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 Administration 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 Administration, and based on these observations, apply Extract Interface, too.
1 | <?php |
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13 | class Administration extends Symphony |
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14 | { |
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15 | /** |
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16 | * The class representation of the current Symphony backend page, |
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17 | * which is a subclass of the `HTMLPage` class. Symphony uses a convention |
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18 | * of prefixing backend page classes with 'content'. ie. 'contentBlueprintsSections' |
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19 | * |
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20 | * @var HTMLPage |
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21 | */ |
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22 | public $Page; |
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23 | /** |
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24 | * The path of the current page, ie. '/blueprints/sections/' |
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25 | * |
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26 | * @var string |
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27 | */ |
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28 | private $_currentPage = null; |
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29 | /** |
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30 | * An associative array of the page's callback, including the keys |
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31 | * 'driver', which is a lowercase version of `$this->_currentPage` |
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32 | * with any slashes removed, 'classname', which is the name of the class |
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33 | * for this page, 'pageroot', which is the root page for the given page, (ie. |
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34 | * excluding /saved/, /created/ or any sub pages of the current page that are |
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35 | * handled using the _switchboard function. |
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36 | * |
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37 | * @see toolkit.AdministrationPage#__switchboard() |
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38 | * @var array |
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39 | */ |
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40 | private $_callback = null; |
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41 | |||
42 | /** |
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43 | * Overrides the default Symphony constructor to add XSRF checking |
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44 | */ |
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45 | protected function __construct() |
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54 | |||
55 | /** |
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56 | * This function returns an instance of the Administration |
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57 | * class. It is the only way to create a new Administration, as |
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58 | * it implements the Singleton interface |
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59 | * |
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60 | * @return Administration |
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61 | */ |
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62 | public static function instance() |
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70 | |||
71 | /** |
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72 | * Returns the current Page path, excluding the domain and Symphony path. |
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73 | * |
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74 | * @return string |
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75 | * The path of the current page, ie. '/blueprints/sections/' |
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76 | */ |
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77 | public function getCurrentPageURL() |
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81 | |||
82 | /** |
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83 | * Called by index.php, this function is responsible for rendering the current |
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84 | * page on the Frontend. Two delegates are fired, AdminPagePreGenerate and |
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85 | * AdminPagePostGenerate. This function runs the Profiler for the page build |
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86 | * process. |
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87 | * |
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88 | * @uses AdminPagePreBuild |
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89 | * @uses AdminPagePreGenerate |
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90 | * @uses AdminPagePostGenerate |
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91 | * @see core.Symphony#__buildPage() |
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92 | * @see boot.getCurrentPage() |
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93 | * @param string $page |
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94 | * The result of getCurrentPage, which returns the $_GET['symphony-page'] |
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95 | * variable. |
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96 | * @throws Exception |
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97 | * @throws SymphonyErrorPage |
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98 | * @return string |
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99 | * The HTML of the page to return |
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100 | */ |
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101 | public function display($page) |
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157 | |||
158 | /** |
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159 | * Given the URL path of a Symphony backend page, this function will |
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160 | * attempt to resolve the URL to a Symphony content page in the backend |
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161 | * or a page provided by an extension. This function checks to ensure a user |
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162 | * is logged in, otherwise it will direct them to the login page |
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163 | * |
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164 | * @param string $page |
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165 | * The URL path after the root of the Symphony installation, including a starting |
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166 | * slash, such as '/login/' |
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167 | * @throws SymphonyErrorPage |
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168 | * @throws Exception |
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169 | * @return HTMLPage |
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170 | */ |
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171 | private function __buildPage($page) |
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275 | |||
276 | /** |
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277 | * Overrides the Symphony isLoggedIn function to allow Authors |
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278 | * to become logged into the backend when `$_REQUEST['auth-token']` |
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279 | * is present. This logs an Author in using the loginFromToken function. |
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280 | * A token may be 6 or 8 characters in length in the backend. A 6 or 16 character token |
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281 | * is used for forget password requests, whereas the 8 character token is used to login |
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282 | * an Author into the page |
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283 | * |
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284 | * @see core.Symphony#loginFromToken() |
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285 | * @return boolean |
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286 | */ |
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287 | public static function isLoggedIn() |
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297 | |||
298 | /** |
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299 | * This function resolves the string of the page to the relevant |
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300 | * backend page class. The path to the backend page is split on |
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301 | * the slashes and the resulting pieces used to determine if the page |
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302 | * is provided by an extension, is a section (index or entry creation) |
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303 | * or finally a standard Symphony content page. If no page driver can |
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304 | * be found, this function will return false. |
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305 | * |
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306 | * @uses AdminPagePostCallback |
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307 | * @param string $page |
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308 | * The full path (including the domain) of the Symphony backend page |
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309 | * @return array|boolean |
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310 | * If successful, this function will return an associative array that at the |
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311 | * very least will return the page's classname, pageroot, driver, driver_location |
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312 | * and context, otherwise this will return false. |
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313 | */ |
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314 | public function getPageCallback($page = null) |
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315 | { |
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316 | if (!$page && !is_null($this->_callback)) { |
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317 | return $this->_callback; |
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318 | } elseif (!$page && is_null($this->_callback)) { |
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319 | trigger_error(__('Cannot request a page callback without first specifying the page.')); |
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320 | } |
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321 | |||
322 | $this->_currentPage = SYMPHONY_URL . preg_replace('/\/{2,}/', '/', $page); |
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323 | $bits = preg_split('/\//', trim($page, '/'), 3, PREG_SPLIT_NO_EMPTY); |
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324 | $callback = array( |
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325 | 'driver' => null, |
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326 | 'driver_location' => null, |
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327 | 'context' => array(), |
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328 | 'classname' => null, |
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329 | 'pageroot' => null |
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330 | ); |
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331 | |||
332 | // Login page, /symphony/login/ |
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333 | if ($bits[0] === 'login') { |
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334 | $callback['driver'] = 'login'; |
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335 | $callback['driver_location'] = CONTENT . '/content.login.php'; |
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336 | $callback['classname'] = 'contentLogin'; |
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337 | $callback['pageroot'] = '/login/'; |
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338 | |||
339 | // Extension page, /symphony/extension/{extension_name}/ |
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340 | } elseif ($bits[0] === 'extension' && isset($bits[1])) { |
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341 | $extension_name = $bits[1]; |
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342 | $bits = preg_split('/\//', trim($bits[2], '/'), 2, PREG_SPLIT_NO_EMPTY); |
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343 | |||
344 | // check if extension is enabled, if it's not, pretend the extension doesn't |
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345 | // even exist. #2367 |
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346 | if (!ExtensionManager::isInstalled($extension_name)) { |
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347 | return false; |
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348 | } |
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349 | |||
350 | $callback['driver'] = 'index'; |
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351 | $callback['classname'] = 'contentExtension' . ucfirst($extension_name) . 'Index'; |
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352 | $callback['pageroot'] = '/extension/' . $extension_name . '/'; |
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353 | $callback['extension'] = $extension_name; |
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354 | |||
355 | if (isset($bits[0])) { |
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356 | $callback['driver'] = $bits[0]; |
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357 | $callback['classname'] = 'contentExtension' . ucfirst($extension_name) . ucfirst($bits[0]); |
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358 | $callback['pageroot'] .= $bits[0] . '/'; |
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359 | } |
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360 | |||
361 | View Code Duplication | if (isset($bits[1])) { |
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362 | $callback['context'] = preg_split('/\//', $bits[1], -1, PREG_SPLIT_NO_EMPTY); |
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363 | } |
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364 | |||
365 | $callback['driver_location'] = EXTENSIONS . '/' . $extension_name . '/content/content.' . $callback['driver'] . '.php'; |
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366 | // Extensions won't be part of the autoloader chain, so first try to require them if they are available. |
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367 | if (!is_file($callback['driver_location'])) { |
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368 | return false; |
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369 | } else { |
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370 | require_once $callback['driver_location']; |
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371 | } |
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372 | |||
373 | // Publish page, /symphony/publish/{section_handle}/ |
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374 | } elseif ($bits[0] === 'publish') { |
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375 | if (!isset($bits[1])) { |
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376 | return false; |
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377 | } |
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378 | |||
379 | $callback['driver'] = 'publish'; |
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380 | $callback['driver_location'] = CONTENT . '/content.publish.php'; |
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381 | $callback['pageroot'] = '/' . $bits[0] . '/' . $bits[1] . '/'; |
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382 | $callback['classname'] = 'contentPublish'; |
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383 | |||
384 | // Everything else |
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385 | } else { |
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386 | $callback['driver'] = ucfirst($bits[0]); |
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387 | $callback['pageroot'] = '/' . $bits[0] . '/'; |
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388 | |||
389 | if (isset($bits[1])) { |
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390 | $callback['driver'] = $callback['driver'] . ucfirst($bits[1]); |
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391 | $callback['pageroot'] .= $bits[1] . '/'; |
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392 | } |
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393 | |||
394 | $callback['classname'] = 'content' . $callback['driver']; |
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395 | $callback['driver'] = strtolower($callback['driver']); |
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396 | $callback['driver_location'] = CONTENT . '/content.' . $callback['driver'] . '.php'; |
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397 | } |
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398 | |||
399 | // Parse the context |
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400 | if (isset($callback['classname'])) { |
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401 | $page = new $callback['classname']; |
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402 | |||
403 | // Named context |
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404 | if (method_exists($page, 'parseContext')) { |
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405 | $page->parseContext($callback['context'], $bits); |
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406 | |||
407 | // Default context |
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408 | View Code Duplication | } elseif (isset($bits[2])) { |
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409 | $callback['context'] = preg_split('/\//', $bits[2], -1, PREG_SPLIT_NO_EMPTY); |
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410 | } |
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411 | } |
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412 | |||
413 | /** |
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414 | * Immediately after determining which class will resolve the current page, this |
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415 | * delegate allows extension to modify the routing or provide additional information. |
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416 | * |
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417 | * @since Symphony 2.3.1 |
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418 | * @delegate AdminPagePostCallback |
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419 | * @param string $context |
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420 | * '/backend/' |
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421 | * @param string $page |
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422 | * The current URL string, after the SYMPHONY_URL constant (which is `/symphony/` |
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423 | * at the moment. |
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424 | * @param array $parts |
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425 | * An array representation of `$page` |
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426 | * @param array $callback |
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427 | * An associative array that contains `driver`, `pageroot`, `classname` and |
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428 | * `context` keys. The `driver_location` is the path to the class to render this |
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429 | * page, `driver` should be the view to render, the `classname` the name of the |
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430 | * class, `pageroot` the rootpage, before any extra URL params and `context` can |
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431 | * provide additional information about the page |
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432 | */ |
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433 | Symphony::ExtensionManager()->notifyMembers('AdminPagePostCallback', '/backend/', array( |
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434 | 'page' => $this->_currentPage, |
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435 | 'parts' => $bits, |
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436 | 'callback' => &$callback |
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437 | )); |
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438 | |||
439 | if (!isset($callback['driver_location']) || !is_file($callback['driver_location'])) { |
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440 | return false; |
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441 | } |
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442 | |||
443 | return $callback; |
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444 | } |
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445 | |||
446 | /** |
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447 | * If a page is not found in the Symphony backend, this function should |
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448 | * be called which will raise a customError to display the default Symphony |
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449 | * page not found template |
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450 | */ |
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451 | public function errorPageNotFound() |
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459 | |||
460 | /** |
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461 | * This function determines whether an administrative alert can be |
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462 | * displayed on the current page. It ensures that the page exists, |
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463 | * and the user is logged in and a developer |
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464 | * |
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465 | * @since Symphony 2.2 |
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466 | * @return boolean |
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467 | */ |
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468 | private function __canAccessAlerts() |
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476 | |||
477 | /** |
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478 | * Scan the install directory to look for new migrations that can be applied |
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479 | * to update this version of Symphony. If one if found, a new Alert is added |
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480 | * to the page. |
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481 | * |
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482 | * @since Symphony 2.5.2 |
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483 | * @return boolean |
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484 | * Returns true if there is an update available, false otherwise. |
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485 | */ |
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486 | public function checkCoreForUpdates() |
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514 | |||
515 | /** |
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516 | * Checks all installed extensions to see any have an outstanding update. If any do |
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517 | * an Alert will be added to the current page directing the Author to the Extension page |
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518 | * |
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519 | * @since Symphony 2.5.2 |
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520 | */ |
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521 | public function checkExtensionsForUpdates() |
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538 | } |
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539 |
If you define a variable conditionally, it can happen that it is not defined for all execution paths.
Let’s take a look at an example:
In the above example, the variable $x is defined if you pass “foo” or “bar” as argument for $a. However, since the switch statement has no default case statement, if you pass any other value, the variable $x would be undefined.
Available Fixes
Check for existence of the variable explicitly:
Define a default value for the variable:
Add a value for the missing path: