mirror of
https://github.com/mrclay/minify.git
synced 2025-02-23 00:12:36 +01:00
263 lines
8.3 KiB
PHP
263 lines
8.3 KiB
PHP
<?php
|
|
/**
|
|
* Class HTTP_ConditionalGet
|
|
* @package Minify
|
|
* @subpackage HTTP
|
|
*/
|
|
|
|
/**
|
|
* Implement conditional GET via a timestamp or hash of content
|
|
*
|
|
* E.g. Content from DB with update time:
|
|
* <code>
|
|
* list($updateTime, $content) = getDbUpdateAndContent();
|
|
* $cg = new HTTP_ConditionalGet(array(
|
|
* 'lastModifiedTime' => $updateTime
|
|
* ));
|
|
* $cg->sendHeaders();
|
|
* if ($cg->cacheIsValid) {
|
|
* exit();
|
|
* }
|
|
* echo $content;
|
|
* </code>
|
|
*
|
|
* E.g. Content from DB with no update time:
|
|
* <code>
|
|
* $content = getContentFromDB();
|
|
* $cg = new HTTP_ConditionalGet(array(
|
|
* 'contentHash' => md5($content)
|
|
* ));
|
|
* $cg->sendHeaders();
|
|
* if ($cg->cacheIsValid) {
|
|
* exit();
|
|
* }
|
|
* echo $content;
|
|
* </code>
|
|
*
|
|
* E.g. Static content with some static includes:
|
|
* <code>
|
|
* // before content
|
|
* $cg = new HTTP_ConditionalGet(array(
|
|
* 'lastUpdateTime' => max(
|
|
* filemtime(__FILE__)
|
|
* ,filemtime('/path/to/header.inc')
|
|
* ,filemtime('/path/to/footer.inc')
|
|
* )
|
|
* ));
|
|
* $cg->sendHeaders();
|
|
* if ($cg->cacheIsValid) {
|
|
* exit();
|
|
* }
|
|
* </code>
|
|
* @package Minify
|
|
* @subpackage HTTP
|
|
* @author Stephen Clay <steve@mrclay.org>
|
|
*/
|
|
class HTTP_ConditionalGet {
|
|
|
|
/**
|
|
* Does the client have a valid copy of the requested resource?
|
|
*
|
|
* You'll want to check this after instantiating the object. If true, do
|
|
* not send content, just call sendHeaders() if you haven't already.
|
|
*
|
|
* @var bool
|
|
*/
|
|
public $cacheIsValid = null;
|
|
|
|
/**
|
|
* @param array $spec options
|
|
*
|
|
* 'isPublic': (bool) if true, the Cache-Control header will contain
|
|
* "public", allowing proxy caches to cache the content. Otherwise
|
|
* "private" will be sent, allowing only browsers to cache. (default false)
|
|
*
|
|
* 'lastModifiedTime': (int) if given, both ETag AND Last-Modified headers
|
|
* will be sent with content. This is recommended.
|
|
*
|
|
* 'contentHash': (string) if given, only the ETag header can be sent with
|
|
* content (only HTTP1.1 clients can conditionally GET). The given string
|
|
* should be short with no quote characters and always change when the
|
|
* resource changes (recommend md5()). This is not needed/used if
|
|
* lastModifiedTime is given.
|
|
*
|
|
* 'invalidate': (bool) if true, the client cache will be considered invalid
|
|
* without testing. Effectively this disables conditional GET.
|
|
* (default false)
|
|
*
|
|
* 'maxAge': (int) if given, this will set the Cache-Control max-age in
|
|
* seconds, and also set the Expires header to the equivalent GMT date.
|
|
* After the max-age period has passed, the browser will again send a
|
|
* conditional GET to revalidate its cache.
|
|
*
|
|
* @return null
|
|
*/
|
|
public function __construct($spec) {
|
|
$scope = (isset($spec['isPublic']) && $spec['isPublic'])
|
|
? 'public'
|
|
: 'private';
|
|
$maxAge = 0;
|
|
// backwards compatibility (can be removed later)
|
|
if (isset($spec['setExpires'])
|
|
&& is_numeric($spec['setExpires'])
|
|
&& ! isset($spec['maxAge'])) {
|
|
$spec['maxAge'] = $spec['setExpires'] - $_SERVER['REQUEST_TIME'];
|
|
}
|
|
if (isset($spec['maxAge'])) {
|
|
$maxAge = $spec['maxAge'];
|
|
$this->_headers['Expires'] = self::gmtDate(
|
|
$_SERVER['REQUEST_TIME'] + $spec['maxAge']
|
|
);
|
|
}
|
|
if (isset($spec['lastModifiedTime'])) {
|
|
// base both headers on time
|
|
$this->_setLastModified($spec['lastModifiedTime']);
|
|
$this->_setEtag($spec['lastModifiedTime'], $scope);
|
|
} else {
|
|
// hope to use ETag
|
|
if (isset($spec['contentHash'])) {
|
|
$this->_setEtag($spec['contentHash'], $scope);
|
|
}
|
|
}
|
|
$this->_headers['Cache-Control'] = "max-age={$maxAge}, {$scope}, must-revalidate";
|
|
// invalidate cache if disabled, otherwise check
|
|
$this->cacheIsValid = (isset($spec['invalidate']) && $spec['invalidate'])
|
|
? false
|
|
: $this->_isCacheValid();
|
|
}
|
|
|
|
/**
|
|
* Get array of output headers to be sent
|
|
*
|
|
* In the case of 304 responses, this array will only contain the response
|
|
* code header: array('_responseCode' => 'HTTP/1.0 304 Not Modified')
|
|
*
|
|
* Otherwise something like:
|
|
* <code>
|
|
* array(
|
|
* 'Cache-Control' => 'max-age=0, public, must-revalidate'
|
|
* ,'ETag' => '"foobar"'
|
|
* )
|
|
* </code>
|
|
*
|
|
* @return array
|
|
*/
|
|
public function getHeaders() {
|
|
return $this->_headers;
|
|
}
|
|
|
|
/**
|
|
* Set the Content-Length header in bytes
|
|
*
|
|
* With most PHP configs, as long as you don't flush() output, this method
|
|
* is not needed and PHP will buffer all output and set Content-Length for
|
|
* you. Otherwise you'll want to call this to let the client know up front.
|
|
*
|
|
* @param int $bytes
|
|
*
|
|
* @return int copy of input $bytes
|
|
*/
|
|
public function setContentLength($bytes) {
|
|
return $this->_headers['Content-Length'] = $bytes;
|
|
}
|
|
|
|
/**
|
|
* Send headers
|
|
*
|
|
* @see getHeaders()
|
|
*
|
|
* Note this doesn't "clear" the headers. Calling sendHeaders() will
|
|
* call header() again (but probably have not effect) and getHeaders() will
|
|
* still return the headers.
|
|
*
|
|
* @return null
|
|
*/
|
|
public function sendHeaders() {
|
|
$headers = $this->_headers;
|
|
if (array_key_exists('_responseCode', $headers)) {
|
|
header($headers['_responseCode']);
|
|
unset($headers['_responseCode']);
|
|
}
|
|
foreach ($headers as $name => $val) {
|
|
header($name . ': ' . $val);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Get a GMT formatted date for use in HTTP headers
|
|
*
|
|
* <code>
|
|
* header('Expires: ' . HTTP_ConditionalGet::gmtdate($time));
|
|
* </code>
|
|
*
|
|
* @param int $time unix timestamp
|
|
*
|
|
* @return string
|
|
*/
|
|
public static function gmtDate($time) {
|
|
return gmdate('D, d M Y H:i:s \G\M\T', $time);
|
|
}
|
|
|
|
protected $_headers = array();
|
|
protected $_lmTime = null;
|
|
protected $_etag = null;
|
|
|
|
protected function _setEtag($hash, $scope) {
|
|
$this->_etag = '"' . $hash
|
|
. substr($scope, 0, 3)
|
|
. '"';
|
|
$this->_headers['ETag'] = $this->_etag;
|
|
}
|
|
|
|
protected function _setLastModified($time) {
|
|
$this->_lmTime = (int)$time;
|
|
$this->_headers['Last-Modified'] = self::gmtDate($time);
|
|
}
|
|
|
|
/**
|
|
* Determine validity of client cache and queue 304 header if valid
|
|
*/
|
|
protected function _isCacheValid()
|
|
{
|
|
if (null === $this->_etag) {
|
|
// lmTime is copied to ETag, so this condition implies that the
|
|
// client received neither ETag nor Last-Modified, so can't
|
|
// possibly has a valid cache.
|
|
return false;
|
|
}
|
|
$isValid = ($this->resourceMatchedEtag() || $this->resourceNotModified());
|
|
if ($isValid) {
|
|
$this->_headers['_responseCode'] = 'HTTP/1.0 304 Not Modified';
|
|
}
|
|
return $isValid;
|
|
}
|
|
|
|
protected function resourceMatchedEtag() {
|
|
if (!isset($_SERVER['HTTP_IF_NONE_MATCH'])) {
|
|
return false;
|
|
}
|
|
$cachedEtagList = get_magic_quotes_gpc()
|
|
? stripslashes($_SERVER['HTTP_IF_NONE_MATCH'])
|
|
: $_SERVER['HTTP_IF_NONE_MATCH'];
|
|
$cachedEtags = split(',', $cachedEtagList);
|
|
foreach ($cachedEtags as $cachedEtag) {
|
|
if (trim($cachedEtag) == $this->_etag) {
|
|
return true;
|
|
}
|
|
}
|
|
return false;
|
|
}
|
|
|
|
protected function resourceNotModified() {
|
|
if (!isset($_SERVER['HTTP_IF_MODIFIED_SINCE'])) {
|
|
return false;
|
|
}
|
|
$ifModifiedSince = $_SERVER['HTTP_IF_MODIFIED_SINCE'];
|
|
if (false !== ($semicolon = strrpos($ifModifiedSince, ';'))) {
|
|
// IE has tacked on extra data to this header, strip it
|
|
$ifModifiedSince = substr($ifModifiedSince, 0, $semicolon);
|
|
}
|
|
return ($ifModifiedSince == self::gmtDate($this->_lmTime));
|
|
}
|
|
}
|