有换行符的FILTER_SANITIZE_SPECIAL_CHARS问题

Question

Does anybody know how to prevent FILTER_SANITIZE_SPECIAL_CHARS from converting the line breaks ( ) into ( &#10 ; ).

I'm developing a simple commenting system for my website and I found that the php filter converts to so when using nl2br() there are no line breaks.

help please.

thanks :)

Answer 1

filter_var with the FILTER_SANITIZE_SPECIAL_CHARS option is doing what it is supposed to do:

HTML-escape '"<>& and characters with ASCII value less than 32, optionally strip or encode other special characters.

The newline character ( ) has an ASCII value of less than 32, so will be converted to 
. You could therefore use html_entity_decode to convert them back to their original characters:

$string = "line 1
line 2";
$filtered = filter_var($string, FILTER_SANITIZE_SPECIAL_CHARS);
echo "$filtered
";
echo(html_entity_decode($filtered));

Outputs:

line 1
line 2
line 1
line 2

But I guess that defeats the object of using FILTER_SANITIZE_SPECIAL_CHARS in the first place.

If it is only the newline that is causing the problem, you could replace the HTML character entity (
) with a newline character, before using nl2br():

echo str_replace('
', "
", $filtered);

Outputs:

line 1
line 2

Or perhaps even better, skip the middle step, and replace the HTML character entity (
) with <br />:

echo str_replace('&#10;', '<br />', $filtered);

Outputs:

line 1<br />line 2

...but I'm not 100% sure what it is you are trying to do.