I want to be able that users can enter their emailaddress in an input and that the activation link gets resend
You'll need to write a plugin, which can generate activation URLs using the UsersService:
echo craft()->users->getPasswordResetUrl($user);
If you want to send the user an activation email instead of echoing a link in the frontend, you can use the sendActivationEmail
method instead:
craft()->users->sendActivationEmail($user);
Note that for both methods, $user
should be an instance of UserModel, meaning you'll first need to pull the relevant user:
$user = craft()->users->getUserByEmail($userEmail);
As for the actual plugin implementation, it depends what you need/want (I'm guessing you're building your own login form/logic?). You could go with a basic template variable to output the activation URL:
<a href="{{ craft.myPlugin.getActivationUrl }}">Click here to activate your account now</a>
...or you could create a controller which would provide a link for re-sending the activation email:
<a href="{{ actionUrl( 'myPlugin/sendActivationEmail' ) }}">Click to resend activation email</a>