FlaskBB Event Hooks

flaskbb.plugins.spec.flaskbb_event_post_save_before(post)

Hook for handling a post before it has been saved.

Parameters:post (flaskbb.forum.models.Post) – The post which triggered the event.
flaskbb.plugins.spec.flaskbb_event_post_save_after(post, is_new)

Hook for handling a post after it has been saved.

Parameters:
flaskbb.plugins.spec.flaskbb_event_topic_save_before(topic)

Hook for handling a topic before it has been saved.

Parameters:topic (flaskbb.forum.models.Topic) – The topic which triggered the event.
flaskbb.plugins.spec.flaskbb_event_topic_save_after(topic, is_new)

Hook for handling a topic after it has been saved.

Parameters:
flaskbb.plugins.spec.flaskbb_event_user_registered(username)

Hook for handling events after a user is registered

Parameters:username – The username of the newly registered user.
flaskbb.plugins.spec.flaskbb_authenticate(identifier, secret)

Hook for authenticating users in FlaskBB. This hook should return either an instance of flaskbb.user.models.User or None.

If a hook decides that all attempts for authentication should end, it may raise a flaskbb.core.exceptions.StopAuthentication and include a reason why authentication was stopped.

Only the first User result will used and the default FlaskBB authentication is tried last to give others an attempt to authenticate the user instead.

See also: AuthenticationProvider

Example of alternative auth:

def ldap_auth(identifier, secret):
    "basic ldap example with imaginary ldap library"
    user_dn = "uid={},ou=flaskbb,dc=flaskbb,dc=org"
    try:
        ldap.bind(user_dn, secret)
        return User.query.join(
            UserLDAP
        ).filter(
            UserLDAP.dn==user_dn
        ).with_entities(User).one()
    except:
        return None

@impl
def flaskbb_authenticate(identifier, secret):
    return ldap_auth(identifier, secret)

Example of ending authentication:

def prevent_login_with_too_many_failed_attempts(identifier):
    user = User.query.filter(
        db.or_(
            User.username == identifier,
            User.email == identifier
        )
    ).first()

    if user is not None:
        if has_too_many_failed_logins(user):
            raise StopAuthentication(_(
                "Your account is temporarily locked due to too many login attempts"
            ))

@impl(tryfirst=True)
def flaskbb_authenticate(user, identifier):
    prevent_login_with_too_many_failed_attempts(identifier)
flaskbb.plugins.spec.flaskbb_post_authenticate(user)

Hook for handling actions that occur after a user is authenticated but before setting them as the current user.

This could be used to handle MFA. However, these calls will be blocking and should be taken into account.

Responses from this hook are not considered at all. If a hook should need to prevent the user from logging in, it should register itself as tryfirst and raise a flaskbb.core.exceptions.StopAuthentication and include why the login was prevented.

See also: PostAuthenticationHandler

Example:

def post_auth(user):
    today = utcnow()
    if is_anniversary(today, user.date_joined):
        flash(_("Happy registerversary!"))

@impl
def flaskbb_post_authenticate(user):
    post_auth(user)
flaskbb.plugins.spec.flaskbb_authentication_failed(identifier)

Hook for handling authentication failure events. This hook will only be called when no authentication providers successfully return a user or a flaskbb.core.exceptions.StopAuthentication is raised during the login process.

See also: AuthenticationFailureHandler

Example:

def mark_failed_logins(identifier):
    user = User.query.filter(
        db.or_(
            User.username == identifier,
            User.email == identifier
        )
    ).first()

    if user is not None:
        if user.login_attempts is None:
            user.login_attempts = 1
        else:
            user.login_attempts += 1
        user.last_failed_login = utcnow()
flaskbb.plugins.spec.flaskbb_reauth_attempt(user, secret)

Hook for handling reauth in FlaskBB

These hooks receive the currently authenticated user and the entered secret. Only the first response from this hook is considered – similar to the authenticate hooks. A successful attempt should return True, otherwise None for an unsuccessful or untried reauth from an implementation. Reauth will be considered a failure if no implementation return True.

If a hook decides that a reauthenticate attempt should cease, it may raise StopAuthentication.

See also: ReauthenticateProvider

Example of checking secret or passing to the next implementer:

@impl
def flaskbb_reauth_attempt(user, secret):
    if check_password(user.password, secret):
        return True

Example of forcefully ending reauth:

@impl
def flaskbb_reauth_attempt(user, secret):
    if user.login_attempts > 5:
        raise StopAuthentication(_("Too many failed authentication attempts"))
flaskbb.plugins.spec.flaskbb_post_reauth(user)

Hook called after successfully reauthenticating.

These hooks are called a user has passed the flaskbb_reauth_attempt hooks but before their reauth is confirmed so a post reauth implementer may still force a reauth to fail by raising StopAuthentication.

Results from these hooks are not considered.

See also: PostReauthenticateHandler

flaskbb.plugins.spec.flaskbb_reauth_failed(user)

Hook called if a reauth fails.

These hooks will only be called if no implementation for flaskbb_reauth_attempt returns a True result or if an implementation raises StopAuthentication.

If an implementation raises ForceLogout it should register itself as trylast to give other reauth failed handlers an opprotunity to run first.

See also: ReauthenticateFailureHandler