Duplicate code is one of the most pungent code smells. A rule that is often used is to re-structure code once it is duplicated in three or more places.
Common duplication problems, and corresponding solutions are:
Complex classes like CommentingController often do a lot of different things. To break such a class down, we need to identify a cohesive component within that class. A common approach to find such a component is to look for fields/methods that share the same prefixes, or suffixes. You can also have a look at the cohesion graph to spot any un-connected, or weakly-connected components.
Once you have determined the fields that belong together, you can apply the Extract Class refactoring. If the component makes sense as a sub-class, Extract Subclass is also a candidate, and is often faster.
While breaking up the class, it is a good idea to analyze how other classes use CommentingController, and based on these observations, apply Extract Interface, too.
| 1 | <?php  | 
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| 7 | class CommentingController extends Controller  | 
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| 8 | { | 
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| 9 | |||
| 10 | private static $allowed_actions = array(  | 
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| 11 | 'delete',  | 
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| 12 | 'spam',  | 
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| 13 | 'ham',  | 
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| 14 | 'approve',  | 
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| 15 | 'rss',  | 
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| 16 | 'CommentsForm',  | 
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| 17 | 'reply',  | 
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| 18 | 'doPostComment',  | 
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| 19 | 'doPreviewComment'  | 
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| 20 | );  | 
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| 21 | |||
| 22 | private static $url_handlers = array(  | 
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| 23 | 'reply/$ParentCommentID//$ID/$OtherID' => 'reply',  | 
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| 24 | );  | 
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| 25 | |||
| 26 | /**  | 
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| 27 | * Fields required for this form  | 
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| 28 | *  | 
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| 29 | * @var array  | 
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| 30 | * @config  | 
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| 31 | */  | 
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| 32 | private static $required_fields = array(  | 
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| 33 | 'Name',  | 
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| 34 | 'Email',  | 
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| 35 | 'Comment'  | 
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| 36 | );  | 
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| 37 | |||
| 38 | /**  | 
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| 39 | * Base class this commenting form is for  | 
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| 40 | *  | 
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| 41 | * @var string  | 
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| 42 | */  | 
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| 43 | private $baseClass = "";  | 
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| 44 | |||
| 45 | /**  | 
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| 46 | * The record this commenting form is for  | 
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| 47 | *  | 
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| 48 | * @var DataObject  | 
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| 49 | */  | 
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| 50 | private $ownerRecord = null;  | 
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| 51 | |||
| 52 | /**  | 
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| 53 | * Parent controller record  | 
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| 54 | *  | 
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| 55 | * @var Controller  | 
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| 56 | */  | 
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| 57 | private $ownerController = null;  | 
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| 58 | |||
| 59 | /**  | 
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| 60 | * Backup url to return to  | 
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| 61 | *  | 
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| 62 | * @var string  | 
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| 63 | */  | 
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| 64 | protected $fallbackReturnURL = null;  | 
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| 65 | |||
| 66 | /**  | 
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| 67 | * Set the base class to use  | 
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| 68 | *  | 
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| 69 | * @param string $class  | 
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| 70 | */  | 
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| 71 | public function setBaseClass($class)  | 
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| 75 | |||
| 76 | /**  | 
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| 77 | * Get the base class used  | 
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| 78 | *  | 
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| 79 | * @return string  | 
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| 80 | */  | 
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| 81 | public function getBaseClass()  | 
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| 85 | |||
| 86 | /**  | 
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| 87 | * Set the record this controller is working on  | 
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| 88 | *  | 
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| 89 | * @param DataObject $record  | 
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| 90 | */  | 
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| 91 | public function setOwnerRecord($record)  | 
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| 95 | |||
| 96 | /**  | 
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| 97 | * Get the record  | 
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| 98 | *  | 
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| 99 | * @return DataObject  | 
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| 100 | */  | 
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| 101 | public function getOwnerRecord()  | 
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| 105 | |||
| 106 | /**  | 
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| 107 | * Set the parent controller  | 
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| 108 | *  | 
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| 109 | * @param Controller $controller  | 
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| 110 | */  | 
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| 111 | public function setOwnerController($controller)  | 
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| 115 | |||
| 116 | /**  | 
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| 117 | * Get the parent controller  | 
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| 118 | *  | 
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| 119 | * @return Controller  | 
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| 120 | */  | 
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| 121 | public function getOwnerController()  | 
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| 125 | |||
| 126 | /**  | 
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| 127 | * Get the commenting option for the current state  | 
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| 128 | *  | 
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| 129 | * @param string $key  | 
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| 130 | * @return mixed Result if the setting is available, or null otherwise  | 
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| 131 | */  | 
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| 132 | public function getOption($key)  | 
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| 147 | |||
| 148 | /**  | 
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| 149 | * Workaround for generating the link to this controller  | 
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| 150 | *  | 
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| 151 | * @return string  | 
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| 152 | */  | 
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| 153 | public function Link($action = '', $id = '', $other = '')  | 
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| 157 | |||
| 158 | /**  | 
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| 159 | * Outputs the RSS feed of comments  | 
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| 160 | *  | 
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| 161 | * @return HTMLText  | 
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| 162 | */  | 
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| 163 | public function rss()  | 
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| 167 | |||
| 168 | /**  | 
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| 169 | * Return an RSSFeed of comments for a given set of comments or all  | 
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| 170 | * comments on the website.  | 
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| 171 | *  | 
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| 172 | * To maintain backwards compatibility with 2.4 this supports mapping  | 
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| 173 | * of PageComment/rss?pageid= as well as the new RSS format for comments  | 
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| 174 |      * of CommentingController/rss/{classname}/{id} | 
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| 175 | *  | 
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| 176 | * @param SS_HTTPRequest  | 
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| 177 | *  | 
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| 178 | * @return RSSFeed  | 
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| 179 | */  | 
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| 180 | public function getFeed(SS_HTTPRequest $request)  | 
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| 226 | |||
| 227 | /**  | 
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| 228 |      * Deletes a given {@link Comment} via the URL. | 
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| 229 | */  | 
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| 230 | View Code Duplication | public function delete()  | 
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| 249 | |||
| 250 | /**  | 
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| 251 |      * Marks a given {@link Comment} as spam. Removes the comment from display | 
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| 252 | */  | 
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| 253 | View Code Duplication | public function spam()  | 
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| 269 | |||
| 270 | /**  | 
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| 271 |      * Marks a given {@link Comment} as ham (not spam). | 
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| 272 | */  | 
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| 273 | View Code Duplication | public function ham()  | 
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| 289 | |||
| 290 | /**  | 
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| 291 |      * Marks a given {@link Comment} as approved. | 
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| 292 | */  | 
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| 293 | View Code Duplication | public function approve()  | 
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| 309 | |||
| 310 | /**  | 
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| 311 | * Redirect back to referer if available, ensuring that only site URLs  | 
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| 312 | * are allowed to avoid phishing. If it's an AJAX request render the  | 
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| 313 | * comment in it's new state  | 
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| 314 | */  | 
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| 315 | private function renderChangedCommentState($comment)  | 
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| 338 | |||
| 339 | /**  | 
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| 340 | * Returns the comment referenced in the URL (by ID). Permission checking  | 
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| 341 | * should be done in the callee.  | 
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| 342 | *  | 
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| 343 | * @return Comment|false  | 
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| 344 | */  | 
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| 345 | public function getComment()  | 
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| 360 | |||
| 361 | /**  | 
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| 362 | * Create a reply form for a specified comment  | 
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| 363 | *  | 
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| 364 | * @param Comment $comment  | 
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| 365 | */  | 
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| 366 | public function ReplyForm($comment)  | 
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| 384 | |||
| 385 | |||
| 386 | /**  | 
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| 387 | * Request handler for reply form.  | 
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| 388 | * This method will disambiguate multiple reply forms in the same method  | 
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| 389 | *  | 
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| 390 | * @param SS_HTTPRequest $request  | 
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| 391 | */  | 
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| 392 | public function reply(SS_HTTPRequest $request)  | 
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| 403 | |||
| 404 | /**  | 
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| 405 | * Post a comment form  | 
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| 406 | *  | 
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| 407 | * @return Form  | 
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| 408 | */  | 
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| 409 | public function CommentsForm()  | 
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| 410 |     { | 
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| 411 |         $usePreview = $this->getOption('use_preview'); | 
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| 412 | |||
| 413 |         $nameRequired = _t('CommentInterface.YOURNAME_MESSAGE_REQUIRED', 'Please enter your name'); | 
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| 414 |         $emailRequired = _t('CommentInterface.EMAILADDRESS_MESSAGE_REQUIRED', 'Please enter your email address'); | 
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| 415 |         $emailInvalid = _t('CommentInterface.EMAILADDRESS_MESSAGE_EMAIL', 'Please enter a valid email address'); | 
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| 416 |         $urlInvalid = _t('CommentInterface.COMMENT_MESSAGE_URL', 'Please enter a valid URL'); | 
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| 417 |         $commentRequired = _t('CommentInterface.COMMENT_MESSAGE_REQUIRED', 'Please enter your comment'); | 
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| 418 | |||
| 419 | $fields = new FieldList(  | 
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| 420 | $dataFields = new CompositeField(  | 
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| 421 | // Name  | 
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| 422 |                 TextField::create("Name", _t('CommentInterface.YOURNAME', 'Your name')) | 
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| 423 | ->setCustomValidationMessage($nameRequired)  | 
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| 424 |                     ->setAttribute('data-msg-required', $nameRequired), | 
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| 425 | |||
| 426 | |||
| 427 | EmailField::create(  | 
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| 428 | "Email",  | 
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| 429 |                     _t('CommentingController.EMAILADDRESS', "Your email address (will not be published)") | 
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| 430 | )  | 
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| 431 | ->setCustomValidationMessage($emailRequired)  | 
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| 432 |                     ->setAttribute('data-msg-required', $emailRequired) | 
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| 433 |                     ->setAttribute('data-msg-email', $emailInvalid) | 
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| 434 |                     ->setAttribute('data-rule-email', true), | 
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| 435 | |||
| 436 | // Url  | 
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| 437 |                 TextField::create("URL", _t('CommentingController.WEBSITEURL', "Your website URL")) | 
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| 438 |                     ->setAttribute('data-msg-url', $urlInvalid) | 
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| 439 |                     ->setAttribute('data-rule-url', true), | 
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| 440 | |||
| 441 | // Comment  | 
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| 442 |                 TextareaField::create("Comment", _t('CommentingController.COMMENTS', "Comments")) | 
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| 443 | ->setCustomValidationMessage($commentRequired)  | 
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| 444 |                     ->setAttribute('data-msg-required', $commentRequired) | 
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| 445 | ),  | 
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| 446 |             HiddenField::create("ParentID"), | 
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| 447 |             HiddenField::create("ReturnURL"), | 
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| 448 |             HiddenField::create("ParentCommentID"), | 
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| 449 |             HiddenField::create("BaseClass") | 
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| 450 | );  | 
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| 451 | |||
| 452 | // Preview formatted comment. Makes most sense when shortcodes or  | 
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| 453 | // limited HTML is allowed. Populated by JS/Ajax.  | 
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| 454 |         if ($usePreview) { | 
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| 455 | $fields->insertAfter(  | 
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| 456 |                 ReadonlyField::create('PreviewComment', _t('CommentInterface.PREVIEWLABEL', 'Preview')) | 
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| 457 |                     ->setAttribute('style', 'display: none'), // enable through JS | 
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| 458 | 'Comment'  | 
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| 459 | );  | 
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| 460 | }  | 
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| 461 | |||
| 462 |         $dataFields->addExtraClass('data-fields'); | 
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| 463 | |||
| 464 | // save actions  | 
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| 465 | $actions = new FieldList(  | 
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| 466 |             new FormAction("doPostComment", _t('CommentInterface.POST', 'Post')) | 
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| 467 | );  | 
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| 468 |         if ($usePreview) { | 
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| 469 | $actions->push(  | 
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| 470 |                 FormAction::create('doPreviewComment', _t('CommentInterface.PREVIEW', 'Preview')) | 
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| 471 |                     ->addExtraClass('action-minor') | 
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| 472 |                     ->setAttribute('style', 'display: none') // enable through JS | 
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| 473 | );  | 
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| 474 | }  | 
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| 475 | |||
| 476 | // required fields for server side  | 
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| 477 | $required = new RequiredFields($this->config()->required_fields);  | 
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| 478 | |||
| 479 | // create the comment form  | 
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| 480 | $form = new Form($this, 'CommentsForm', $fields, $actions, $required);  | 
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| 481 | |||
| 482 | // if the record exists load the extra required data  | 
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| 483 |         if ($record = $this->getOwnerRecord()) { | 
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| 484 | |||
| 485 | // Load member data  | 
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| 486 | $member = Member::currentUser();  | 
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| 487 |             if (($record->CommentsRequireLogin || $record->PostingRequiredPermission) && $member) { | 
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| 488 | $fields = $form->Fields();  | 
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| 489 | |||
| 490 |                 $fields->removeByName('Name'); | 
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| 491 |                 $fields->removeByName('Email'); | 
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| 492 |                 $fields->insertBefore(new ReadonlyField("NameView", _t('CommentInterface.YOURNAME', 'Your name'), $member->getName()), 'URL'); | 
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| 493 |                 $fields->push(new HiddenField("Name", "", $member->getName())); | 
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| 494 |                 $fields->push(new HiddenField("Email", "", $member->Email)); | 
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| 495 | }  | 
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| 496 | |||
| 497 | // we do not want to read a new URL when the form has already been submitted  | 
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| 498 | // which in here, it hasn't been.  | 
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| 499 | $form->loadDataFrom(array(  | 
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| 500 | 'ParentID' => $record->ID,  | 
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| 501 | 'ReturnURL' => $this->request->getURL(),  | 
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| 502 | 'BaseClass' => $this->getBaseClass()  | 
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| 503 | ));  | 
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| 504 | }  | 
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| 505 | |||
| 506 | // Set it so the user gets redirected back down to the form upon form fail  | 
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| 507 | $form->setRedirectToFormOnValidationError(true);  | 
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| 508 | |||
| 509 | // load any data from the cookies  | 
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| 510 |         if ($data = Cookie::get('CommentsForm_UserData')) { | 
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| 511 | $data = Convert::json2array($data);  | 
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| 512 | |||
| 513 | $form->loadDataFrom(array(  | 
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| 514 | "Name" => isset($data['Name']) ? $data['Name'] : '',  | 
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| 515 | "URL" => isset($data['URL']) ? $data['URL'] : '',  | 
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| 516 | "Email" => isset($data['Email']) ? $data['Email'] : ''  | 
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| 517 | ));  | 
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| 518 | // allow previous value to fill if comment not stored in cookie (i.e. validation error)  | 
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| 519 |             $prevComment = Cookie::get('CommentsForm_Comment'); | 
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| 520 |             if ($prevComment && $prevComment != '') { | 
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| 521 |                 $form->loadDataFrom(array("Comment" => $prevComment)); | 
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| 522 | }  | 
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| 523 | }  | 
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| 524 | |||
| 525 |         if (!empty($member)) { | 
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| 526 | $form->loadDataFrom($member);  | 
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| 527 | }  | 
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| 528 | |||
| 529 | // hook to allow further extensions to alter the comments form  | 
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| 530 |         $this->extend('alterCommentForm', $form); | 
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| 531 | |||
| 532 | return $form;  | 
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| 533 | }  | 
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| 534 | |||
| 535 | /**  | 
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| 536 |      * Process which creates a {@link Comment} once a user submits a comment from this form. | 
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| 537 | *  | 
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| 538 | * @param array $data  | 
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| 539 | * @param Form $form  | 
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| 540 | */  | 
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| 541 | public function doPostComment($data, $form)  | 
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| 639 | |||
| 640 | public function doPreviewComment($data, $form)  | 
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| 646 | |||
| 647 | public function redirectBack()  | 
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| 681 | }  | 
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| 682 | 
You can fix this by adding a namespace to your class:
When choosing a vendor namespace, try to pick something that is not too generic to avoid conflicts with other libraries.