1 | <?php |
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31 | class SQLite3Cache extends CacheProvider |
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32 | { |
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33 | /** |
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34 | * The ID field will store the cache key. |
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35 | */ |
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36 | const ID_FIELD = 'k'; |
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37 | |||
38 | /** |
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39 | * The data field will store the serialized PHP value. |
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40 | */ |
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41 | const DATA_FIELD = 'd'; |
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42 | |||
43 | /** |
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44 | * The expiration field will store a date value indicating when the |
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45 | * cache entry should expire. |
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46 | */ |
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47 | const EXPIRATION_FIELD = 'e'; |
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48 | |||
49 | /** |
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50 | * @var SQLite3 |
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51 | */ |
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52 | private $sqlite; |
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53 | |||
54 | /** |
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55 | * @var string |
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56 | */ |
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57 | private $table; |
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58 | |||
59 | /** |
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60 | * Constructor. |
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61 | * |
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62 | * Calling the constructor will ensure that the database file and table |
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63 | * exist and will create both if they don't. |
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64 | * |
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65 | * @param SQLite3 $sqlite |
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66 | * @param string $table |
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67 | */ |
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68 | public function __construct(SQLite3 $sqlite, $table) |
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69 | { |
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70 | $this->sqlite = $sqlite; |
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71 | $this->table = (string) $table; |
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72 | |||
73 | list($id, $data, $exp) = $this->getFields(); |
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74 | |||
75 | return $this->sqlite->exec(sprintf( |
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76 | 'CREATE TABLE IF NOT EXISTS %s(%s TEXT PRIMARY KEY NOT NULL, %s BLOB, %s INTEGER)', |
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77 | $table, |
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78 | $id, |
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79 | $data, |
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80 | $exp |
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81 | )); |
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82 | } |
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83 | |||
84 | /** |
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85 | * {@inheritdoc} |
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86 | */ |
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87 | protected function doFetch($id) |
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88 | { |
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89 | $item = $this->findById($id) |
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90 | |||
91 | if (!$item) { |
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92 | return false; |
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93 | } |
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94 | |||
95 | return unserialize($item[self::DATA_FIELD]); |
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96 | } |
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97 | |||
98 | /** |
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99 | * {@inheritdoc} |
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100 | */ |
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101 | protected function doContains($id) |
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102 | { |
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103 | return null !== $this->findById($id, false); |
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104 | } |
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105 | |||
106 | /** |
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107 | * {@inheritdoc} |
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108 | */ |
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109 | protected function doSave($id, $data, $lifeTime = 0) |
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110 | { |
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111 | $statement = $this->sqlite->prepare(sprintf( |
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112 | 'INSERT OR REPLACE INTO %s (%s) VALUES (:id, :data, :expire)', |
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113 | $this->table, |
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114 | implode(',', $this->getFields()) |
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115 | )); |
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116 | |||
117 | $statement->bindValue(':id', $id); |
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118 | $statement->bindValue(':data', serialize($data), SQLITE3_BLOB); |
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119 | $statement->bindValue(':expire', $lifeTime > 0 ? time() + $lifeTime : null); |
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120 | |||
121 | return $statement->execute() instanceof SQLite3Result; |
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122 | } |
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123 | |||
124 | /** |
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125 | * {@inheritdoc} |
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126 | */ |
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127 | protected function doDelete($id) |
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128 | { |
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129 | list($idField) = $this->getFields(); |
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130 | |||
131 | $statement = $this->sqlite->prepare(sprintf( |
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132 | 'DELETE FROM %s WHERE %s = :id', |
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133 | $this->table, |
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134 | $idField |
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135 | )); |
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136 | |||
137 | $statement->bindValue(':id', $id); |
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138 | |||
139 | return $statement->execute() instanceof SQLite3Result; |
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140 | } |
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141 | |||
142 | /** |
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143 | * {@inheritdoc} |
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144 | */ |
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145 | protected function doFlush() |
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146 | { |
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147 | return $this->sqlite->exec(sprintf('DELETE FROM %s', $this->table)); |
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148 | } |
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149 | |||
150 | /** |
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151 | * {@inheritdoc} |
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152 | */ |
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153 | protected function doGetStats() |
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154 | { |
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155 | // no-op. |
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156 | } |
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157 | |||
158 | /** |
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159 | * Find a single row by ID. |
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160 | * |
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161 | * @param mixed $id |
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162 | * @param bool $includeData |
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163 | * |
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164 | * @return array|null |
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165 | */ |
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166 | private function findById($id, $includeData = true) |
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167 | { |
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168 | list($idField) = $fields = $this->getFields(); |
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169 | |||
170 | if (!$includeData) { |
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171 | $key = array_search(static::DATA_FIELD, $fields); |
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172 | unset($fields[$key]); |
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173 | } |
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174 | |||
175 | $statement = $this->sqlite->prepare(sprintf( |
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176 | 'SELECT %s FROM %s WHERE %s = :id LIMIT 1', |
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177 | implode(',', $fields), |
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178 | $this->table, |
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179 | $idField |
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180 | )); |
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181 | |||
182 | $statement->bindValue(':id', $id, SQLITE3_TEXT); |
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183 | |||
184 | $item = $statement->execute()->fetchArray(SQLITE3_ASSOC); |
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185 | |||
186 | if ($item === false) { |
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187 | return null; |
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188 | } |
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189 | |||
190 | if ($this->isExpired($item)) { |
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191 | $this->doDelete($id); |
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192 | |||
193 | return null; |
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194 | } |
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195 | |||
196 | return $item; |
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197 | } |
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198 | |||
199 | /** |
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200 | * Gets an array of the fields in our table. |
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201 | * |
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202 | * @return array |
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203 | */ |
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204 | private function getFields() |
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205 | { |
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206 | return [static::ID_FIELD, static::DATA_FIELD, static::EXPIRATION_FIELD]; |
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207 | } |
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208 | |||
209 | /** |
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210 | * Check if the item is expired. |
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211 | * |
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212 | * @param array $item |
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213 | * |
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214 | * @return bool |
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215 | */ |
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216 | private function isExpired(array $item) |
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217 | { |
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218 | return isset($item[static::EXPIRATION_FIELD]) && |
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219 | $item[self::EXPIRATION_FIELD] !== null && |
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220 | $item[self::EXPIRATION_FIELD] < time(); |
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221 | } |
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223 |