<?php
/**
* @see https://github.com/laminas/laminas-mail for the canonical source repository
* @copyright https://github.com/laminas/laminas-mail/blob/master/COPYRIGHT.md
* @license https://github.com/laminas/laminas-mail/blob/master/LICENSE.md New BSD License
*/
namespace Laminas\Mail\Header;
use Laminas\Mail\Headers;
use Laminas\Mime\Mime;
/**
* Utility class used for creating wrapped or MIME-encoded versions of header
* values.
*/
abstract class HeaderWrap
{
/**
* Wrap a long header line
*
* @param string $value
* @param HeaderInterface $header
* @return string
*/
public static function wrap($value, HeaderInterface $header)
{
if ($header instanceof UnstructuredInterface) {
return static::wrapUnstructuredHeader($value, $header);
} elseif ($header instanceof StructuredInterface) {
return static::wrapStructuredHeader($value, $header);
}
return $value;
}
/**
* Wrap an unstructured header line
*
* Wrap at 78 characters or before, based on whitespace.
*
* @param string $value
* @param HeaderInterface $header
* @return string
*/
protected static function wrapUnstructuredHeader($value, HeaderInterface $header)
{
$encoding = $header->getEncoding();
if ($encoding == 'ASCII') {
return wordwrap($value, 78, Headers::FOLDING);
}
return static::mimeEncodeValue($value, $encoding, 78);
}
/**
* Wrap a structured header line
*
* @param string $value
* @param StructuredInterface $header
* @return string
*/
protected static function wrapStructuredHeader($value, StructuredInterface $header)
{
$delimiter = $header->getDelimiter();
$length = strlen($value);
$lines = [];
$temp = '';
for ($i = 0; $i < $length; $i++) {
$temp .= $value[$i];
if ($value[$i] == $delimiter) {
$lines[] = $temp;
$temp = '';
}
}
return implode(Headers::FOLDING, $lines);
}
/**
* MIME-encode a value
*
* Performs quoted-printable encoding on a value, setting maximum
* line-length to 998.
*
* @param string $value
* @param string $encoding
* @param int $lineLength maximum line-length, by default 998
* @return string Returns the mime encode value without the last line ending
*/
public static function mimeEncodeValue($value, $encoding, $lineLength = 998)
{
return Mime::encodeQuotedPrintableHeader($value, $encoding, $lineLength, Headers::EOL);
}
/**
* MIME-decode a value
*
* Performs quoted-printable decoding on a value.
*
* @param string $value
* @return string Returns the mime encode value without the last line ending
*/
public static function mimeDecodeValue($value)
{
// unfold first, because iconv_mime_decode is discarding "\n" with no apparent reason
// making the resulting value no longer valid.
// see https://tools.ietf.org/html/rfc2822#section-2.2.3 about unfolding
$parts = explode(Headers::FOLDING, $value);
$value = implode(' ', $parts);
$decodedValue = iconv_mime_decode($value, ICONV_MIME_DECODE_CONTINUE_ON_ERROR, 'UTF-8');
// imap (unlike iconv) can handle multibyte headers which are splitted across multiple line
if (self::isNotDecoded($value, $decodedValue) && extension_loaded('imap')) {
return array_reduce(
imap_mime_header_decode(imap_utf8($value)),
function ($accumulator, $headerPart) {
return $accumulator . $headerPart->text;
},
''
);
}
return $decodedValue;
}
private static function isNotDecoded($originalValue, $value)
{
return 0 === strpos($value, '=?')
&& strlen($value) - 2 === strpos($value, '?=')
&& false !== strpos($originalValue, $value);
}
/**
* Test if is possible apply MIME-encoding
*
* @param string $value
* @return bool
*/
public static function canBeEncoded($value)
{
// avoid any wrapping by specifying line length long enough
// "test" -> 4
// "x-test: =?ISO-8859-1?B?dGVzdA==?=" -> 33
// 8 +2 +3 +3 -> 16
$charset = 'UTF-8';
$lineLength = strlen($value) * 4 + strlen($charset) + 16;
$preferences = [
'scheme' => 'Q',
'input-charset' => $charset,
'output-charset' => $charset,
'line-length' => $lineLength,
];
$encoded = iconv_mime_encode('x-test', $value, $preferences);
return (false !== $encoded);
}
}