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 Google_Http_Request 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 Google_Http_Request, and based on these observations, apply Extract Interface, too.
| 1 | <?php  | 
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| 30 | class Google_Http_Request  | 
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| 31 | { | 
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| 32 | const GZIP_UA = " (gzip)";  | 
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| 33 | |||
| 34 | private $batchHeaders = array(  | 
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| 35 | 'Content-Type' => 'application/http',  | 
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| 36 | 'Content-Transfer-Encoding' => 'binary',  | 
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| 37 | 'MIME-Version' => '1.0',  | 
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| 38 | );  | 
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| 39 | |||
| 40 | protected $queryParams;  | 
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| 41 | protected $requestMethod;  | 
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| 42 | protected $requestHeaders;  | 
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| 43 | protected $baseComponent = null;  | 
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| 44 | protected $path;  | 
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| 45 | protected $postBody;  | 
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| 46 | protected $userAgent;  | 
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| 47 | protected $canGzip = null;  | 
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| 48 | |||
| 49 | protected $responseHttpCode;  | 
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| 50 | protected $responseHeaders;  | 
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| 51 | protected $responseBody;  | 
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| 52 | |||
| 53 | protected $expectedClass;  | 
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| 54 | protected $expectedRaw = false;  | 
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| 55 | |||
| 56 | public $accessKey;  | 
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| 57 | |||
| 58 | public function __construct(  | 
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| 69 | |||
| 70 | /**  | 
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| 71 | * Misc function that returns the base url component of the $url  | 
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| 72 | * used by the OAuth signing class to calculate the base string  | 
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| 73 | * @return string The base url component of the $url.  | 
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| 74 | */  | 
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| 75 | public function getBaseComponent()  | 
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| 79 | |||
| 80 | /**  | 
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| 81 | * Set the base URL that path and query parameters will be added to.  | 
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| 82 | * @param $baseComponent string  | 
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| 83 | */  | 
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| 84 | public function setBaseComponent($baseComponent)  | 
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| 88 | |||
| 89 | /**  | 
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| 90 | * Enable support for gzipped responses with this request.  | 
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| 91 | */  | 
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| 92 | public function enableGzip()  | 
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| 98 | |||
| 99 | /**  | 
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| 100 | * Disable support for gzip responses with this request.  | 
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| 101 | */  | 
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| 102 | public function disableGzip()  | 
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| 113 | |||
| 114 | /**  | 
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| 115 | * Can this request accept a gzip response?  | 
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| 116 | * @return bool  | 
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| 117 | */  | 
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| 118 | public function canGzip()  | 
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| 122 | |||
| 123 | /**  | 
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| 124 | * Misc function that returns an array of the query parameters of the current  | 
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| 125 | * url used by the OAuth signing class to calculate the signature  | 
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| 126 | * @return array Query parameters in the query string.  | 
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| 127 | */  | 
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| 128 | public function getQueryParams()  | 
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| 132 | |||
| 133 | /**  | 
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| 134 | * Set a new query parameter.  | 
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| 135 | * @param $key - string to set, does not need to be URL encoded  | 
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| 136 | * @param $value - string to set, does not need to be URL encoded  | 
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| 137 | */  | 
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| 138 | public function setQueryParam($key, $value)  | 
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| 142 | |||
| 143 | /**  | 
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| 144 | * @return string HTTP Response Code.  | 
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| 145 | */  | 
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| 146 | public function getResponseHttpCode()  | 
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| 150 | |||
| 151 | /**  | 
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| 152 | * @param int $responseHttpCode HTTP Response Code.  | 
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| 153 | */  | 
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| 154 | public function setResponseHttpCode($responseHttpCode)  | 
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| 158 | |||
| 159 | /**  | 
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| 160 | * @return $responseHeaders (array) HTTP Response Headers.  | 
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                         | 
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| 161 | */  | 
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| 162 | public function getResponseHeaders()  | 
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| 166 | |||
| 167 | /**  | 
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| 168 | * @return string HTTP Response Body  | 
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| 169 | */  | 
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| 170 | public function getResponseBody()  | 
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| 174 | |||
| 175 | /**  | 
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| 176 | * Set the class the response to this request should expect.  | 
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| 177 | *  | 
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| 178 | * @param $class string the class name  | 
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| 179 | */  | 
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| 180 | public function setExpectedClass($class)  | 
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| 184 | |||
| 185 | /**  | 
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| 186 | * Retrieve the expected class the response should expect.  | 
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| 187 | * @return string class name  | 
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| 188 | */  | 
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| 189 | public function getExpectedClass()  | 
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| 193 | |||
| 194 | /**  | 
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| 195 | * Enable expected raw response  | 
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| 196 | */  | 
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| 197 | public function enableExpectedRaw()  | 
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| 201 | |||
| 202 | /**  | 
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| 203 | * Disable expected raw response  | 
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| 204 | */  | 
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| 205 | public function disableExpectedRaw()  | 
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| 209 | |||
| 210 | /**  | 
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| 211 | * Expected raw response or not.  | 
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| 212 | * @return boolean expected raw response  | 
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| 213 | */  | 
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| 214 | public function getExpectedRaw()  | 
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| 218 | |||
| 219 | /**  | 
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| 220 | * @param array $headers The HTTP response headers  | 
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| 221 | * to be normalized.  | 
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| 222 | */  | 
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| 223 | View Code Duplication | public function setResponseHeaders($headers)  | 
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| 232 | |||
| 233 | /**  | 
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| 234 | * @param string $key  | 
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| 235 | * @return array|boolean Returns the requested HTTP header or  | 
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| 236 | * false if unavailable.  | 
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| 237 | */  | 
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| 238 | public function getResponseHeader($key)  | 
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| 244 | |||
| 245 | /**  | 
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| 246 | * @param string $responseBody The HTTP response body.  | 
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| 247 | */  | 
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| 248 | public function setResponseBody($responseBody)  | 
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| 252 | |||
| 253 | /**  | 
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| 254 | * @return string $url The request URL.  | 
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| 255 | */  | 
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| 256 | public function getUrl()  | 
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| 263 | |||
| 264 | /**  | 
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| 265 | * @return string $method HTTP Request Method.  | 
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| 266 | */  | 
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| 267 | public function getRequestMethod()  | 
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| 271 | |||
| 272 | /**  | 
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| 273 | * @return array $headers HTTP Request Headers.  | 
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| 274 | */  | 
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| 275 | public function getRequestHeaders()  | 
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| 279 | |||
| 280 | /**  | 
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| 281 | * @param string $key  | 
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| 282 | * @return array|boolean Returns the requested HTTP header or  | 
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| 283 | * false if unavailable.  | 
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| 284 | */  | 
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| 285 | public function getRequestHeader($key)  | 
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| 291 | |||
| 292 | /**  | 
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| 293 | * @return string $postBody HTTP Request Body.  | 
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| 294 | */  | 
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| 295 | public function getPostBody()  | 
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| 299 | |||
| 300 | /**  | 
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| 301 | * @param string $url the url to set  | 
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| 302 | */  | 
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| 303 | public function setUrl($url)  | 
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| 326 | |||
| 327 | /**  | 
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| 328 | * @param string $method Set he HTTP Method and normalize  | 
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| 329 | * it to upper-case, as required by HTTP.  | 
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| 330 | *  | 
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| 331 | */  | 
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| 332 | public function setRequestMethod($method)  | 
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| 336 | |||
| 337 | /**  | 
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| 338 | * @param array $headers The HTTP request headers  | 
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| 339 | * to be set and normalized.  | 
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| 340 | */  | 
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| 341 | View Code Duplication | public function setRequestHeaders($headers)  | 
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| 349 | |||
| 350 | /**  | 
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| 351 | * @param string $postBody the postBody to set  | 
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| 352 | */  | 
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| 353 | public function setPostBody($postBody)  | 
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| 357 | |||
| 358 | /**  | 
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| 359 | * Set the User-Agent Header.  | 
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| 360 | * @param string $userAgent The User-Agent.  | 
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| 361 | */  | 
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| 362 | public function setUserAgent($userAgent)  | 
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| 369 | |||
| 370 | /**  | 
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| 371 | * @return string The User-Agent.  | 
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| 372 | */  | 
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| 373 | public function getUserAgent()  | 
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| 377 | |||
| 378 | /**  | 
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| 379 | * Returns a cache key depending on if this was an OAuth signed request  | 
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| 380 | * in which case it will use the non-signed url and access key to make this  | 
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| 381 | * cache key unique per authenticated user, else use the plain request url  | 
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| 382 | * @return string The md5 hash of the request cache key.  | 
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| 383 | */  | 
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| 384 | public function getCacheKey()  | 
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| 398 | |||
| 399 | public function getParsedCacheControl()  | 
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| 410 | |||
| 411 | /**  | 
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| 412 | * @param string $id  | 
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| 413 | * @return string A string representation of the HTTP Request.  | 
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| 414 | */  | 
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| 415 | public function toBatchString($id)  | 
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| 441 | |||
| 442 | /**  | 
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| 443 | * Our own version of parse_str that allows for multiple variables  | 
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| 444 | * with the same name.  | 
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| 445 | * @param $string - the query string to parse  | 
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| 446 | */  | 
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| 447 | private function parseQuery($string)  | 
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| 465 | |||
| 466 | /**  | 
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| 467 | * A version of build query that allows for multiple  | 
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| 468 | * duplicate keys.  | 
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| 469 | * @param $parts array of key value pairs  | 
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| 470 | */  | 
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| 471 | private function buildQuery($parts)  | 
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| 485 | |||
| 486 | /**  | 
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| 487 | * If we're POSTing and have no body to send, we can send the query  | 
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| 488 | * parameters in there, which avoids length issues with longer query  | 
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| 489 | * params.  | 
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| 490 | */  | 
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| 491 | public function maybeMoveParametersToBody()  | 
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| 504 | }  | 
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| 505 | 
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