for this, such as

  • Sending a SMS code to users to verify that their have a valid cellphone

  • Allowing users to upload a photo or scanned image of their identity document

  • Sending users a code through postal code

  • Allowing users to go to to a physical office and check their documentation

  • Checking some information through other systems (as a Municipal Census on the case of Municipalities, Cities or Towns)

  • Having a list of valid users emails

Right now Decidim supports only a few of these cases, but we have an internal API where you can program your own kind of authorizations.

Introduction

Each decidim instance is in full control of its authorizations, and can customize:

  • The different methods to be used by users to get verified. For example, through a census, by uploading their identity documents, or by receiving a verification home at their address.

  • The different actions in decidim that require authorization, and which authorization method they require. For example, a decidim instance might choose to require census authorization to create proposals, but a fully verified address via a verification code sent by postal mail for voting on proposals.

Types of authorization methods

Decidim implements two type of authorization methods:

  • Form authorizations.

    When your verification method is simple enough, you can use a Rectify::Form to implement it. "Simple" here means that the authorization can be granted with the submission of a single form. For example, to validate a user against a census API you will need a form with some fields that your users will use to authenticate against a census (for example, an ID and a Postal Code). You'll implement this with a form class. See the documentation for the parent class or have a look at some live examples, such as:

    To register your handler, use

    # config/initializers/decidim.rb

Decidim::Verifications.register_workflow(:census) do |workflow|
  workflow.form = "<myAuthorizationHandlerClass"
end

  • Workflow authorizations.

    For more complex scenarios requiring several steps or admin intervention, you can register a verification flow.

    For example:

    # config/initializers/decidim.rb

Decidim::Verifications.register_workflow(:my_verification) do |workflow|
  workflow.engine = Decidim::Verifications::MyVerification::Engine
  workflow.admin_engine = Decidim::Verifications::MyVerification::AdminEngine
end

    Inside these engines, you can implement any steps required for the authorization to succeed, via one or more custom controllers and views. You can create partial Authorization records (with the verified_at column set to nil) and hold partial verification data in the verification_metadata column, or even a partial verification attachment in the verification_attachment column.

    Decidim currently requires that your main engine defines two routes:

    • new_authorization_path: This is the entry point to start the authorization process.

    • edit_authorization_path: This is the entry point to resume an existing authorization process.

SMS verification

Decidim comes with a verification workflow designed to verify users by sending an SMS to their mobile phone.

Much like a Census verification you just need to implement a class that sends an SMS code using your preferred provider.

In order to setup Decidim with SMS verification you need to:

  1. Create a class that accepts two parameters when initializing it (mobile phone and code) and a method named deliver_code that will send an SMS and return a truthy or falsey value if the delivery was OK or not.
  2. Set the sms_gateway_service configuration variable to the name of the class that you just created (use a String, not the actual class) at config/initializers/decidim.rb.

Keep in mind that Decidim won't store a free text version of the mobile phone, only a hashed version so we can avoid duplicates and guarantee the users' privacy.

You can find an example here.

Authorization options

Sometimes you want to scope authorizations only to users that meet certain requirements. For example, you might only allow users registered at a certain postal code to be verified and thus perform certain actions.

You can do this with authorization options. For example, in the case just presented, you should define something like this in your authorization workflow:

Decidim::Verifications.register_workflow(:my_workflow) do |workflow|
  workflow.form = "MyAuthorizationHandler"

  workflow.options do |options|
    options.attribute :postal_code, type: :string, required: false
  end
end

The format of the options you can define is the standard for a virtus attribute, plus an additional required (true by default) option were you can choose whether the option is compulsory when configuring the workflow as a permission for an action or not.

Custom action authorizers

Custom action authorizers are an advanced component that can be used in both types of authorization methods to customize some parts of the authorization process. These are particulary useful when used within verification options, which are set in the admin zone related to a component action. As a result, a verification method will be allowed to change the authorization logic and the appearance based on the context where the authorization is being performed.

For example, you can require authorization for supporting proposals in a participatory process, and also restrict it to users with postal codes 12345 and 12346. The example authorization handler included in this module allows to do that. As an admin user, you should visit the proposals componenent permissions screen, choose the Example authorization as the authorization handler name for the vote action and type something like { allowed_postal_codes: ["12345", "12346"] } in the Options field placed below.

You can override default behavior implementing a class that inherits form Decidim::Verifications::DefaultActionAuthorizer and override some methods or that implement its public methods:

  • The initialize method receives the current authorization process context and saves it in local variables. This include the current authorization user state (an Authorization record), permission options related to the action is trying to perform and the current component where the authorization is taking place.

  • The authorize method is responsible of evaluating the authorization process context and determine if the user authorization is :ok or in any other status.

  • The redirect_params method allows to add additional query string parameters when redirecting to the authorization form. This is useful to send to the authorization form the permission options information that could be useful to adapt its behavior or appearance.

To be used by the verification method, this class should be referenced by name in its workflow manifest:

# config/initializers/decidim.rb

Decidim::Verifications.register_workflow(:my_verification) do |workflow|
  workflow.engine = Decidim::Verifications::MyVerification::Engine
  workflow.admin_engine = Decidim::Verifications::MyVerification::AdminEngine
  workflow.action_authorizer = "Decidim::Verifications::MyVerification::ActionAuthorizer"
end

Check the example authorization handler and the DefaultActionAuthorizer class for additional technical details.

How Handlers work

For a workflow to be visible in the user's profile, the organization must have it in it's available_authorizations and the given handler must exist. The name of the handler must match the authorization name plus the "Hander" suffix. It also has to be in the Decidim::Verifications namespace.

The handler is both the Form object that the user must fill in order to be verified, but also the validator of the filled information in order to grant the authorization.

Installation

Add this line to your application's Gemfile:

gem 'decidim-verifications'

And then execute:

bundle

Contributing

See Decidim.

License

See Decidim.