Detecting emails in a text

Question

I\'m trying to create a function that translates every occurrence of a plain text email address in a given string into it\'s htmlized version.

Let\'s say I h

Answer 1

$str = preg_replace('/([a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,6})/', '<a href="mailto:$1">$1</a>', $str);

where ([a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,6}) is the regular expression used for detecting an email address (this is a general example, email addresses may be more complicated than this and not all addresses may be covered, but finding the perfect regex for emails is up to you)

Answer 2

There's always matching every sequence of non-space characters and testing those with filter_var, but this is probably one of those cases where it's just better to use regular expressions.

echo preg_replace('/(([\w!#$%&\'*+\-\/=?^`{|}~]|\\\\\\\\|\\\\?"|\\\\ )+\.)*([\w!#$%&\'*+\-\/=?^`{|}~]|\\\\\\\\|\\\\?"|\\\\ )+@((\w+[\.-])*[a-zA-Z]{2,}|\[(\d{1,3}\.){3}\d{1,3}\])/', '<a href="mailto:$0">$0</a>', $str);

I've tried to follow the standard as best I could without making it ridiculously compliant. And anybody who puts comments in his or her e-mail address can just be forgotten safely, I think. And it definitely works for common e-mails.

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EDIT: After a long, difficult struggle, here's my regular expression to match everything:

((([a-zA-Z0-9!\#\$%&'*+\-\/=?^_`{|}~]+|"([a-zA-Z0-9!\#\$%&'*+\-\/=?^_`{|}~(),:;<>@\[\]]|\\[ \\"])+")\.)*([a-zA-Z0-9!\#\$%&'*+\-\/=?^_`{|}~]+|"([a-zA-Z0-9!\#\$%&'*+\-\/=?^_`{|}~(),:;<>@\[\]]|\\[ \\"])+"))@((([a-zA-Z0-9]([a-zA-Z0-9]*(\-[a-zA-Z0-9]*)*)?\.)*[a-zA-Z]{2,}|\[((0?\d{1,2}|1\d{2}|2[0-4]\d|25[0-5])\.){3}(0?\d{1,2}|1\d{2}|2[0-4]\d|25[0-5])\]|\[[Ii][Pp][vV]6(:[0-9a-fA-F]{0,4}){6}\]))

Enjoy escaping it!

Answer 3

filter_var is nice to validate an email, but Dominic Sayers' is_email is even better, and my personal choice.

source code: http://code.google.com/p/isemail/source/browse/PHP/trunk/is_email.php

about: http://isemail.info/about

Answer 4

The code below should work fine, but it regex is easier to go with.

$str = "Send me an email to bob@example.com.";

   function htmlizestring($a){

        if(substr_count($a,"@") != 1){
            return false;
        }else{
            $b4 = stristr($a,"@",true);
            $b4pos = strripos($b4," ")+1;
            $b4 = trim(substr($b4,$b4pos));
            $after = stristr($a,"@");           
            if(substr_count($after, " ") == 0){
                $after=rtrim($after," .,");
            }else{
                $after=trim(stristr($after," ",true));
            }
            $email = $b4.$after;
            echo $email;
            if(filter_var($email, FILTER_VALIDATE_EMAIL)){
                echo "Send me an email at: <a href='mailto:".$email."'>".$email."</a>";
            }else{
                return false;
            }
        }   

    }

    htmlizestring($str);

I happen to use stristr() with the third parameter TRUE, which only works on php 5.3+