FMMSS

Flask Mailman Static Subscribe

A Flask app running a POST API to handle subscribing to a Mailman 3 list from a static website. Designed to attach to an existing docker-mailman network, this app will take requests to subscribe or unsubscribe users via the Python mailmanclient.

Form Markup

Subscribe

• listEmail - The email address you would like to subscribe to the list
• listName - The name of the person you would like to subscribe to the list
• list-name - Where name is an arbitrary string. value of list-foo should be the Mailman list name like list@list.com. Accepts multiple list-name fields in the form so you can optionally subscribe someone to multiple lists at one time
• success_redirect_url - The URL you'd like the API to redirect to if the subscription was successful
• error_redirect_url - The URL you'd like the API to redirect to if the subscription was unsuccessful
• email - Honeypot field (see below for more details). This field should be hidden and is intended to prevent spam

Example

<form action="https://fmmss.example.com/1.0/subscribe" method="post">
  <label for="listEmail">Email address:</label><br>
  <input type="text" name="listEmail" value=""><br>
  <label for="listName">Name:</label><br>
  <input type="text" name="name" value=""><br><br>
  <input type="hidden" name="list-writers" value="name@example.com" />
  <input type="hidden" name="success_redirect_url" value="https://example.com/subscribe-success.html">
  <input type="hidden" name="error_redirect_url" value="https://example.com/subscribe-error.html">
  <input class="ohnohoney" type="text" name="email" tabindex="-1" autocomplete="off">
  <input type="submit" value="Join the List">
</form>

See below for more details on the ohnohoney class.

Unsubscribe

• email - The address you'd like to unsubscribe
• list - The list you'd like to unsubscribe the person from
• success_redirect_url - The URL you'd like the API to redirect to if the unsubscription was successful
• error_redirect_url - The URL you'd like the API to redirect to if the unsubscription was unsuccessful

Spam Prevention with Honey Pot

To prevent bots from submitting spam subscriptions, I use a honeypot on the subscription form. This isn't a required field but if you find yourselves with swarming bees, the honey pot might help. The name="email" input attribute is guaranteed to trap the bot into filling out the field. The ohnohoney class visually hides the field though. So if the POST request contains information in the email field, we can assume it's spam. To hide the honey pot field, add the class ohnohoney and include the following CSS somewhere in your stylesheet:

.ohnohoney{
    opacity: 0;
    position: absolute;
    top: 0;
    left: 0;
    height: 0;
    width: 0;
    z-index: -1;
}