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<?php
/*
* This file is part of the Symfony package.
*
* (c) Fabien Potencier <fabien@symfony.com>
*
* For the full copyright and license information, please view the LICENSE
* file that was distributed with this source code.
*/
namespace Symfony\Component\HttpFoundation;
/**
* HTTP header utility functions.
*
* @author Christian Schmidt <github@chsc.dk>
*/
class HeaderUtils
{
public const DISPOSITION_ATTACHMENT = 'attachment';
public const DISPOSITION_INLINE = 'inline';
/**
* This class should not be instantiated.
*/
private function __construct()
{
}
/**
* Splits an HTTP header by one or more separators.
*
* Example:
*
* HeaderUtils::split("da, en-gb;q=0.8", ",;")
* // => ['da'], ['en-gb', 'q=0.8']]
*
* @param string $separators List of characters to split on, ordered by
* precedence, e.g. ",", ";=", or ",;="
*
* @return array Nested array with as many levels as there are characters in
* $separators
*/
public static function split(string $header, string $separators): array
{
$quotedSeparators = preg_quote($separators, '/');
preg_match_all('
/
(?!\s)
(?:
# quoted-string
"(?:[^"\\\\]|\\\\.)*(?:"|\\\\|$)
|
# token
[^"'.$quotedSeparators.']+
)+
(?<!\s)
|
# separator
\s*
(?<separator>['.$quotedSeparators.'])
\s*
/x', trim($header), $matches, \PREG_SET_ORDER);
return self::groupParts($matches, $separators);
}
/**
* Combines an array of arrays into one associative array.
*
* Each of the nested arrays should have one or two elements. The first
* value will be used as the keys in the associative array, and the second
* will be used as the values, or true if the nested array only contains one
* element. Array keys are lowercased.
*
* Example:
*
* HeaderUtils::combine([["foo", "abc"], ["bar"]])
* // => ["foo" => "abc", "bar" => true]
*/
public static function combine(array $parts): array
{
$assoc = [];
foreach ($parts as $part) {
$name = strtolower($part[0]);
$value = $part[1] ?? true;
$assoc[$name] = $value;
}
return $assoc;
}
/**
* Joins an associative array into a string for use in an HTTP header.
*
* The key and value of each entry are joined with "=", and all entries
* are joined with the specified separator and an additional space (for
* readability). Values are quoted if necessary.
*
* Example:
*
* HeaderUtils::toString(["foo" => "abc", "bar" => true, "baz" => "a b c"], ",")
* // => 'foo=abc, bar, baz="a b c"'
*/
public static function toString(array $assoc, string $separator): string
{
$parts = [];
foreach ($assoc as $name => $value) {
if (true === $value) {
$parts[] = $name;
} else {
$parts[] = $name.'='.self::quote($value);
}
}
return implode($separator.' ', $parts);
}
/**
* Encodes a string as a quoted string, if necessary.
*
* If a string contains characters not allowed by the "token" construct in
* the HTTP specification, it is backslash-escaped and enclosed in quotes
* to match the "quoted-string" construct.
*/
public static function quote(string $s): string
{
if (preg_match('/^[a-z0-9!#$%&\'*.^_`|~-]+$/i', $s)) {
return $s;
}
return '"'.addcslashes($s, '"\\"').'"';
}
/**
* Decodes a quoted string.
*
* If passed an unquoted string that matches the "token" construct (as
* defined in the HTTP specification), it is passed through verbatimly.
*/
public static function unquote(string $s): string
{
return preg_replace('/\\\\(.)|"/', '$1', $s);
}
/**
* Generates an HTTP Content-Disposition field-value.
*
* @param string $disposition One of "inline" or "attachment"
* @param string $filename A unicode string
* @param string $filenameFallback A string containing only ASCII characters that
* is semantically equivalent to $filename. If the filename is already ASCII,
* it can be omitted, or just copied from $filename
*
* @return string A string suitable for use as a Content-Disposition field-value
*
* @throws \InvalidArgumentException
*
* @see RFC 6266
*/
public static function makeDisposition(string $disposition, string $filename, string $filenameFallback = ''): string
{
if (!\in_array($disposition, [self::DISPOSITION_ATTACHMENT, self::DISPOSITION_INLINE])) {
throw new \InvalidArgumentException(sprintf('The disposition must be either "%s" or "%s".', self::DISPOSITION_ATTACHMENT, self::DISPOSITION_INLINE));
}
if ('' === $filenameFallback) {
$filenameFallback = $filename;
}
// filenameFallback is not ASCII.
if (!preg_match('/^[\x20-\x7e]*$/', $filenameFallback)) {
throw new \InvalidArgumentException('The filename fallback must only contain ASCII characters.');
}
// percent characters aren't safe in fallback.
if (str_contains($filenameFallback, '%')) {
throw new \InvalidArgumentException('The filename fallback cannot contain the "%" character.');
}
// path separators aren't allowed in either.
if (str_contains($filename, '/') || str_contains($filename, '\\') || str_contains($filenameFallback, '/') || str_contains($filenameFallback, '\\')) {
throw new \InvalidArgumentException('The filename and the fallback cannot contain the "/" and "\\" characters.');
}
$params = ['filename' => $filenameFallback];
if ($filename !== $filenameFallback) {
$params['filename*'] = "utf-8''".rawurlencode($filename);
}
return $disposition.'; '.self::toString($params, ';');
}
private static function groupParts(array $matches, string $separators, bool $first = true): array
{
$separator = $separators[0];
$partSeparators = substr($separators, 1);
$i = 0;
$partMatches = [];
$previousMatchWasSeparator = false;
foreach ($matches as $match) {
if (!$first && $previousMatchWasSeparator && isset($match['separator']) && $match['separator'] === $separator) {
$previousMatchWasSeparator = true;
$partMatches[$i][] = $match;
} elseif (isset($match['separator']) && $match['separator'] === $separator) {
$previousMatchWasSeparator = true;
++$i;
} else {
$previousMatchWasSeparator = false;
$partMatches[$i][] = $match;
}
}
$parts = [];
if ($partSeparators) {
foreach ($partMatches as $matches) {
$parts[] = self::groupParts($matches, $partSeparators, false);
}
} else {
foreach ($partMatches as $matches) {
$parts[] = self::unquote($matches[0][0]);
}
if (!$first && 2 < \count($parts)) {
$parts = [
$parts[0],
implode($separator, \array_slice($parts, 1)),
];
}
}
return $parts;
}
}