Complex classes like MySQLi 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 MySQLi, and based on these observations, apply Extract Interface, too.
1 | <?php |
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9 | class MySQLi extends _Abstract { |
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10 | /** |
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11 | * @var \MySQLi Instance of DB connection |
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12 | */ |
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13 | protected $instance; |
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14 | /** |
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15 | * @inheritdoc |
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16 | */ |
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17 | function __construct ($database, $user = '', $password = '', $host = 'localhost', $prefix = '') { |
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18 | $start = microtime(true); |
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19 | /** |
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20 | * Parsing of $host variable, detecting port and persistent connection |
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21 | */ |
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22 | list($host, $port) = $this->get_host_and_port($host); |
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23 | $this->instance = new \MySQLi($host, $user, $password, $database, $port); |
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24 | if (!is_object($this->instance) || $this->instance->connect_errno) { |
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25 | return; |
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26 | } |
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27 | $this->database = $database; |
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28 | /** |
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29 | * Changing DB charset if necessary |
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30 | */ |
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31 | if ($this->instance->character_set_name() != 'utf8mb4') { |
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32 | $this->instance->set_charset('utf8mb4'); |
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33 | } |
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34 | $this->connected = true; |
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35 | $this->connecting_time = microtime(true) - $start; |
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36 | $this->db_type = 'mysql'; |
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37 | $this->prefix = $prefix; |
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38 | } |
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39 | /** |
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40 | * Parse host string into host and port separately |
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41 | * |
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42 | * Understands `p:` prefix for persistent connections |
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43 | * |
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44 | * @param string $host_string |
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45 | * |
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46 | * @return array |
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47 | */ |
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48 | protected function get_host_and_port ($host_string) { |
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49 | $host = explode(':', $host_string); |
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50 | $port = ini_get('mysqli.default_port') ?: 3306; |
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51 | switch (count($host)) { |
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52 | case 1: |
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53 | $host = $host[0]; |
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54 | break; |
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55 | case 2: |
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56 | if ($host[0] == 'p') { |
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57 | $host = "$host[0]:$host[1]"; |
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58 | } else { |
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59 | list($host, $port) = $host; |
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60 | } |
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61 | break; |
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62 | case 3: |
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63 | $port = $host[2]; |
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64 | $host = "$host[0]:$host[1]"; |
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65 | } |
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66 | return [$host, $port]; |
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67 | } |
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68 | /** |
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69 | * @inheritdoc |
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70 | * |
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71 | * @return false|\mysqli_result |
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72 | */ |
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73 | protected function q_internal ($query) { |
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88 | /** |
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89 | * @inheritdoc |
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90 | */ |
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91 | protected function q_multi_internal ($query) { |
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98 | /** |
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99 | * @inheritdoc |
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100 | * |
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101 | * @param false|\mysqli_result $query_result |
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102 | */ |
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103 | function f ($query_result, $single_column = false, $array = false, $indexed = false) { |
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122 | /** |
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123 | * @inheritdoc |
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124 | */ |
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125 | function id () { |
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128 | /** |
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129 | * @inheritdoc |
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130 | */ |
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131 | function affected () { |
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134 | /** |
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135 | * @inheritdoc |
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136 | * |
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137 | * @param false|\mysqli_result $query_result |
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138 | */ |
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139 | function free ($query_result) { |
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145 | /** |
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146 | * @inheritdoc |
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147 | */ |
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148 | function columns ($table, $like = false) { |
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160 | /** |
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161 | * @inheritdoc |
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162 | */ |
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163 | function tables ($like = false) { |
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171 | /** |
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172 | * @inheritdoc |
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173 | */ |
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174 | protected function s_internal ($string, $single_quotes_around) { |
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178 | /** |
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179 | * @inheritdoc |
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180 | */ |
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181 | function server () { |
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184 | /** |
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185 | * @inheritdoc |
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186 | */ |
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187 | function __destruct () { |
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193 | } |
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194 |