fwdform2

A simple server for forwarding web forms to email addresses.

Inspired by fwdform.

Use cases

• You want to forward a simple contact form to an email address.
• You have a (S3) static site and don't want to run a server.
• You want to forward arbitrary form fields formatted as human-readable email.
• You want to send an automated response email (using a template) when users submit a form.

Prerequisites

• A free Heroku account.
• A free Mailgun account.
• The Heroku CLI.

In order to take advantage of your free monthly Mailgun email quota, after signing up, please follow the instructions to setup and verify your Mailgun domain name.

Note: Mailgun requires you to select the Concept plan and provide credit card details to move your domain out of the sandbox (even though you still get 10,000 free emails per month). However, for basic usage, you can leave your domain in the sandbox and manually enter each email recipient as Mailgun Authorized Recipients.

Manually deploy to Heroku

If you don't want to deploy manually, press the "Deploy to Heroku" button at the top of the page.

1. Clone fwdform2:

   git clone https://github.com/glassechidna/fwdform2.git

2. Create a Heroku app, add a PostgreSQL database and configure your Mailgun details:

   heroku create
   heroku addons:add heroku-postgresql:hobby-dev
   heroku config:set MAILGUN_DOMAIN=<MAILGUN_DOMAIN> \
                     MAILGUN_API_KEY=<KEY> \
                     REQUESTS_CA_BUNDLE=/etc/ssl/certs/ca-certificates.crt

   Setting REQUESTS_CA_BUNDLE as /etc/ssl/certs/ca-certificates.crt ensures that the host's SSL certificate authorities are utilised rather than the (potentially dated) CAs packaged with Python. In the past this has proven to be be necessary to communicate with Mailgun, so this is a suggested setting.

3. Deploy fwdform2 to your Heroku app:

   git push heroku master

4. Run the setup script and ensure one dyno is running:

   heroku run ./setup.py
   heroku ps:scale web=1

   setup.py will perform one-time app setup e.g. creating the database.

Usage

Your Heroku Web URL

General usage of fwdform2 will require you to know your Heroku Web URL (WEB_URL).

Your Heroku Web URL was printed when your first setup your Heroku app, however you can retrieve it again by entering:

heroku info

Registration API

A simple API is provided to register email receivers. However, for security reasons it is disabled by default.

You can enable it as follows:

heroku config:set REGISTRATION_ENABLED=yes \
                  REGISTRATION_PASSWORD=<SOME_PASSWORD>

Although it's password protected, it is suggested that you disable the registration API when you've finished using it.

heroku config:unset REGISTRATION_ENABLED REGISTRATION_PASSWORD

Note: Don't forget to either move your Mailgun domain out of sandbox mode, or alternatively add each user as an Authorized Recipient.

Register a user

Endpoint: /user/<register> (HTTP POST)

Parameters:

• email

Returns:

• private_token
• public_token

Registering a user from command line

One of the simplest ways to register a user is to call the registration API from command line as follows:

curl --data "email=<your_email>&password=<your_password>" <WEB_URL>/register

This will return information in the form:

Public token: <public_token>, Private token: <private_token>

Write down or otherwise save these two pieces of information.

Keep the private token to yourself, it's effectively your password, associated with <your_email>. You will need this token to take advantage of some advanced features of fwdform2.

You will need the public token for setting up forms on your website, this is not secret.

Delete a user

Endpoint: /user/<public_token> (HTTP DELETE)

Parameters:

• token

Token is the user's private_token.

Deleting a user from command line

curl -X DELETE --data "token=<private_token>" <WEB_URL>/user/<public_token>

Forward a simple message

Endpoint: /user/<public_token> (HTTP POST)

Parameters:

• message
• name
• email
• redirect

message is required, all other parameters are optional.

redirect can be specified as a URL. Instead of returning a 200 Success status code, a 302 Redirect to redirect will be issued.

Testing from command line

curl --data "name=Test%20Person&message=Hello" <WEB_URL>/user/<public_token>

Troubleshooting

If this does not work (an error is returned), then it's likely an issue with your Mailgun setup. First, double check your MAILGUN_DOMAIN and MAILGUN_API_KEY are correct.

Also, ensure that you've either added your email as an Authorized Recipient or provided payment information in Mailgun. Regardless of whether you chose the "Concept" plan or remain on the "Free" (sandboxed) plan, you'll have a quota of emails each month that are 100% free (10,000/month at the time of writing).

HTML

A message form for your website would look something like:

<form action="<WEB_URL>/user/<public_token>" method="POST">
    <div>
        Name: <input name="name" type="text">
    </div>
    <div>
        E-mail: <input name="email" type="text">
    </div>
    <div>
        Message: <textarea name="message" rows="6" cols="120"></textarea>
    </div>
    <div>
        <input name="redirect" type="hidden" value="https://<YOUR_WEBSITE>/<YOUR_POST_SUBMISSION_PAGE>">
        <input type="submit" value="Submit">
    </div>
</form>

Advanced usage: Registered forms

Sometimes we want to do something a bit more advanced than sending a plain-text message to an email address.

Instead we may want our form to:

• Send emails containing HTML.
• Send an automated response to the person who submitted the form (i.e. a confirmation email)*.
• Generate our emails (in particular our automated response) from a template.

In order to achieve this we can register some additional information with the server to make this possible.

* Sending automated responses will almost certainly require that your Mailgun Domain is out of sandbox mode. Otherwise, Mailgun will return an error (and so will fwdform2) whenever we try send an automated response to someone who isn't an authorized recipient.

Registering a form

You may want to have multiple forms with different behavior all delivered to the one email address (user). As such each fwdform2 user may register multiple forms that will all be delivered to them.

Endpoint: /user/<public_token>/form (HTTP POST)

Parameters:

• token
• subject
• body
• html_body
• response_subject
• response_body
• response_html_body
• response_from
• response_reply_to

token is the user's private_token.

token, subject and body are required, all other parameters are optional.

Note: To send an automated response, at a minimum a response_body must be provided. You cannot provide response_html_body on its lonesome, a plain-text body must always be provided.

subject, body, html_body, response_subject, response_body and response_html_body can all be provided as a template, where occurrences of %parameter% will be replaced by a parameter in the submitted form.

e.g. If you provide response_body as:

Hi %name%,

Thanks for reaching out. We'll get back to you ASAP.

- Us

Then in the submitted form include a name parameter, the submitter's name will automatically be substituted into the auto-response email.

Returns:

• form_token

Registering a form from command line

curl --data "token=<private_token>&subject=Just%20saying%20hi&body=Hello%20%25name%25" <WEB_URL>/user/<public_token>/form

Note: We've URL encoded our spaces and percentage signs as %20 and %25 respectively. Web browsers will do this for you automatically, doing this manually is typically only necessary from command line.

Delete a form

Endpoint: /form/<form_token> (HTTP DELETE)

Parameters:

• token

Token is the user's private_token. Users can only delete forms that they created.

Deleting a form from command line

curl -X DELETE --data "token=<private_token>" <WEB_URL>/form/<form_token>

Forward a form

Endpoint: /form/<form_token> (HTTP POST)

Parameters:

• email
• redirect
• Any custom parameters you want to use in your templates.

There are no required parameters. However, if you want to send an automated response, an email must be provided.

redirect can be specified as a URL. Instead of returning a 200 Success status code, a 302 Redirect to redirect will be issued.

Testing from command line

curl --data "name=John%20Smith" <WEB_URL>/form/<form_token>