Email Obfuscation Response Filter

The Email Obfuscator (a.k.a. Email Obfuscation Response Filter) uses an event
listener for each generated response to search for emails using regexes. The
emails are obfuscated depending on where the text is found, helping to prevent
email scraping and reduce spam.

Obfuscations

Emails in a Mailto-Link

Example: <a href="mailto:[email protected]">

• The email string excluding mailto: is reversed,
  e.g. <a href="mailto:moc.liame@tset">
• An onfocus and an onmousedown JS listeners are added inline; these will
  revert the email address following the mailto: prefix back to its original
  form. These two events cover the following cases: right-click, left-click
  and focus with tab.
  Note that:
  • onfocus would do it for most browsers, but Safari needs onmousedown
  • Reverting the already reversed email is only done once in a page load

All other Emails

Example: <a>[email protected]</a>

• A span with display:none containing a text with delimiters that are invalid
  email characters is added in the middle of the email, e.g.
  <a>test@<span style='display:none'>!zilch!</span>email.com</a>

Exclusions

• Any email that is invalid (according to PHP's filter_var function)
• Everything in the backoffice (admin pages)
• Emails inside HTML-attributes (placeholder attribute for input fields)
• Exclude Ajax webform request:
  • Because Ajax is usually used when sending a web form.
    This means that the request does not contain HTML, but a JSON object in
    which HTML is encoded with Unicode.
    The regex does not apply here and it is not necessary to obfuscate this
    email address as it is added by the sender.
• Content in routes that are whitelisted (see below)

Whitelisting Routes

• Define whitelisted (excluded) routes in settings.php
  

      $settings['email_obfuscator'] = [
       'ignored_routes' => [
         'rest.api_layout_footer.GET',
         'editor.link_dialog'
       ]
     ];
  

  For these routes, no obfuscation will take place.

• IMPORTANT: If you are using CKEditor 4 you should whitelist the route editor.link_dialog to avoid
  obfuscating the email in the CKEditor link dialog.

Disabling use of data-nosnippet

• The attribute data-nosnippet is used by default, to disable displaying the $displayNoneText in search results.
  It is possible to disable it in settings.php

     $settings['email_obfuscator'] = [
       'use_datanosnippet' => FALSE,
     ];
  

• IMPORTANT: The data-nosnippet attribute is officially supported ONLY by the Googlebot. Support from other bots is not guaranteed.