Do not autorespond to numbers on Blacklist

[abbyad]

Following up on #201, users and administrators need to be able to ignore/hide messages from specific numbers or ranges of numbers. This is particularly important for MNO messages, which we do not want to respond to.

First iteration may just be available in app_settings, but eventually we will need some design work to decide the best way to present this to users.

[mandric]

We should also support blacklisting number like "Orange" since the telecom provider can create messages originating from that string. Also does this feature only apply to auto-responses? What if a valid form is sent via a blacklisted from string? I assume we need to ignore responses setup by registration configurations or any other feature.

[abbyad]

We are finding several projects that end up in message loops with the operator when the gateway is out of credit. Once credit is added, all the pending auto-replies get sent, eating up the newly added credit.

@browndav we already have a similar feature for not sending a number to the gateway, so would it be low effort to do something similar that to avoid sending to any other number as well?

As pointed out by @mandric, we should accept text strings as well as phone numbers.

[abbyad]

If someone jumps in to take this, a good place to start looking is how we avoid message loops with the gateway_number in medic-sentinel/transitions/default_responses.js

[mandric]

How do we plan to define a blacklist? Could it be a comma separated list of strings in app_settings somewhere?

[mandric]

Also assuming we need this feature on all branches/release channels.

[abbyad]

Correct, we are getting urgent requests for this from many projects so we should push this to all branches.

Having it as a comma separated field in app_settings only would be acceptable for now. If we can surface this to the configuration/settings/advanced that would be even better.

[mandric]

Should we also consider having a "whitelist" option, so you only setup responses to numbers that are in the facilities list or something?

[mandric]

Thinking the blacklisted function might behave like this:

isBlacklisted(str, from)

string	from	returns
+123	+123	true
+123	+999	false
+123	+123999999	true
SAFARI	SAFARICOM	true
Safari	SAFARICOM	true
+123,+456,+789	+456	true
+123,+456,+789	+4569999999	true
SAFARI, ORANGE	ORANGE NET	true
SAFARI, ORANGE NET	ORANGE	false
VIVO	EM VIVO	false

[abbyad]

That would seem to work well @mandric.

I think that having a whitelist would be good to include as well. My understanding is that you could send to a whitelisted number, even if it is in the blacklisted list. Is that right?

Also, are we checking if it is a valid number before sending? This would be useful to know for creating the blacklists.

[mandric]

Nope, no checking if phone numbers are valid, we just take the number the gateway passed to us in the message and use it.

[mandric]

It might be useful to put a warnings property on a doc or something and when the system attempts to send a message to a blacklisted number the doc is marked with a warning. Otherwise the silent failing to add a message or response could lead to confusion. It might be useful for the system to have a way to say: "You wanted me to send to this phone but it's blacklisted."

[mandric]

Also for the record not crazy about using the term “blacklist” but can’t think of anything else at the moment. Maybe “deny list” or “reject list”?

[mandric]

forms only mode:

[mandric]

Not sure if I should flag/invalidate the record (add an error to it). Currently just shows up as valid with denied messages.

[garethbowen]

Looks good. I've added one comment about style preference.

[mandric]

Henok, a new RC build should be available shortly with this update. Let me know if you have any time to acceptance test this one again, thanks!

[mandric]

@henokgetachew or @abbyad when you get a chance please acceptance test. Latest RC is running here: https://rc.dev.medicmobile.org/