Support sending MMS without an image

[ajohn25]

Is your feature request related to a problem? Please describe. Many organizations would prefer that longer messages be automatically converted to MMS, which can be cheaper to send than many segment long SMS messages.

Describe the solution you'd like An organization setting that sets a limit for how long SMS messages can be for the organization. Messages above this segment limit should be automatically converted to MMS.

Describe alternatives you've considered

• Hardcode an SMS segment limit and don't allow users to edit what this limit is
• Force users to add empty brackets [] or a similar character sequence to convert a message to MMS

[ajohn25]

Goals and Non-Goals

Goals:

• Allow admins to specify a "maximum segment length" for SMS messages. Messages that contain more segments than this value will automatically be converted to MMS

Non-Goals:

• Larger refactoring of MMS sending experience in Spoke

Milestones

Mid February release goal

Existing Solution

Users must find an image to attach to a long SMS to convert the messsage to MMS

Proposed Solution

Schema Changes:

N/A - maximum SMS length will be tracked via an organization setting

Backend Changes:

1. Track maximumSMSLength as an organization setting which defaults to 3 segments. Under all currently proposed pricing structures, a 4 segment SMS is more expensive than 1 MMS message.
2. Adjust sendMessage in assemble-numbers so that mediaUrls is set to an empty array when an SMS message is longer than the set maximum SMS length
3. Remove the restriction in switchboard's telnyx service that mediaUrls must have a length
4. Telnyx will send an empty array of media URLs as MMS (should test to confirm)

UI Changes:

TBD

Alternative Solutions

See alternatives listed at top of issue

Testability, Monitoring and Alerting

Write tests as part of PR

Cross-Team Impact

Open Questions

1. Backend changes review
2. UI review

Detailed Scoping and Timeline

[ajohn25]

For proposed backend changes, note that there are 2 messages in switchboard currently with empty array media URLs. These were the 1st 2 messages sent during initial setup, so proposing this solution with the assumption that empty media URLs are not currently sent from Spoke under normal conditions.

These 2 messages which I believe to be exceptions can be found via this query select * from outbound_messages where id in ('631c1f14-9711-11ee-80ff-d3689a7cf198', 'fbd7146c-971a-11ee-80ec-4f2f548ea12a')

[ajohn25]

@bchrobot could you review the proposal above?

[bchrobot]

Sounds good overall. A few pieces of feedback:

• maximumSMSLength -> maxSmsSegmentLength to clarify that it's segments. Ideally this would also convey conversion to MMS but I didn't love any of the ideas I came up with for that (mmsAutoConversionSegmentCount, mmsConversionAfterNSegments, maxSmsSegmentsBeforeAutoMms)
• It might be better UX to have a "Automatically convert SMS to MMS if more than n segments?" toggle with a conditional number field
• If this is going to be a default across all instances, either add a migration that sets the org feature (e.g. UPDATE ... SET features = (features::jsonb || jsonb_build_object('maximumSMSLength', 3))::text) or include example SQL in PR description to be run manually
  • Update createOrganization mutation to set this for new orgs https://github.com/With-the-Ranks/Spoke/blob/b8761c733bbca905651b7067d27eb2140f5929b7/src/server/api/root-mutations.ts#L1239-L1250
• Consider a UI change to Message Review to indicate to admins that a seemingly text-only message is in fact an MMS
• Switchboard will need to be updated to use MMS queue for media_urls = []: https://github.com/politics-rewired/switchboard/blob/00281a6036d081013b37590c8df2c0193d45abce/schema-dump.sql#L2874-L2889
• Question: the segment count check will now happen in both the client (script editor) and the server (automatic conversion) is that right? Ideally the same module can be used in both places, although the directory structure is not currently great for that kind of reuse.
  • The admin script editor may want to get a reminder about the auto-conversion behavior.
• Question: is there any use case for supporting campaign-level exceptions to the organization policy?