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FormatJson.php
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1 <?php
26 class FormatJson {
34  const UTF8_OK = 1;
35 
46  const XMLMETA_OK = 2;
47 
55  const ALL_OK = self::UTF8_OK | self::XMLMETA_OK;
56 
63  const FORCE_ASSOC = 0x100;
64 
70  const TRY_FIXING = 0x200;
71 
77  const STRIP_COMMENTS = 0x400;
78 
85  private const BAD_CHARS = [
86  "\u{2028}", // U+2028 LINE SEPARATOR
87  "\u{2029}", // U+2029 PARAGRAPH SEPARATOR
88  ];
89 
93  private const BAD_CHARS_ESCAPED = [
94  '\u2028', // U+2028 LINE SEPARATOR
95  '\u2029', // U+2029 PARAGRAPH SEPARATOR
96  ];
97 
115  public static function encode( $value, $pretty = false, $escaping = 0 ) {
116  if ( !is_string( $pretty ) ) {
117  $pretty = $pretty ? ' ' : false;
118  }
119 
120  // PHP escapes '/' to prevent breaking out of inline script blocks using '</script>',
121  // which is hardly useful when '<' and '>' are escaped (and inadequate), and such
122  // escaping negatively impacts the human readability of URLs and similar strings.
123  $options = JSON_UNESCAPED_SLASHES;
124  $options |= $pretty !== false ? JSON_PRETTY_PRINT : 0;
125  $options |= ( $escaping & self::UTF8_OK ) ? JSON_UNESCAPED_UNICODE : 0;
126  $options |= ( $escaping & self::XMLMETA_OK ) ? 0 : ( JSON_HEX_TAG | JSON_HEX_AMP );
127  $json = json_encode( $value, $options );
128  if ( $json === false ) {
129  return false;
130  }
131 
132  if ( $pretty !== false && $pretty !== ' ' ) {
133  // Change the four-space indent to a tab indent
134  $json = str_replace( "\n ", "\n\t", $json );
135  while ( strpos( $json, "\t " ) !== false ) {
136  $json = str_replace( "\t ", "\t\t", $json );
137  }
138 
139  if ( $pretty !== "\t" ) {
140  // Change the tab indent to the provided indent
141  $json = str_replace( "\t", $pretty, $json );
142  }
143  }
144  if ( $escaping & self::UTF8_OK ) {
145  $json = str_replace( self::BAD_CHARS, self::BAD_CHARS_ESCAPED, $json );
146  }
147 
148  return $json;
149  }
150 
174  public static function decode( $value, $assoc = false ) {
175  return json_decode( $value, $assoc );
176  }
177 
188  public static function parse( $value, $options = 0 ) {
189  if ( $options & self::STRIP_COMMENTS ) {
190  $value = self::stripComments( $value );
191  }
192  $assoc = ( $options & self::FORCE_ASSOC ) !== 0;
193  $result = json_decode( $value, $assoc );
194  $code = json_last_error();
195 
196  if ( $code === JSON_ERROR_SYNTAX && ( $options & self::TRY_FIXING ) !== 0 ) {
197  // The most common error is the trailing comma in a list or an object.
198  // We cannot simply replace /,\s*[}\]]/ because it could be inside a string value.
199  // But we could use the fact that JSON does not allow multi-line string values,
200  // And remove trailing commas if they are et the end of a line.
201  // JSON only allows 4 control characters: [ \t\r\n]. So we must not use '\s' for matching.
202  // Regex match ,]<any non-quote chars>\n or ,\n] with optional spaces/tabs.
203  $count = 0;
204  $value =
205  preg_replace( '/,([ \t]*[}\]][^"\r\n]*([\r\n]|$)|[ \t]*[\r\n][ \t\r\n]*[}\]])/', '$1',
206  $value, -1, $count );
207  if ( $count > 0 ) {
208  $result = json_decode( $value, $assoc );
209  if ( JSON_ERROR_NONE === json_last_error() ) {
210  // Report warning
211  $st = Status::newGood( $result );
212  $st->warning( wfMessage( 'json-warn-trailing-comma' )->numParams( $count ) );
213  return $st;
214  }
215  }
216  }
217 
218  switch ( $code ) {
219  case JSON_ERROR_NONE:
220  return Status::newGood( $result );
221  default:
222  return Status::newFatal( wfMessage( 'json-error-unknown' )->numParams( $code ) );
223  case JSON_ERROR_DEPTH:
224  $msg = 'json-error-depth';
225  break;
226  case JSON_ERROR_STATE_MISMATCH:
227  $msg = 'json-error-state-mismatch';
228  break;
229  case JSON_ERROR_CTRL_CHAR:
230  $msg = 'json-error-ctrl-char';
231  break;
232  case JSON_ERROR_SYNTAX:
233  $msg = 'json-error-syntax';
234  break;
235  case JSON_ERROR_UTF8:
236  $msg = 'json-error-utf8';
237  break;
238  case JSON_ERROR_RECURSION:
239  $msg = 'json-error-recursion';
240  break;
241  case JSON_ERROR_INF_OR_NAN:
242  $msg = 'json-error-inf-or-nan';
243  break;
244  case JSON_ERROR_UNSUPPORTED_TYPE:
245  $msg = 'json-error-unsupported-type';
246  break;
247  }
248  return Status::newFatal( $msg );
249  }
250 
259  public static function stripComments( $json ) {
260  // Ensure we have a string
261  $str = (string)$json;
262  $buffer = '';
263  $maxLen = strlen( $str );
264  $mark = 0;
265 
266  $inString = false;
267  $inComment = false;
268  $multiline = false;
269 
270  for ( $idx = 0; $idx < $maxLen; $idx++ ) {
271  switch ( $str[$idx] ) {
272  case '"':
273  $lookBehind = ( $idx - 1 >= 0 ) ? $str[$idx - 1] : '';
274  if ( !$inComment && $lookBehind !== '\\' ) {
275  // Either started or ended a string
276  $inString = !$inString;
277  }
278  break;
279 
280  case '/':
281  $lookAhead = ( $idx + 1 < $maxLen ) ? $str[$idx + 1] : '';
282  $lookBehind = ( $idx - 1 >= 0 ) ? $str[$idx - 1] : '';
283  if ( $inString ) {
284  break;
285 
286  } elseif ( !$inComment &&
287  ( $lookAhead === '/' || $lookAhead === '*' )
288  ) {
289  // Transition into a comment
290  // Add characters seen to buffer
291  $buffer .= substr( $str, $mark, $idx - $mark );
292  // Consume the look ahead character
293  $idx++;
294  // Track state
295  $inComment = true;
296  $multiline = $lookAhead === '*';
297 
298  } elseif ( $multiline && $lookBehind === '*' ) {
299  // Found the end of the current comment
300  $mark = $idx + 1;
301  $inComment = false;
302  $multiline = false;
303  }
304  break;
305 
306  case "\n":
307  if ( $inComment && !$multiline ) {
308  // Found the end of the current comment
309  $mark = $idx + 1;
310  $inComment = false;
311  }
312  break;
313  }
314  }
315  if ( $inComment ) {
316  // Comment ends with input
317  // Technically we should check to ensure that we aren't in
318  // a multiline comment that hasn't been properly ended, but this
319  // is a strip filter, not a validating parser.
320  $mark = $maxLen;
321  }
322  // Add final chunk to buffer before returning
323  return $buffer . substr( $str, $mark, $maxLen - $mark );
324  }
325 }
static newFatal( $message,... $parameters)
Factory function for fatal errors.
Definition: StatusValue.php:69
const ALL_OK
Skip escaping as many characters as reasonably possible.
Definition: FormatJson.php:55
static encode( $value, $pretty=false, $escaping=0)
Returns the JSON representation of a value.
Definition: FormatJson.php:115
const BAD_CHARS_ESCAPED
Escape sequences for characters listed in FormatJson::BAD_CHARS.
Definition: FormatJson.php:93
const UTF8_OK
Skip escaping most characters above U+007F for readability and compactness.
Definition: FormatJson.php:34
const TRY_FIXING
If set, attempt to fix invalid JSON.
Definition: FormatJson.php:70
const FORCE_ASSOC
If set, treat JSON objects &#39;{...}&#39; as associative arrays.
Definition: FormatJson.php:63
static newGood( $value=null)
Factory function for good results.
Definition: StatusValue.php:81
static decode( $value, $assoc=false)
Decodes a JSON string.
Definition: FormatJson.php:174
const STRIP_COMMENTS
If set, strip comments from input before parsing as JSON.
Definition: FormatJson.php:77
static stripComments( $json)
Remove multiline and single line comments from an otherwise valid JSON input string.
Definition: FormatJson.php:259
const BAD_CHARS
Characters problematic in JavaScript.
Definition: FormatJson.php:85
wfMessage( $key,... $params)
This is the function for getting translated interface messages.
static parse( $value, $options=0)
Decodes a JSON string.
Definition: FormatJson.php:188
const XMLMETA_OK
Skip escaping the characters &#39;<&#39;, &#39;>&#39;, and &#39;&&#39;, which have special meanings in HTML and XML...
Definition: FormatJson.php:46