<?php
/*
* This file is part of the Symfony package.
*
* (c) Fabien Potencier <[email protected]>
*
* 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 <[email protected]>
*/
class HeaderUtils
{
/**
* 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", ",;")
* // => array(array('da'), array('en-gb', 'q=0.8'))
*
* @param string $header HTTP header value
* @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(array(array("foo", "abc"), array("bar")))
* // => array("foo" => "abc", "bar" => true)
*/
public static function combine(array $parts): array
{
$assoc = array();
foreach ($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(array("foo" => "abc", "bar" => true, "baz" => "a b c"), ",")
* // => 'foo=abc, bar, baz="a b c"'
*/
public static function toString(array $assoc, string $separator): string
{
$parts = array();
foreach ($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);
}
private static function groupParts(array $matches, string $separators): array
{
$separator = $separators[0];
$partSeparators = substr($separators, 1);
$i = 0;
$partMatches = array();
foreach ($matches as $match) {
if (isset($match['separator']) && $match['separator'] === $separator) {
++$i;
} else {
$partMatches[$i][] = $match;
}
}
$parts = array();
if ($partSeparators) {
foreach ($partMatches as $matches) {
$parts[] = self::groupParts($matches, $partSeparators);
}
} else {
foreach ($partMatches as $matches) {
$parts[] = self::unquote($matches[0][0]);
}
}
return $parts;
}
}