nextcloud /
server
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 Manager 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 Manager, and based on these observations, apply Extract Interface, too.
| 1 | <?php |
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| 56 | class Manager extends PublicEmitter implements IUserManager { |
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| 57 | /** |
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| 58 | * @var \OCP\UserInterface[] $backends |
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| 59 | */ |
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| 60 | private $backends = array(); |
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| 61 | |||
| 62 | /** |
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| 63 | * @var \OC\User\User[] $cachedUsers |
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| 64 | */ |
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| 65 | private $cachedUsers = array(); |
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| 66 | |||
| 67 | /** |
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| 68 | * @var \OCP\IConfig $config |
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| 69 | */ |
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| 70 | private $config; |
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| 71 | |||
| 72 | /** |
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| 73 | * @param \OCP\IConfig $config |
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| 74 | */ |
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| 75 | public function __construct(IConfig $config = null) { |
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| 91 | |||
| 92 | /** |
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| 93 | * Get the active backends |
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| 94 | * @return \OCP\UserInterface[] |
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| 95 | */ |
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| 96 | public function getBackends() { |
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| 99 | |||
| 100 | /** |
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| 101 | * register a user backend |
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| 102 | * |
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| 103 | * @param \OCP\UserInterface $backend |
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| 104 | */ |
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| 105 | public function registerBackend($backend) { |
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| 108 | |||
| 109 | /** |
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| 110 | * remove a user backend |
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| 111 | * |
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| 112 | * @param \OCP\UserInterface $backend |
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| 113 | */ |
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| 114 | public function removeBackend($backend) { |
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| 120 | |||
| 121 | /** |
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| 122 | * remove all user backends |
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| 123 | */ |
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| 124 | public function clearBackends() { |
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| 128 | |||
| 129 | /** |
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| 130 | * get a user by user id |
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| 131 | * |
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| 132 | * @param string $uid |
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| 133 | * @return \OC\User\User|null Either the user or null if the specified user does not exist |
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| 134 | */ |
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| 135 | public function get($uid) { |
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| 146 | |||
| 147 | /** |
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| 148 | * get or construct the user object |
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| 149 | * |
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| 150 | * @param string $uid |
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| 151 | * @param \OCP\UserInterface $backend |
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| 152 | * @param bool $cacheUser If false the newly created user object will not be cached |
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| 153 | * @return \OC\User\User |
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| 154 | */ |
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| 155 | protected function getUserObject($uid, $backend, $cacheUser = true) { |
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| 176 | |||
| 177 | /** |
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| 178 | * check if a user exists |
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| 179 | * |
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| 180 | * @param string $uid |
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| 181 | * @return bool |
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| 182 | */ |
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| 183 | public function userExists($uid) { |
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| 187 | |||
| 188 | /** |
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| 189 | * Check if the password is valid for the user |
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| 190 | * |
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| 191 | * @param string $loginName |
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| 192 | * @param string $password |
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| 193 | * @return mixed the User object on success, false otherwise |
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| 194 | */ |
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| 195 | public function checkPassword($loginName, $password) { |
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| 211 | |||
| 212 | /** |
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| 213 | * search by user id |
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| 214 | * |
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| 215 | * @param string $pattern |
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| 216 | * @param int $limit |
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| 217 | * @param int $offset |
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| 218 | * @return \OC\User\User[] |
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| 219 | */ |
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| 220 | View Code Duplication | public function search($pattern, $limit = null, $offset = null) { |
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| 240 | |||
| 241 | /** |
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| 242 | * search by displayName |
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| 243 | * |
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| 244 | * @param string $pattern |
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| 245 | * @param int $limit |
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| 246 | * @param int $offset |
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| 247 | * @return \OC\User\User[] |
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| 248 | */ |
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| 249 | View Code Duplication | public function searchDisplayName($pattern, $limit = null, $offset = null) { |
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| 269 | |||
| 270 | /** |
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| 271 | * @param string $uid |
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| 272 | * @param string $password |
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| 273 | * @throws \Exception |
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| 274 | * @return bool|\OC\User\User the created user or false |
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| 275 | */ |
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| 276 | public function createUser($uid, $password) { |
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| 313 | |||
| 314 | /** |
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| 315 | * returns how many users per backend exist (if supported by backend) |
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| 316 | * |
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| 317 | * @return array an array of backend class as key and count number as value |
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| 318 | */ |
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| 319 | public function countUsers() { |
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| 340 | |||
| 341 | /** |
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| 342 | * The callback is executed for each user on each backend. |
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| 343 | * If the callback returns false no further users will be retrieved. |
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| 344 | * |
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| 345 | * @param \Closure $callback |
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| 346 | * @param string $search |
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| 347 | * @since 9.0.0 |
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| 348 | */ |
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| 349 | public function callForAllUsers(\Closure $callback, $search = '') { |
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| 369 | |||
| 370 | /** |
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| 371 | * @param string $email |
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| 372 | * @return IUser[] |
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| 373 | * @since 9.1.0 |
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| 374 | */ |
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| 375 | public function getByEmail($email) { |
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| 382 | } |
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| 383 |
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Let’s take a look at an example:
In the above example, the authenticate() method works fine as long as you just pass instances of MyUser. However, if you now also want to pass a different implementation of User which does not have a getDisplayName() method, the code will break.
Available Fixes
Change the type-hint for the parameter:
Add an additional type-check:
Add the method to the interface: