crate /
crate-pdo
Complex classes like PDO 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 PDO, and based on these observations, apply Extract Interface, too.
| 1 | <?php |
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| 29 | class PDO extends BasePDO implements PDOInterface |
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| 30 | { |
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| 31 | const VERSION = '0.4.0'; |
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| 32 | const DRIVER_NAME = 'crate'; |
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| 33 | |||
| 34 | const DSN_REGEX = '/^(?:crate:)(?:((?:[\w\d\.-]+:\d+\,?)+))\/?([\w]+)?$/'; |
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| 35 | |||
| 36 | const CRATE_ATTR_HTTP_BASIC_AUTH = 1000; |
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| 37 | /** |
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| 38 | * deprecated since version 0.4 |
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| 39 | * @deprecated |
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| 40 | */ |
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| 41 | const ATTR_HTTP_BASIC_AUTH = self::CRATE_ATTR_HTTP_BASIC_AUTH; |
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| 42 | const CRATE_ATTR_DEFAULT_SCHEMA = 1001; |
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| 43 | |||
| 44 | const PARAM_FLOAT = 6; |
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| 45 | const PARAM_DOUBLE = 7; |
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| 46 | const PARAM_LONG = 8; |
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| 47 | const PARAM_ARRAY = 9; |
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| 48 | const PARAM_OBJECT = 10; |
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| 49 | const PARAM_TIMESTAMP = 11; |
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| 50 | const PARAM_IP = 12; |
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| 51 | |||
| 52 | /** |
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| 53 | * @var array |
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| 54 | */ |
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| 55 | private $attributes = [ |
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| 56 | 'defaultFetchMode' => self::FETCH_BOTH, |
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| 57 | 'errorMode' => self::ERRMODE_SILENT, |
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| 58 | 'statementClass' => 'Crate\PDO\PDOStatement', |
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| 59 | 'timeout' => 5.0, |
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| 60 | 'auth' => [], |
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| 61 | 'defaultSchema' => 'doc' |
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| 62 | ]; |
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| 63 | |||
| 64 | /** |
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| 65 | * @var Http\ClientInterface |
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| 66 | */ |
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| 67 | private $client; |
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| 68 | |||
| 69 | /** |
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| 70 | * @var PDOStatement|null |
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| 71 | */ |
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| 72 | private $lastStatement; |
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| 73 | |||
| 74 | /** |
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| 75 | * @var callable |
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| 76 | */ |
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| 77 | private $request; |
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| 78 | |||
| 79 | /** |
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| 80 | * {@inheritDoc} |
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| 81 | * |
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| 82 | * @param string $dsn The HTTP endpoint to call |
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| 83 | * @param null $username Unused |
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| 84 | * @param null $passwd Unused |
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| 85 | * @param null|array $options Attributes to set on the PDO |
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| 86 | */ |
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| 87 | 4 | public function __construct($dsn, $username, $passwd, $options) |
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| 88 | { |
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| 89 | 4 | foreach (ArrayUtils::toArray($options) as $attribute => $value) { |
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| 90 | 1 | $this->setAttribute($attribute, $value); |
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| 91 | 4 | } |
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| 92 | |||
| 93 | 4 | $dsnParts = self::parseDSN($dsn); |
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| 94 | 4 | $servers = self::serversFromDsnParts($dsnParts); |
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| 95 | |||
| 96 | 4 | $this->client = new Http\Client($servers, [ |
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| 97 | 4 | 'timeout' => $this->attributes['timeout'] |
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| 98 | 4 | ]); |
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| 99 | |||
| 100 | 4 | if (!empty($username) && !empty($passwd)) { |
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| 101 | 1 | $this->setAttribute(PDO::CRATE_ATTR_HTTP_BASIC_AUTH, [$username, $passwd]); |
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| 102 | 1 | } |
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| 103 | |||
| 104 | 4 | if (!empty($dsnParts[1])) { |
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| 105 | $this->setAttribute(PDO::CRATE_ATTR_DEFAULT_SCHEMA, $dsnParts[1]); |
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| 106 | } |
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| 107 | |||
| 108 | // Define a callback that will be used in the PDOStatements |
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| 109 | // This way we don't expose this as a public api to the end users. |
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| 110 | $this->request = function (PDOStatement $statement, $sql, array $parameters) { |
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| 111 | |||
| 112 | $this->lastStatement = $statement; |
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| 113 | |||
| 114 | try { |
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| 115 | |||
| 116 | return $this->client->execute($sql, $parameters); |
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| 117 | |||
| 118 | } catch (Exception\RuntimeException $e) { |
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| 119 | |||
| 120 | if ($this->getAttribute(PDO::ATTR_ERRMODE) === PDO::ERRMODE_EXCEPTION) { |
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| 121 | throw new Exception\PDOException($e->getMessage(), $e->getCode()); |
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| 122 | } |
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| 123 | |||
| 124 | if ($this->getAttribute(PDO::ATTR_ERRMODE) === PDO::ERRMODE_WARNING) { |
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| 125 | trigger_error(sprintf('[%d] %s', $e->getCode(), $e->getMessage()), E_USER_WARNING); |
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| 126 | } |
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| 127 | |||
| 128 | // should probably wrap this in a error object ? |
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| 129 | return [ |
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| 130 | 'code' => $e->getCode(), |
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| 131 | 'message' => $e->getMessage() |
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| 132 | ]; |
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| 133 | } |
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| 134 | }; |
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| 135 | 4 | } |
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| 136 | |||
| 137 | /** |
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| 138 | * Extract servers and optional custom schema from DSN string |
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| 139 | * |
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| 140 | * @param string $dsn The DSN string |
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| 141 | * |
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| 142 | * @return array An array of ['host:post,host:port,...', 'schema'] |
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| 143 | */ |
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| 144 | 36 | private static function parseDSN($dsn) |
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| 145 | { |
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| 146 | 36 | $matches = array(); |
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| 147 | |||
| 148 | 36 | if (!preg_match(static::DSN_REGEX, $dsn, $matches)) { |
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| 149 | 4 | throw new PDOException(sprintf('Invalid DSN %s', $dsn)); |
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| 150 | } |
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| 151 | |||
| 152 | 32 | return array_slice($matches, 1); |
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| 153 | } |
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| 154 | |||
| 155 | /** |
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| 156 | * Extract host:port pairs out of the DSN parts |
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| 157 | * |
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| 158 | * @param array $dsnParts The parts of the parsed DSN string |
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| 159 | * |
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| 160 | * @return array An array of host:port strings |
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| 161 | */ |
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| 162 | 31 | private static function serversFromDsnParts($dsnParts) |
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| 163 | { |
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| 164 | 31 | return explode(',', trim($dsnParts[0], ',')); |
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| 165 | } |
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| 166 | |||
| 167 | /** |
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| 168 | * {@inheritDoc} |
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| 169 | */ |
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| 170 | 1 | public function prepare($statement, $options = null) |
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| 171 | { |
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| 172 | 1 | $options = ArrayUtils::toArray($options); |
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| 173 | |||
| 174 | 1 | if (isset($options[PDO::ATTR_CURSOR])) { |
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| 175 | trigger_error(sprintf('%s not supported', __METHOD__), E_USER_WARNING); |
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| 176 | return true; |
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| 177 | } |
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| 178 | |||
| 179 | 1 | return new PDOStatement($this, $this->request, $statement, $options); |
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| 180 | } |
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| 181 | |||
| 182 | /** |
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| 183 | * {@inheritDoc} |
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| 184 | */ |
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| 185 | 1 | public function beginTransaction() |
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| 189 | |||
| 190 | /** |
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| 191 | * {@inheritDoc} |
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| 192 | */ |
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| 193 | 1 | public function commit() |
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| 197 | |||
| 198 | /** |
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| 199 | * {@inheritDoc} |
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| 200 | */ |
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| 201 | 1 | public function rollBack() |
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| 205 | |||
| 206 | /** |
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| 207 | * {@inheritDoc} |
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| 208 | */ |
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| 209 | 1 | public function inTransaction() |
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| 213 | |||
| 214 | /** |
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| 215 | * {@inheritDoc} |
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| 216 | */ |
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| 217 | public function exec($statement) |
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| 218 | { |
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| 219 | $statement = $this->prepare($statement); |
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| 220 | $result = $statement->execute(); |
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| 221 | |||
| 222 | return $result === false ? false : $statement->rowCount(); |
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| 223 | } |
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| 224 | |||
| 225 | /** |
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| 226 | * {@inheritDoc} |
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| 227 | */ |
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| 228 | public function query($statement) |
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| 229 | { |
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| 230 | $statement = $this->prepare($statement); |
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| 231 | $result = $statement->execute(); |
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| 232 | |||
| 233 | return $result === false ? false : $statement; |
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| 234 | } |
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| 235 | |||
| 236 | /** |
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| 237 | * {@inheritDoc} |
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| 238 | */ |
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| 239 | 1 | public function lastInsertId($name = null) |
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| 243 | |||
| 244 | /** |
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| 245 | * {@inheritDoc} |
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| 246 | */ |
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| 247 | public function errorCode() |
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| 251 | |||
| 252 | /** |
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| 253 | * {@inheritDoc} |
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| 254 | */ |
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| 255 | public function errorInfo() |
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| 259 | |||
| 260 | /** |
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| 261 | * {@inheritDoc} |
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| 262 | */ |
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| 263 | 6 | public function setAttribute($attribute, $value) |
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| 264 | { |
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| 265 | switch ($attribute) { |
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| 266 | 6 | case self::ATTR_DEFAULT_FETCH_MODE: |
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| 267 | 1 | $this->attributes['defaultFetchMode'] = $value; |
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| 268 | 1 | break; |
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| 269 | |||
| 270 | 5 | case self::ATTR_ERRMODE: |
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| 271 | 1 | $this->attributes['errorMode'] = $value; |
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| 272 | 1 | break; |
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| 273 | |||
| 274 | 4 | case self::ATTR_TIMEOUT: |
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| 275 | 1 | $this->attributes['timeout'] = (int)$value; |
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| 276 | 1 | if (is_object($this->client)) { |
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| 277 | 1 | $this->client->setTimeout((int)$value); |
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| 278 | 1 | } |
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| 279 | 1 | break; |
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| 280 | |||
| 281 | 3 | case self::CRATE_ATTR_HTTP_BASIC_AUTH: |
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| 282 | 1 | $this->attributes['auth'] = $value; |
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| 283 | 1 | if (is_object($this->client) && is_array($value)) { |
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| 284 | 1 | list($user, $password) = $value; |
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| 285 | 1 | $this->client->setHttpBasicAuth($user, $password); |
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| 286 | 1 | } |
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| 287 | 1 | break; |
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| 288 | |||
| 289 | 2 | case self::CRATE_ATTR_DEFAULT_SCHEMA: |
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| 290 | 1 | $this->attributes['defaultSchema'] = $value; |
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| 291 | 1 | if (is_object($this->client)) { |
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| 292 | 1 | $this->client->setDefaultSchema($value); |
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| 293 | 1 | } |
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| 294 | 1 | break; |
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| 295 | |||
| 296 | 1 | default: |
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| 297 | 1 | throw new Exception\PDOException('Unsupported driver attribute'); |
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| 298 | 1 | } |
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| 299 | 5 | } |
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| 300 | |||
| 301 | /** |
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| 302 | * {@inheritDoc} |
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| 303 | */ |
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| 304 | 9 | public function getAttribute($attribute) |
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| 305 | { |
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| 306 | switch ($attribute) { |
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| 307 | 9 | case PDO::ATTR_PERSISTENT: |
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| 308 | 1 | return false; |
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| 309 | |||
| 310 | 8 | case PDO::ATTR_PREFETCH: |
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| 311 | 1 | return false; |
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| 312 | |||
| 313 | 7 | case PDO::ATTR_CLIENT_VERSION: |
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| 314 | 1 | return self::VERSION; |
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| 315 | |||
| 316 | 6 | case PDO::ATTR_SERVER_VERSION: |
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| 317 | return $this->client->getServerVersion(); |
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| 318 | |||
| 319 | 6 | case PDO::ATTR_SERVER_INFO: |
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| 320 | return $this->client->getServerInfo(); |
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| 321 | |||
| 322 | 6 | case PDO::ATTR_TIMEOUT: |
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| 323 | 1 | return $this->attributes['timeout']; |
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| 324 | |||
| 325 | 5 | case PDO::CRATE_ATTR_HTTP_BASIC_AUTH: |
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| 326 | return $this->attributes['auth']; |
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| 327 | |||
| 328 | 5 | case PDO::ATTR_DEFAULT_FETCH_MODE: |
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| 329 | 1 | return $this->attributes['defaultFetchMode']; |
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| 330 | |||
| 331 | 4 | case PDO::ATTR_ERRMODE: |
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| 332 | 1 | return $this->attributes['errorMode']; |
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| 333 | |||
| 334 | 3 | case PDO::ATTR_DRIVER_NAME: |
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| 335 | 1 | return static::DRIVER_NAME; |
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| 336 | |||
| 337 | 2 | case PDO::ATTR_STATEMENT_CLASS: |
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| 338 | return [$this->attributes['statementClass']]; |
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| 339 | |||
| 340 | 2 | case PDO::CRATE_ATTR_DEFAULT_SCHEMA: |
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| 341 | return $this->attributes['defaultSchema']; |
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| 342 | |||
| 343 | 2 | default: |
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| 344 | // PHP Switch is a lose comparison |
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| 345 | 2 | if ($attribute === PDO::ATTR_AUTOCOMMIT) { |
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| 346 | 1 | return true; |
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| 347 | } |
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| 348 | |||
| 349 | 1 | throw new Exception\PDOException('Unsupported driver attribute'); |
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| 350 | 2 | } |
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| 351 | } |
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| 352 | |||
| 353 | /** |
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| 354 | * {@inheritDoc} |
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| 355 | */ |
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| 356 | 4 | public function quote($string, $parameter_type = PDO::PARAM_STR) |
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| 357 | { |
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| 358 | switch ($parameter_type) { |
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| 359 | 4 | case PDO::PARAM_INT: |
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| 360 | 1 | return (int)$string; |
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| 361 | |||
| 362 | 4 | case PDO::PARAM_BOOL: |
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| 363 | 1 | return (bool)$string; |
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| 364 | |||
| 365 | 4 | case PDO::PARAM_NULL: |
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| 366 | 1 | return null; |
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| 367 | |||
| 368 | 3 | case PDO::PARAM_LOB: |
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| 369 | 1 | throw new Exception\UnsupportedException('This is not supported by crate.io'); |
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| 370 | |||
| 371 | 2 | case PDO::PARAM_STR: |
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| 372 | 1 | throw new Exception\UnsupportedException('This is not supported, please use prepared statements.'); |
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| 373 | |||
| 374 | 1 | default: |
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| 375 | 1 | throw new Exception\InvalidArgumentException('Unknown param type'); |
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| 376 | 1 | } |
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| 377 | } |
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| 378 | |||
| 379 | /** |
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| 380 | * {@inheritDoc} |
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| 381 | */ |
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| 382 | 1 | public static function getAvailableDrivers() |
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| 386 | } |
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| 387 |
Loading history...
If you return a value from a function or method, it should be a sub-type of the type that is given by the parent type f.e. an interface, or abstract method. This is more formally defined by the Lizkov substitution principle, and guarantees that classes that depend on the parent type can use any instance of a child type interchangably. This principle also belongs to the SOLID principles for object oriented design.
Let’s take a look at an example:
Our function
my_functionexpects aPostobject, and outputs the author of the post. The base classPostreturns a simple string and outputting a simple string will work just fine. However, the child classBlogPostwhich is a sub-type ofPostinstead decided to return anobject, and is therefore violating the SOLID principles. If aBlogPostwere passed tomy_function, PHP would not complain, but ultimately fail when executing thestrtouppercall in its body.