FloodNotifications

Flood Notifications

We intend to build a system which will allow users to sign up for notifications when a particular set of gages they're interested in has reach flood stage, and again when the waters have receded.

Requirements

• A user will be able to give an email address which will receive timely notifications of flood status changes.
• Various kinds of events can be separately subscribed to per gage:
  • Flood status begins (define a notification water level threshold per gage?)
  • Road underwater
  • Road clear
• When it becomes possible to predict flood events, each predictable event should have a separate notification

Possible Requirements

• Other notification channels besides email
  • Text message?
  • Phone calls?

• Other notification events that are not per-gage
  • Region-wide "flood event starting"?

Explicit Non-Requirements

• We will not support sending notifications to non-registered users (i.e. you can't just give us an email address, you have to create an account with a password)

Open Questions

• How frequently will notifications go out?
• Do we need to have per-user or per-gage memory of last time a notification happened for a particular gage to avoid spam? (example: water level reaches road, goes below road level, goes above, all within a short period of time)
• Do we need to track history of notifications we sent? If so, how and where?

Building Blocks

This will depend on implementing LoginAndSecurity. Also, future-flood notifications will depend on FloodForecasting.

Email Notifications

Doing email notifications will depend on (at least) having these features:

Email address verification

Add a workflow for verifying email addresses:

• Remember verification status (flag already exists in database; need to verify it works and clear all existing statuses)
• Clear verified flag if email address changes
• Generate and send 'click here to verify' email
• Build 'click here to verify' page
• Subscribe UI needs to show if email address is pending (or prevent subscribing until verified)
  • add email verify status to AuthenticateResult so UI has access

Subscription management

Each individual event that can be subscribed to will need a subscribe/unsubscribe UI.

Additionally it probably makes sense to have a single "Manage my subscriptions" page.

There will also need to be a simple "Unsubscribe me from all notifications" page that the email notifications can link to.

Background processing

A background task will run at some appropriate frequency to monitor the state of all notifiable events.