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lib/Apache/AuthCookie.pm  view on Meta::CPAN

protected, this method will set C<$r-E<gt>connection-E<gt>user>
anyway.  Use it as a PerlFixupHandler, unless you have a better idea.

=head2 encoding($r): string

Return the ${auth_name}Encoding setting that is in effect for this request.

=head2 requires_encoding($r): string

Return the ${auth_name}RequiresEncoding setting that is in effect for this request.

=head2 decoded_user($r): string

If you have set ${auth_name}Encoding, then this will return the decoded value of
C<< $r->connection->user >>.

=head2 decoded_requires($r): arrayref

This method returns the C<< $r->requires >> array, with the C<requirement>
values decoded if C<${auth_name}RequiresEncoding> is in effect for this
request.

=head2 handle_cache(): void

If C<${auth_name}Cache> is defined, this sets up the response so that the
client will not cache the result.  This sents C<no_cache> in the apache request
object and sends the appropriate headers so that the client will not cache the
response.

=head2 remove_cookie(): void

Adds a C<Set-Cookie> header that instructs the client to delete the cookie
immediately.

=head2 params($r): Apache::AuthCookie::Params

Get the params object for this request.

=head2 login($r)

This method handles the submission of the login form.  It will call
the C<authen_cred()> method, passing it C<$r> and all the submitted
data with names like C<"credential_#">, where # is a number.  These will
be passed in a simple array, so the prototype is
C<$self-E<gt>authen_cred($r, @credentials)>.  After calling
C<authen_cred()>, we set the user's cookie and redirect to the
URL contained in the C<"destination"> submitted form field.

=head2 untaint_destination($uri)

This method returns a modified version of the destination parameter
before embedding it into the response header. Per default it escapes
CR, LF and TAB characters of the uri to avoid certain types of
security attacks. You can override it to more limit the allowed
destinations, e.g., only allow relative uris, only special hosts or
only limited set of characters.

=head2 logout($r)

This is simply a convenience method that unsets the session key for
you.  You can call it in your logout scripts.  Usually this looks like
C<$r-E<gt>auth_type-E<gt>logout($r);>.

=head2 authenticate($r)

This method is one you'll use in a server config file (httpd.conf,
.htaccess, ...) as a PerlAuthenHandler.  If the user provided a
session key in a cookie, the C<authen_ses_key()> method will get
called to check whether the key is valid.  If not, or if there is no
key provided, we redirect to the login form.

=head2 login_form()

This method is responsible for displaying the login form. The default
implementation will make an internal redirect and display the URL you
specified with the C<PerlSetVar WhatEverLoginScript> configuration
directive. You can overwrite this method to provide your own
mechanism.

=head2 login_form_status($r)

This method returns the HTTP status code that will be returned with the login
form response.  The default behaviour is to return FORBIDDEN, except for some
known browsers which ignore HTML content for FORBIDDEN responses (e.g.:
SymbianOS).  You can override this method to return custom codes.

Note that FORBIDDEN is the most correct code to return as the given request was
not authorized to view the requested page.  You should only change this if
FORBIDDEN does not work.

=head2 get_satisfy(): string

Get the C<Satisfy> value for the current request, or C<all> if it is not
configured.

=head2 authorize($r)

This will step through the C<require> directives you've given for
protected documents and make sure the user passes muster.  The
C<require valid-user> and C<require user joey-jojo> directives are
handled for you.  You can implement custom directives, such as
C<require species hamster>, by defining a method called C<species()>
in your subclass, which will then be called.  The method will be
called as C<$r-E<gt>species($r, $args)>, where C<$args> is everything
on your C<require> line after the word C<species>.  The method should
return OK on success and FORBIDDEN on failure.

=head2 send_cookie($session_key)

By default this method simply sends out the session key you give it.
If you need to change the default behavior (perhaps to update a
timestamp in the key) you can override this method.

=head2 send_p3p(): void

Set a P3P response header if C<${auth_name}P3P> is configured.  The value of
the header is whatever is in the C<${auth_name}P3P> setting.

=head2 cookie_string(%args): string

Generate a cookie string. C<%args> are:

lib/Apache/AuthCookie.pm  view on Meta::CPAN

server configuration as handled by the ->login() method - see example
in the SYNOPSIS section).

=item 2.

The various user input fields (username, passwords, etc.) must be
named 'credential_0', 'credential_1', etc. on the form.  These will
get passed to your authen_cred() method.

=item 3.

You must define a form field called 'destination' that tells
AuthCookie where to redirect the request after successfully logging
in.  Typically this value is obtained from C<$r-E<gt>prev-E<gt>uri>.
See the login.pl script in t/eg/.

=back

In addition, you might want your login page to be able to tell why
the user is being asked to log in.  In other words, if the user sent
bad credentials, then it might be useful to display an error message
saying that the given username or password are invalid.  Also, it
might be useful to determine the difference between a user that sent
an invalid auth cookie, and a user that sent no auth cookie at all.  To
cope with these situations, B<AuthCookie> will set
C<$r-E<gt>subprocess_env('AuthCookieReason')> to one of the following values.

=over 4

=item I<no_cookie>

The user presented no cookie at all.  Typically this means the user is
trying to log in for the first time.

=item I<bad_cookie>

The cookie the user presented is invalid.  Typically this means that the user
is not allowed access to the given page.

=item I<bad_credentials>

The user tried to log in, but the credentials that were passed are invalid.

=back

You can examine this value in your login form by examining
C<$r-E<gt>prev-E<gt>subprocess_env('AuthCookieReason')> (because it's
a sub-request).

Of course, if you want to give more specific information about why
access failed when a cookie is present, your C<authen_ses_key()>
method can set arbitrary entries in C<$r-E<gt>subprocess_env>.

=head1 THE LOGOUT SCRIPT

If you want to let users log themselves out (something that can't be
done using Basic Auth), you need to create a logout script.  For an
example, see t/htdocs/docs/logout.pl.  Logout scripts may want to take
advantage of AuthCookie's C<logout()> method, which will set the
proper cookie headers in order to clear the user's cookie.  This
usually looks like C<$r-E<gt>auth_type-E<gt>logout($r);>.

Note that if you don't necessarily trust your users, you can't count
on cookie deletion for logging out.  You'll have to expire some
server-side login information too.  AuthCookie doesn't do this for
you, you have to handle it yourself.

=head1 ENCODING AND CHARACTER SETS

=head2 Encoding

AuthCookie provides support for decoding POST/GET data if you tell it what the
client encoding is.  You do this by setting the C<< ${auth_name}Encoding >>
setting in C<httpd.conf>.  E.g.:

 PerlSetVar WhateEverEncoding UTF-8
 # and you also need to arrange for charset=UTF-8 at the end of the
 # Content-Type header with something like:
 AddDefaultCharset UTF-8

Note that you B<can> use charsets other than C<UTF-8>, however, you need to
arrange for the browser to send the right encoding back to the server.

If you have turned on Encoding support by setting C<< ${auth_name}Encoding >>,
this has the following effects:

=over 4

=item *

The internal pure-perl params processing subclass will be used, even if
libapreq is installed.  libapreq does not handle encoding.

=item *

POST/GET data intercepted by AuthCookie will be decoded to perl's internal
format using L<Encode/decode>.

=item *

The value stored in C<< $r-E<gt>connection-E<gt>user >> will be encoded as
B<bytes>, not characters using the configured encoding name.  This is because
the value stored by mod_perl is a C API string, and not a perl string.  You can
use L</decoded_user()> to get user string encoded using B<character> semantics.

=back

This does has some caveats:

=over 4

=item *

your L</authen_cred()> and L</authen_ses_key()> function is expected to return
a decoded username, either by passing it through L<Encode/decode()>, or, by
turning on the UTF8 flag if appropriate.

=item *

Due to the way HTTP works, cookies cannot contain non-ASCII characters.
Because of this, if you are including the username in your generated session
key, you will need to escape any non-ascii characters in the session key
returned by L</authen_cred()>.

=item *

Similarly, you must reverse this escaping process in L</authen_ses_key()> and
return a L<Encode/decode()> decoded username.  If your L</authen_cred()>
function already only generates ASCII-only session keys then you do not need to
worry about any of this.

=item *

The value stored in C<< $r-E<gt>connection-E<gt>user >> will be encoded using
bytes semantics using the configured B<Encoding>.  If you want the decoded user
value, use L</decoded_user()> instead.

=back

=head2 Requires

You can also specify what the charset is of the Apache C<< $r-E<gt>requires >>
data is by setting C<< ${auth_name}RequiresEncoding >> in httpd.conf.

E.g.:

 PerlSetVar WhatEverRequiresEncoding UTF-8

This will make it so that AuthCookie will decode your C<requires> directives
using the configured character set.  You really only need to do this if you
have used non-ascii characters in any of your C<requires> directives in
httpd.conf.  e.g.:

 requires user programmør

=head1 ABOUT SESSION KEYS

Unlike the sample AuthCookieHandler, you have you verify the user's
login and password in C<authen_cred()>, then you do something
like:

    my $date = localtime;
    my $ses_key = MD5->hexhash(join(';', $date, $PID, $PAC));

save C<$ses_key> along with the user's login, and return C<$ses_key>.

Now C<authen_ses_key()> looks up the C<$ses_key> passed to it and
returns the saved login.  I use Oracle to store the session key and
retrieve it later, see the ToDo section below for some other ideas.

=head2 TO DO

=over 4

=item *

It might be nice if the logout method could accept some parameters
that could make it easy to redirect the user to another URI, or
whatever.  I'd have to think about the options needed before I
implement anything, though.

=back

=head1 HISTORY

Originally written by Eric Bartley <bartley@purdue.edu>

versions 2.x were written by Ken Williams <ken@forum.swarthmore.edu>

=head1 SEE ALSO

L<perl(1)>, L<mod_perl(1)>, L<Apache(1)>.

=head1 SOURCE

The development version is on github at L<https://github.com/mschout/apache-authcookie>
and may be cloned from L<https://github.com/mschout/apache-authcookie.git>

=head1 BUGS

Please report any bugs or feature requests on the bugtracker website
L<https://github.com/mschout/apache-authcookie/issues>

When submitting a bug or request, please include a test-file or a
patch to an existing test-file that illustrates the bug or desired
feature.

=head1 AUTHOR

Michael Schout <mschout@cpan.org>

=head1 COPYRIGHT AND LICENSE

This software is copyright (c) 2000 by Ken Williams.

This is free software; you can redistribute it and/or modify it under
the same terms as the Perl 5 programming language system itself.

=cut

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