-
-__END__
-
-=head1 NAME
-
-CGI::Auth::Flexible - web authentication optionally using cookies
-
-=head1 SYNOPSYS
-
- my $verifier = CGI::Auth::Flexible->new_verifier(setting => value,...);
- my $authreq = $verifier->new_request($cgi_query_object);
-
- # simple applications
- $authreq->check_ok() or return;
-
- # sophisticated applications
- my $divert_kind = $authreq->check_divert();
- if ($divert_kind) { ... print diversion page and quit ... }
-
- # while handling the request
- $user = $authreq->get_username();
- $authreq->check_mutate();
-
-=head1 DESCRIPTION
-
-CGI::Auth::Flexible is a library which you can use to add a
-forms/cookie-based login facility to a Perl web application.
-
-CGI::Auth::Flexible doesn't interfere with your application's URL path
-namespace and just needs a few (configurable) form parameter and
-cookie name(s) for its own use. It tries to avoid making assumptions
-about the implementation structure of your application.
-
-Because CGI::Auth::Flexible is licenced under the AGPLv3, you will
-probably need to provide a facility to allow users (even ones not
-logged in) to download the source code for your web app. Conveniently
-by default CGI::Auth::Flexible provides (for pure Perl webapps) a
-mechanism for users to get the source.
-
-CGI::Auth::Flexible is designed to try to stop you accidentally
-granting access by misunderstanding the API. (Also it, of course,
-guards against cross-site scripting.) You do need to make sure to
-call CGI::Auth::Flexible before answering AJAX requests as well as
-before generating HTML pages, of course, and to call it in every
-entrypoint to your system.
-
-=head2 INITIALISATION
-
-Your application should, on startup (eg, when it is loaded by
-mod_perl) do
-C<< $verifier = CGI::Auth::Flexible->new_verifier(settings...) >>.
-This call can be expensive and is best amortised.
-
-The resulting verifier object can be used to process individual
-requests, in each case with
-C<< $authreq = CGI::Auth::Flexible->new_request($cgi_query) >>.
-
-=head2 SIMPLE APPLICATIONS
-
-The simplist usage is to call C<< $request->check_ok() >> which will
-check the user's authentication. If the user is not logged in it will
-generate a login form (or redirection or other appropriate page) and
-return false; your application should not then processing that request
-any further. If the user is logged in it will return true.
-
-After calling C<check_ok> you can use C<< $request->get_username >>
-to find out which user the request came from.
-
-=head2 SOPHISTICATED APPLICATIONS
-
-If you want to handle the flow control and to generate login forms,
-redirections, etc., yourself, you can say
-C<< $divert = $request->check_divert >>. This returns undef if
-the user is logged in, or I<divert spec> if some kind of login
-page or diversion should be generated.
-
-=head2 GENERATING (MUTATING) FORMS AND AJAX QUERIES
-
-When you generate a C<POST> form or AJAX request you need to include a
-special secret hidden form parameter for the benefit of
-CGI::Auth::Generic. This form parameter will be checked by
-C<check_ok>/C<check_divert> and should be ignored by your application.
-
-By default the hidden parameter is called C<caf_assochash>. After
-calling C<check_ok> or C<check_divert> the value to put in your form
-can be obtained from C<secret_hidden_val>; C<secret_hidden_html> will
-generate the whole HTML C<< <input...> >> element.
-
-Do not put the secret value in URLs for C<GET> requests.
-
-=head2 MUTATING OPERATIONS AND EXTERNAL LINKS INTO YOUR SITE
-
-By default CGI::Auth::Flexible does not permit external links into
-your site. All GET requests give a "click to continue" page which
-submits a form which loads your app's main page. In this
-configuration all your application's forms and AJAX requests should
-use C<POST>. This restriction arises from complicated deficiencies
-in the web's security architecture.
-
-The alternative is for your application to always make a special check
-when the incoming request is going to do some kind of action (such as
-modifying the user's setup, purchasing goods, or whatever) rather than
-just display HTML pages. Then non-mutating pages can be linked to
-from other, untrustworthy, websites.
-
-To support external links, and C<GET> requests, pass
-C<< promise_check_mutate => 1 >> in I<settings>, and then call
-C<< $authreq->check_mutate() >> before taking any actions. If the
-incoming request is not suitable then C<< $authreq->check_mutate() >>
-will call C<die>.
-
-You must make sure that you have no mutating C<GET> requests in your
-application - but you shouldn't have any of those anyway.
-
-=head2 DATA STORAGE
-
-CGI::Auth::Flexible needs to store various information in plain files;
-it does this in the directory specified by the C<dir> parameter.
-
-=head1 SOURCE CODE DOWNLOAD
-
-By default, CGI::Auth::Flexible provides a facility for users to
-download the source code for the running version of your web
-application.
-
-This facility makes a number of important assumptions which you need
-to check. Note that if the provided facility is not sufficient
-because your application is more sophisticated than it copes with (or
-if you disable the builtin facility), you may need to implement a
-functioning alternative to avoid violating the AGPLv3 licence.
-
-Here are the most important (default) assumptions:
-
-=over
-
-=item *
-
-Your app's source code is available by looking at @INC, $0 and
-S<$ENV{'SCRIPT_FILENAME'}> (the B<source items>). See
-C<srcdump_listitems>. Where these point to files or directories under
-revision control, the source item is the whole containing vcs tree.
-
-=item *
-
-Specifically, there are no compiled or autogenerated Perl
-files, Javascript resources, etc., which are not contained in one of
-the source item directories. (Files which came with your operating
-system install don't need to be shipped as they fall under the system
-library exceptio.)
-
-=item *
-
-You have not installed any modified versions of system
-libraries (including system-supplied) Perl modules in C</usr> outside
-C</usr/local>. See C<srcdump_system_dir>.
-
-=item *
-
-For each source item in a dvcs, the entire dvcs history does
-not contain anything confidential (or libellous). Also, all files which
-contain secrets are in the dvcs's C<.ignore> file. See
-C<srcdump_vcsscript_git> et al.
-
-=item *
-
-For each source item NOT in a dvcs, there are no confidential
-files with the world-readable bit set (being in a world-inaccessible
-directory is not sufficient). See C<srcdump_excludes>.
-
-=item *
-
-You have none of your app's source code in C</etc>.
-
-=item *
-
-You don't regard pathnames on your server as secret.
-
-=item *
-
-You don't intentionally load Perl code by virtule of C<.>
-being in C<@INC> by default. (See C<srcdump_filter_cwd>.)
-
-=back
-
-=head1 MAIN FUNCTIONS AND METHODS
-
-=over
-
-=item C<< CGI::Auth::Flexible->new_verifier(setting => value, ...) >>
-
-Initialises an instance and returns a verifier object.
-The arguments are setting pairs like a hash initialiser.
-See L</SETTINGS> below.
-
-=item C<< $verifier->new_request($cgi_query) >>
-
-Prepares to process a request. C<$cgi_query> should normally
-be the query object from L<CGI(3perl)>. Most of the default
-hook methods assume that it is; however if you replace enough of
-the hook methods then you can pass any value you like and it
-will be passed to your hooks.
-
-The return value is the authentication request object (C<$authreq>)
-which is used to check the incoming request and will contain
-information about its credentials.
-
-=item C<< $authreq->check_divert() >>
-
-Checks whether the user is logged in. Returns undef if the user is
-logged in and we should service the request. Otherwise returns a
-divert spec (see L</DIVERT SPEC>) saying what should happen instead.
-
-This method may die if it doesn't like the request, in which case
-the request needs to be rejected.
-
-=item C<< $authreq->check_ok() >>
-
-Checks whether the user is logged in. Returns true if the user is
-logged in and we should service the request.
-
-Otherwise it handles the request itself, generating any appropriate
-redirect, login form, or continuation page. It then returns false and
-the application should not process the request further.
-
-=item C<< $verifier->disconnect() >>
-
-Discards the resources (open files, etc.) in the verifier object.
-
-=back