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:
| 1 | <?php |
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| 5 | trait Language { |
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| 6 | |||
| 7 | /** |
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| 8 | * \addtogroup Localization Localization |
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| 9 | * @{ |
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| 10 | */ |
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| 11 | |||
| 12 | /** \brief Store the language for a multi-language bot */ |
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| 13 | public $language; |
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| 14 | |||
| 15 | /** \brief Table contaning bot users data in the sql database. */ |
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| 16 | public $user_table = '"User"'; |
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| 17 | |||
| 18 | /** \brief Name of the column that represents the user id in the sql database */ |
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| 19 | public $id_column = 'chat_id'; |
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| 20 | |||
| 21 | /** |
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| 22 | * \brief Get current user language from the database, and set it in $language. |
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| 23 | * @param $default_language <i>Optional</i>. Default language to return in case of errors. |
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| 24 | * @return Language set for the current user, $default_language on errors. |
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| 25 | */ |
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| 26 | public function getLanguageDatabase($default_language = 'en') { |
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| 75 | |||
| 76 | /** |
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| 77 | * \brief Get current user language from redis, as a cache, and set it in language. |
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| 78 | * \details Using redis database as cache, seeks the language in it, if there isn't |
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| 79 | * then get the language from the sql database and store it (with default expiring of one day) in redis. |
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| 80 | * It also change $language parameter of the bot to the language returned. |
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| 81 | * @param $default_language <i>Optional</i>. Default language to return in case of errors. |
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| 82 | * @param $expiring_time <i>Optional</i>. Set the expiring time for the language on redis each time it is took from the sql database. |
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| 83 | * @return Language for the current user, $default_language on errors. |
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| 84 | */ |
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| 85 | public function getLanguageRedis($default_language = 'en', $expiring_time = '86400') : string { |
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| 111 | |||
| 112 | /** |
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| 113 | * \brief Set the current user language in both redis, sql database and $language. |
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| 114 | * \details Save it on database first, then create the expiring key on redis. |
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| 115 | * @param $language The new language to set. |
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| 116 | * @param $expiring_time <i>Optional</i>. Time for the language key in redis to expire. |
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| 117 | * @return On sucess, return true, throw exception otherwise. |
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| 118 | */ |
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| 119 | public function setLanguageRedis($language, $expiring_time = '86400') { |
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| 151 | |||
| 152 | /** @} */ |
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| 153 | |||
| 154 | } |
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| 155 |
In PHP traits cannot be used for type-hinting as they do not define a well-defined structure. This is because any class that uses a trait can rename that trait’s methods.
If you would like to return an object that has a guaranteed set of methods, you could create a companion interface that lists these methods explicitly.