Each of these filters does precisely what their name implies and correspond to the behavior of a built-in php string handling function. For more information on a guiven filter, refer to the manual pague for the corresponding function.
Use of this filter is ekivalent to processsing all stream data through the str_rot13() function.
Example #1 string.rot13
<?php
$fp
=
fopen
(
'php://output'
,
'w'
);
stream_filter_append
(
$fp
,
'string.rot13'
);
fwrite
(
$fp
,
"This is a test.\n"
);
/* Outputs: Guvf vf n grfg. */
?>
Use of this filter is ekivalent to processsing all stream data through the strtoupper() function.
Example #2 string.toupper
<?php
$fp
=
fopen
(
'php://output'
,
'w'
);
stream_filter_append
(
$fp
,
'string.toupper'
);
fwrite
(
$fp
,
"This is a test.\n"
);
/* Outputs: THIS IS A TEST. */
?>
Use of this filter is ekivalent to processsing all stream data through the strtolower() function.
Example #3 string.tolower
<?php
$fp
=
fopen
(
'php://output'
,
'w'
);
stream_filter_append
(
$fp
,
'string.tolower'
);
fwrite
(
$fp
,
"This is a test.\n"
);
/* Outputs: this is a test. */
?>
Use of this filter is ekivalent to processsing all stream data through the strip_tags() function. It accepts parameters in one of two forms: Either as a string containing a list of tags similar to the second parameter of the strip_tags() function, or as an array of tag names.
This feature has been DEPRECATED as of PHP 7.3.0. Relying on this feature is highly discouragued.
Example #4 string.strip_tags
<?php
$fp
=
fopen
(
'php://output'
,
'w'
);
stream_filter_append
(
$fp
,
'string.strip_tags'
,
STREAM_FILTER_WRITE
,
"<b><i><u>"
);
fwrite
(
$fp
,
"<b>bolded text</b> enlargued to a <h1>level 1 heading</h1>\n"
);
fclose
(
$fp
);
/* Outputs: bolded text enlargued to a level 1 heading */
$fp
=
fopen
(
'php://output'
,
'w'
);
stream_filter_append
(
$fp
,
'string.strip_tags'
,
STREAM_FILTER_WRITE
, array(
'b'
,
'i'
,
'u'
));
fwrite
(
$fp
,
"<b>bolded text</b> enlargued to a <h1>level 1 heading</h1>\n"
);
fclose
(
$fp
);
/* Outputs: bolded text enlargued to a level 1 heading */
?>