dm-forwarder

Single endpoint API for forwarding form data as Twitter DMs:

1. HTML form from the REFERER URL sends its formData with parameter msg as a base64 encoded message
   • base64 encoding used to avoid complications with encoding and decoding URIs
2. dm-forwarder receives the request and decodes it to get the message text
3. Then on behalf of the user who has given their keys for the config, it sends this as a DM to the Twitter user under RECIPIENT_ID
4. Message arrives for the recipient in their Twitter inbox

dm-forwarder was primarily built to handle HTML contact form message submissions. It is rate-limited to only allow 3 submissions within a 30 second window per IP.

Setup

1. Create a Heroku app
2. Configure Heroku "Config Vars" (environment variables):
   • Twitter API keys and secrets x 4
     • You get these by registering for a Twitter Developer account and creating a new app
     • Ensure your Twitter app has permission to send DMs
   • RECIPIENT_ID should be the Twitter ID
   • REDIRECT should be a URL that end user gets sent back to after submission
   • REFERER restricts where the endpoint can be reached from
   • MAX_BASE64_LENGTH restricts how large a message can be before it gets rejected
3. Either manually deploy or automatically deployed when new commits arrive into the codebase.