SimpleCaptcha plugin to stop basic bots

actions/register.php

@@ -131,7 +131,11 @@ class RegisterAction extends Action
             // TRANS: Client error displayed when trying to register while already logged in.
             $this->clientError(_('Already logged in.'));
         } else if ($_SERVER['REQUEST_METHOD'] == 'POST') {
-            $this->tryRegister();
+            try {
+                $this->tryRegister();
+            } catch (ClientException $e) {
+                $this->showForm($e->getMessage());
+            }
         } else {
             $this->showForm();
         }

lib/default.php

@@ -324,6 +324,7 @@ $default =
                             'OStatus' => array(),
                             'Poll' => array(),
                             'SearchSub' => array(),
+                            'SimpleCaptcha' => array(),
                             'TagSub' => array(),
                             'WebFinger' => array(),
                         ),

plugins/SimpleCaptcha/SimpleCaptchaPlugin.php

@@ -0,0 +1,66 @@
+<?php
+/*
+ * GNU Social - a federating social network
+ * Copyright (C) 2014, Free Software Foundation, Inc.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+if (!defined('GNUSOCIAL')) { exit(1); }
+
+/**
+ * @package     Plugin
+ * @maintainer  Mikael Nordfeldth <mmn@hethane.se>
+ */
+class SimpleCaptchaPlugin extends Plugin
+{
+    public function onEndRegistrationFormData(Action $action)
+    {
+        $action->elementStart('li');
+        // TRANS: Field label.
+        $action->input('simplecaptcha', _m('Captcha'), null,
+                        // TRANS: The instruction box for our simple captcha plugin
+                        sprintf(_m('Copy this to the textbox: "%s"'), $this->getCaptchaText()),
+                        // TRANS: Placeholder in the text box
+                        /* name=id */ null, /* required */ true, ['placeholder'=>_m('Prove that you are sentient.')]);
+        $action->elementEnd('li');
+        return true;
+    }
+
+    protected function getCaptchaText()
+    {
+        return common_config('site', 'name');
+    }
+
+    public function onStartRegistrationTry(Action $action)
+    {
+        if ($action->arg('simplecaptcha') !== $this->getCaptchaText()) {
+            throw new ClientException(_m('Captcha does not match!'));
+        }
+        return true;
+    }
+
+    public function onPluginVersion(array &$versions)
+    {
+        $versions[] = array('name' => 'Simple Captcha',
+                            'version' => GNUSOCIAL_VERSION,
+                            'author' => 'Mikael Nordfeldth',
+                            'homepage' => 'https://gnu.io/social',
+                            'rawdescription' =>
+                            // TRANS: Plugin description.
+                            _m('A simple captcha to get rid of spambots.'));
+
+        return true;
+    }
+}