emObA effectively and automatically makes it difficult for spambots to harvest email addresses from your Wordpress-powered blog. Email addresses may be placed in posts, comments, and pages, as html links, in a special “easy email” form, or as the address itself, and they will be protected by emObA automatically. All email addresses appearing on your blog will appear on the screen (if JavaScript is enabled) as active links to normal, valid, and correct email addresses, but to spambots they will have no recognizable features. (As usual, the actual email appears in the status bar when hovering.)
The email addresses occur in the HTML source only in a well-hidden encoding. The email address is converted to hexadecimal and appears only as the value of a JavaScript variable. That encoded email is separated in the JavaScript from the telltale mailto: to further confuse spambots.
emObA recognizes, and produces obfuscated active (click-to-send) email links for
<a href="mailto:you@example.com">Real Name</a>), allowing class and style attributes (but ignoring other attributes), and allowing an email Subject using the syntax mailto:you@example.com?subject=....[EMAIL Real Name | you@example.com], also allowing the ?subject=... ] syntax. (The much more fragile [Real Name] you@example.com of earlier emObA versions remains available if legacy is chosen.)you@example.com, with or without mailto: in front of it. (?subject= syntax not allowed here.)These will all appear as active email links displaying "Real Name". In the cases of a bare email link (one which has no Real Name) or a link in which the Real Name is the email itself, the link will show as the email displayed in human-readable form, eg you [@] example [.] com, where the [@] and [.] are either text symbols or graphic images (as set in administration), hiding the email addresses from spambots.
If JavaScript is not enabled, the email will appear in obfuscated but human-readable form but the link will not be active.
I believe any legitimate email will be recognized. However, no attempt at validation is made -- certain illegally formed addresses will also be recognized, for example, ones containing two successive .'s. (Note: Legal characters before the @ are !#$%&'*+/=?^_{|}~- and `.)
I've designed this plug-in with "real name" emails in mind -- <a href="mailto:you@example.com">Real Name</a> or [EMAIL Real Name | you@example.com], which display as Real Name. This will follow whatever styling you apply to your text and to links. However, if you primarily obfuscate lists of bare email addresses -- you@example.com -- you may not be satisfied with the appearance. They will appear with either glyphs or specified text symbols in place of @ and . . The color and weights of the glyphs are fixed (though they do change size with surrounding text), and they don't look exactly like the font symbols they replace. And if text symbols are used, they certainly don't look exactly like @ and ..
Version 2.0 — 4 December 2010 Author's emObA web page emObA at WordPress.org
![\"dot\"](\"".EMOBA_PLUGIN_URL."dot-glyph.gif\")
" );
}else{
define("AT_SYMBOL", $emoba_options['at-char']);
define("DOT_SYMBOL", $emoba_options['dot-char']);
}
/****
This replaces "@" with AT_SYMBOL and "." with DOT_SYMBOL
If $email doesn't include "@", it isn't an email; don't modify any dots in it.
****/
function emoba_symb_email($email) {
if (!strpos($email, '@')) return $email;
$email = str_replace('.', DOT_SYMBOL, $email); // must be first -- avoid replacing dot in IMG filename!
$email = str_replace('@', AT_SYMBOL, $email);
return '' . $email . '';
}
/****
This constructs a glyphed or textified email address
****/
function emoba_readable_email($email="", $name="(Hover)" ) {
$transformed_email = emoba_symb_email($email);
$addr = '' . $name . '';
return $addr;
}
/****
This converts the email's string of character ordinals to %-hex representation
It splits off any ?subject=yyy, replaces spaces by %20, and tacks it back onto the
encoded email.
****/
function emoba_hexify_mailto($mailto) {
$mt = explode('?', $mailto);
$hexified = '';
for ($i=0; $i < strlen($mt[0]); $i++)
$hexified .= '%' . strtoupper(base_convert(ord($mt[0][$i]), 10, 16));
if (strlen($mt[1])>0) {
$mt[1] = str_replace(' ', '%20', $mt[1]);
$hexified .= '?'.$mt[1];
}
return $hexified;
}
/****
The JavaScript for creating the email link and popup
****/
function emoba_addJScript($email, $ename, $id, $estyle=null, $eclass=null) {
global $emoba_options;
$link = emoba_hexify_mailto($email);
$clean_name = str_replace("<", "<", $ename);
$emoba_js = "";
return $emoba_js;
}
/****
This is the RE expression for detecting email addresses.
****/
define( "EMAILADDR", "([^,;<>\@\][\001-\040\200-\377]+@[A-Za-z0-9.-]+\.[A-Za-z]{2,6})" );
// Not necessarily legal e-address: Allows \t,\n, etc and two successive .'s
/****
The main function.
1. Detect and process emails, in this order:
a. as a link Name
b. as a special email encoding [Name] A@B.C
c. as a raw email A@B.C (The "Name" in this case is the email itself.) This will be a link if BARE_TO_LINK==true.
If Name is an email, it will be obfuscated appropriately.
2. Each of these creates a random-id span which includes the Name and pop-up email with graphics for @ and . (in case JavaScript is off), and inserts JavaScript.
3. The JavaScript (via emoba_addJScript()) replaces the with the approriate link.(with the address encoded).
4. CSS (for classes emoba-pop, emoba-hover) creates the hover effect when JavaScript is turned off.
****/
function emoba_replace($content) {
global $emoba_options;
// (1) convert full email link Name
$content = preg_replace_callback(
'`