Complex classes like FileCache 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 FileCache, and based on these observations, apply Extract Interface, too.
1 | <?php |
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22 | class FileCache implements CacheInterface, CounterInterface |
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23 | { |
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24 | // TODO garbage collection |
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25 | |||
26 | /** |
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27 | * @var string control characters for keys, reserved by PSR-16 |
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28 | */ |
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29 | const PSR16_RESERVED = '/\{|\}|\(|\)|\/|\\\\|\@|\:/u'; |
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30 | |||
31 | /** |
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32 | * @var string |
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33 | */ |
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34 | private $cache_path; |
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35 | |||
36 | /** |
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37 | * @var int |
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38 | */ |
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39 | private $default_ttl; |
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40 | |||
41 | /** |
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42 | * @param string $cache_path absolute root path of cache-file folder |
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43 | * @param int $default_ttl default time-to-live (in seconds) |
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44 | * |
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45 | * @throws InvalidArgumentException if the specified cache-path does not exist (or is not writable) |
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46 | */ |
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47 | 13 | public function __construct($cache_path, $default_ttl) |
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48 | { |
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49 | 13 | if (! file_exists($cache_path) && file_exists(dirname($cache_path))) { |
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50 | 13 | @mkdir($cache_path, 0777, true); // ensure that the parent path exists |
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51 | } |
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52 | |||
53 | 13 | $path = realpath($cache_path); |
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54 | |||
55 | 13 | if ($path === false) { |
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56 | throw new InvalidArgumentException("cache path does not exist: {$cache_path}"); |
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57 | } |
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58 | |||
59 | 13 | if (! is_writable($path . DIRECTORY_SEPARATOR)) { |
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60 | throw new InvalidArgumentException("cache path is not writable: {$cache_path}"); |
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61 | } |
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62 | |||
63 | 13 | $this->cache_path = $path; |
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64 | 13 | $this->default_ttl = $default_ttl; |
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65 | 13 | } |
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66 | |||
67 | 12 | public function get($key, $default = null) |
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68 | { |
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69 | 12 | $path = $this->getPath($key); |
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70 | |||
71 | 12 | $expires_at = @filemtime($path); |
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72 | |||
73 | 12 | if ($expires_at === false) { |
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74 | 11 | return $default; // file not found |
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75 | } |
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76 | |||
77 | 10 | if ($this->getTime() >= $expires_at) { |
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78 | 4 | @unlink($path); // file expired |
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79 | |||
80 | 4 | return $default; |
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81 | } |
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82 | |||
83 | 9 | $data = @file_get_contents($path); |
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84 | |||
85 | 9 | if ($data === false) { |
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86 | return $default; // race condition: file not found |
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87 | } |
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88 | |||
89 | 9 | if ($data === 'b:0;') { |
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90 | return false; // because we can't otherwise distinguish a FALSE return-value from unserialize() |
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91 | } |
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92 | |||
93 | 9 | $value = @unserialize($data); |
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94 | |||
95 | 9 | if ($value === false) { |
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96 | return $default; // unserialize() failed |
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97 | } |
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98 | |||
99 | 9 | return $value; |
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100 | } |
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101 | |||
102 | 12 | public function set($key, $value, $ttl = null) |
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103 | { |
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104 | 12 | $path = $this->getPath($key); |
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105 | |||
106 | 12 | $dir = dirname($path); |
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107 | |||
108 | 12 | if (! file_exists($dir)) { |
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109 | 10 | @mkdir($dir, 0777, true); // ensure that the parent path exists |
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110 | } |
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111 | |||
112 | 12 | $temp_path = $this->cache_path . DIRECTORY_SEPARATOR . uniqid('', true); |
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113 | |||
114 | 12 | if (is_int($ttl)) { |
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115 | 3 | $expires_at = $this->getTime() + $ttl; |
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116 | } elseif ($ttl instanceof DateInterval) { |
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117 | 1 | $expires_at = date_create_from_format("U", $this->getTime())->add($ttl)->getTimestamp(); |
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118 | 8 | } elseif ($ttl === null) { |
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119 | 8 | $expires_at = $this->getTime() + $this->default_ttl; |
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120 | } else { |
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121 | throw new InvalidArgumentException("invalid TTL: " . print_r($ttl, true)); |
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122 | } |
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123 | |||
124 | 12 | if (false === @file_put_contents($temp_path, serialize($value))) { |
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125 | return false; |
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126 | } |
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127 | |||
128 | 12 | if (@touch($temp_path, $expires_at) && @rename($temp_path, $path)) { |
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129 | 12 | return true; |
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130 | } |
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131 | |||
132 | @unlink($temp_path); |
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133 | |||
134 | return false; |
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135 | } |
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136 | |||
137 | 2 | public function delete($key) |
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138 | { |
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139 | 2 | @unlink($this->getPath($key)); |
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140 | 2 | } |
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141 | |||
142 | 13 | public function clear() |
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143 | { |
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144 | 13 | $paths = $this->listPaths(); |
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145 | |||
146 | 13 | foreach ($paths as $path) { |
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147 | 8 | @unlink($path); |
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148 | } |
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149 | 13 | } |
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150 | |||
151 | 2 | public function getMultiple($keys) |
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152 | { |
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153 | 2 | $values = []; |
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154 | |||
155 | 2 | foreach ($keys as $key) { |
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156 | 2 | $values[$key] = $this->get($key); |
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157 | } |
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158 | |||
159 | 2 | return $values; |
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160 | } |
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161 | |||
162 | 2 | public function setMultiple($items, $ttl = null) |
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163 | { |
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164 | 2 | $ok = true; |
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165 | |||
166 | 2 | foreach ($items as $key => $value) { |
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167 | 2 | $ok = $this->set($key, $value, $ttl) && $ok; |
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168 | } |
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169 | |||
170 | 2 | return $ok; |
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171 | } |
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172 | |||
173 | 1 | public function deleteMultiple($keys) |
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174 | { |
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175 | 1 | foreach ($keys as $key) { |
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176 | 1 | $this->delete($key); |
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177 | } |
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178 | 1 | } |
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179 | |||
180 | 1 | public function has($key) |
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181 | { |
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182 | 1 | return $this->get($key, $this) !== $this; |
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183 | } |
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184 | |||
185 | 2 | public function increment($key, $step = 1) |
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186 | { |
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187 | 2 | $path = $this->getPath($key); |
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188 | |||
189 | 2 | $dir = dirname($path); |
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190 | |||
191 | 2 | if (! file_exists($dir)) { |
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192 | 2 | @mkdir($dir, 0777, true); // ensure that the parent path exists |
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193 | } |
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194 | |||
195 | 2 | $lock_path = $dir . DIRECTORY_SEPARATOR . ".lock"; // allows max. 256 client locks at one time |
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196 | |||
197 | 2 | $lock_handle = fopen($lock_path, "w"); |
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198 | |||
199 | 2 | flock($lock_handle, LOCK_EX); |
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200 | |||
201 | 2 | $value = $this->get($key, 0) + $step; |
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202 | |||
203 | 2 | $ok = $this->set($key, $value); |
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204 | |||
205 | 2 | flock($lock_handle, LOCK_UN); |
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206 | |||
207 | 2 | return $ok ? $value : false; |
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208 | } |
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209 | |||
210 | 1 | public function decrement($key, $step = 1) |
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211 | { |
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212 | 1 | return $this->increment($key, -$step); |
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213 | } |
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214 | |||
215 | /** |
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216 | * Clean up expired cache-files. |
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217 | * |
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218 | * This method is outside the scope of the PSR-16 cache concept, and is specific to |
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219 | * this implementation, being a file-cache. |
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220 | * |
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221 | * In scenarios with dynamic keys (such as Session IDs) you should call this method |
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222 | * periodically - for example from a scheduled daily cron-job. |
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223 | * |
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224 | * @return void |
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225 | */ |
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226 | 1 | public function cleanExpired() |
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227 | { |
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228 | 1 | $now = $this->getTime(); |
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229 | |||
230 | 1 | $paths = $this->listPaths(); |
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231 | |||
232 | 1 | foreach ($paths as $path) { |
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233 | 1 | if ($now > filemtime($path)) { |
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234 | 1 | @unlink($path); |
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235 | } |
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236 | } |
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237 | 1 | } |
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238 | |||
239 | /** |
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240 | * For a given cache key, obtain the absolute file path |
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241 | * |
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242 | * @param string $key |
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243 | * |
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244 | * @return string absolute path to cache-file |
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245 | * |
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246 | * @throws InvalidArgumentException if the specified key contains a character reserved by PSR-16 |
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247 | */ |
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248 | 13 | protected function getPath($key) |
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249 | { |
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250 | 13 | if (preg_match(self::PSR16_RESERVED, $key, $match) === 1) { |
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251 | throw new InvalidArgumentException("invalid character in key: {$match[0]}"); |
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252 | } |
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253 | |||
254 | 13 | $hash = hash("sha256", $key); |
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255 | |||
256 | 13 | return $this->cache_path |
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257 | 13 | . DIRECTORY_SEPARATOR |
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258 | 13 | . strtoupper($hash[0]) |
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259 | 13 | . DIRECTORY_SEPARATOR |
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260 | 13 | . strtoupper($hash[1]) |
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261 | 13 | . DIRECTORY_SEPARATOR |
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262 | 13 | . substr($hash, 2); |
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263 | } |
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264 | |||
265 | /** |
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266 | * @return int current timestamp |
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267 | */ |
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268 | 13 | protected function getTime() |
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272 | |||
273 | /** |
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274 | * @return Generator|string[] |
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275 | */ |
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276 | 13 | protected function listPaths() |
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277 | { |
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278 | 13 | $iterator = new RecursiveDirectoryIterator( |
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279 | 13 | $this->cache_path, |
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280 | 13 | FilesystemIterator::CURRENT_AS_PATHNAME | FilesystemIterator::SKIP_DOTS |
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281 | ); |
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282 | |||
283 | 13 | $iterator = new RecursiveIteratorIterator($iterator); |
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284 | |||
285 | 13 | foreach ($iterator as $path) { |
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293 | } |
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294 |
If you suppress an error, we recommend checking for the error condition explicitly: