I imagine a plugin that modifies the login screen to use <http://recaptcha.net/>. You would then be required to fill in the captcha as well as log in in the normal way.
+-- [[users/Will]]
+
> I hate CAPTCHAs with a passion. Someone else is welcome to write such a
> plugin.
>
>> Something like the moinmoin global <http://master.moinmo.in/BadContent>
>> list?
+>>> OpenID can be thought of as pushing the problem of determining if
+>>> someone is a human or a spambot back from the openid consumer to the
+>>> openid provider. So, providers that make it possible for spambots to
+>>> use their openids, or that are even set up explicitly for use in
+>>> spamming, would be the ones to block. Or, providers that are known to
+>>> use very good screening for humans would be the ones to allow.
+>>> (Openid delegation makes it a bit harder than just looking at the
+>>> openid url though.) --[[Joey]]
+
+>>>> Well, OpenID only addresses authentication issues, not authorisation issues.
+>>>> Given that it is trivial to set up your own OpenID provider (a full provider, not
+>>>> just a forward to another provider), I can't see a
+>>>> blacklist working in the long term (it would be like blacklisting email).
+>>>> A whitelist might work (it would not be quite as bad as whitelisting email). In any case,
+>>>> there is now a captcha plugin for those that want it. It is accessible
+>>>> (there is an audio option) and serves a social purpose along with
+>>>> keeping bots out (the captcha is used to help digitise hard to read
+>>>> words in books for [Carnegie Mellon University](http://www.cs.cmu.edu/) and
+>>>> [The Internet Archive](http://www.archive.org/) ). Finally, because the actual captcha is outsourced
+>>>> it means that someone else is taking care of keeping it ahead of
+>>>> the bot authors.
+
Okie - I have a first pass of this. There are still some issues.
Currently the code verifies the CAPTCHA. If you get it right then you're fine.
> This is still not fixed. I would have thought the following patch would
> have fixed this second issue, but it doesn't.
+(code snipped as a working [[patch]] is below)
+
+>> What seems to be happing here is that the openid plugin defines a
+>> validate hook for openid_url that calls validate(). validate() in turn
+>> redirects the user to the openid server for validation, and exits. If
+>> the openid plugins' validate hook is called before your recaptcha
+>> validator, your code never gets a chance to run. I don't know how to
+>> control the other that FormBuilder validates fields, but the only fix I
+>> can see is to somehow influence that order.
+>>
+>> Hmm, maybe you need to move your own validation code out of the validate
+>> hook. Instead, just validate the captcha in the formbuilder_setup hook.
+>> The problem with this approach is that if validation fails, you can't
+>> just flag it as invalid and let formbuilder handle that. Instead, you'd
+>> have to hack something in to redisplay the captcha by hand. --[[Joey]]
+
+>>> Fixed this. I just modified the OpenID plugin to check if the captcha
+>>> succeeded or failed. Seeing as the OpenID plugin is the one that is
+>>> abusing the normal validate method, I figured it was best to keep
+>>> the fix in the same place. I also added a config switch so you can set if
+>>> the captcha is needed for OpenID logins. OpenID defaults to ignoring
+>>> the captcha.
+>>> Patch is inline below.
+>>> I think this whole thing is working now.
+
+>>>> Ok, glad it's working. Not thrilled that it needs to modify the
+>>>> openid plugin, especially as I'm not sure if i I will integrate the
+>>>> captcha plugin into mainline. Also because it's not very clean to have
+>>>> the oprnid plugin aware of another plugin like that. I'd like to
+>>>> prusue my idea of not doing the captcha validation in the validate
+>>>> hook.
+
--- a/IkiWiki/Plugin/openid.pm
+++ b/IkiWiki/Plugin/openid.pm
-@@ -61,6 +61,7 @@ sub formbuilder_setup (@) { #{{{
- # Skip all other required fields in this case.
- foreach my $field ($form->field) {
- next if $field eq "openid_url";
-+ next if $field eq "recaptcha";
- $form->field(name => $field, required => 0,
- validate => '/.*/');
- }
+@@ -18,6 +18,7 @@ sub getopt () { #{{{
+ error($@) if $@;
+ Getopt::Long::Configure('pass_through');
+ GetOptions("openidsignup=s" => \$config{openidsignup});
++ GetOptions("openidneedscaptcha=s" => \$config{openidneedscaptcha});
+ } #}}}
+
+ sub formbuilder_setup (@) { #{{{
+@@ -61,6 +62,7 @@ sub formbuilder_setup (@) { #{{{
+ # Skip all other required fields in this case.
+ foreach my $field ($form->field) {
+ next if $field eq "openid_url";
++ next if $config{openidneedscaptcha} && $field eq "recaptcha";
+ $form->field(name => $field, required => 0,
+ validate => '/.*/');
+ }
+@@ -96,6 +98,18 @@ sub validate ($$$;$) { #{{{
+ }
+ }
+
++ if ($config{openidneedscaptcha} && defined $form->field("recaptcha")) {
++ foreach my $field ($form->field) {
++ next unless ($field eq "recaptcha");
++ if (! $field->validate) {
++ # if they didn't get the captcha right,
++ # then just claim we validated ok so the
++ # captcha can cause a fail
++ return 1;
++ }
++ }
++ }
++
+ my $check_url = $claimed_identity->check_url(
+ return_to => IkiWiki::cgiurl(do => "postsignin"),
+ trust_root => $config{cgiurl},
Instructions
}
1;
-