mysociety /
theyworkforyou
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 Postcode 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 Postcode, and based on these observations, apply Extract Interface, too.
| 1 | <?php |
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| 9 | class Postcode |
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| 10 | { |
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| 11 | |||
| 12 | /** |
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| 13 | * Postcode To Constituency |
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| 14 | */ |
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| 15 | |||
| 16 | 2 | public static function postcodeToConstituency($postcode) { |
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| 19 | |||
| 20 | /** |
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| 21 | * Postcode To Constituencies |
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| 22 | */ |
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| 23 | |||
| 24 | 1 | public static function postcodeToConstituencies($postcode) { |
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| 27 | |||
| 28 | /** |
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| 29 | * Postcode To Constituencies (Internal) |
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| 30 | * |
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| 31 | * @param boolean $mp_only |
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| 32 | */ |
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| 33 | |||
| 34 | 3 | private static function postcodeToConstituenciesInternal($postcode, $mp_only) { |
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| 35 | 3 | global $last_postcode, $last_postcode_value; |
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| 36 | |||
| 37 | 3 | $postcode = preg_replace('#[^a-z0-9]#i', '', $postcode); |
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| 38 | 3 | $postcode = self::canonicalisePostcode($postcode); |
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| 39 | |||
| 40 | 3 | if ($last_postcode == $postcode) { |
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| 41 | 1 | $return_value = $mp_only ? $last_postcode_value['WMC'] : $last_postcode_value; |
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| 42 | 1 | twfy_debug ("TIME", "Postcode $postcode looked up last time, is " . ( is_array($return_value) ? implode(', ', $return_value) : $return_value )); |
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| 43 | 1 | return $return_value; |
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| 44 | } |
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| 45 | |||
| 46 | 3 | if (!validate_postcode($postcode)) { |
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| 47 | 1 | return ''; |
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| 48 | } |
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| 49 | |||
| 50 | 2 | $ret = self::postcodeFetchFromDb($postcode); |
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| 51 | 2 | if (!$ret) { |
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| 52 | $ret = self::postcodeFetchFromMapit($postcode); |
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| 53 | } |
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| 54 | |||
| 55 | 2 | if (is_string($ret)) return $ret; |
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| 56 | |||
| 57 | 2 | $last_postcode = $postcode; |
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| 58 | 2 | $last_postcode_value = $ret; |
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| 59 | 2 | return $mp_only ? $ret['WMC'] : $ret; |
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| 60 | } |
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| 61 | |||
| 62 | /** |
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| 63 | * Fetch Postcode Information from DB |
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| 64 | * |
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| 65 | * @param string $postcode |
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| 66 | */ |
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| 67 | |||
| 68 | 2 | private static function postcodeFetchFromDb($postcode) { |
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| 89 | |||
| 90 | /** |
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| 91 | * Fetch Postcode Information from MapIt |
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| 92 | * |
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| 93 | * @param string $postcode |
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| 94 | */ |
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| 95 | |||
| 96 | private static function postcodeFetchFromMapit($postcode) { |
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| 97 | if (!defined('OPTION_MAPIT_URL') || !OPTION_MAPIT_URL) { |
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| 98 | return ''; |
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| 99 | } |
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| 100 | $filename = 'postcode/' . rawurlencode($postcode); |
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| 101 | $ch = curl_init(OPTION_MAPIT_URL . $filename); |
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| 102 | curl_setopt($ch, CURLOPT_RETURNTRANSFER, true); |
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| 103 | curl_setopt($ch, CURLOPT_CONNECTTIMEOUT, 20); |
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| 104 | curl_setopt($ch, CURLOPT_FOLLOWLOCATION, true); |
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| 105 | curl_setopt($ch, CURLOPT_TIMEOUT, 10); |
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| 106 | $file = curl_exec($ch); |
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| 107 | if (curl_errno($ch)) { |
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| 108 | $errno = curl_errno($ch); |
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| 109 | trigger_error("Postcode database: " . $errno . ' ' . curl_error($ch), E_USER_WARNING); |
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| 110 | return 'CONNECTION_TIMED_OUT'; |
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| 111 | } |
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| 112 | curl_close($ch); |
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| 113 | |||
| 114 | $r = json_decode($file, true); |
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| 115 | if (!$r) { |
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| 116 | trigger_error("Postcode database is not working. Content:\n".$file.", request: ". $filename, E_USER_WARNING); |
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| 117 | return ''; |
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| 118 | } |
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| 119 | if (isset($r['error']) || !isset($r['areas'])) { |
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| 120 | return ''; |
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| 121 | } |
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| 122 | $areas = array(); |
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| 123 | foreach ($r['areas'] as $row) { |
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| 124 | if (in_array($row['type'], array('WMC', 'SPC', 'SPE', 'NIE'))) |
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| 125 | $areas[$row['type']] = utf8_decode($row['name']); |
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| 126 | } |
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| 127 | |||
| 128 | if (!isset($areas['WMC'])) { |
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| 129 | return ''; |
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| 130 | } |
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| 131 | |||
| 132 | # Normalise name - assume SP and NI are already so... |
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| 133 | $normalised = Constituencies::normaliseConstituencyName(strtolower($areas['WMC'])); |
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| 134 | if ($normalised) { |
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| 135 | $areas['WMC'] = $normalised; |
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| 136 | if (self::postcodeIsScottish($postcode)) { |
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| 137 | $serialized = "$areas[WMC]|$areas[SPC]|$areas[SPE]"; |
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| 138 | } elseif (self::postcodeIsNi($postcode)) { |
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| 139 | $serialized = "$areas[WMC]|$areas[NIE]"; |
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| 140 | } else { |
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| 141 | $serialized = $normalised; |
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| 142 | } |
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| 143 | $db = new \ParlDB; |
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| 144 | $db->query('replace into postcode_lookup values(:postcode, :serialized)', |
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| 145 | array( |
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| 146 | ':postcode' => $postcode, |
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| 147 | ':serialized' => $serialized |
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| 148 | )); |
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| 149 | } else { |
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| 150 | return ''; |
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| 151 | } |
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| 152 | |||
| 153 | return $areas; |
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| 154 | } |
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| 155 | |||
| 156 | /** |
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| 157 | * Canonicalise Postcode |
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| 158 | * |
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| 159 | * Take a postcode and turn it into a tidied, uppercased canonical version. |
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| 160 | */ |
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| 161 | |||
| 162 | 6 | public static function canonicalisePostcode($pc) { |
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| 169 | |||
| 170 | /** |
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| 171 | * Is Postcode Scottish? |
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| 172 | */ |
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| 173 | |||
| 174 | 3 | public static function postcodeIsScottish($pc) { |
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| 211 | |||
| 212 | /** |
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| 213 | * Is Postcode Northern Irish? |
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| 214 | */ |
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| 215 | |||
| 216 | 3 | public static function postcodeIsNi($pc) { |
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| 222 | |||
| 223 | } |
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| 224 | |||
| 225 |
