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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| 54 | class Manager extends PublicEmitter implements IUserManager { |
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| 55 | /** |
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| 56 | * @var \OCP\UserInterface[] $backends |
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| 57 | */ |
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| 58 | private $backends = array(); |
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| 59 | |||
| 60 | /** |
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| 61 | * @var \OC\User\User[] $cachedUsers |
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| 62 | */ |
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| 63 | private $cachedUsers = array(); |
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| 64 | |||
| 65 | /** |
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| 66 | * @var \OCP\IConfig $config |
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| 67 | */ |
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| 68 | private $config; |
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| 69 | |||
| 70 | /** |
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| 71 | * @param \OCP\IConfig $config |
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| 72 | */ |
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| 73 | public function __construct(IConfig $config = null) { |
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| 89 | |||
| 90 | /** |
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| 91 | * Get the active backends |
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| 92 | * @return \OCP\UserInterface[] |
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| 93 | */ |
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| 94 | public function getBackends() { |
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| 97 | |||
| 98 | /** |
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| 99 | * register a user backend |
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| 100 | * |
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| 101 | * @param \OCP\UserInterface $backend |
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| 102 | */ |
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| 103 | public function registerBackend($backend) { |
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| 106 | |||
| 107 | /** |
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| 108 | * remove a user backend |
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| 109 | * |
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| 110 | * @param \OCP\UserInterface $backend |
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| 111 | */ |
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| 112 | public function removeBackend($backend) { |
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| 118 | |||
| 119 | /** |
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| 120 | * remove all user backends |
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| 121 | */ |
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| 122 | public function clearBackends() { |
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| 126 | |||
| 127 | /** |
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| 128 | * get a user by user id |
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| 129 | * |
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| 130 | * @param string $uid |
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| 131 | * @return \OC\User\User|null Either the user or null if the specified user does not exist |
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| 132 | */ |
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| 133 | public function get($uid) { |
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| 144 | |||
| 145 | /** |
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| 146 | * get or construct the user object |
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| 147 | * |
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| 148 | * @param string $uid |
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| 149 | * @param \OCP\UserInterface $backend |
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| 150 | * @param bool $cacheUser If false the newly created user object will not be cached |
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| 151 | * @return \OC\User\User |
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| 152 | */ |
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| 153 | protected function getUserObject($uid, $backend, $cacheUser = true) { |
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| 174 | |||
| 175 | /** |
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| 176 | * check if a user exists |
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| 177 | * |
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| 178 | * @param string $uid |
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| 179 | * @return bool |
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| 180 | */ |
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| 181 | public function userExists($uid) { |
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| 185 | |||
| 186 | /** |
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| 187 | * Check if the password is valid for the user |
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| 188 | * |
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| 189 | * @param string $loginName |
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| 190 | * @param string $password |
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| 191 | * @return mixed the User object on success, false otherwise |
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| 192 | */ |
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| 193 | public function checkPassword($loginName, $password) { |
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| 209 | |||
| 210 | /** |
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| 211 | * search by user id |
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| 212 | * |
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| 213 | * @param string $pattern |
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| 214 | * @param int $limit |
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| 215 | * @param int $offset |
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| 216 | * @return \OC\User\User[] |
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| 217 | */ |
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| 218 | View Code Duplication | public function search($pattern, $limit = null, $offset = null) { |
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| 238 | |||
| 239 | /** |
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| 240 | * search by displayName |
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| 241 | * |
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| 242 | * @param string $pattern |
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| 243 | * @param int $limit |
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| 244 | * @param int $offset |
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| 245 | * @return \OC\User\User[] |
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| 246 | */ |
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| 247 | View Code Duplication | public function searchDisplayName($pattern, $limit = null, $offset = null) { |
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| 267 | |||
| 268 | /** |
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| 269 | * @param string $uid |
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| 270 | * @param string $password |
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| 271 | * @throws \Exception |
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| 272 | * @return bool|\OC\User\User the created user or false |
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| 273 | */ |
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| 274 | public function createUser($uid, $password) { |
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| 311 | |||
| 312 | /** |
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| 313 | * returns how many users per backend exist (if supported by backend) |
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| 314 | * |
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| 315 | * @return array an array of backend class as key and count number as value |
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| 316 | */ |
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| 317 | public function countUsers() { |
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| 338 | |||
| 339 | /** |
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| 340 | * The callback is executed for each user on each backend. |
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| 341 | * If the callback returns false no further users will be retrieved. |
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| 342 | * |
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| 343 | * @param \Closure $callback |
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| 344 | * @param string $search |
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| 345 | * @since 9.0.0 |
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| 346 | */ |
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| 347 | public function callForAllUsers(\Closure $callback, $search = '') { |
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| 367 | } |
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| 368 |
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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: