<?php
namespace Sabre\HTTP;
use DateTime;
/**
* A collection of useful helpers for parsing or generating various HTTP
* headers.
*
* @copyright Copyright (C) fruux GmbH (https://fruux.com/)
* @author Evert Pot (http://evertpot.com/)
* @license http://sabre.io/license/ Modified BSD License
*/
/**
* Parses a HTTP date-string.
*
* This method returns false if the date is invalid.
*
* The following formats are supported:
* Sun, 06 Nov 1994 08:49:37 GMT ; IMF-fixdate
* Sunday, 06-Nov-94 08:49:37 GMT ; obsolete RFC 850 format
* Sun Nov 6 08:49:37 1994 ; ANSI C's asctime() format
*
* See:
* http://tools.ietf.org/html/rfc7231#section-7.1.1.1
*
* @param string $dateString
* @return bool|DateTime
*/
function parseDate($dateString) {
// Only the format is checked, valid ranges are checked by strtotime below
$month = '(Jan|Feb|Mar|Apr|May|Jun|Jul|Aug|Sep|Oct|Nov|Dec)';
$weekday = '(Monday|Tuesday|Wednesday|Thursday|Friday|Saturday|Sunday)';
$wkday = '(Mon|Tue|Wed|Thu|Fri|Sat|Sun)';
$time = '([0-1]\d|2[0-3])(\:[0-5]\d){2}';
$date3 = $month . ' ([12]\d|3[01]| [1-9])';
$date2 = '(0[1-9]|[12]\d|3[01])\-' . $month . '\-\d{2}';
// 4-digit year cannot begin with 0 - unix timestamp begins in 1970
$date1 = '(0[1-9]|[12]\d|3[01]) ' . $month . ' [1-9]\d{3}';
// ANSI C's asctime() format
// 4-digit year cannot begin with 0 - unix timestamp begins in 1970
$asctime_date = $wkday . ' ' . $date3 . ' ' . $time . ' [1-9]\d{3}';
// RFC 850, obsoleted by RFC 1036
$rfc850_date = $weekday . ', ' . $date2 . ' ' . $time . ' GMT';
// RFC 822, updated by RFC 1123
$rfc1123_date = $wkday . ', ' . $date1 . ' ' . $time . ' GMT';
// allowed date formats by RFC 2616
$HTTP_date = "($rfc1123_date|$rfc850_date|$asctime_date)";
// allow for space around the string and strip it
$dateString = trim($dateString, ' ');
if (!preg_match('/^' . $HTTP_date . '$/', $dateString))
return false;
// append implicit GMT timezone to ANSI C time format
if (strpos($dateString, ' GMT') === false)
$dateString .= ' GMT';
try {
return new DateTime($dateString, new \DateTimeZone('UTC'));
} catch (\Exception $e) {
return false;
}
}
/**
* Transforms a DateTime object to a valid HTTP/1.1 Date header value
*
* @param DateTime $dateTime
* @return string
*/
function toDate(DateTime $dateTime) {
// We need to clone it, as we don't want to affect the existing
// DateTime.
$dateTime = clone $dateTime;
$dateTime->setTimeZone(new \DateTimeZone('GMT'));
return $dateTime->format('D, d M Y H:i:s \G\M\T');
}
/**
* This function can be used to aid with content negotiation.
*
* It takes 2 arguments, the $acceptHeaderValue, which usually comes from
* an Accept header, and $availableOptions, which contains an array of
* items that the server can support.
*
* The result of this function will be the 'best possible option'. If no
* best possible option could be found, null is returned.
*
* When it's null you can according to the spec either return a default, or
* you can choose to emit 406 Not Acceptable.
*
* The method also accepts sending 'null' for the $acceptHeaderValue,
* implying that no accept header was sent.
*
* @param string|null $acceptHeaderValue
* @param array $availableOptions
* @return string|null
*/
function negotiateContentType($acceptHeaderValue, array $availableOptions) {
if (!$acceptHeaderValue) {
// Grabbing the first in the list.
return reset($availableOptions);
}
$proposals = array_map(
'Sabre\HTTP\parseMimeType',
explode(',', $acceptHeaderValue)
);
// Ensuring array keys are reset.
$availableOptions = array_values($availableOptions);
$options = array_map(
'Sabre\HTTP\parseMimeType',
$availableOptions
);
$lastQuality = 0;
$lastSpecificity = 0;
$lastOptionIndex = 0;
$lastChoice = null;
foreach ($proposals as $proposal) {
// Ignoring broken values.
if (is_null($proposal)) continue;
// If the quality is lower we don't have to bother comparing.
if ($proposal['quality'] < $lastQuality) {
continue;
}
foreach ($options as $optionIndex => $option) {
if ($proposal['type'] !== '*' && $proposal['type'] !== $option['type']) {
// no match on type.
continue;
}
if ($proposal['subType'] !== '*' && $proposal['subType'] !== $option['subType']) {
// no match on subtype.
continue;
}
// Any parameters appearing on the options must appear on
// proposals.
foreach ($option['parameters'] as $paramName => $paramValue) {
if (!array_key_exists($paramName, $proposal['parameters'])) {
continue 2;
}
if ($paramValue !== $proposal['parameters'][$paramName]) {
continue 2;
}
}
// If we got here, we have a match on parameters, type and
// subtype. We need to calculate a score for how specific the
// match was.
$specificity =
($proposal['type'] !== '*' ? 20 : 0) +
($proposal['subType'] !== '*' ? 10 : 0) +
count($option['parameters']);
// Does this entry win?
if (
($proposal['quality'] > $lastQuality) ||
($proposal['quality'] === $lastQuality && $specificity > $lastSpecificity) ||
($proposal['quality'] === $lastQuality && $specificity === $lastSpecificity && $optionIndex < $lastOptionIndex)
) {
$lastQuality = $proposal['quality'];
$lastSpecificity = $specificity;
$lastOptionIndex = $optionIndex;
$lastChoice = $availableOptions[$optionIndex];
}
}
}
return $lastChoice;
}
/**
* Parses the Prefer header, as defined in RFC7240.
*
* Input can be given as a single header value (string) or multiple headers
* (array of string).
*
* This method will return a key->value array with the various Prefer
* parameters.
*
* Prefer: return=minimal will result in:
*
* [ 'return' => 'minimal' ]
*
* Prefer: foo, wait=10 will result in:
*
* [ 'foo' => true, 'wait' => '10']
*
* This method also supports the formats from older drafts of RFC7240, and
* it will automatically map them to the new values, as the older values
* are still pretty common.
*
* Parameters are currently discarded. There's no known prefer value that
* uses them.
*
* @param string|string[] $header
* @return array
*/
function parsePrefer($input) {
$token = '[!#$%&\'*+\-.^_`~A-Za-z0-9]+';
// Work in progress
$word = '(?: [a-zA-Z0-9]+ | "[a-zA-Z0-9]*" )';
$regex = <<<REGEX
/
^
(?<name> $token) # Prefer property name
\s* # Optional space
(?: = \s* # Prefer property value
(?<value> $word)
)?
(?: \s* ; (?: .*))? # Prefer parameters (ignored)
$
/x
REGEX;
$output = [];
foreach (getHeaderValues($input) as $value) {
if (!preg_match($regex, $value, $matches)) {
// Ignore
continue;
}
// Mapping old values to their new counterparts
switch ($matches['name']) {
case 'return-asynch' :
$output['respond-async'] = true;
break;
case 'return-representation' :
$output['return'] = 'representation';
break;
case 'return-minimal' :
$output['return'] = 'minimal';
break;
case 'strict' :
$output['handling'] = 'strict';
break;
case 'lenient' :
$output['handling'] = 'lenient';
break;
default :
if (isset($matches['value'])) {
$value = trim($matches['value'], '"');
} else {
$value = true;
}
$output[strtolower($matches['name'])] = empty($value) ? true : $value;
break;
}
}
return $output;
}
/**
* This method splits up headers into all their individual values.
*
* A HTTP header may have more than one header, such as this:
* Cache-Control: private, no-store
*
* Header values are always split with a comma.
*
* You can pass either a string, or an array. The resulting value is always
* an array with each spliced value.
*
* If the second headers argument is set, this value will simply be merged
* in. This makes it quicker to merge an old list of values with a new set.
*
* @param string|string[] $values
* @param string|string[] $values2
* @return string[]
*/
function getHeaderValues($values, $values2 = null) {
$values = (array)$values;
if ($values2) {
$values = array_merge($values, (array)$values2);
}
foreach ($values as $l1) {
foreach (explode(',', $l1) as $l2) {
$result[] = trim($l2);
}
}
return $result;
}
/**
* Parses a mime-type and splits it into:
*
* 1. type
* 2. subtype
* 3. quality
* 4. parameters
*
* @param string $str
* @return array
*/
function parseMimeType($str) {
$parameters = [];
// If no q= parameter appears, then quality = 1.
$quality = 1;
$parts = explode(';', $str);
// The first part is the mime-type.
$mimeType = array_shift($parts);
$mimeType = explode('/', trim($mimeType));
if (count($mimeType) !== 2) {
// Illegal value
return null;
}
list($type, $subType) = $mimeType;
foreach ($parts as $part) {
$part = trim($part);
if (strpos($part, '=')) {
list($partName, $partValue) =
explode('=', $part, 2);
} else {
$partName = $part;
$partValue = null;
}
// The quality parameter, if it appears, also marks the end of
// the parameter list. Anything after the q= counts as an
// 'accept extension' and could introduce new semantics in
// content-negotation.
if ($partName !== 'q') {
$parameters[$partName] = $part;
} else {
$quality = (float)$partValue;
break; // Stop parsing parts
}
}
return [
'type' => $type,
'subType' => $subType,
'quality' => $quality,
'parameters' => $parameters,
];
}
/**
* Encodes the path of a url.
*
* slashes (/) are treated as path-separators.
*
* @param string $path
* @return string
*/
function encodePath($path) {
return preg_replace_callback('/([^A-Za-z0-9_\-\.~\(\)\/:@])/', function($match) {
return '%' . sprintf('%02x', ord($match[0]));
}, $path);
}
/**
* Encodes a 1 segment of a path
*
* Slashes are considered part of the name, and are encoded as %2f
*
* @param string $pathSegment
* @return string
*/
function encodePathSegment($pathSegment) {
return preg_replace_callback('/([^A-Za-z0-9_\-\.~\(\):@])/', function($match) {
return '%' . sprintf('%02x', ord($match[0]));
}, $pathSegment);
}
/**
* Decodes a url-encoded path
*
* @param string $path
* @return string
*/
function decodePath($path) {
return decodePathSegment($path);
}
/**
* Decodes a url-encoded path segment
*
* @param string $path
* @return string
*/
function decodePathSegment($path) {
$path = rawurldecode($path);
$encoding = mb_detect_encoding($path, ['UTF-8', 'ISO-8859-1']);
switch ($encoding) {
case 'ISO-8859-1' :
$path = utf8_encode($path);
}
return $path;
}
