|
1
|
|
|
<?php |
|
2
|
|
|
|
|
3
|
|
|
namespace SilverStripe\Control\Middleware; |
|
4
|
|
|
|
|
5
|
|
|
use SilverStripe\Control\HTTPRequest; |
|
6
|
|
|
use SilverStripe\Control\HTTPResponse; |
|
7
|
|
|
use SilverStripe\Core\Injector\Injectable; |
|
8
|
|
|
|
|
9
|
|
|
/** |
|
10
|
|
|
* Handles internal change detection via etag / ifmodifiedsince headers, |
|
11
|
|
|
* conditonally sending a 304 not modified if possible. |
|
12
|
|
|
*/ |
|
13
|
|
|
class ChangeDetectionMiddleware implements HTTPMiddleware |
|
14
|
|
|
{ |
|
15
|
|
|
use Injectable; |
|
16
|
|
|
|
|
17
|
|
|
/** |
|
18
|
|
|
* Generate response for the given request |
|
19
|
|
|
* |
|
20
|
|
|
* @param HTTPRequest $request |
|
21
|
|
|
* @param callable $delegate |
|
22
|
|
|
* @return HTTPResponse |
|
23
|
|
|
*/ |
|
24
|
|
|
public function process(HTTPRequest $request, callable $delegate) |
|
25
|
|
|
{ |
|
26
|
|
|
/** @var HTTPResponse $response */ |
|
27
|
|
|
$response = $delegate($request); |
|
28
|
|
|
if (!$response) { |
|
|
|
|
|
|
29
|
|
|
return null; |
|
30
|
|
|
} |
|
31
|
|
|
|
|
32
|
|
|
// Ignore etag for no-store |
|
33
|
|
|
$cacheControl = $response->getHeader('Cache-Control'); |
|
34
|
|
|
if ($cacheControl && strstr($cacheControl, 'no-store')) { |
|
35
|
|
|
return $response; |
|
36
|
|
|
} |
|
37
|
|
|
|
|
38
|
|
|
// Generate, assign, and conditionally check etag |
|
39
|
|
|
$etag = $this->generateETag($response); |
|
40
|
|
|
if ($etag) { |
|
41
|
|
|
$response->addHeader('ETag', $etag); |
|
42
|
|
|
|
|
43
|
|
|
// Check if we have a match |
|
44
|
|
|
$ifNoneMatch = $request->getHeader('If-None-Match'); |
|
45
|
|
|
if ($ifNoneMatch === $etag) { |
|
46
|
|
|
return $this->sendNotModified($request, $response); |
|
47
|
|
|
} |
|
48
|
|
|
} |
|
49
|
|
|
|
|
50
|
|
|
// Check If-Modified-Since |
|
51
|
|
|
$ifModifiedSince = $request->getHeader('If-Modified-Since'); |
|
52
|
|
|
$lastModified = $response->getHeader('Last-Modified'); |
|
53
|
|
|
if ($ifModifiedSince && $lastModified && strtotime($ifModifiedSince) >= strtotime($lastModified)) { |
|
54
|
|
|
return $this->sendNotModified($request, $response); |
|
55
|
|
|
} |
|
56
|
|
|
|
|
57
|
|
|
return $response; |
|
58
|
|
|
} |
|
59
|
|
|
|
|
60
|
|
|
/** |
|
61
|
|
|
* @param HTTPResponse|string $response |
|
62
|
|
|
* @return string|false |
|
63
|
|
|
*/ |
|
64
|
|
|
protected function generateETag(HTTPResponse $response) |
|
65
|
|
|
{ |
|
66
|
|
|
// Existing e-tag |
|
67
|
|
|
$etag = $response->getHeader('ETag'); |
|
68
|
|
|
if ($etag) { |
|
69
|
|
|
return $etag; |
|
70
|
|
|
} |
|
71
|
|
|
|
|
72
|
|
|
// Generate etag from body |
|
73
|
|
|
return sprintf('"%s"', md5($response->getBody())); |
|
74
|
|
|
} |
|
75
|
|
|
|
|
76
|
|
|
/** |
|
77
|
|
|
* Sent not-modified response |
|
78
|
|
|
* |
|
79
|
|
|
* @param HTTPRequest $request |
|
80
|
|
|
* @param HTTPResponse $response |
|
81
|
|
|
* @return mixed |
|
82
|
|
|
*/ |
|
83
|
|
|
protected function sendNotModified(HTTPRequest $request, HTTPResponse $response) |
|
84
|
|
|
{ |
|
85
|
|
|
// 304 is invalid for destructive requests |
|
86
|
|
|
if (in_array($request->httpMethod(), ['POST', 'DELETE', 'PUT'])) { |
|
87
|
|
|
$response->setStatusCode(412); |
|
88
|
|
|
} else { |
|
89
|
|
|
$response->setStatusCode(304); |
|
90
|
|
|
} |
|
91
|
|
|
$response->setBody(''); |
|
92
|
|
|
return $response; |
|
93
|
|
|
} |
|
94
|
|
|
} |
|
95
|
|
|
|
silverstripe /
silverstripe-framework
Loading history...