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 CommentsExtension 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 CommentsExtension, and based on these observations, apply Extract Interface, too.
| 1 | <?php | ||
| 8 | class CommentsExtension extends DataExtension | ||
|  | |||
| 9 | { | ||
| 10 | /** | ||
| 11 | * Default configuration values | ||
| 12 | * | ||
| 13 | * enabled: Allows commenting to be disabled even if the extension is present | ||
| 14 | * enabled_cms: Allows commenting to be enabled or disabled via the CMS | ||
| 15 | * require_login: Boolean, whether a user needs to login (required for required_permission) | ||
| 16 | * require_login_cms: Allows require_login to be set via the CMS | ||
| 17 | * required_permission: Permission (or array of permissions) required to comment | ||
| 18 | * include_js: Enhance operation by ajax behaviour on moderation links (required for use_preview) | ||
| 19 | * use_gravatar: Set to true to show gravatar icons | ||
| 20 |      * gravatar_default:            Theme for 'not found' gravatar {@see http://gravatar.com/site/implement/images} | ||
| 21 | * gravatar_rating: Gravatar rating (same as the standard default) | ||
| 22 | * show_comments_when_disabled: Show older comments when commenting has been disabled. | ||
| 23 | * order_comments_by: Default sort order. | ||
| 24 | * order_replies_by: Sort order for replies. | ||
| 25 | * comments_holder_id: ID for the comments holder | ||
| 26 | * comment_permalink_prefix: ID prefix for each comment | ||
| 27 | * require_moderation: Require moderation for all comments | ||
| 28 | * require_moderation_cms: Ignore other comment moderation config settings and set via CMS | ||
| 29 | * frontend_moderation: Display unmoderated comments in the frontend, if the user can moderate them. | ||
| 30 | * frontend_spam: Display spam comments in the frontend, if the user can moderate them. | ||
| 31 | * html_allowed: Allow for sanitized HTML in comments | ||
| 32 | * use_preview: Preview formatted comment (when allowing HTML) | ||
| 33 | * nested_comments: Enable nested comments | ||
| 34 | * nested_depth: Max depth of nested comments in levels (where root is 1 depth) 0 means no limit. | ||
| 35 | * | ||
| 36 | * @var array | ||
| 37 | * | ||
| 38 | * @config | ||
| 39 | */ | ||
| 40 | private static $comments = array( | ||
| 41 | 'enabled' => true, | ||
| 42 | 'enabled_cms' => false, | ||
| 43 | 'require_login' => false, | ||
| 44 | 'require_login_cms' => false, | ||
| 45 | 'required_permission' => false, | ||
| 46 | 'include_js' => true, | ||
| 47 | 'use_gravatar' => false, | ||
| 48 | 'gravatar_size' => 80, | ||
| 49 | 'gravatar_default' => 'identicon', | ||
| 50 | 'gravatar_rating' => 'g', | ||
| 51 | 'show_comments_when_disabled' => false, | ||
| 52 | 'order_comments_by' => '"Created" DESC', | ||
| 53 | 'order_replies_by' => false, | ||
| 54 | 'comments_per_page' => 10, | ||
| 55 | 'comments_holder_id' => 'comments-holder', | ||
| 56 | 'comment_permalink_prefix' => 'comment-', | ||
| 57 | 'require_moderation' => false, | ||
| 58 | 'require_moderation_nonmembers' => false, | ||
| 59 | 'require_moderation_cms' => false, | ||
| 60 | 'frontend_moderation' => false, | ||
| 61 | 'frontend_spam' => false, | ||
| 62 | 'html_allowed' => false, | ||
| 63 |         'html_allowed_elements' => array('a', 'img', 'i', 'b'), | ||
| 64 | 'use_preview' => false, | ||
| 65 | 'nested_comments' => false, | ||
| 66 | 'nested_depth' => 2, | ||
| 67 | ); | ||
| 68 | |||
| 69 | /** | ||
| 70 | * @var array | ||
| 71 | */ | ||
| 72 | private static $db = array( | ||
| 73 | 'ProvideComments' => 'Boolean', | ||
| 74 | 'ModerationRequired' => 'Enum(\'None,Required,NonMembersOnly\',\'None\')', | ||
| 75 | 'CommentsRequireLogin' => 'Boolean', | ||
| 76 | ); | ||
| 77 | |||
| 78 | /** | ||
| 79 | * CMS configurable options should default to the config values, but respect | ||
| 80 | * default values specified by the object | ||
| 81 | */ | ||
| 82 | public function populateDefaults() | ||
| 111 | |||
| 112 | |||
| 113 | /** | ||
| 114 |      * If this extension is applied to a {@link SiteTree} record then | ||
| 115 | * append a Provide Comments checkbox to allow authors to trigger | ||
| 116 | * whether or not to display comments | ||
| 117 | * | ||
| 118 |      * @todo Allow customization of other {@link Commenting} configuration | ||
| 119 | * | ||
| 120 | * @param FieldList $fields | ||
| 121 | */ | ||
| 122 | public function updateSettingsFields(FieldList $fields) | ||
| 166 | |||
| 167 | /** | ||
| 168 | * Get comment moderation rules for this parent | ||
| 169 | * | ||
| 170 | * None: No moderation required | ||
| 171 | * Required: All comments | ||
| 172 | * NonMembersOnly: Only anonymous users | ||
| 173 | * | ||
| 174 | * @return string | ||
| 175 | */ | ||
| 176 | public function getModerationRequired() | ||
| 188 | |||
| 189 | /** | ||
| 190 | * Determine if users must be logged in to post comments | ||
| 191 | * | ||
| 192 | * @return boolean | ||
| 193 | */ | ||
| 194 | public function getCommentsRequireLogin() | ||
| 202 | |||
| 203 | /** | ||
| 204 | * Returns the RelationList of all comments against this object. Can be used as a data source | ||
| 205 | * for a gridfield with write access. | ||
| 206 | * | ||
| 207 | * @return CommentList | ||
| 208 | */ | ||
| 209 | public function AllComments() | ||
| 218 | |||
| 219 | /** | ||
| 220 | * Returns all comments against this object, with with spam and unmoderated items excluded, for use in the frontend | ||
| 221 | * | ||
| 222 | * @return CommentList | ||
| 223 | */ | ||
| 224 | public function AllVisibleComments() | ||
| 244 | |||
| 245 | /** | ||
| 246 | * Returns the root level comments, with spam and unmoderated items excluded, for use in the frontend | ||
| 247 | * | ||
| 248 | * @return CommentList | ||
| 249 | */ | ||
| 250 | public function Comments() | ||
| 262 | |||
| 263 | /** | ||
| 264 | * Returns a paged list of the root level comments, with spam and unmoderated items excluded, | ||
| 265 | * for use in the frontend | ||
| 266 | * | ||
| 267 | * @return PaginatedList | ||
| 268 | */ | ||
| 269 | View Code Duplication | public function PagedComments() | |
| 281 | |||
| 282 | /** | ||
| 283 | * Check if comments are configured for this page even if they are currently disabled. | ||
| 284 | * Do not include the comments on pages which don't have id's such as security pages | ||
| 285 | * | ||
| 286 | * @deprecated since version 2.0 | ||
| 287 | * | ||
| 288 | * @return boolean | ||
| 289 | */ | ||
| 290 | public function getCommentsConfigured() | ||
| 295 | |||
| 296 | /** | ||
| 297 | * Determine if comments are enabled for this instance | ||
| 298 | * | ||
| 299 | * @return boolean | ||
| 300 | */ | ||
| 301 | public function getCommentsEnabled() | ||
| 315 | |||
| 316 | /** | ||
| 317 | * Get the HTML ID for the comment holder in the template | ||
| 318 | * | ||
| 319 | * @return string | ||
| 320 | */ | ||
| 321 | public function getCommentHolderID() | ||
| 325 | |||
| 326 | /** | ||
| 327 | * @deprecated since version 2.0 | ||
| 328 | */ | ||
| 329 | public function getPostingRequiresPermission() | ||
| 334 | |||
| 335 | /** | ||
| 336 | * Permission codes required in order to post (or empty if none required) | ||
| 337 | * | ||
| 338 | * @return string|array Permission or list of permissions, if required | ||
| 339 | */ | ||
| 340 | public function getPostingRequiredPermission() | ||
| 344 | |||
| 345 | public function canPost() | ||
| 350 | |||
| 351 | /** | ||
| 352 | * Determine if a user can post comments on this item | ||
| 353 | * | ||
| 354 | * @param Member $member Member to check | ||
| 355 | * | ||
| 356 | * @return boolean | ||
| 357 | */ | ||
| 358 | public function canPostComment($member = null) | ||
| 385 | |||
| 386 | /** | ||
| 387 | * Determine if this member can moderate comments in the CMS | ||
| 388 | * | ||
| 389 | * @param Member $member | ||
| 390 | * | ||
| 391 | * @return boolean | ||
| 392 | */ | ||
| 393 | public function canModerateComments($member = null) | ||
| 403 | |||
| 404 | public function getRssLink() | ||
| 409 | |||
| 410 | /** | ||
| 411 | * Gets the RSS link to all comments | ||
| 412 | * | ||
| 413 | * @return string | ||
| 414 | */ | ||
| 415 | public function getCommentRSSLink() | ||
| 419 | |||
| 420 | public function getRssLinkPage() | ||
| 425 | |||
| 426 | /** | ||
| 427 | * Get the RSS link to all comments on this page | ||
| 428 | * | ||
| 429 | * @return string | ||
| 430 | */ | ||
| 431 | public function getCommentRSSLinkPage() | ||
| 437 | |||
| 438 | /** | ||
| 439 | * Comments interface for the front end. Includes the CommentAddForm and the composition | ||
| 440 | * of the comments display. | ||
| 441 | * | ||
| 442 | * To customize the html see templates/CommentInterface.ss or extend this function with | ||
| 443 | * your own extension. | ||
| 444 | * | ||
| 445 | * @todo Cleanup the passing of all this configuration based functionality | ||
| 446 | * | ||
| 447 | * @see docs/en/Extending | ||
| 448 | */ | ||
| 449 | public function CommentsForm() | ||
| 450 |     { | ||
| 451 | // Check if enabled | ||
| 452 | $enabled = $this->getCommentsEnabled(); | ||
| 453 |         if ($enabled && $this->owner->getCommentsOption('include_js')) { | ||
| 454 | Requirements::javascript(THIRDPARTY_DIR . '/jquery/jquery.js'); | ||
| 455 | Requirements::javascript(THIRDPARTY_DIR . '/jquery-entwine/dist/jquery.entwine-dist.js'); | ||
| 456 | Requirements::javascript(THIRDPARTY_DIR . '/jquery-validate/lib/jquery.form.js'); | ||
| 457 | Requirements::javascript(COMMENTS_THIRDPARTY . '/jquery-validate/jquery.validate.min.js'); | ||
| 458 |             Requirements::add_i18n_javascript('comments/javascript/lang'); | ||
| 459 |             Requirements::javascript('comments/javascript/CommentsInterface.js'); | ||
| 460 | } | ||
| 461 | |||
| 462 | $controller = CommentingController::create(); | ||
| 463 | $controller->setOwnerRecord($this->owner); | ||
| 464 | $controller->setBaseClass($this->ownerBaseClass); | ||
| 465 | $controller->setOwnerController(Controller::curr()); | ||
| 466 | |||
| 467 |         $moderatedSubmitted = Session::get('CommentsModerated'); | ||
| 468 |         Session::clear('CommentsModerated'); | ||
| 469 | |||
| 470 | $form = ($enabled) ? $controller->CommentsForm() : false; | ||
| 471 | |||
| 472 | // a little bit all over the show but to ensure a slightly easier upgrade for users | ||
| 473 | // return back the same variables as previously done in comments | ||
| 474 | return $this | ||
| 475 | ->owner | ||
| 476 | ->customise(array( | ||
| 477 | 'AddCommentForm' => $form, | ||
| 478 | 'ModeratedSubmitted' => $moderatedSubmitted, | ||
| 479 | )) | ||
| 480 |             ->renderWith('CommentsInterface'); | ||
| 481 | } | ||
| 482 | |||
| 483 | /** | ||
| 484 |      * Returns whether this extension instance is attached to a {@link SiteTree} object | ||
| 485 | * | ||
| 486 | * @return bool | ||
| 487 | */ | ||
| 488 | public function attachedToSiteTree() | ||
| 494 | |||
| 495 | /** | ||
| 496 |      * @deprecated 1.0 Please use {@link CommentsExtension->CommentsForm()} | ||
| 497 | */ | ||
| 498 | public function PageComments() | ||
| 504 | |||
| 505 | /** | ||
| 506 | * Get the commenting option for this object | ||
| 507 | * | ||
| 508 | * This can be overridden in any instance or extension to customise the option available | ||
| 509 | * | ||
| 510 | * @param string $key | ||
| 511 | * | ||
| 512 | * @return mixed Result if the setting is available, or null otherwise | ||
| 513 | */ | ||
| 514 | public function getCommentsOption($key) | ||
| 530 | |||
| 531 | /** | ||
| 532 | * Add moderation functions to the current fieldlist | ||
| 533 | * | ||
| 534 | * @param FieldList $fields | ||
| 535 | */ | ||
| 536 | protected function updateModerationFields(FieldList $fields) | ||
| 591 | |||
| 592 | public function updateCMSFields(FieldList $fields) | ||
| 604 | } | ||
| 605 | 
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.