1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
|
<?php
namespace MediaWiki\Rest\HeaderParser;
/**
* This is a parser for "HTTP-date" as defined by RFC 7231.
*
* Normally in MediaWiki, dates in HTTP headers are converted using
* ConvertibleTimestamp or strtotime(), and this is encouraged by RFC 7231:
*
* "Recipients of timestamp values are encouraged to be robust in parsing
* timestamps unless otherwise restricted by the field definition."
*
* In the case of If-Modified-Since, we are in fact otherwise restricted, since
* RFC 7232 says:
*
* "A recipient MUST ignore the If-Modified-Since header field if the
* received field-value is not a valid HTTP-date"
*
* So it is not correct to use strtotime() or ConvertibleTimestamp to parse
* If-Modified-Since.
*/
class HttpDate extends HeaderParserBase {
private const DAY_NAMES = [
'Mon' => true,
'Tue' => true,
'Wed' => true,
'Thu' => true,
'Fri' => true,
'Sat' => true,
'Sun' => true
];
private const MONTHS_BY_NAME = [
'Jan' => 1,
'Feb' => 2,
'Mar' => 3,
'Apr' => 4,
'May' => 5,
'Jun' => 6,
'Jul' => 7,
'Aug' => 8,
'Sep' => 9,
'Oct' => 10,
'Nov' => 11,
'Dec' => 12,
];
private const DAY_NAMES_LONG = [
'Monday',
'Tuesday',
'Wednesday',
'Thursday',
'Friday',
'Saturday',
'Sunday',
];
/** @var string */
private $dayName;
/** @var string */
private $day;
/** @var int */
private $month;
/** @var int */
private $year;
/** @var string */
private $hour;
/** @var string */
private $minute;
/** @var string */
private $second;
/**
* Parse an HTTP-date string
*
* @param string $dateString
* @return int|null The UNIX timestamp, or null if the date was invalid
*/
public static function parse( $dateString ) {
$parser = new self( $dateString );
if ( $parser->execute() ) {
return $parser->getUnixTime();
} else {
return null;
}
}
/**
* A convenience function to convert a UNIX timestamp to the preferred
* IMF-fixdate format for HTTP header output.
*
* @param int $unixTime
* @return false|string
*/
public static function format( $unixTime ) {
return gmdate( 'D, d M Y H:i:s \G\M\T', $unixTime );
}
/**
* Private constructor. Use the public static functions for public access.
*
* @param string $input
*/
private function __construct( $input ) {
$this->setInput( $input );
}
/**
* Parse the input string
*
* @return bool True for success
*/
private function execute() {
$this->pos = 0;
try {
$this->consumeFixdate();
$this->assertEnd();
return true;
} catch ( HeaderParserError $e ) {
}
$this->pos = 0;
try {
$this->consumeRfc850Date();
$this->assertEnd();
return true;
} catch ( HeaderParserError $e ) {
}
$this->pos = 0;
try {
$this->consumeAsctimeDate();
$this->assertEnd();
return true;
} catch ( HeaderParserError $e ) {
}
return false;
}
/**
* Execute the IMF-fixdate rule, or throw an exception
*
* @throws HeaderParserError
*/
private function consumeFixdate() {
$this->consumeDayName();
$this->consumeString( ', ' );
$this->consumeDate1();
$this->consumeString( ' ' );
$this->consumeTimeOfDay();
$this->consumeString( ' GMT' );
}
/**
* Execute the day-name rule, and capture the result.
*
* @throws HeaderParserError
*/
private function consumeDayName() {
$next3 = substr( $this->input, $this->pos, 3 );
if ( isset( self::DAY_NAMES[$next3] ) ) {
$this->dayName = $next3;
$this->pos += 3;
} else {
$this->error( 'expected day-name' );
}
}
/**
* Execute the date1 rule
*
* @throws HeaderParserError
*/
private function consumeDate1() {
$this->consumeDay();
$this->consumeString( ' ' );
$this->consumeMonth();
$this->consumeString( ' ' );
$this->consumeYear();
}
/**
* Execute the day rule, and capture the result.
*
* @throws HeaderParserError
*/
private function consumeDay() {
$this->day = $this->consumeFixedDigits( 2 );
}
/**
* Execute the month rule, and capture the result
*
* @throws HeaderParserError
*/
private function consumeMonth() {
$next3 = substr( $this->input, $this->pos, 3 );
if ( isset( self::MONTHS_BY_NAME[$next3] ) ) {
$this->month = self::MONTHS_BY_NAME[$next3];
$this->pos += 3;
} else {
$this->error( 'expected month' );
}
}
/**
* Execute the year rule, and capture the result
*
* @throws HeaderParserError
*/
private function consumeYear() {
$this->year = (int)$this->consumeFixedDigits( 4 );
}
/**
* Execute the time-of-day rule
* @throws HeaderParserError
*/
private function consumeTimeOfDay() {
$this->hour = $this->consumeFixedDigits( 2 );
$this->consumeString( ':' );
$this->minute = $this->consumeFixedDigits( 2 );
$this->consumeString( ':' );
$this->second = $this->consumeFixedDigits( 2 );
}
/**
* Execute the rfc850-date rule
*
* @throws HeaderParserError
*/
private function consumeRfc850Date() {
$this->consumeDayNameLong();
$this->consumeString( ', ' );
$this->consumeDate2();
$this->consumeString( ' ' );
$this->consumeTimeOfDay();
$this->consumeString( ' GMT' );
}
/**
* Execute the date2 rule.
*
* @throws HeaderParserError
*/
private function consumeDate2() {
$this->consumeDay();
$this->consumeString( '-' );
$this->consumeMonth();
$this->consumeString( '-' );
$year = $this->consumeFixedDigits( 2 );
// RFC 2626 section 11.2
$currentYear = (int)gmdate( 'Y' );
$startOfCentury = (int)round( $currentYear, -2 );
$this->year = $startOfCentury + intval( $year );
$pivot = $currentYear + 50;
if ( $this->year > $pivot ) {
$this->year -= 100;
}
}
/**
* Execute the day-name-l rule
*
* @throws HeaderParserError
*/
private function consumeDayNameLong() {
foreach ( self::DAY_NAMES_LONG as $dayName ) {
if ( substr_compare( $this->input, $dayName, $this->pos, strlen( $dayName ) ) === 0 ) {
$this->dayName = substr( $dayName, 0, 3 );
$this->pos += strlen( $dayName );
return;
}
}
$this->error( 'expected day-name-l' );
}
/**
* Execute the asctime-date rule
*
* @throws HeaderParserError
*/
private function consumeAsctimeDate() {
$this->consumeDayName();
$this->consumeString( ' ' );
$this->consumeDate3();
$this->consumeString( ' ' );
$this->consumeTimeOfDay();
$this->consumeString( ' ' );
$this->consumeYear();
}
/**
* Execute the date3 rule
*
* @throws HeaderParserError
*/
private function consumeDate3() {
$this->consumeMonth();
$this->consumeString( ' ' );
if ( ( $this->input[$this->pos] ?? '' ) === ' ' ) {
$this->pos++;
$this->day = '0' . $this->consumeFixedDigits( 1 );
} else {
$this->day = $this->consumeFixedDigits( 2 );
}
}
/**
* Convert the captured results to a UNIX timestamp.
* This should only be called after parsing succeeds.
*
* @return int
*/
private function getUnixTime() {
return gmmktime( (int)$this->hour, (int)$this->minute, (int)$this->second,
$this->month, (int)$this->day, $this->year );
}
}
|
