# The two-step activation workflow

The two-step activation workflow, found in django_registration.backends.activation, implements a two-step registration process: a user signs up, an inactive account is created, and an email is sent containing an activation link which must be clicked to make the account active.

## Behavior and configuration

A default URLconf is provided, which you can `include()` in your URL configuration; that URLconf is django_registration.backends.activation.urls. For example, to place user registration under the URL prefix /accounts/, you could place the following in your root URLconf:

    from django.urls import include, path

    urlpatterns = [
        # Other URL patterns ...
        path('accounts/', include('django_registration.backends.activation.urls')),
        path('accounts/', include('django.contrib.auth.urls')),
        # More URL patterns ...
    ]

That also sets up the views from django.contrib.auth (login, logout, password reset, etc.).

This workflow makes use of up to three settings (click for details on each):

- `ACCOUNT_ACTIVATION_DAYS`

- `REGISTRATION_OPEN`

- `REGISTRATION_SALT` (see also note below)

By default, this workflow uses `RegistrationForm` as its form class for user registration; this can be overridden by passing the keyword argument form_class to the registration view.

## Views

Two views are provided to implement the signup/activation process. These subclass the base views of django-registration, so anything that can be overridden/customized there can equally be overridden/customized here. There are some additional customization points specific to this implementation, which are listed below.

For an overview of the templates used by these views (other than those specified below), and their context variables, see the quick start guide.

class django_registration.backends.activation.views.RegistrationView

  A subclass of `django_registration.views.RegistrationView` implementing the signup portion of this workflow.

  Important customization points unique to this class are:

  create_inactive_user(form)

    Creates and returns an inactive user account, and calls `send_activation_email()` to send the email with the activation key. The argument form is a valid registration form instance passed from `register()`.

    Parameters

      form (django_registration.forms.RegistrationForm) – The registration form.

    Return type

      django.contrib.auth.models.AbstractUser

  get_activation_key(user)

    Given an instance of the user model, generates and returns an activation key (a string) for that user account.

    Parameters

      user (django.contrib.auth.models.AbstractUser) – The new user account.

    Return type

      str

  get_email_context(activation_key)

    Returns a dictionary of values to be used as template context when generating the activation email.

    Parameters

      activation_key (str) – The activation key for the new user account.

    Return type

      dict

  send_activation_email(user)

    Given an inactive user account, generates and sends the activation email for that account.

    Parameters

      user (django.contrib.auth.models.AbstractUser) – The new user account.

    Return type

      None

  email_body_template

    A string specifying the template to use for the body of the activation email. Default is “django_registration/activation_email_body.txt”.

  email_subject_template

    A string specifying the template to use for the subject of the activation email. Default is “django_registration/activation_email_subject.txt”. Note that, to avoid header-injection vulnerabilities, the result of rendering this template will be forced into a single line of text, stripping newline characters.

class django_registration.backends.activation.views.ActivationView

  A subclass of `django_registration.views.ActivationView` implementing the activation portion of this workflow.

  Errors in activating the user account will raise `ActivationError`, with one of the following values for the exception’s code:

  “already_activated”

    Indicates the account has already been activated.

  “bad_username”

    Indicates the username decoded from the activation key is invalid (does not correspond to any user account).

  “expired”

    Indicates the account/activation key has expired.

  “invalid_key”

    Generic indicator that the activation key was invalid.

  Important customization points unique to this class are:

  get_user(username)

    Given a username (determined by the activation key), looks up and returns the corresponding instance of the user model. If no such account exists, raises `ActivationError` as described above. In the base implementation, checks the `is_active` field to avoid re-activating already-active accounts, and raises `ActivationError` with code already_activated to indicate this case.

    Parameters

      username (str) – The username of the new user account.

    Return type

      django.contrib.auth.models.AbstractUser

    Raises

      django_registration.exceptions.ActivationError – if no matching inactive user account exists.

  validate_key(activation_key)

    Given the activation key, verifies that it carries a valid signature and a timestamp no older than the number of days specified in the setting ACCOUNT_ACTIVATION_DAYS, and returns the username from the activation key. Raises `ActivationError`, as described above, if the activation key has an invalid signature or if the timestamp is too old.

    Parameters

      activation_key (str) – The activation key for the new user account.

    Return type

      str

    Raises

      django_registration.exceptions.ActivationError – if the activation key has an invalid signature or is expired.

  Note

  URL patterns for activation

  Although the actual value used in the activation key is the new user account’s username, the URL pattern for `ActivationView` does not need to match all possible legal characters in a username. The activation key that will be sent to the user (and thus matched in the URL) is produced by `django.core.signing.dumps()`, which base64-encodes its output. Thus, the only characters this pattern needs to match are those from the URL-safe base64 alphabet, plus the colon (”:”) which is used as a separator.

  The default URL pattern for the activation view in django_registration.backends.activation.urls handles this for you.

## How it works

When a user signs up, the activation workflow creates a new user instance to represent the account, and sets the is_active field to `False`. It then sends an email to the address provided during signup, containing a link to activate the account. When the user clicks the link, the activation view sets is_active to `True`, after which the user can log in.

The activation key is the username of the new account, signed using Django’s cryptographic signing tools (specifically, `dumps()` is used, to produce a guaranteed-URL-safe value). The activation process includes verification of the signature prior to activation, as well as verifying that the user is activating within the permitted window (as specified in the setting `ACCOUNT_ACTIVATION_DAYS`, mentioned above), through use of Django’s `TimestampSigner`.

## Security considerations

The activation key emailed to the user in the activation workflow is a value obtained by using Django’s cryptographic signing tools. The activation key is of the form:

    encoded_username:timestamp:signature

where encoded_username is the username of the new account, timestamp is the timestamp of the time the user registered, and signature is an HMAC of the username and timestamp. The username and HMAC will be URL-safe base64 encoded; the timestamp will be base62 encoded.

Django’s implementation uses the value of the `SECRET_KEY` setting as the key for HMAC; additionally, it permits the specification of a salt value which can be used to “namespace” different uses of HMAC across a Django-powered site.

The activation workflow will use the value (a string) of the setting `REGISTRATION_SALT` as the salt, defaulting to the string “registration” if that setting is not specified. This value does not need to be kept secret (only `SECRET_KEY` does); it serves only to ensure that other parts of a site which also produce signed values from user input could not be used as a way to generate activation keys for arbitrary usernames (and vice-versa).