NAME
Dancer2::Plugin::Auth::Extensible - extensible authentication framework
for Dancer2 apps
DESCRIPTION
A user authentication and authorisation framework plugin for Dancer2
apps.
Makes it easy to require a user to be logged in to access certain
routes, provides role-based access control, and supports various
authentication methods/sources (config file, database, Unix system
users, etc).
Designed to support multiple authentication realms and to be as
extensible as possible, and to make secure password handling easy. The
base class for auth providers makes handling "RFC2307"-style hashed
passwords really simple, so you have no excuse for storing plain-text
passwords. A simple script called generate-crypted-password to generate
RFC2307-style hashed passwords is included, or you can use
Crypt::SaltedHash yourself to do so, or use the "slappasswd" utility if
you have it installed.
SYNOPSIS
Configure the plugin to use the authentication provider class you wish
to use:
plugins:
Auth::Extensible:
realms:
users:
provider: Config
....
The configuration you provide will depend on the authentication provider
module in use. For a simple example, see
Dancer2::Plugin::Auth::Extensible::Provider::Config.
Define that a user must be logged in and have the proper permissions to
access a route:
get '/secret' => require_role Confidant => sub { tell_secrets(); };
Define that a user must be logged in to access a route - and find out
who is logged in with the "logged_in_user" keyword:
get '/users' => require_login sub {
my $user = logged_in_user;
return "Hi there, $user->{username}";
};
AUTHENTICATION PROVIDERS
For flexibility, this authentication framework uses simple
authentication provider classes, which implement a simple interface and
do whatever is required to authenticate a user against the chosen source
of authentication.
For an example of how simple provider classes are, so you can build your
own if required or just try out this authentication framework plugin
easily, see Dancer2::Plugin::Auth::Extensible::Provider::Config.
This framework supplies the following providers out-of-the-box:
Dancer2::Plugin::Auth::Extensible::Provider::Unix
Authenticates users using system accounts on Linux/Unix type boxes
Dancer2::Plugin::Auth::Extensible::Provider::Config
Authenticates users stored in the app's config
The following external providers are also available on the CPAN:
Dancer2::Plugin::Auth::Extensible::Provider::DBIC
Authenticates users stored in a database table using
Dancer2::Plugin::DBIC
Dancer2::Plugin::Auth::Extensible::Provider::Database
Authenticates users stored in a database table
Dancer2::Plugin::Auth::Extensible::Provider::IMAP
Authenticates users via in an IMAP server.
Dancer2::Plugin::Auth::Extensible::Provider::LDAP
Authenticates users stored in an LDAP directory.
Dancer2::Plugin::Auth::Extensible::Provider::Usergroup
An alternative Dancer2::Plugin::DBIC-based provider.
Need to write your own? Just create a new provider class which consumes
Dancer2::Plugin::Auth::Extensible::Role::Provider and implements the
required methods, and you're good to go!
CONTROLLING ACCESS TO ROUTES
Keywords are provided to check if a user is logged in / has appropriate
roles.
require_login - require the user to be logged in
get '/dashboard' => require_login sub { .... };
If the user is not logged in, they will be redirected to the login page
URL to log in. The default URL is "/login" - this may be changed with
the "login_page" option.
require_role - require the user to have a specified role
get '/beer' => require_role BeerDrinker => sub { ... };
Requires that the user be logged in as a user who has the specified
role. If the user is not logged in, they will be redirected to the login
page URL. If they are logged in, but do not have the required role, they
will be redirected to the access denied URL.
If "disable_roles" configuration option is set to a true value then
using "require_role" will cause the application to croak on load.
require_any_role - require the user to have one of a list of roles
get '/drink' => require_any_role [qw(BeerDrinker VodaDrinker)] => sub {
...
};
Requires that the user be logged in as a user who has any one (or more)
of the roles listed. If the user is not logged in, they will be
redirected to the login page URL. If they are logged in, but do not have
any of the specified roles, they will be redirected to the access denied
URL.
If "disable_roles" configuration option is set to a true value then
using "require_any_roles" will cause the application to croak on load.
require_all_roles - require the user to have all roles listed
get '/foo' => require_all_roles [qw(Foo Bar)] => sub { ... };
Requires that the user be logged in as a user who has all of the roles
listed. If the user is not logged in, they will be redirected to the
login page URL. If they are logged in but do not have all of the
specified roles, they will be redirected to the access denied URL.
If "disable_roles" configuration option is set to a true value then
using "require_all_roles" will cause the application to croak on load.
NO-REDIRECT LOGIN
By default when a page is requested that requires login and the user is
not logged in then the plugin redirects the user to the "login_page" and
sets "return_url" to the page originally requested. After successful
login the user is redirected to the originally-requested page.
As an alternative if "login_without_redirect" is true then the login
process happens with no redirects. Instead a 401 "Unauthorized" code is
returned and a login page is displayed. This login page is posted to the
original URI and on successful login an internal "forward" in
Dancer2::Manual is performed so that the originally requested page is
displayed. Any "params" in Dancer2::Manual from the original request are
added to the forward so that they are available to the page's route
handler either using "params" in Dancer2::Manual or "query_parameters"
in Dancer2::Manual.
This relies on the login form having no "action" set and also it must
use "__auth_extensible_username" and "__auth_extensible_password" input
names. Optionally "__auth_extensible_realm" can also be used in a custom
login page.
See <
http://shadow.cat/blog/matt-s-trout/humane-login-screens/> for the
original idea for this functionality.
CUSTOMISING "/login" AND "/login/denied"
login_template
The "login_template" setting determines the name of the view you use for
your custom login page. If this view exists in your application then it
will be used instead of the default login template.
If you are using "login_without_redirect" and assuming you are using
Template::Toolkit then your custom login page should be something like
this:
<h1>Login Required</h1>
<p>You need to log in to continue.</p>
[%- IF login_failed -%]
<p>LOGIN FAILED</p>
[%- END -%]
<form method="post">
<label for="username">Username:</label>
<input type="text" name="__auth_extensible_username" id="username">
<br />
<label for="password">Password:</label>
<input type="password" name="__auth_extensible_password" id="password">
<br />
<input type="submit" value="Login">
</form>
[%- IF reset_password_handler -%]
<form method="post" action="[% login_page %]">
<h2>Password reset</h2>
<p>Enter your username to obtain an email to reset your password</p>
<label for="username_reset">Username:</label>
<input type="text" name="username_reset" id="username_reset">
<input type="submit" name="submit_reset" value="Submit">
</form>
[%- END -%]
If you are not using "login_without_redirect" and assuming you are using
Template::Toolkit then your custom login page should be something like
this:
<h1>Login Required</h1>
<p>You need to log in to continue.</p>
[%- IF login_failed -%]
<p>LOGIN FAILED</p>
[%- END -%]
<form method="post">
<label for="username">Username:</label>
<input type="text" name="username" id="username">
<br />
<label for="password">Password:</label>
<input type="password" name="password" id="password">
<br />
<input type="submit" value="Login">
[%- IF return_url -%]
<input type="hidden" name="return_url" value="[% return_url %]">
[%- END -%]
[%- IF reset_password_handler -%]
<h2>Password reset</h2>
<p>Enter your username to obtain an email to reset your password</p>
<label for="username_reset">Username:</label>
<input type="text" name="username_reset" id="username_reset">
<input type="submit" name="submit_reset" value="Submit">
[%- END -%]
</form>
Replacing the default " /login " and " /login/denied " routes
By default, the plugin adds a route to present a simple login form at
that URL. If you would rather add your own, set the "no_default_pages"
setting to a true value, and define your own route which responds to
"/login" with a login page. Alternatively you can let DPAE add the
routes and handle the status codes, etc. and simply define the setting
"login_page_handler" and/or "permission_denied_page_handler" with the
name of a subroutine to be called to handle the route. Note that it must
be a fully qualified sub. E.g.
plugins:
Auth::Extensible:
login_page_handler: 'My::App::login_page_handler'
permission_denied_page_handler: 'My::App::permission_denied_page_handler'
Then in your code you might simply use a template:
sub permission_denied_page_handler {
template 'account/login';
}
If the user is logged in, but tries to access a route which requires a
specific role they don't have, they will be redirected to the
"permission denied" page URL, which defaults to "/login/denied" but may
be changed using the "denied_page" option.
Again, by default a route is added to respond to that URL with a default
page; again, you can disable this by setting "no_default_pages" and
creating your own.
This would still leave the routes "post '/login'" and "any '/logout'"
routes in place. To disable them too, set the option "no_login_handler"
to a true value. In this case, these routes should be defined by the
user, and should do at least the following:
post '/login' => sub {
my ($success, $realm) = authenticate_user(
params->{username}, params->{password}
);
if ($success) {
# change session ID if we have a new enough D2 version with support
# (security best practice on privilege level change)
app->change_session_id
if app->can('change_session_id');
session logged_in_user => params->{username};
session logged_in_user_realm => $realm;
# other code here
} else {
# authentication failed
}
};
any '/logout' => sub {
app->destroy_session;
};
If you want to use the default "post '/login'" and "any '/logout'"
routes you can configure them. See below.
The default routes also contain functionality for a user to perform
password resets. See the "PASSWORD RESETS" documentation for more
details.
KEYWORDS
The following keywords are provided in additional to the route
decorators specified in "CONTROLLING ACCESS TO ROUTES":
logged_in_user
Returns a hashref of details of the currently logged-in user or some
kind of user object, if there is one.
The details you get back will depend upon the authentication provider in
use.
get_user_details
Returns a hashref of details of the specified user. The realm can
optionally be specified as the second parameter. If the realm is not
specified, each realm will be checked, and the first matching user will
be returned.
The details you get back will depend upon the authentication provider in
use.
user_has_role
Check if a user has the role named.
By default, the currently-logged-in user will be checked, so you need
only name the role you're looking for:
if (user_has_role('BeerDrinker')) { pour_beer(); }
You can also provide the username to check;
if (user_has_role($user, $role)) { .... }
If "disable_roles" configuration option is set to a true value then
using "user_has_role" will cause the application to croak at runtime.
user_roles
Returns a list of the roles of a user.
By default, roles for the currently-logged-in user will be checked;
alternatively, you may supply a username to check.
Returns a list or arrayref depending on context.
If "disable_roles" configuration option is set to a true value then
using "user_roles" will cause the application to croak at runtime.
authenticate_user
Usually you'll want to let the built-in login handling code deal with
authenticating users, but in case you need to do it yourself, this
keyword accepts a username and password, and optionally a specific
realm, and checks whether the username and password are valid.
For example:
if (authenticate_user($username, $password)) {
...
}
If you are using multiple authentication realms, by default each realm
will be consulted in turn. If you only wish to check one of them (for
instance, you're authenticating an admin user, and there's only one
realm which applies to them), you can supply the realm as an optional
third parameter.
In boolean context, returns simply true or false; in list context,
returns "($success, $realm)".
logged_in_user_lastlogin
Returns (as a DateTime object) the time of the last successful login of
the current logged in user.
To enable this functionality, set the configuration key
"record_lastlogin" to a true value. The backend provider must support
write access for a user and have lastlogin functionality implemented.
update_user
Updates a user's details. If the authentication provider supports it,
this keyword allows a user's details to be updated within the backend
data store.
In order to update the user's details, the keyword should be called with
the username to be updated, followed by a hash of the values to be
updated. Note that whilst the password can be updated using this method,
any new value will be stored directly into the provider as-is, not
encrypted. It is recommended to use "user_password" instead.
If only one realm is configured then this will be used to search for the
user. Otherwise, the realm must be specified with the realm key.
# Update user, only one realm configured
update_user "jsmith", surname => "Smith"
# Update a user's username, more than one realm
update_user "jsmith", realm => "dbic", username => "jjones"
The updated user's details are returned, as per logged_in_user.
update_current_user
The same as update_user, but does not take a username as the first
parameter, instead updating the currently logged-in user.
# Update user, only one realm configured
update_current_user surname => "Smith"
The updated user's details are returned, as per logged_in_user.
create_user
Creates a new user, if the authentication provider supports it.
Optionally sends a welcome message with a password reset request, in
which case an email key must be provided.
This function works in the same manner as update_user, except that the
username key is mandatory. As with update_user, it is recommended not to
set a password directly using this method, otherwise it will be stored
in plain text.
The realm to use must be specified with the key "realm" if there is more
than one realm configured.
# Create new user
create_user username => "jsmith", realm => "dbic", surname => "Smith"
# Create new user and send welcome email
create_user username => "jsmith", email => "
[email protected]", email_welcome => 1
On success, the created user's details are returned, as per
logged_in_user.
The text sent in the welcome email can be customised in 2 ways, in the
same way as password_reset_send:
welcome_send
This can be used to specify a subroutine that will be called to
perform the entire message construction and email sending. Note that
it must be a fully-qualified sub such as
"My::App:email_welcome_send". The subroutine will be passed the dsl
as the first parameter, followed by a hash with the keys "code",
"email" and "user", which contain the generated reset code, user
email address, and user hashref respectively. For example:
sub reset_send_handler {
my ($dsl, %params) = @_;
my $user_email = $params{email};
my $reset_code = $params{code};
# Send email
return $result;
}
welcome_text
This can be used to generate the text for the welcome email, with
this module sending the actual email itself. It must be a
fully-qualified sub, as per the previous option. It will be passed
the same parameters as welcome_send, and should return a hash with
the same keys as password_reset_send_email.
password_reset_send
"password_reset_send" sends a user an email with a password reset link.
Along with "user_password", it allows a user to reset their password.
The function must be called with the key "username" and a value that is
the username. The username specified will be sent an email with a link
to reset their password. Note that the provider being used must return
the email address in the key "email", which in the case of a database
will normally require that column to exist in the user's table. The
provider must be able to write values to the user in order for this
function to store the generated code.
If the username is not found, a value of 0 is returned. If the username
is found and the email is sent successfully, 1 is returned. Otherwise
undef is returned. Note: if you are displaying a success message, and
you do not want people to be able to check the existance of a user on
your system, then you should check for the return value being defined,
not true. For example:
say "Success" if defined password_reset_send username => username;
Note that this still leaves the possibility of checking the existance of
a user if the email send mechanism is failing.
The realm can also be specified using the key realm:
password_reset_send username => 'jsmith', realm => 'dbic'
Default text for the email is automatically produced and emailed. This
can be customized with one of 2 config parameters:
password_reset_send_email
This can be used to specify a subroutine that will be called to
perform the entire message construction and email sending. Note that
it must be a fully-qualified sub such as
"My::App:reset_send_handler". The subroutine will be passed the dsl
as the first parameter, followed by a hash with the keys "code" and
"email", which contain the generated reset code and user email
address respectively. For example:
sub reset_send_handler {
my ($dsl, %params) = @_;
my $user_email = $params{email};
my $reset_code = $params{code};
# Send email
return $result;
}
password_reset_text
This can be used to generate the text for the email, with this
module sending the actual email itself. It must be a fully-qualified
sub, as per the previous option. It will be passed the same
parameters as password_reset_send_email, and should return a hash
with the following keys:
subject
The subject of the email message.
from
The sender of the email message (optional, can also be specified
using "mail_from".
plain
Plain text for the email. Either this, or html, or both should
be returned.
html
HTML text for the email (optional, as per plain).
Here is an example subroutine:
sub reset_text_handler {
my ($dsl, %params) = @_;
return (
from => '"My name" <
[email protected]',
subject => 'the subject',
plain => "reset here: $params{code}",
);
}
# Example configuration
Auth::Extensible:
mailer:
module: Mail::Message # Module to send email with
options: # Module options
via: sendmail
mail_from: '"My app" <
[email protected]>'
password_reset_text: MyApp::reset_send
user_password
This provides various functions to check or reset a user's password,
either from a reset code that was previously send by password_reset_send
or directly by specifying a username and password. Functions that update
a password rely on a provider that has write access to a user's details.
By default, the user to update is the currently logged-in user. A
specific user can be specified with the key "username" for a certain
username, or "code" for a previously sent reset code. Using these
parameters on their own will return the username if it is a valid
request.
If the above parameters are specified with the additional parameter
"new_password", then the password will be set to that value, assuming
that it is a valid request.
The realm can be optionally specified with the keyword "realm".
Examples:
Check the logged-in user's password:
user_password password => 'mysecret'
Check a specific user's password:
user_password username => 'jsmith', password => 'bigsecret'
Check a previously sent reset code:
user_password code => 'XXXX'
Reset a password with a previously sent code:
user_password code => 'XXXX', new_password => 'newsecret'
Change a user's password (username optional)
user_password username => 'jbloggs', password => 'old', new_password => 'secret'
Force set a specific user's password, without checking existing
password:
user_password username => 'jbloggs', new_password => 'secret'
logged_in_user_password_expired
Returns true if the password of the currently logged in user has
expired. To use this functionality, the provider must support the
"password_expired" function, and must be configured accordingly. See the
relevant provider for full configuration details.
Note that this functionality does not prevent the user accessing any
protected pages, even if the password has expired. This is so that the
developer can still leave some protected routes available, such as a
page to change the password. Therefore, if using this functionality, it
is suggested that a check is done in the "before" hook:
hook before => sub {
if (logged_in_user_password_expired)
{
# Redirect to user details page if password expired, but only if that
# is not the currently request page to prevent redirect loops
redirect '/password_update' unless request->uri eq '/password_update';
}
}
PASSWORD RESETS
A variety of functionality is provided to make it easier to manage
requests from users to reset their passwords. The keywords
password_reset_send and user_password form the core of this
functionality - see the documentation of these keywords for full
details. This functionality can only be used with a provider that
supports write access.
When utilising this functionality, it is wise to only allow passwords to
be reset with a POST request. This is because some email scanners "open"
links before delivering the email to the end user. With only a
single-use GET request, this will result in the link being "used" by the
time it reaches the end user, thus rendering it invalid.
Password reset functionality is also built-in to the default route
handlers. To enable this, set the configuration value
"reset_password_handler" to a true value (having already configured the
mail handler, as per the keyword documentation above). Once this is
done, the default login page will contain additional form controls to
allow the user to enter their username and request a reset password
link.
By default, the default handlers will generate a random 8 character
password using Session::Token. To use your own function, set
"password_generator" in your configuration. See the "SAMPLE
CONFIGURATION" for an example.
If using "login_page_handler" to replace the default login page, you can
still use the default password reset handlers. Add 2 controls to your
form for submitting a password reset request: a text input called
username_reset for the username, and submit_reset to submit the request.
Your login_page_handler is then passed the following additional params:
new_password
Contains the new automatically-generated password, once the password
reset has been performed successfully.
reset_sent
Is true when a password reset has been emailed to the user.
password_code_valid
Is true when a valid password reset code has been submitted with a
GET request. In this case, the user should be given the chance to
confirm with a POST request, with a form control called
"confirm_reset".
For a full example, see the default handler in this module's code.
SAMPLE CONFIGURATION
In your application's configuation file:
session: simple
plugins:
Auth::Extensible:
# Set to 1 if you want to disable the use of roles (0 is default)
# If roles are disabled then any use of role-based route decorators
# will cause app to croak on load. Use of 'user_roles' and
# 'user_has_role' will croak at runtime.
disable_roles: 0
# Set to 1 to use the no-redirect login functionality
login_without_redirect: 0
# Set the view name for a custom login page, defaults to 'login'
login_template: login
# After /login: If no return_url is given: land here ('/' is default)
user_home_page: '/user'
# After /logout: If no return_url is given: land here (no default)
exit_page: '/'
# Mailer options for reset password and welcome emails
mailer:
module: Mail::Message # Email module to use
options: # Options for module
via: sendmail # Options passed to $msg->send
mail_from: '"App name" <
[email protected]>' # From email address
# Set to true to enable password reset code in the default handlers
reset_password_handler: 1
password_generator: My::App::random_pw # Optional random password generator
# Set to a true value to enable recording of successful last login times
record_lastlogin: 1
# Password reset functionality
password_reset_send_email: My::App::reset_send # Customise sending sub
password_reset_text: My::App::reset_text # Customise reset text
# create_user options
welcome_send: My::App::welcome_send # Customise welcome email sub
welcome_text: My::App::welcome_text # Customise welcome email text
# List each authentication realm, with the provider to use and the
# provider-specific settings (see the documentation for the provider
# you wish to use)
realms:
realm_one:
priority: 3 # Defaults to 0. Realms are checked in descending order
provider: Database
db_connection_name: 'foo'
realm_two:
priority: 0 # Will be checked after realm_one
provider: Config
Please note that you must have a session provider configured. The
authentication framework requires sessions in order to track information
about the currently logged in user. Please see Dancer2::Core::Session
for information on how to configure session management within your
application.
METHODS
auth_provider($dsl, $realm)
Given a realm, returns a configured and ready to use instance of the
provider specified by that realm's config.
HOOKS
This plugin provides the following hooks:
before_authenticate_user
Called at the start of "authenticate_user".
Receives a hash reference of "username", "password" and "realm".
after_authenticate_user
Called at the end of "authenticate_user".
Receives a hash reference of "username", "password", "realm", "errors"
and "success".
"realm" is the realm that the user authenticated against of undef if
auth failed.
The value of "errors" is an array reference of any errors thrown by
authentication providers (if any).
The value of "success" is either 1 or 0 to show whether or not
authentication was successful.
before_create_user
Called at the start of "create_user".
Receives a hash reference of the arguments passed to "create_user".
after_create_user
Called at the end of "create_user".
Receives the requested username, the created user (or undef) and an
array reference of any errors from the main method or from the provider.
login_required
permission_denied
after_login_success
Called after successful login just before redirect is called.
AUTHOR
David Precious, "<davidp at preshweb.co.uk>"
Dancer2 port of Dancer::Plugin::Auth::Extensible by:
Stefan Hornburg (Racke), "<racke at linuxia.de>"
Conversion to Dancer2's new plugin system plus much cleanup & reorg:
Peter Mottram (SysPete), "<peter at sysnix.com>"
BUGS / FEATURE REQUESTS
This is an early version; there may still be bugs present or features
missing.
This is developed on GitHub - please feel free to raise issues or pull
requests against the repo at:
<
https://github.com/PerlDancer/Dancer2-Plugin-Auth-Extensible>
ACKNOWLEDGEMENTS
Valuable feedback on the early design of this module came from many
people, including Matt S Trout (mst), David Golden (xdg), Damien
Krotkine (dams), Daniel Perrett, and others.
Configurable login/logout URLs added by Rene (hertell)
Regex support for require_role by chenryn
Support for user_roles looking in other realms by Colin Ewen (casao)
LDAP provider added by Mark Meyer (ofosos)
Documentation fix by Vince Willems.
Henk van Oers (GH #8, #13, #55).
Andrew Beverly (GH #6, #7, #10, #17, #22, #24, #25, #26, #54). This
includes support for creating and editing users and manage user
passwords.
Gabor Szabo (GH #11, #16, #18).
Evan Brown (GH #20, #32).
Jason Lewis (Unix provider problem).
Matt S. Trout (mst) for Zero redirect login the easy and friendly way
<
http://shadow.cat/blog/matt-s-trout/humane-login-screens/>.
LICENSE AND COPYRIGHT
Copyright 2012-16 David Precious.
This program is free software; you can redistribute it and/or modify it
under the terms of either: the GNU General Public License as published
by the Free Software Foundation; or the Artistic License.
See
http://dev.perl.org/licenses/ for more information.
