Zest emailhider

This document describes the zest.emailhider package.

Dependencies

This package depends on jquery.pyproxy to integrate python code with jquery code.

Overview

This package provides a mechanism to hide email addresses with JavaScript. Or actually: with this package you can hide your email addresses by default so they are never in the html; with javascript the addresses are then fetched and displayed.

For every content item in your site you can have exactly one email address, as we look up the email address for an object by its UID. For objects for which you want this you should register a simple adapter to the IMailable interface, so we can ask this adapter for an email attribute and a UID method. The 'emailhider' view is provided to generate the placeholder link.

Objects display a placeholder link with a hidden-email class, a uid rel attribute and a email-uid-<some uid> class set to the UID of an object; when the page is loaded some jQuery is run to make a request for all those links to replace them with a 'mailto' link for that object. Using this mechanism the email address isn't visible in the initial page load, and it requires JavaScript to be seen - so it is much harder for spammers to harvest.

Special case: when the uid contains 'email' or 'address' it is clearly no real uid. In that case we do nothing with the IMailable interface but we try to get a property with this 'uid' from the property sheet of the portal. Main use case is of course the 'email_from_address', but you can add other addresses as well, like 'info_email'. If you want to display the email_from address in for example a static portlet on any page in the site, use this html code:

<a class="hidden-email email-uid-email_from_address"
   rel="email_from_address">
   Activate JavaScript to see this address.</a>

You can load the test_emailhider page to see if this works.

Instructions for your own package

What do you need to do if you want to use this in your own package, for your own content type?

First you need to make your content type adaptable to the IMailable interface, either directly or via an adapter.

If your content type already has a UID method (like all Archetypes content types) and an email attribute, you can use some zcml like this:

<class class=".content.MyContentType">
  <implements interface="zest.emailhider.interfaces.IMailable" />
</class>

If not, then you need to register an adapter for your content type that has this method and attribute. For example something like this:

from zope.component import adapts
from zope.interface import implements
from zest.emailhider.interfaces import IMailable
from your.package.interfaces import IMyContentType

class MailableAdapter(object):
    adapts(IMyContentType)
    implements(IMailable)

    def __init__(self, context):
        self.context = context

    def UID(self):
        return self.context.my_special_uid_attribute

    @property
    def email(self):
        return self.context.getSomeContactAddress()

Second, in the page template of your content type you need to add code to show the placeholder text instead of the real email address:

<span>For more information contact us via email:</span>
<span tal:replace="structure context/@@emailhider" />

Note that if you want this to still work when zest.emailhider is not installed, you can use this code instead:

<span tal:replace="structure context/@@emailhider|context/email" />

This shows the unprotected plain text email when zest.emailhider is is not available. When you are using zest.emailhider 2.6 or higher this works a bit better, as we have introduced an own browser layer: the @@emailhider page is only available when zest.emailhider is actually installed in the Plone Site. This also makes it safe to use zest.emailhider when you have more than one Plone Site in a single Zope instance and want emailhider to only be used in one them.

Note that the generated code in the template is very small, so you can also look at the page template in zest.emailhider and copy some code from there and change it to your own needs. As long as your objects can be found by UID in the uid_catalog and your content type can be adapted to IMailable to get the email attribute, it should all work fine.

Note on KSS usage in older releases

Older releases (until and including 1.3) used KSS instead of jQuery. As our functionality should of course also work for anonymous users, we had to make KSS publicly accessible. So all javascript that was needed for KSS was loaded for anonymous users as well.

We cannot undo that automatically, as the package has no way of knowing if the same change was needed by some other package or was done for other valid reasons by a Manager. So you should check the javascript registry in the ZMI and see if this needs to be undone so anonymous users no longer get the kss javascripts as they no longer need that.

For reference, this is the normal line in the Condition field of ++resource++kukit.js (all on one line):

python: not
here.restrictedTraverse('@@plone_portal_state').anonymous() and
here.restrictedTraverse('@@kss_devel_mode').isoff()

and this is the normal line in the Condition field of ++resource++kukit-devel.js (all on one line):

python: not
here.restrictedTraverse('@@plone_portal_state').anonymous() and
here.restrictedTraverse('@@kss_devel_mode').ison()

Compatibility

Version 3.0 should work on Plone 4.1, 4.2, 4.3, 5.0.

For older Plone versions, please stick to the 2.x line. Latest release as of writing is 2.7.

Note that on Plone 5.0 we are not completely modern: we register our css and javascript in the old portal tools, not in the new resource registry. So it ends up in the Plone legacy bundle.