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 Swift_Message_Headers 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 Swift_Message_Headers, and based on these observations, apply Extract Interface, too.
| 1 | <?php |
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| 19 | class Swift_Message_Headers |
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| 20 | { |
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| 21 | /** |
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| 22 | * Headers which may contain email addresses, and therefore should take notice when encoding |
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| 23 | * @var array headers |
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| 24 | */ |
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| 25 | protected $emailContainingHeaders = array( |
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| 26 | "To", "From", "Reply-To", "Cc", "Bcc", "Return-Path", "Sender"); |
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| 27 | /** |
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| 28 | * The encoding format used for the body of the document |
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| 29 | * @var string format |
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| 30 | */ |
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| 31 | protected $encoding = "B"; |
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| 32 | /** |
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| 33 | * The charset used in the headers |
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| 34 | * @var string |
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| 35 | */ |
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| 36 | protected $charset = false; |
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| 37 | /** |
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| 38 | * A collection of headers |
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| 39 | * @var array headers |
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| 40 | */ |
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| 41 | protected $headers = array(); |
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| 42 | /** |
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| 43 | * A container of references to the headers |
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| 44 | * @var array |
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| 45 | */ |
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| 46 | protected $lowerHeaders = array(); |
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| 47 | /** |
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| 48 | * Attributes appended to headers |
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| 49 | * @var array |
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| 50 | */ |
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| 51 | protected $attributes = array(); |
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| 52 | /** |
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| 53 | * If QP or Base64 encoding should be forced |
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| 54 | * @var boolean |
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| 55 | */ |
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| 56 | protected $forceEncoding = false; |
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| 57 | /** |
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| 58 | * The language used in the headers (doesn't really matter much) |
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| 59 | * @var string |
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| 60 | */ |
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| 61 | protected $language = "en-us"; |
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| 62 | /** |
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| 63 | * Cached, pre-built headers |
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| 64 | * @var string |
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| 65 | */ |
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| 66 | protected $cached = array(); |
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| 67 | /** |
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| 68 | * The line ending used in the headers |
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| 69 | * @var string |
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| 70 | */ |
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| 71 | protected $LE = "\r\n"; |
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| 72 | |||
| 73 | /** |
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| 74 | * Set the line ending character to use |
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| 75 | * @param string The line ending sequence |
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| 76 | * @return boolean |
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| 77 | */ |
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| 78 | public function setLE($le) |
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| 88 | /** |
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| 89 | * Get the line ending sequence |
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| 90 | * @return string |
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| 91 | */ |
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| 92 | public function getLE() |
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| 96 | /** |
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| 97 | * Reset the cache state in these headers |
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| 98 | */ |
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| 99 | public function uncacheAll() |
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| 106 | /** |
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| 107 | * Add a header or change an existing header value |
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| 108 | * @param string The header name, for example "From" or "Subject" |
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| 109 | * @param string The value to be inserted into the header. This is safe from header injection. |
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| 110 | */ |
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| 111 | public function set($name, $value) |
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| 142 | /** |
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| 143 | * Get the value at a given header |
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| 144 | * @param string The name of the header, for example "From" or "Subject" |
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| 145 | * @return string |
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| 146 | * @throws Swift_Message_MimeException If no such header exists |
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| 147 | * @see hasHeader |
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| 148 | */ |
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| 149 | public function get($name) |
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| 157 | /** |
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| 158 | * Remove a header from the list |
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| 159 | * @param string The name of the header |
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| 160 | */ |
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| 161 | public function remove($name) |
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| 172 | /** |
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| 173 | * Just fetch the array containing the headers |
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| 174 | * @return array |
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| 175 | */ |
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| 176 | public function getList() |
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| 180 | /** |
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| 181 | * Check if a header has been set or not |
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| 182 | * @param string The name of the header, for example "From" or "Subject" |
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| 183 | * @return boolean |
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| 184 | */ |
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| 185 | public function has($name) |
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| 190 | /** |
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| 191 | * Set the language used in the headers to $lang (e.g. en-us, en-gb, sv etc) |
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| 192 | * @param string The language to use |
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| 193 | */ |
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| 194 | public function setLanguage($lang) |
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| 198 | /** |
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| 199 | * Get the language used in the headers to $lang (e.g. en-us, en-gb, sv etc) |
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| 200 | * @return string |
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| 201 | */ |
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| 202 | public function getLanguage() |
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| 206 | /** |
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| 207 | * Set the charset used in the headers |
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| 208 | * @param string The charset name |
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| 209 | * @param string $charset |
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| 210 | */ |
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| 211 | public function setCharset($charset) |
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| 215 | /** |
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| 216 | * Get the current charset used |
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| 217 | * @return string |
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| 218 | */ |
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| 219 | public function getCharset() |
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| 223 | /** |
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| 224 | * Specify the encoding to use for the headers if characters outside the 7-bit-printable ascii range are found |
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| 225 | * This encoding will never be used if only 7-bit-printable characters are found in the headers. |
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| 226 | * Possible values are: |
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| 227 | * - QP |
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| 228 | * - Q |
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| 229 | * - Quoted-Printable |
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| 230 | * - B |
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| 231 | * - Base64 |
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| 232 | * NOTE: Q, QP, Quoted-Printable are all the same; as are B and Base64 |
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| 233 | * @param string The encoding format to use |
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| 234 | * @param string $encoding |
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| 235 | * @return boolean |
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| 236 | */ |
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| 237 | public function setEncoding($encoding) |
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| 250 | /** |
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| 251 | * Get the encoding format used in this document |
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| 252 | * @return string |
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| 253 | */ |
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| 254 | public function getEncoding() |
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| 258 | /** |
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| 259 | * Turn on or off forced header encoding |
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| 260 | * @param boolean On/Off |
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| 261 | */ |
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| 262 | public function forceEncoding($force=true) |
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| 266 | /** |
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| 267 | * Set an attribute in a major header |
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| 268 | * For example $headers->setAttribute("Content-Type", "format", "flowed") |
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| 269 | * @param string The main header these values exist in |
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| 270 | * @param string The name for this value |
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| 271 | * @param string The value to set |
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| 272 | * @throws Swift_Message_MimeException If no such header exists |
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| 273 | */ |
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| 274 | public function setAttribute($header, $name, $value) |
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| 294 | /** |
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| 295 | * Check if a header has a given attribute applied to it |
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| 296 | * @param string The name of the main header |
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| 297 | * @param string The name of the attribute |
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| 298 | * @param string $name |
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| 299 | * @return boolean |
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| 300 | */ |
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| 301 | public function hasAttribute($header, $name) |
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| 314 | /** |
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| 315 | * Get the value for a given attribute on a given header |
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| 316 | * @param string The name of the main header |
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| 317 | * @param string The name of the attribute |
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| 318 | * @param string $header |
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| 319 | * @param string $name |
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| 320 | * @return string |
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| 321 | * @throws Swift_Message_MimeException If no header is set |
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| 322 | */ |
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| 323 | public function getAttribute($header, $name) |
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| 340 | /** |
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| 341 | * Remove an attribute from a header |
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| 342 | * @param string The name of the header to remove the attribute from |
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| 343 | * @param string The name of the attribute to remove |
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| 344 | */ |
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| 345 | public function removeAttribute($header, $name) |
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| 354 | /** |
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| 355 | * Get a list of all the attributes in the given header. |
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| 356 | * @param string The name of the header |
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| 357 | * @return array |
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| 358 | */ |
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| 359 | public function listAttributes($header) |
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| 368 | /** |
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| 369 | * Get the header in it's compliant, encoded form |
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| 370 | * @param string The name of the header |
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| 371 | * @return string |
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| 372 | * @throws Swift_Message_MimeException If the header doesn't exist |
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| 373 | */ |
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| 374 | public function getEncoded($name) |
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| 484 | /** |
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| 485 | * Build the list of attributes for appending to the given header |
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| 486 | * This is RFC 2231 & 2047 compliant. |
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| 487 | * A HUGE thanks to Joaquim Homrighausen for heaps of help, advice |
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| 488 | * and testing to get this working rock solid. |
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| 489 | * @param string The header built without attributes |
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| 490 | * @param string The lowercase name of the header |
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| 491 | * @param string $header_line |
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| 492 | * @param string $header_name |
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| 493 | * @return string |
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| 494 | * @throws Swift_Message_MimeException If no such header exists or there are no attributes |
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| 495 | */ |
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| 496 | protected function buildAttributes($header_line, $header_name) |
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| 563 | /** |
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| 564 | * Compile the list of headers which have been set and return an ascii string |
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| 565 | * The return value should always be 7-bit ascii and will have been cleaned for header injection |
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| 566 | * If this looks complicated it's probably because it is!! Keeping everything compliant is not easy. |
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| 567 | * This is RFC 2822 compliant |
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| 568 | * @return string |
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| 569 | */ |
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| 570 | public function build() |
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| 580 | } |
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| 581 |
Very long variable names usually make code harder to read. It is therefore recommended not to make variable names too verbose.