modules/invisimail/invisimail.module

<?php

// $Id: invisimail.module,v 1.2.2.1 2007/10/01 22:59:58 crell Exp $

/**
 * @file
 * This module provides a filter that will search content for email addresses
 * and replace them with their ascii equivalents before display. This is not
 * a complete protection from spam harvesters, but it is some help.
 */

/**
 * Implementation of hook_help().
 *
 */
function invisimail_help($section) {
  switch ($section) {
    case 'admin/help#invisimail':
      return t('<p>The invisimail module privides a filter to hide email addresses from email harvesting spam-bots.</p><p>How it works: Invisimail scans content for email addresses and then converts each character of the address to its ASCII-code equivalent. The email address will appear normally on the page, but the source html will not appear as an email address. For even more security, the filter can use a JavaScript write command to further obscure the email address.</p><p>For example:<br /><i>you@example.com</i> will appear in the html source as: <div style="font-family:courier;border:1px solid #666;padding: 5px">&amp;#121;&amp;#111;&amp;#117;&amp;#64;&amp;#101;&amp;#120;&amp;#97;&amp;#109;&amp;#112;&amp;#108;&amp;#101;&amp;#46;&amp;#99;&amp;#111;&amp;#109;</div></p><p>With the JavaScript and Auto-link options enabled, the source would become: <div style="font-family:courier;border:1px solid #666;padding: 5px">&lt;script type=\'text/javascript\'&gt;&lt;!--<br />
document.write(\'&lt;a href= "&amp;#109;&amp;#97;&amp;#105;&amp;#108;&amp;#116;&amp;#111;&amp;#58;\' + \'&amp;#121;&amp;#111;&amp;#117;&amp;#64;\' + \'&amp;#101;&amp;#120;&amp;#97;&amp;#109;&amp;#112;&amp;#108;&amp;#101;&amp;#46;\' + \'&amp;#99;&amp;#111;&amp;#109;\' + \'"&gt;\' + \'&amp;#121;&amp;#111;&amp;#117;&amp;#64;\' + \'&amp;#101;&amp;#120;&amp;#97;&amp;#109;&amp;#112;&amp;#108;&amp;#101;&amp;#46;\' + \'&amp;#99;&amp;#111;&amp;#109;\' + \'&lt;/a&gt;\');<br />
//--&gt;<br />
&lt;/script&gt;</div></p><p>Doesn\'t look like an email address, does it?</p><p>Of course the best protection against spam-bots is to not publish an email address at all, but on a community site some users are going to publish email addresses. Invisimail provides another level of security to keep them from recieving spam.</p><p>To configure Invisimail, select "configure" next to the <a href="%url">input format</a> you\'d like to use. Enable "Encode Email Addresses" and submit the form. Then select the "configure" tab to choose options for Invisimail.</p>', array('%url' => url('admin/filters')));
  }
}

/**
 * Implementation of hook_filter_tips().
 *
 */
function invisimail_filter_tips($delta, $format, $long = FALSE) {
  switch ($delta) {
    case 0:
      if ($long) {
        return t('Every email address in the input text will be replaced with its ascii equivalent.');
      }
      break;
  }
}

/**
 * Implementation of hook_filter().
 *
 */
function invisimail_filter($op, $delta = 0, $format = -1, $text = '') {
  if ($op == 'list') {
    return array(0 => t('Encode email addresses'));
  }

  switch ($delta) {
    case 0:
      switch ($op) {
        case 'description':
          return t('Hide email addresses from spam-bots.');

        case 'prepare':
          return $text;

        case 'process':
          return invisimail($text, $format);

        case 'settings':
          $form['invisimail_settings'] = array(
            '#type' => 'fieldset',
            '#title' => t('Invisimail email address encoding filter'),
            '#collapsible' => true, '#collapsed' => true
          );

          $form['invisimail_settings']['invisimail_js_'.$format] = array(
            '#type' => 'radios',
            '#title' => t('JavaScript'),
            '#default_value' => variable_get('invisimail_js_'.$format, FALSE),
            '#options' => array(FALSE => t('No JavaScript - greater compatibility'), TRUE => t('Use JavaScript - greater security')),
            '#description' => t('Selecting "Use JavaScript" will nearly guarantee protection from spam harvesters. However email addresses will not appear for browsers without JavaScript capability.'),
          );

          $form['invisimail_settings']['invisimail_link_'.$format] = array(
            '#type' => 'radios',
            '#title' => t('Auto-link Emails'),
            '#default_value' => variable_get('invisimail_link_'.$format, FALSE),
            '#options' => array(FALSE => t('Do not create links.'), TRUE => t('Automatically create links from email addresses.')),
            '#description' => t('Selecting "Automatically create links" will convert email addresses into a clickable "mailto:" link.'),
          );
          return $form;
      }
      break;
  }
}

function invisimail($string, $format) {
  $pattern = "!(<p>|<li>|<br />|[ \n\r\t\(])([A-Za-z0-9._-]+@[A-Za-z0-9._-]+\.[A-Za-z]{2,4})([.,]?)(?=(</p>|</li>|<br />|[ \n\r\t\)]))!i";
  
  // the callback needs to know what filter we're using
  // however there's no way to hand off that variable
  // so we'll set a global variable
  $GLOBALS['invisimail_format'] = $format;

  return preg_replace_callback($pattern, 'invisimail_callback', $string);
 }

function invisimail_callback($matches) {
  return $matches[1] . invisimail_ascii_encode($matches[2]) . $matches[3];
}

function invisimail_ascii_encode($string) {
  $format = $GLOBALS['invisimail_format'];
  $js = variable_get('invisimail_js_'.$format, FALSE);
  $link = variable_get('invisimail_link_'.$format, FALSE);
    
  if ($js) {
    $output = "<script type='text/javascript'><!--
    document.write('";
  }
  
  for ($i=0; $i < strlen($string); $i++)	 {
    $char = substr($string, $i, 1);
    $encode .= '&#'.ord($char).';';	 	 
    if ($js) {
      if (in_array($char, array('.', '@'))) {
      // break strings after ats and dots
        $encode .= "'+'";
      }
    }
  }
  
  if ($link && !$js) {
    // ascii in this next line is "mailto:"
    $output .= "<a href=\"&#109;&#97;&#105;&#108;&#116;&#111;&#58;$encode\">$encode</a>";
  }
  elseif ($link && $js) {
    $output .= "<a href=\"&#109;&#97;&#105;&#108;&#116;&#111;&#58;'+'$encode'+'\">'+'$encode'+'</a>";    
  }
  else {
    $output .= $encode;
  }

  if ($js) {
    $output .= "');
    //-->
    </script>";
  }
    
  return $output;
} 

?>
1	<?php
2
3	// $Id: invisimail.module,v 1.2.2.1 2007/10/01 22:59:58 crell Exp $
4
5	/**
6	* @file
7	* This module provides a filter that will search content for email addresses
8	* and replace them with their ascii equivalents before display. This is not
9	* a complete protection from spam harvesters, but it is some help.
10	*/
11
12	/**
13	* Implementation of hook_help().
14	*
15	*/
16	function invisimail_help($section) {
17	switch ($section) {
18	case 'admin/help#invisimail':
19	return t('<p>The invisimail module privides a filter to hide email addresses from email harvesting spam-bots.</p><p>How it works: Invisimail scans content for email addresses and then converts each character of the address to its ASCII-code equivalent. The email address will appear normally on the page, but the source html will not appear as an email address. For even more security, the filter can use a JavaScript write command to further obscure the email address.</p><p>For example:<br /><i>you@example.com</i> will appear in the html source as: <div style="font-family:courier;border:1px solid #666;padding: 5px">&#121;&#111;&#117;&#64;&#101;&#120;&#97;&#109;&#112;&#108;&#101;&#46;&#99;&#111;&#109;</div></p><p>With the JavaScript and Auto-link options enabled, the source would become: <div style="font-family:courier;border:1px solid #666;padding: 5px"><script type=\'text/javascript\'><!--<br />
20	document.write(\'<a href= "&#109;&#97;&#105;&#108;&#116;&#111;&#58;\' + \'&#121;&#111;&#117;&#64;\' + \'&#101;&#120;&#97;&#109;&#112;&#108;&#101;&#46;\' + \'&#99;&#111;&#109;\' + \'">\' + \'&#121;&#111;&#117;&#64;\' + \'&#101;&#120;&#97;&#109;&#112;&#108;&#101;&#46;\' + \'&#99;&#111;&#109;\' + \'</a>\');<br />
21	//--><br />
22	</script></div></p><p>Doesn\'t look like an email address, does it?</p><p>Of course the best protection against spam-bots is to not publish an email address at all, but on a community site some users are going to publish email addresses. Invisimail provides another level of security to keep them from recieving spam.</p><p>To configure Invisimail, select "configure" next to the <a href="%url">input format</a> you\'d like to use. Enable "Encode Email Addresses" and submit the form. Then select the "configure" tab to choose options for Invisimail.</p>', array('%url' => url('admin/filters')));
23	}
24	}
25
26	/**
27	* Implementation of hook_filter_tips().
28	*
29	*/
30	function invisimail_filter_tips($delta, $format, $long = FALSE) {
31	switch ($delta) {
32	case 0:
33	if ($long) {
34	return t('Every email address in the input text will be replaced with its ascii equivalent.');
35	}
36	break;
37	}
38	}
39
40	/**
41	* Implementation of hook_filter().
42	*
43	*/
44	function invisimail_filter($op, $delta = 0, $format = -1, $text = '') {
45	if ($op == 'list') {
46	return array(0 => t('Encode email addresses'));
47	}
48
49	switch ($delta) {
50	case 0:
51	switch ($op) {
52	case 'description':
53	return t('Hide email addresses from spam-bots.');
54
55	case 'prepare':
56	return $text;
57
58	case 'process':
59	return invisimail($text, $format);
60
61	case 'settings':
62	$form['invisimail_settings'] = array(
63	'#type' => 'fieldset',
64	'#title' => t('Invisimail email address encoding filter'),
65	'#collapsible' => true, '#collapsed' => true
66	);
67
68	$form['invisimail_settings']['invisimail_js_'.$format] = array(
69	'#type' => 'radios',
70	'#title' => t('JavaScript'),
71	'#default_value' => variable_get('invisimail_js_'.$format, FALSE),
72	'#options' => array(FALSE => t('No JavaScript - greater compatibility'), TRUE => t('Use JavaScript - greater security')),
73	'#description' => t('Selecting "Use JavaScript" will nearly guarantee protection from spam harvesters. However email addresses will not appear for browsers without JavaScript capability.'),
74	);
75
76	$form['invisimail_settings']['invisimail_link_'.$format] = array(
77	'#type' => 'radios',
78	'#title' => t('Auto-link Emails'),
79	'#default_value' => variable_get('invisimail_link_'.$format, FALSE),
80	'#options' => array(FALSE => t('Do not create links.'), TRUE => t('Automatically create links from email addresses.')),
81	'#description' => t('Selecting "Automatically create links" will convert email addresses into a clickable "mailto:" link.'),
82	);
83	return $form;
84	}
85	break;
86	}
87	}
88
89	function invisimail($string, $format) {
90	$pattern = "!(<p>\|<li>\|<br />\|[ \n\r\t\(])([A-Za-z0-9._-]+@[A-Za-z0-9._-]+\.[A-Za-z]{2,4})([.,]?)(?=(</p>\|</li>\|<br />\|[ \n\r\t\)]))!i";
91
92	// the callback needs to know what filter we're using
93	// however there's no way to hand off that variable
94	// so we'll set a global variable
95	$GLOBALS['invisimail_format'] = $format;
96
97	return preg_replace_callback($pattern, 'invisimail_callback', $string);
98	}
99
100	function invisimail_callback($matches) {
101	return $matches[1] . invisimail_ascii_encode($matches[2]) . $matches[3];
102	}
103
104	function invisimail_ascii_encode($string) {
105	$format = $GLOBALS['invisimail_format'];
106	$js = variable_get('invisimail_js_'.$format, FALSE);
107	$link = variable_get('invisimail_link_'.$format, FALSE);
108
109	if ($js) {
110	$output = "<script type='text/javascript'><!--
111	document.write('";
112	}
113
114	for ($i=0; $i < strlen($string); $i++) {
115	$char = substr($string, $i, 1);
116	$encode .= '&#'.ord($char).';';
117	if ($js) {
118	if (in_array($char, array('.', '@'))) {
119	// break strings after ats and dots
120	$encode .= "'+'";
121	}
122	}
123	}
124
125	if ($link && !$js) {
126	// ascii in this next line is "mailto:"
127	$output .= "<a href=\"mailto:$encode\">$encode</a>";
128	}
129	elseif ($link && $js) {
130	$output .= "<a href=\"mailto:'+'$encode'+'\">'+'$encode'+'</a>";
131	}
132	else {
133	$output .= $encode;
134	}
135
136	if ($js) {
137	$output .= "');
138	//-->
139	</script>";
140	}
141
142	return $output;
143	}
144
145	?>