File Coverage

blib/lib/Yancy/Plugin/Auth/Password.pm

Criterion	Covered	Total	%
statement	170	188	90.4
branch	47	64	73.4
condition	21	38	55.2
subroutine	22	22	100.0
pod	0	4	0.0
total	260	316	82.2

package Yancy::Plugin::Auth::Password;
our $VERSION = '1.087';
# ABSTRACT: A simple password-based auth

#pod =encoding utf8
#pod
#pod =head1 SYNOPSIS
#pod
#pod     use Mojolicious::Lite;
#pod     plugin Yancy => {
#pod         backend => 'sqlite://myapp.db',
#pod         schema => {
#pod             users => {
#pod                 'x-id-field' => 'username',
#pod                 properties => {
#pod                     username => { type => 'string' },
#pod                     password => { type => 'string', format => 'password' },
#pod                 },
#pod             },
#pod         },
#pod     };
#pod     app->yancy->plugin( 'Auth::Password' => {
#pod         schema => 'users',
#pod         username_field => 'username',
#pod         password_field => 'password',
#pod         password_digest => {
#pod             type => 'SHA-1',
#pod         },
#pod     } );
#pod
#pod =head1 DESCRIPTION
#pod
#pod B This module is C and its API may change before
#pod Yancy v2.000 is released.
#pod
#pod This plugin provides a basic password-based authentication scheme for
#pod a site.
#pod
#pod This module composes the L role
#pod to provide the
#pod L
#pod authorization method.
#pod
#pod =head2 Adding Users
#pod
#pod To add the initial user (or any user), use the L
#pod command|Mojolicious::Command::eval>:
#pod
#pod     ./myapp.pl eval 'yancy->create( users => { username => "dbell", password => "123qwe" } )'
#pod
#pod This plugin adds the L filter to the C field, so
#pod the password passed to C<< yancy->create >> will be properly hashed in
#pod the database.
#pod
#pod You can use this same technique to edit users from the command-line if
#pod someone gets locked out:
#pod
#pod     ./myapp.pl eval 'yancy->update( users => "dbell", { password => "123qwe" } )'
#pod
#pod =head2 Migrate from Auth::Basic
#pod
#pod To migrate from the deprecated L module, you
#pod should set the C config setting to the C
#pod settings from your Auth::Basic configuration. If they are the same as your
#pod current password digest settings, you don't need to do anything at all.
#pod
#pod     # Migrate from Auth::Basic, which had SHA-1 passwords, to
#pod     # Auth::Password using SHA-256 passwords
#pod     app->yancy->plugin( 'Auth::Password' => {
#pod         schema => 'users',
#pod         username_field => 'username',
#pod         password_field => 'password',
#pod         migrate_digest => {
#pod             type => 'SHA-1',
#pod         },
#pod         password_digest => {
#pod             type => 'SHA-256',
#pod         },
#pod     } );
#pod
#pod     # Migrate from Auth::Basic, which had SHA-1 passwords, to
#pod     # Auth::Password using SHA-1 passwords
#pod     app->yancy->plugin( 'Auth::Password' => {
#pod         schema => 'users',
#pod         username_field => 'username',
#pod         password_field => 'password',
#pod         password_digest => {
#pod             type => 'SHA-1',
#pod         },
#pod     } );
#pod
#pod =head2 Verifying Yancy Passwords in SQL (or other languages)
#pod
#pod Passwords are stored as base64. The Perl L module's removes the
#pod trailing padding from a base64 string. This means that if you try to use
#pod another method to verify passwords, you must also remove any trailing
#pod C<=> from the base64 hash you generate.
#pod
#pod Here are some examples for how to generate the same password hash in
#pod different databases/languages:
#pod
#pod * Perl:
#pod
#pod     $ perl -MDigest -E'say Digest->new( "SHA-1" )->add( "password" )->b64digest'
#pod     W6ph5Mm5Pz8GgiULbPgzG37mj9g
#pod
#pod * MySQL:
#pod
#pod     mysql> SELECT TRIM( TRAILING "=" FROM TO_BASE64( UNHEX( SHA1( "password" ) ) ) );
#pod     +--------------------------------------------------------------------+
#pod     | TRIM( TRAILING "=" FROM TO_BASE64( UNHEX( SHA1( "password" ) ) ) ) |
#pod     +--------------------------------------------------------------------+
#pod     | W6ph5Mm5Pz8GgiULbPgzG37mj9g                                        |
#pod     +--------------------------------------------------------------------+
#pod
#pod * Postgres:
#pod
#pod     yancy=# CREATE EXTENSION pgcrypto;
#pod     CREATE EXTENSION
#pod     yancy=# SELECT TRIM( TRAILING '=' FROM encode( digest( 'password', 'sha1' ), 'base64' ) );
#pod                 rtrim
#pod     -----------------------------
#pod      W6ph5Mm5Pz8GgiULbPgzG37mj9g
#pod     (1 row)
#pod
#pod =head1 CONFIGURATION
#pod
#pod This plugin has the following configuration options.
#pod
#pod =head2 schema
#pod
#pod The name of the Yancy schema that holds users. Required.
#pod
#pod =head2 username_field
#pod
#pod The name of the field in the schema which is the user's identifier.
#pod This can be a user name, ID, or e-mail address, and is provided by the
#pod user during login.
#pod
#pod This field is optional. If not specified, the schema's ID field will
#pod be used. For example, if the schema uses the C field as
#pod a unique identifier, we don't need to provide a C.
#pod
#pod     plugin Yancy => {
#pod         schema => {
#pod             users => {
#pod                 'x-id-field' => 'username',
#pod                 properties => {
#pod                     username => { type => 'string' },
#pod                     password => { type => 'string' },
#pod                 },
#pod             },
#pod         },
#pod     };
#pod     app->yancy->plugin( 'Auth::Password' => {
#pod         schema => 'users',
#pod         password_digest => { type => 'SHA-1' },
#pod     } );
#pod
#pod =head2 password_field
#pod
#pod The name of the field to use for the password. Defaults to C.
#pod
#pod This field will automatically be set up to use the L filter to
#pod properly hash the password when updating it.
#pod
#pod =head2 password_digest
#pod
#pod This is the hashing mechanism that should be used for hashing passwords.
#pod This value should be a hash of digest configuration. The one required
#pod field is C, and should be a type supported by the L module:
#pod
#pod =over
#pod
#pod =item * MD5 (part of core Perl)
#pod
#pod =item * SHA-1 (part of core Perl)
#pod
#pod =item * SHA-256 (part of core Perl)
#pod
#pod =item * SHA-512 (part of core Perl)
#pod
#pod =item * Bcrypt (recommended)
#pod
#pod =back
#pod
#pod Additional fields are given as configuration to the L module.
#pod Not all Digest types require additional configuration.
#pod
#pod There is no default: Perl core provides SHA-1 hashes, but those aren't good
#pod enough. We recommend installing L for password hashing.
#pod
#pod     # Use Bcrypt for passwords
#pod     # Install the Digest::Bcrypt module first!
#pod     app->yancy->plugin( 'Auth::Basic' => {
#pod         password_digest => {
#pod             type => 'Bcrypt',
#pod             cost => 12,
#pod             salt => 'abcdefgh♥stuff',
#pod         },
#pod     } );
#pod
#pod Digest information is stored with the password so that password digests
#pod can be updated transparently when necessary. Changing the digest
#pod configuration will result in a user's password being upgraded the next
#pod time they log in.
#pod
#pod =head2 allow_register
#pod
#pod If true, allow the visitor to register their own user account.
#pod
#pod =head2 register_fields
#pod
#pod An array of fields to show to the user when registering an account. By
#pod default, all required fields from the schema will be presented in the
#pod form to register.
#pod
#pod =head2 Sessions
#pod
#pod This module uses L
#pod sessions|https://mojolicious.org/perldoc/Mojolicious/Controller#session>
#pod to store the login information in a secure, signed cookie.
#pod
#pod To configure the default expiration of a session, use
#pod L
#pod default_expiration|https://mojolicious.org/perldoc/Mojolicious/Sessions#default_expiration>.
#pod
#pod     use Mojolicious::Lite;
#pod     # Expire a session after 1 day of inactivity
#pod     app->sessions->default_expiration( 24 * 60 * 60 );
#pod
#pod =head1 FILTERS
#pod
#pod This module provides the following filters. See L
#pod Configuration> for how to use filters.
#pod
#pod =head2 auth.digest
#pod
#pod Run the field value through the configured password L object and
#pod store the Base64-encoded result instead.
#pod
#pod =head1 HELPERS
#pod
#pod This plugin has the following helpers.
#pod
#pod =head2 yancy.auth.current_user
#pod
#pod Get the current user from the session, if any. Returns C if no
#pod user was found in the session.
#pod
#pod     my $user = $c->yancy->auth->current_user
#pod         || return $c->render( status => 401, text => 'Unauthorized' );
#pod
#pod =head2 yancy.auth.require_user
#pod
#pod Validate there is a logged-in user and optionally that the user data has
#pod certain values. See L.
#pod
#pod     # Display the user dashboard, but only to logged-in users
#pod     my $auth_route = $app->routes->under( '/user', $app->yancy->auth->require_user );
#pod     $auth_route->get( '' )->to( 'user#dashboard' );
#pod
#pod =head2 yancy.auth.login_form
#pod
#pod Return an HTML string containing the rendered login form.
#pod
#pod     %# Display a login form to an unauthenticated visitor
#pod     % if ( !$c->yancy->auth->current_user ) {
#pod         %= $c->yancy->auth->login_form
#pod     % }
#pod
#pod The login form will create a C hidden field to try to bring
#pod the user back to what they were doing when they were asked to log in.
#pod This field defaults to the value of the C parameter or the
#pod value of the C flash value. If neither is set, it defaults to
#pod the HTTP referrer if the form is displayed on the login page (under the
#pod URL C) or the current page.
#pod
#pod     # Redirect user to login page, and return them here
#pod     under sub( $c ) {
#pod         return 1 if $c->yancy->auth->current_user;
#pod         $c->flash({ return_to => $c->req->url });
#pod         $c->redirect_to('yancy.auth.password.login');
#pod         return undef;
#pod     }
#pod
#pod     # Build a link to log in and then redirect to the dashboard
#pod     $c->url_for( 'yancy.auth.password.login' )
#pod         ->query({ return_to => $c->url_for( 'dashboard' ) });
#pod
#pod =head2 yancy.auth.logout
#pod
#pod Log out any current account. Use this in your own controller actions to
#pod perform a logout.
#pod
#pod =head1 ROUTES
#pod
#pod This plugin creates the following L
#pod routes|https://mojolicious.org/perldoc/Mojolicious/Guides/Routing#Named-routes>.
#pod Use named routes with helpers like
#pod L,
#pod L, and
#pod L.
#pod
#pod =head2 yancy.auth.password.login_form
#pod
#pod Display the login form using the L template. This route handles C
#pod requests and can be used with the L,
#pod L,
#pod and L helpers.
#pod
#pod     %= link_to Login => 'yancy.auth.password.login_form'
#pod     <%= link_to 'yancy.auth.password.login_form', begin %>Login<% end %>
#pod     Login here: <%= url_for 'yancy.auth.password.login_form' %>
#pod
#pod =head2 yancy.auth.password.login
#pod
#pod Handle login by checking the user's username and password. This route
#pod handles C requests and can be used with the
#pod L
#pod and L
#pod helpers.
#pod
#pod     %= form_for 'yancy.auth.password.login' => begin
#pod         %= text_field 'username', placeholder => 'Username'
#pod         %= text_field 'password', placeholder => 'Password'
#pod         %= submit_button
#pod     % end
#pod
#pod =head2 yancy.auth.password.logout
#pod
#pod Clear the current login and allow the user to log in again. This route handles C
#pod requests and can be used with the L,
#pod L,
#pod and L helpers.
#pod
#pod     %= link_to Logout => 'yancy.auth.password.logout'
#pod     <%= link_to 'yancy.auth.password.logout', begin %>Logout<% end %>
#pod     Logout here: <%= url_for 'yancy.auth.password.logout' %>
#pod
#pod =head2 yancy.auth.password.register_form
#pod
#pod Display the form to register a new user, if registration is enabled. This route handles C
#pod requests and can be used with the L,
#pod L,
#pod and L helpers.
#pod
#pod     %= link_to Register => 'yancy.auth.password.register_form'
#pod     <%= link_to 'yancy.auth.password.register_form', begin %>Register<% end %>
#pod     Register here: <%= url_for 'yancy.auth.password.register_form' %>
#pod
#pod =head2 yancy.auth.password.register
#pod
#pod Register a new user, if registration is enabled. This route
#pod handles C requests and can be used with the
#pod L
#pod and L
#pod helpers.
#pod
#pod     %= form_for 'yancy.auth.password.register' => begin
#pod         %= text_field 'username', placeholder => 'Username'
#pod         %= text_field 'password', placeholder => 'Password'
#pod         %= text_field 'password-verify', placeholder => 'Password (again)'
#pod         %# ... Display other fields required for registration
#pod         %= submit_button
#pod     % end
#pod
#pod =head1 TEMPLATES
#pod
#pod To override these templates, add your own at the designated path inside
#pod your app's C directory.
#pod
#pod =head2 yancy/auth/password/login_form.html.ep
#pod
#pod The form to log in.
#pod
#pod =head2 yancy/auth/password/login_page.html.ep
#pod
#pod The page containing the form to log in. Uses the C
#pod template for the form itself.
#pod
#pod =head2 yancy/auth/unauthorized.html.ep
#pod
#pod This template displays an error message that the user is not authorized
#pod to view this page. This most-often appears when the user is not logged
#pod in.
#pod
#pod =head2 yancy/auth/unauthorized.json.ep
#pod
#pod This template renders a JSON object with an "errors" array explaining
#pod the error.
#pod
#pod =head2 layouts/yancy/auth.html.ep
#pod
#pod The layout that Yancy uses when displaying the login form, the
#pod unauthorized error message, and other auth-related pages.
#pod
#pod =head2 yancy/auth/password/register.html.ep
#pod
#pod The page containing the form to register a new user. Will display all of the
#pod L.
#pod
#pod =head1 SEE ALSO
#pod
#pod L
#pod
#pod =cut

use Mojo::Base 'Mojolicious::Plugin';
use Role::Tiny::With;
with 'Yancy::Plugin::Auth::Role::RequireUser';
use Yancy::Util qw( currym derp );
use Digest;

has log =>;
has schema =>;
has username_field =>;
has password_field => 'password';
has allow_register => 0;
has plugin_field => undef;
has register_fields => sub { [] };
has moniker => 'password';
has default_digest =>;
has route =>;
has logout_route =>;

# The Auth::Basic digest configuration to migrate from. Auth::Basic did
# not store the digest information in the password, so we need to fix
# it.
has migrate_digest =>;

sub register {
    my ( $self, $app, $config ) = @_;
    $self->init( $app, $config );
    $app->helper(
        'yancy.auth.current_user' => currym( $self, 'current_user' ),
    );
    $app->helper(
        'yancy.auth.logout' => currym( $self, 'logout' ),
    );
    $app->helper(
        'yancy.auth.login_form' => currym( $self, 'login_form' ),
    );
}

sub init {
    my ( $self, $app, $config ) = @_;
    my $schema_name = $config->{schema} || $config->{collection}
        || die "Error configuring Auth::Password plugin: No schema defined\n";
    derp "'collection' configuration in Auth::Token is now 'schema'. Please fix your configuration.\n"
        if $config->{collection};
    my $schema = $app->yancy->schema( $schema_name );
    die sprintf(
        q{Error configuring Auth::Password plugin: Collection "%s" not found}."\n",
        $schema_name,
    ) unless $schema;

    $self->log( $app->log );
    $self->schema( $schema_name );
    $self->username_field( $config->{username_field} );
    $self->password_field( $config->{password_field} || 'password' );
    $self->default_digest( $config->{password_digest} );
    $self->migrate_digest( $config->{migrate_digest} );
    $self->allow_register( $config->{allow_register} );
    $self->register_fields(
        $config->{register_fields} || $app->yancy->schema( $schema_name )->{required} || []
    );
    $app->yancy->filter->add( 'yancy.plugin.auth.password' => sub {
        my ( $key, $value, $schema, @params ) = @_;
        return $self->_digest_password( $value );
    } );

    # Update the schema to digest the password correctly
    my $field = $schema->{properties}{ $self->password_field };
    if ( !grep { $_ eq 'yancy.plugin.auth.password' } @{ $field->{'x-filter'} || [] } ) {
        push @{ $field->{ 'x-filter' } ||= [] },
            'yancy.plugin.auth.password';
    }
    $field->{ format } = 'password';
    $app->yancy->schema( $schema_name, $schema );

    # Add fields that may not technically be required by the schema, but
    # are required for registration
    my @user_fields = (
        $self->username_field || $schema->{'x-id-field'} || 'id',
        $self->password_field,
    );
    for my $field ( @user_fields ) {
        if ( !grep { $_ eq $field } @{ $self->register_fields } ) {
            unshift @{ $self->register_fields }, $field;
        }
    }

    my $route = $app->yancy->routify( $config->{route}, '/yancy/auth/' . $self->moniker );
    $self->route( $route );
    $route->get( 'register' )->to( cb => currym( $self, '_get_register' ) )->name( 'yancy.auth.password.register_form' );
    $route->post( 'register' )->to( cb => currym( $self, '_post_register' ) )->name( 'yancy.auth.password.register' );
    $self->logout_route(
        $route->get( 'logout' )->to( cb => currym( $self, '_get_logout' ) )->name( 'yancy.auth.password.logout' )
    );
    $route->get( '' )->to( cb => currym( $self, '_get_login' ) )->name( 'yancy.auth.password.login_form' );
    $route->post( '' )->to( cb => currym( $self, '_post_login' ) )->name( 'yancy.auth.password.login' );
}

sub _get_user {
    my ( $self, $c, $username ) = @_;
    my $schema_name = $self->schema;
    my $username_field = $self->username_field;
    my %search;
    if ( my $field = $self->plugin_field ) {
        $search{ $field } = $self->moniker;
    }
    if ( $username_field ) {
        $search{ $username_field } = $username;
        my ( $user ) = @{ $c->yancy->backend->list( $schema_name, \%search, { limit => 1 } )->{items} };
        return $user;
    }
    return $c->yancy->backend->get( $schema_name, $username );
}

sub _digest_password {
    my ( $self, $password ) = @_;
    my $config = $self->default_digest;
    my $digest_config_string = _build_digest_config_string( $config );
    my $digest = _get_digest_by_config_string( $digest_config_string );
    my $password_string = join '$', $digest->add( $password )->b64digest, $digest_config_string;
    return $password_string;
}

sub _set_password {
    my ( $self, $c, $username, $password ) = @_;
    my $password_string = eval { $self->_digest_password( $password ) };
    if ( $@ ) {
        $self->log->error(
            sprintf 'Error setting password for user "%s": %s', $username, $@,
        );
    }

    my $id = $self->_get_id_for_username( $c, $username );
    $c->yancy->backend->set( $self->schema, $id, { $self->password_field => $password_string } );
}

sub _get_id_for_username {
    my ( $self, $c, $username ) = @_;
    my $schema_name = $self->schema;
    my $schema = $c->yancy->schema( $schema_name );
    my $id = $username;
    my $id_field = $schema->{'x-id-field'} || 'id';
    my $username_field = $self->username_field;
    if ( $username_field && $username_field ne $id_field ) {
        $id = $self->_get_user( $c, $username )->{ $id_field };
    }
    return $id;
}

sub current_user {
    my ( $self, $c ) = @_;
    return undef unless my $session = $c->session;
    my $yancy    = $session->{yancy} or return undef;
    my $auth     = $yancy->{auth}    or return undef;
    my $username = $auth->{password} or return undef;
    my $user = $self->_get_user( $c, $username );
    delete $user->{ $self->password_field };
    return $user;
}

sub login_form {
    my ( $self, $c ) = @_;
    my $return_to
        # If we've specified one, go there directly
        = $c->req->param( 'return_to' )
        ? $c->req->param( 'return_to' )
        # Check flash storage, perhaps from a redirect to the login form
        : $c->flash('return_to') ? $c->flash('return_to')
        # If this is the login page, go back to referer
        : $c->current_route =~ /^yancy\.auth/
            && $c->req->headers->referrer
            && $c->req->headers->referrer !~ m{^(?:\w+:|//)}
        ? $c->req->headers->referrer
        # Otherwise, return the user here
        : ( $c->req->url->path || '/' )
        ;
    if ( $return_to =~ m{^(?:\w+:|//)} ) {
        return $c->reply->exception(
            q{`return_to` can not contain URL scheme or host},
        );
    }
    return $c->render_to_string(
        'yancy/auth/password/login_form',
        plugin => $self,
        return_to => $return_to,
    );
}

sub _get_login {
    my ( $self, $c ) = @_;
    return $c->render( 'yancy/auth/password/login_page',
        plugin => $self,
    );
}

sub _post_login {
    my ( $self, $c ) = @_;
    my $user = $c->param( 'username' );
    my $pass = $c->param( 'password' );
    if ( $self->_check_pass( $c, $user, $pass ) ) {
        $c->session->{yancy}{auth}{password} = $user;
        my $to = $c->req->param( 'return_to' ) || '/';

        # Do not allow return_to to redirect the user to another site.
        # http://cwe.mitre.org/data/definitions/601.html
        if ( $to =~ m{^(?:\w+:|//)} ) {
            return $c->reply->exception(
                q{`return_to` can not contain URL scheme or host},
            );
        }

        $c->res->headers->location( $to );
        return $c->rendered( 303 );
    }
    $c->flash( error => 'Username or password incorrect' );
    return $c->render( 'yancy/auth/password/login_page',
        status => 400,
        plugin => $self,
        user => $user,
        login_failed => 1,
    );
}

sub _get_register {
    my ( $self, $c ) = @_;
    if ( !$self->allow_register ) {
        $c->app->log->error( 'Registration not allowed (set allow_register)' );
        $c->reply->not_found;
        return;
    }
    return $c->render( 'yancy/auth/password/register',
        plugin => $self,
    );
}

sub _post_register {
    my ( $self, $c ) = @_;
    if ( !$self->allow_register ) {
        $c->app->log->error( 'Registration not allowed (set allow_register)' );
        $c->reply->not_found;
        return;
    }

    my $schema_name = $self->schema;
    my $schema = $c->yancy->schema( $schema_name );
    my $username_field = $self->username_field || $schema->{'x-id-field'} || 'id';
    my $password_field = $self->password_field;

    my $username = $c->param( $username_field );
    my $pass = $c->param( $self->password_field );
    if ( $pass ne $c->param( $self->password_field . '-verify' ) ) {
        return $c->render( 'yancy/auth/password/register',
            status => 400,
            plugin => $self,
            user => $username,
            error => 'password_verify',
        );
    }
    if ( $self->_get_user( $c, $username ) ) {
        return $c->render( 'yancy/auth/password/register',
            status => 400,
            plugin => $self,
            user => $username,
            error => 'user_exists',
        );
    }

    # Create new user
    my $item = {
        $username_field => $username,
        $password_field => $pass,
        (
            map { $_ => $c->param( $_ ) }
            grep { !/^(?:$username_field|$password_field)$/ }
            @{ $self->register_fields }
        ),
    };
    my $id = eval { $c->yancy->create( $schema_name, $item ) };
    if ( my $exception = $@ ) {
        my $error = ref $exception eq 'ARRAY' ? 'validation' : 'create';
        $c->app->log->error( 'Error creating user: ' . $exception );
        return $c->render( 'yancy/auth/password/register',
            status => 400,
            plugin => $self,
            user => $username,
            error => $error,
            exception => $exception,
        );
    }

    # Get them to log in
    $c->flash( info => 'user_created' );
    return $c->redirect_to( 'yancy.auth.password.login' );
}

sub _get_digest {
    my ( $type, @config ) = @_;
    my $digest = eval {
        Digest->new( $type, @config )
    };
    if ( my $error = $@ ) {
        if ( $error =~ m{Can't locate Digest/${type}\.pm in \@INC} ) {
            die sprintf q{Password digest type "%s" not found}."\n", $type;
        }
        die sprintf "Error loading Digest module: %s\n", $@;
    }
    return $digest;
}

sub _get_digest_by_config_string {
    my ( $config_string ) = @_;
    my @digest_parts = split /\$/, $config_string;
    return _get_digest( @digest_parts );
}

sub _build_digest_config_string {
    my ( $config ) = @_;
    my @config_parts = (
        map { $_, $config->{$_} } grep !/^type$/, keys %$config
    );
    return join '$', $config->{type}, @config_parts;
}

sub _check_pass {
    my ( $self, $c, $username, $input_password ) = @_;
    my $user = $self->_get_user( $c, $username );

    if ( !$user ) {
        $self->log->error(
            sprintf 'Error checking password for user "%s": User does not exist',
            $username
        );
        return undef;
    }

    my ( $user_password, $user_digest_config_string )
        = split /\$/, $user->{ $self->password_field }, 2;

    my $force_upgrade = 0;
    if ( !$user_digest_config_string ) {
        # This password must have come from the Auth::Basic module,
        # which did not have digest configuration stored with the
        # password. So, we need to know what kind of digest to use, and
        # we need to fix the password.
        $user_digest_config_string = _build_digest_config_string(
            $self->migrate_digest || $self->default_digest
        );
        $force_upgrade = 1;
    }

    my $digest = eval { _get_digest_by_config_string( $user_digest_config_string ) };
    if ( $@ ) {
        die sprintf 'Error checking password for user "%s": %s', $username, $@;
    }
    my $check_password = $digest->add( $input_password )->b64digest;

    my $success = $check_password eq $user_password;

    my $default_config_string = _build_digest_config_string( $self->default_digest );
    if ( $success && ( $force_upgrade || $user_digest_config_string ne $default_config_string ) ) {
        # We need to re-create the user's password field using the new
        # settings
        $self->_set_password( $c, $username, $input_password );
    }

    return $success;
}

sub logout {
    my ( $self, $c ) = @_;
    delete $c->session->{yancy}{auth}{password};
}

sub _get_logout {
    my ( $self, $c ) = @_;
    $self->logout( $c );
    $c->res->code( 303 );
    my $redirect_to = $c->param( 'redirect_to' ) // $c->req->headers->referrer // '/';
    if ( $redirect_to eq $c->req->url->path ) {
        $redirect_to = '/';
    }
    return $c->redirect_to( $redirect_to );
}

1;

__END__