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 WordPress_GitHub_Sync_Database 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 WordPress_GitHub_Sync_Database, and based on these observations, apply Extract Interface, too.
1 | <?php |
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10 | class WordPress_GitHub_Sync_Database { |
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11 | |||
12 | /** |
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13 | * Application container. |
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14 | * |
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15 | * @var WordPress_GitHub_Sync |
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16 | */ |
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17 | protected $app; |
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18 | |||
19 | /** |
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20 | * Currently whitelisted post types. |
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21 | * |
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22 | * @var array |
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23 | */ |
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24 | protected $whitelisted_post_types = array( 'post', 'page' ); |
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25 | |||
26 | /** |
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27 | * Currently whitelisted post statuses. |
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28 | * |
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29 | * @var array |
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30 | */ |
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31 | protected $whitelisted_post_statuses = array( 'publish' ); |
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32 | |||
33 | /** |
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34 | * Instantiates a new Database object. |
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35 | * |
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36 | * @param WordPress_GitHub_Sync $app Application container. |
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37 | */ |
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38 | 22 | public function __construct( WordPress_GitHub_Sync $app ) { |
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41 | |||
42 | /** |
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43 | * Queries the database for all of the supported posts. |
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44 | * |
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45 | * @return WordPress_GitHub_Sync_Post[]|WP_Error |
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46 | */ |
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47 | 3 | public function fetch_all_supported() { |
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73 | |||
74 | /** |
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75 | * Queries a post and returns it if it's supported. |
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76 | * |
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77 | * @param int $post_id Post ID to fetch. |
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78 | * |
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79 | * @return WP_Error|WordPress_GitHub_Sync_Post |
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80 | */ |
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81 | 5 | public function fetch_by_id( $post_id ) { |
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99 | |||
100 | /** |
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101 | * Queries for a post by provided sha. |
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102 | * |
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103 | * @param string $sha Post sha to fetch by. |
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104 | * |
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105 | * @return WordPress_GitHub_Sync_Post|WP_Error |
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106 | */ |
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107 | 2 | public function fetch_by_sha( $sha ) { |
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134 | |||
135 | /** |
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136 | * Saves an array of Post objects to the database |
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137 | * and associates their author as well as their latest |
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138 | * |
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139 | * @param WordPress_GitHub_Sync_Post[] $posts Array of Posts to save. |
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140 | * @param string $email Author email. |
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141 | * |
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142 | * @return string|WP_Error |
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143 | */ |
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144 | 6 | public function save_posts( array $posts, $email ) { |
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196 | |||
197 | /** |
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198 | * Deletes a post from the database based on its GitHub path. |
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199 | * |
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200 | * @param string $path Path of Post to delete. |
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201 | * |
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202 | * @return string|WP_Error |
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203 | */ |
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204 | 5 | public function delete_post_by_path( $path ) { |
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286 | |||
287 | /** |
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288 | * Returns the list of post type permitted. |
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289 | * |
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290 | * @return array |
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291 | */ |
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292 | 10 | protected function get_whitelisted_post_types() { |
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295 | |||
296 | /** |
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297 | * Returns the list of post status permitted. |
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298 | * |
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299 | * @return array |
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300 | */ |
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301 | 7 | protected function get_whitelisted_post_statuses() { |
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304 | |||
305 | /** |
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306 | * Formats a whitelist array for a query. |
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307 | * |
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308 | * @param array $whitelist Whitelisted posts to format into query. |
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309 | * |
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310 | * @return string Whitelist formatted for query |
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311 | */ |
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312 | protected function format_for_query( $whitelist ) { |
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319 | |||
320 | /** |
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321 | * Verifies that both the post's status & type |
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322 | * are currently whitelisted |
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323 | * |
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324 | * @param WordPress_GitHub_Sync_Post $post Post to verify. |
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325 | * |
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326 | * @return boolean True if supported, false if not. |
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327 | */ |
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328 | 5 | protected function is_post_supported( WordPress_GitHub_Sync_Post $post ) { |
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348 | |||
349 | /** |
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350 | * Retrieves the commit user for a provided email address. |
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351 | * |
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352 | * Searches for a user with provided email address or returns |
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353 | * the default user saved in the database. |
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354 | * |
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355 | * @param string $email User email address to search for. |
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356 | * |
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357 | * @return WP_Error|WP_User |
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358 | */ |
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359 | 6 | protected function fetch_commit_user( $email ) { |
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381 | |||
382 | /** |
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383 | * Sets the author latest revision |
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384 | * of the provided post ID to the provided user. |
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385 | * |
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386 | * @param int $post_id Post ID to update revision author. |
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387 | * @param int $user_id User ID for revision author. |
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388 | * |
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389 | * @return string|WP_Error |
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390 | */ |
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391 | 6 | protected function set_revision_author( $post_id, $user_id ) { |
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414 | |||
415 | /** |
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416 | * Updates the user ID for the provided post ID. |
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417 | * |
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418 | * Bypassing triggering any hooks, including creating new revisions. |
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419 | * |
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420 | * @param int $post_id Post ID to update. |
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421 | * @param int $user_id User ID to update to. |
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422 | * |
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423 | * @return string|WP_Error |
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424 | */ |
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425 | 6 | protected function set_post_author( $post_id, $user_id ) { |
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458 | |||
459 | /** |
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460 | * Update the provided post's blob sha. |
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461 | * |
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462 | * @param WordPress_GitHub_Sync_Post $post Post to update. |
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463 | * @param string $sha Sha to update to. |
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464 | * |
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465 | * @return bool|int |
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466 | */ |
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467 | 1 | public function set_post_sha( $post, $sha ) { |
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470 | } |
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471 |