Removing emojis from variable

Question

I'm using Smarty to pass in and display the contents of a first_name variable. Some users have Emoji characters (http://en.wikipedia.org/wiki/Emoji) in their first_name and I am wondering how I can either a) conditionally not display a user's first_name if it contains emojis or b) filter out emoji characters from first_name. Can this be done with Smarty? Can it be done with PHP in Smarty?

Answer 1

The emoji are encoded in the block U+1F300–U+1F5FF.

preg_replace('/\xEE[\x80-\xBF][\x80-\xBF]|\xEF[\x81-\x83][\x80-\xBF]/', '', $first_name)

this will strip those out

Answer 2

I tried some of the solutions posted above, but no one worked, however, when I converted the string to UTF-8 using the mb_ function it works properly.

You can use:

trim( preg_replace('/[\x00-\x1F\x80-\xFF]/', '', 
      mb_convert_encoding( $emojiString, "UTF-8" ) ) );

Works for me.

Answer 3

Q: Can this be done with Smarty? A: Yes.

Q: Can it be done with PHP in Smarty? A: Yes. But please don't use PHP tags on template side.

Try to use a variable modifier on a template variable instead.

{* apply modifier to a variable *}
{$first_name|emojistrip}

Put the following content into a file named "modifier.emojistrip.php" in the folder "/smarty/plugins/".

function smarty_modifier_emojistrip($string)
{       
    return preg_replace('/\xEE[\x80-\xBF][\x80-\xBF]|\xEF[\x81-\x83][\x80-\xBF]/', '', $string);
}