ikiwiki should support Central Authentication Service authentication in order to use this SSO mechanism very popular in universities web services.

I have already written a first draft plugin supporting that authentication mechanism. It works for me with my university CAS service. I did not try it with other CAS server but it do not see any reason why it should not work.

What is the best way to submit it to you (just in case it can help my patch follows) ?

--bbb

Inline here is ok; git-am by mail is ok; a git repo I can pull from also ok.

This looks pretty acceptable as-is, but you need to put a copyright and license statement at the top. I have a few questions that I'll insert inline with the patch below. --Joey

I have made some corrections to this patch (my cas plugin) in order to use IkiWiki 3.00 interface and take your comments into account. It should work fine now.

You can pull it from my git repo at http://git.boulgour.com/bbb/ikiwiki.git/ and maybe add it to your main repo.

I will add GNU GPL copyright license statement as soon as I get some free time.

--bbb


diff --git a/IkiWiki/Plugin/cas.pm b/IkiWiki/Plugin/cas.pm
new file mode 100644
index 0000000..ea189df
--- /dev/null
+++ b/IkiWiki/Plugin/cas.pm
@@ -0,0 +1,94 @@
+#!/usr/bin/perl
+# JaSIG CAS support by Bruno Beaufils <bruno@boulgour.com>
+package IkiWiki::Plugin::cas;
+
+use warnings;
+use strict;
+use IkiWiki 2.00;
+use AuthCAS;                  # http://search.cpan.org/~osalaun/AuthCAS-1.3.1/

In ikiwiki we generally deman-load perl modules only when they're used. This avoids loading expensive modules when the CGI isn't doing authentication. Can you do that with AuthCAS? Something like this before the use of it: eval q{use AuthCAS}; error $@ if $@

+
+sub import {
+    hook(type => "getopt", id => "cas", call => \&getopt);
+    hook(type => "auth", id => "cas", call => \&auth);
+    hook(type => "formbuilder_setup", id => "cas", call => \&formbuilder_setup);
+}

Could you please use tabs for indentation of program flow?

+# FIXME: We should check_config to ensure that :
+# * cas_url and ca_file are present

Please fix that..

+# * no other auth plugin are present (at least passwordauth and openid)

Why would you want to make other auth plugins not work? Could a site not legitimatly chose to use this and another auth method?

+sub getopt () {
+    eval q{use Getopt::Long};
+    error($@) if $@;
+    Getopt::Long::Configure('pass_through');
+    GetOptions("cas_url=s" => \$config{cas_url});
+    GetOptions("ca_file=s" => \$config{ca_file});
+}
+
+sub auth ($$) {
+    my $q=shift;
+    my $session=shift;
+
+    my $cas = new AuthCAS(casUrl => $config{'cas'}{'cas_url'},
+                          CAFile => $config{'cas'}{'ca_file'});
+
+    my $service = $config{'cgiurl'};
+    my $ticket = $q->param('ticket');
+
+    unless (defined($ticket)) {
+        $service .= "?$ENV{QUERY_STRING}";
+        my $login_url = $cas->getServerLoginURL($service);
+        debug("CAS: asking a Service Ticket for service $service");
+        IkiWiki::redirect($q, $login_url);
+        exit 0;
+    } else {
+        $service = $service . "?$ENV{QUERY_STRING}";
+        $service =~ s/\&ticket=$ticket//;
+        my $user = $cas->validateST($service, $ticket);
+        if (defined $user) {
+            debug("CAS: validating a Service Ticket ($ticket) for service $service");
+            $session->param(name=>$user);
+            $session->param(CASservice=>$service);
+            IkiWiki::cgi_savesession($session);
+        } else {
+            error("CAS failure: ".&AuthCAS::get_errors());
+        }
+    }
+}
+
+# I use formbuilder_setup and not formbuilder type in order to bypass the
+# Logout processing done in IkiWiki::CGI::cgi_prefs()
+sub formbuilder_setup (@) {
+    my %params=@_;
+    
+    my $form=$params{form};
+    my $session=$params{session};
+    my $cgi=$params{cgi};
+    my $buttons=$params{buttons};
+
+    my $cas = new AuthCAS(casUrl => $config{'cas'}{'cas_url'},
+                          CAFile => $config{'cas'}{'ca_file'});
+
+    if ($form->title eq "preferences") {
+        # Show the login
+        if (! defined $form->field(name => "name")) {
+            $form->field(name => "CAS ID",
+                         disabled => 1,
+                         value => $session->param("name"), 
+                         size => 50,
+                         force => 1,
+                         fieldset => "login");
+        }
+        
+        # Force a logout if asked
+        if ($form->submitted && $form->submitted eq 'Logout')
+        {
+            debug("CAS: asking to remove the Ticket Grant Cookie");
+            IkiWiki::redirect($cgi, $cas->getServerLogoutURL($config{'url'}));
+            $session->delete();
+            exit 0;
+        }
+    }
+}
+
+1
diff --git a/doc/plugins/cas.mdwn b/doc/plugins/cas.mdwn
new file mode 100644
index 0000000..2f2f53e
--- /dev/null
+++ b/doc/plugins/cas.mdwn
@@ -0,0 +1,18 @@
+<span class="createlink"><a href="/ikiwiki.cgi?do=create&amp;from=todo%2Fcas_authentication&amp;page=_template_id__61__plugin_name__61__cas_core__61__0_author__61____34____91____91__bbb" rel="nofollow">?</a> template id&#61;plugin name&#61;cas core&#61;0 author&#61;&#34;&#91;&#91;bbb</span>"]]
+<span class="createlink"><a href="/ikiwiki.cgi?do=create&amp;from=todo%2Fcas_authentication&amp;page=_tag_type%2Fauth" rel="nofollow">?</a>auth</span>
+
+This plugin allows users to use authentication offered by a
+[JaSIG](http://www.ja-sig.org) [<acronym title='Central Authentication
+Service'>CAS</acronym>](http://www.ja-sig.org/products/cas/) server to log
+into the wiki.
+
+The plugin needs the <a href="http://search.cpan.org/search?mode=dist&query=AuthCAS%2D1%2E3%2E1">AuthCAS-1.3.1</a> perl module.

Does it really need that specific version? I think you should lose the version part.

+
+This plugin has two mandatory configuration option. You **must** set `--cas_url`
+to the url of a server offering CAS 2.0 authentication. You must also set the
+`--ca_file` to an absolute path to the file containing CA certificates used by
+the server (generally, aka under Debian, fixing that value to
+`/etc/ssl/certs/ca-certificates.crt` is sufficient).

It would be good to add commented-out examples of these to ikiwiki.setup as well.

+This plugin is not enabled by default. It can not be used with other
+authentication plugin, such as <span class="createlink"><a href="/ikiwiki.cgi?do=create&amp;from=todo%2Fcas_authentication&amp;page=passwordauth" rel="nofollow">?</a>passwordauth</span> or <span class="createlink"><a href="/ikiwiki.cgi?do=create&amp;from=todo%2Fcas_authentication&amp;page=openid" rel="nofollow">?</a>openid</span>.