Complex classes like Parser 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 Parser, and based on these observations, apply Extract Interface, too.
| 1 | <?php |
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| 13 | class Parser { |
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| 14 | |||
| 15 | /** |
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| 16 | * @var ClientInterface |
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| 17 | */ |
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| 18 | private $client; |
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| 19 | |||
| 20 | /** |
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| 21 | * @var array |
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| 22 | */ |
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| 23 | private static $cache; |
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| 24 | |||
| 25 | /** |
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| 26 | * Constructor |
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| 27 | * @param ClientInterface $client HTTP Client |
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| 28 | */ |
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| 29 | public function __construct(ClientInterface $client) { |
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| 32 | |||
| 33 | /** |
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| 34 | * Parses a URL into a an array of metatags |
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| 35 | * |
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| 36 | * @param string $url URL to parse |
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| 37 | * @return array |
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| 38 | */ |
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| 39 | 1 | public function parse($url = '') { |
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| 40 | |||
| 41 | 1 | $data = $this->getImageData($url); |
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| 42 | 1 | if (!$data) { |
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| 43 | 1 | $data = $this->getOEmbedData($url); |
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| 44 | 1 | } |
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| 45 | 1 | if (!$data) { |
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| 46 | 1 | $data = $this->getDOMData($url); |
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| 47 | 1 | if (is_array($data) && !empty($data['oembed_url'])) { |
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| 48 | 1 | foreach ($data['oembed_url'] as $oembed_url) { |
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| 49 | 1 | $oembed_data = $this->parse($oembed_url); |
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| 50 | 1 | if (!empty($oembed_data) && is_array($oembed_data)) { |
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| 51 | 1 | $oembed_data['oembed_url'] = $oembed_data['url']; |
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| 52 | 1 | unset($oembed_data['url']); |
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| 53 | 1 | $data = array_merge($data, $oembed_data); |
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| 54 | 1 | } |
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| 55 | 1 | } |
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| 56 | 1 | } |
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| 57 | 1 | } |
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| 58 | |||
| 59 | 1 | if (!is_array($data)) { |
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| 60 | 1 | $data = array(); |
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| 61 | 1 | } |
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| 62 | |||
| 63 | 1 | if (empty($data['thumbnail_url']) && !empty($data['thumbnails'])) { |
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| 64 | 1 | $data['thumbnail_url'] = $data['thumbnails'][0]; |
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| 65 | 1 | } |
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| 66 | |||
| 67 | 1 | return $data; |
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| 68 | } |
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| 69 | |||
| 70 | /** |
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| 71 | * Parses image metatags |
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| 72 | * |
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| 73 | * @param string $url URL of the image |
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| 74 | * @return array|false |
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| 75 | */ |
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| 76 | 1 | public function getImageData($url = '') { |
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| 87 | |||
| 88 | /** |
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| 89 | * Parses OEmbed data |
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| 90 | * |
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| 91 | * @param string $url URL of the image |
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| 92 | * @return array|false |
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| 93 | */ |
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| 94 | 2 | public function getOEmbedData($url = '') { |
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| 139 | |||
| 140 | /** |
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| 141 | * Parses metatags from DOM |
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| 142 | * |
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| 143 | * @param string $url URL |
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| 144 | * @return array|false |
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| 145 | */ |
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| 146 | 1 | public function getDOMData($url = '') { |
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| 174 | |||
| 175 | /** |
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| 176 | * Check if URL exists and is reachable by making an HTTP request to retrieve header information |
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| 177 | * |
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| 178 | * @param string $url URL of the resource |
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| 179 | * @return boolean |
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| 180 | */ |
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| 181 | 1 | public function exists($url = '') { |
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| 188 | |||
| 189 | /** |
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| 190 | * Validate URL |
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| 191 | * |
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| 192 | * @param string $url URL to validate |
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| 193 | * @return bool |
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| 194 | */ |
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| 195 | public function isValidUrl($url = '') { |
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| 196 | // based on http://php.net/manual/en/function.filter-var.php#104160 |
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| 197 | // adapted by @mrclay in https://github.com/mrclay/Elgg-leaf/blob/62bf31c0ccdaab549a7e585a4412443e09821db3/engine/lib/output.php |
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| 198 | $res = filter_var($url, FILTER_VALIDATE_URL); |
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| 199 | if ($res) { |
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| 200 | return $res; |
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| 201 | } |
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| 202 | // Check if it has unicode chars. |
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| 203 | $l = mb_strlen($url); |
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| 204 | if (strlen($url) == $l) { |
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| 205 | return $res; |
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| 206 | } |
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| 207 | // Replace wide chars by “X”. |
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| 208 | $s = ''; |
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| 209 | for ($i = 0; $i < $l; ++$i) { |
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| 210 | $ch = elgg_substr($url, $i, 1); |
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| 211 | $s .= (strlen($ch) > 1) ? 'X' : $ch; |
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| 212 | } |
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| 213 | // Re-check now. |
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| 214 | return filter_var($s, FILTER_VALIDATE_URL) ? $url : false; |
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| 215 | } |
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| 216 | |||
| 217 | /** |
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| 218 | * Returns head of the resource |
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| 219 | * |
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| 220 | * @param string $url URL of the resource |
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| 221 | * @return Response|false |
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| 222 | */ |
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| 223 | 1 | public function request($url = '') { |
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| 224 | 1 | $url = str_replace(' ', '%20', $url); |
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| 225 | 1 | if (!$this->isValidUrl($url)) { |
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| 226 | return false; |
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| 227 | } |
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| 228 | 1 | if (!isset(self::$cache[$url])) { |
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| 229 | try { |
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| 230 | 1 | $response = $this->client->request('GET', $url); |
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| 231 | 1 | } catch (Exception $e) { |
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| 232 | $response = false; |
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| 233 | error_log("Parser Error for HEAD request ($url): {$e->getMessage()}"); |
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| 234 | } |
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| 235 | 1 | self::$cache[$url] = $response; |
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| 236 | 1 | } |
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| 237 | |||
| 238 | 1 | return self::$cache[$url]; |
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| 239 | } |
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| 240 | |||
| 241 | /** |
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| 242 | * Get contents of the page |
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| 243 | * |
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| 244 | * @param string $url URL of the resource |
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| 245 | * @return string |
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| 246 | */ |
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| 247 | 1 | public function read($url = '') { |
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| 248 | 1 | $body = ''; |
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| 249 | 1 | if (!$this->exists($url)) { |
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| 250 | 1 | return $body; |
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| 251 | } |
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| 252 | |||
| 253 | 1 | $response = $this->request($url); |
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| 254 | 1 | $body = (string) $response->getBody(); |
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| 255 | 1 | return $body; |
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| 256 | } |
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| 257 | |||
| 258 | /** |
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| 259 | * Checks if resource is an html page |
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| 260 | * |
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| 261 | * @param string $url URL of the resource |
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| 262 | * @return boolean |
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| 263 | */ |
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| 264 | 1 | public function isHTML($url = '') { |
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| 265 | 1 | $mime = $this->getContentType($url); |
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| 266 | 1 | return strpos($mime, 'text/html') !== false; |
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| 267 | } |
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| 268 | |||
| 269 | /** |
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| 270 | * Checks if resource is JSON |
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| 271 | * |
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| 272 | * @param string $url URL of the resource |
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| 273 | * @return boolean |
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| 274 | */ |
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| 275 | 1 | public function isJSON($url = '') { |
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| 276 | 1 | $mime = $this->getContentType($url); |
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| 277 | 1 | return strpos($mime, 'json') !== false; |
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| 278 | } |
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| 279 | |||
| 280 | /** |
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| 281 | * Checks if resource is XML |
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| 282 | * |
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| 283 | * @param string $url URL of the resource |
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| 284 | * @return boolean |
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| 285 | */ |
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| 286 | 1 | public function isXML($url = '') { |
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| 287 | 1 | $mime = $this->getContentType($url); |
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| 288 | 1 | return strpos($mime, 'xml') !== false; |
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| 289 | } |
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| 290 | |||
| 291 | /** |
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| 292 | * Checks if resource is an image |
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| 293 | * |
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| 294 | * @param string $url URL of the resource |
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| 295 | * @return boolean |
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| 296 | */ |
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| 297 | 1 | public function isImage($url = '') { |
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| 298 | 1 | $mime = $this->getContentType($url); |
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| 299 | 1 | if ($mime) { |
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| 300 | 1 | list($simple, ) = explode('/', $mime); |
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| 301 | 1 | return ($simple == 'image'); |
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| 302 | } |
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| 303 | |||
| 304 | 1 | return false; |
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| 305 | } |
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| 306 | |||
| 307 | /** |
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| 308 | * Get mime type of the URL content |
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| 309 | * |
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| 310 | * @param string $url URL of the resource |
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| 311 | * @return string |
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| 312 | */ |
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| 313 | 1 | public function getContentType($url = '') { |
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| 314 | 1 | $response = $this->request($url); |
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| 315 | 1 | if ($response instanceof Response) { |
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| 316 | 1 | $header = $response->getHeader('Content-Type'); |
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| 317 | 1 | if (is_array($header) && !empty($header)) { |
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| 318 | 1 | $parts = explode(';', $header[0]); |
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| 319 | 1 | return trim($parts[0]); |
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| 320 | } |
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| 321 | 1 | } |
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| 322 | 1 | return ''; |
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| 323 | } |
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| 324 | |||
| 325 | /** |
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| 326 | * Returns HTML contents of the page |
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| 327 | * |
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| 328 | * @param string $url URL of the resource |
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| 329 | * @return string |
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| 330 | */ |
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| 331 | 1 | public function getHTML($url = '') { |
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| 332 | 1 | if (!$this->isHTML($url)) { |
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| 333 | 1 | return ''; |
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| 334 | } |
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| 335 | 1 | return $this->read($url); |
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| 336 | } |
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| 337 | |||
| 338 | /** |
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| 339 | * Returns HTML contents of the page as a DOMDocument |
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| 340 | * |
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| 341 | * @param string $url URL of the resource |
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| 342 | * @return DOMDocument|false |
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| 343 | */ |
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| 344 | 1 | public function getDOM($url = '') { |
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| 345 | 1 | $html = $this->getHTML($url); |
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| 346 | 1 | if (empty($html)) { |
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| 347 | 1 | return false; |
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| 348 | } |
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| 349 | 1 | $doc = new DOMDocument(); |
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| 350 | |||
| 351 | 1 | libxml_use_internal_errors(true); |
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| 352 | |||
| 353 | 1 | if (is_callable('mb_convert_encoding')) { |
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| 354 | 1 | $doc->loadHTML(mb_convert_encoding($html, 'HTML-ENTITIES', 'UTF-8')); |
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| 355 | 1 | } else { |
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| 356 | $doc->loadHTML($html); |
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| 357 | } |
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| 358 | 1 | if (!$doc->documentURI) { |
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| 359 | 1 | $doc->documentURI = $url; |
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| 360 | 1 | } |
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| 361 | |||
| 362 | 1 | libxml_clear_errors(); |
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| 363 | |||
| 364 | 1 | return $doc; |
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| 365 | } |
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| 366 | |||
| 367 | /** |
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| 368 | * Parses document title |
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| 369 | * |
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| 370 | * @param DOMDocument $doc Document |
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| 371 | * @return string |
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| 372 | */ |
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| 373 | 1 | public function parseTitle(DOMDocument $doc) { |
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| 378 | |||
| 379 | /** |
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| 380 | * Parses <link> tags |
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| 381 | * |
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| 382 | * @param DOMDocument $doc Document |
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| 383 | * @return array |
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| 384 | */ |
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| 385 | 1 | public function parseLinkTags(DOMDocument $doc) { |
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| 386 | |||
| 387 | $meta = array( |
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| 388 | 1 | 'icons' => [], |
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| 389 | 1 | 'thumbnails' => [], |
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| 426 | |||
| 427 | /** |
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| 428 | * Parses <meta> tags |
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| 429 | * |
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| 430 | * @param DOMDocument $doc Document |
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| 431 | * @return array |
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| 432 | */ |
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| 433 | 1 | public function parseMetaTags(DOMDocument $doc) { |
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| 512 | |||
| 513 | /** |
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| 514 | * Parses <img> tags |
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| 515 | * |
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| 516 | * @param DOMDocument $doc Document |
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| 517 | * @return array |
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| 518 | */ |
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| 519 | 1 | public function parseImgTags(DOMDocument $doc) { |
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| 536 | |||
| 537 | /** |
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| 538 | * Normalizes relative URLs |
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| 539 | * |
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| 540 | * @param DOMDocument $doc Document |
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| 541 | * @param string $href URL to normalize |
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| 542 | * @return string|false |
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| 543 | */ |
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| 544 | 1 | public function getAbsoluteURL(DOMDocument $doc, $href = '') { |
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| 571 | |||
| 572 | } |
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| 573 |