MediaWiki  master
ConditionalHeaderUtil.php
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1 <?php
2 
3 namespace MediaWiki\Rest;
4 
8 
10  private $validatorsHaveBeenSet = false;
11  private $eTag;
12  private $lastModified;
14 
30  $this->validatorsHaveBeenSet = true;
31  $this->eTag = $eTag;
32  if ( $lastModified === null ) {
33  $this->lastModified = null;
34  } else {
35  $this->lastModified = ConvertibleTimestamp::convert( TS_UNIX, $lastModified );
36  }
37  if ( $hasRepresentation === null ) {
38  $hasRepresentation = $eTag !== null;
39  }
40  $this->hasRepresentation = $hasRepresentation;
41  }
42 
50  public function checkPreconditions( RequestInterface $request ) {
51  $parser = new IfNoneMatch;
52  if ( $this->eTag !== null ) {
53  $resourceTag = $parser->parseETag( $this->eTag );
54  if ( !$resourceTag ) {
55  throw new \Exception( 'Invalid ETag returned by handler: ' .
56  $parser->getLastError() );
57  }
58  } else {
59  $resourceTag = null;
60  }
61  $getOrHead = in_array( $request->getMethod(), [ 'GET', 'HEAD' ] );
62  if ( $request->hasHeader( 'If-Match' ) ) {
63  $im = $request->getHeader( 'If-Match' );
64  $match = false;
65  foreach ( $parser->parseHeaderList( $im ) as $tag ) {
66  if ( $tag['whole'] === '*' && $this->hasRepresentation ) {
67  $match = true;
68  break;
69  }
70  if ( $this->strongCompare( $resourceTag, $tag ) ) {
71  $match = true;
72  break;
73  }
74  }
75  if ( !$match ) {
76  return 412;
77  }
78  } elseif ( $request->hasHeader( 'If-Unmodified-Since' ) ) {
79  $requestDate = HttpDate::parse( $request->getHeader( 'If-Unmodified-Since' )[0] );
80  if ( $requestDate !== null
81  && ( $this->lastModified === null || $this->lastModified > $requestDate )
82  ) {
83  return 412;
84  }
85  }
86  if ( $request->hasHeader( 'If-None-Match' ) ) {
87  $inm = $request->getHeader( 'If-None-Match' );
88  foreach ( $parser->parseHeaderList( $inm ) as $tag ) {
89  if ( $this->weakCompare( $resourceTag, $tag ) ) {
90  if ( $getOrHead ) {
91  return 304;
92  } else {
93  return 412;
94  }
95  }
96  }
97  } elseif ( $getOrHead && $request->hasHeader( 'If-Modified-Since' ) ) {
98  $requestDate = HttpDate::parse( $request->getHeader( 'If-Modified-Since' )[0] );
99  if ( $requestDate !== null && $this->lastModified !== null
100  && $this->lastModified <= $requestDate
101  ) {
102  return 304;
103  }
104  }
105  // RFC 7232 states that If-Range should be evaluated here. However, the
106  // purpose of If-Range is to cause the Range request header to be
107  // conditionally ignored, not to immediately send a response, so it
108  // doesn't fit here. RFC 7232 only requires that If-Range be checked
109  // after the other conditional header fields, a requirement that is
110  // satisfied if it is processed in Handler::execute().
111  return null;
112  }
113 
124  if ( $this->lastModified !== null && !$response->hasHeader( 'Last-Modified' ) ) {
125  $response->setHeader( 'Last-Modified', HttpDate::format( $this->lastModified ) );
126  }
127  if ( $this->eTag !== null && !$response->hasHeader( 'ETag' ) ) {
128  $response->setHeader( 'ETag', $this->eTag );
129  }
130  }
131 
139  private function weakCompare( $tag1, $tag2 ) {
140  return $tag1['contents'] === $tag2['contents'];
141  }
142 
150  private function strongCompare( $tag1, $tag2 ) {
151  return !$tag1['weak'] && !$tag2['weak'] && $tag1['contents'] === $tag2['contents'];
152  }
153 }
$response
setHeader( $name, $value)
Set or replace the specified header.
applyResponseHeaders(ResponseInterface $response)
Set Last-Modified and ETag headers in the response according to the cached values set by setValidator...
strongCompare( $tag1, $tag2)
The strong comparison function.
getHeader( $name)
Retrieves a message header value by the given case-insensitive name.
hasHeader( $name)
Checks if a header exists by the given case-insensitive name.
getMethod()
Retrieves the HTTP method of the request.
parseETag( $eTag)
Parse an entity-tag such as might be found in an ETag response header.
Definition: IfNoneMatch.php:68
static format( $unixTime)
A convenience function to convert a UNIX timestamp to the preferred IMF-fixdate format for HTTP heade...
Definition: HttpDate.php:89
static parse( $dateString)
Parse an HTTP-date string.
Definition: HttpDate.php:73
weakCompare( $tag1, $tag2)
The weak comparison function.
hasHeader( $name)
Checks if a header exists by the given case-insensitive name.
A request interface similar to PSR-7&#39;s ServerRequestInterface.
A class to assist with the parsing of If-None-Match, If-Match and ETag headers.
Definition: IfNoneMatch.php:8
setValidators( $eTag, $lastModified, $hasRepresentation)
Initialize the object with information about the requested resource.
An interface similar to PSR-7&#39;s ResponseInterface, the primary difference being that it is mutable...
checkPreconditions(RequestInterface $request)
Check conditional request headers in the order required by RFC 7232 section 6.