Convert serialized posts to eml

[pandeyabs]

• Add the serialized Postable to EML converter code for group mailboxes and associated tests.
• We should converge this with Messageable code at some point with a small translator function which converts Postable to Messageable. Reason being that posts are a subset of messages. Although I feel it's a bit premature right now. Once we have tested this in prod a bit, and we know for a fact that posts are indeed a true subset of messages, we can do this convergence.

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Does this PR need a docs update or release note?

• ✅ Yes, it's included
• 🕐 Yes, but in a later PR
• ⛔ No

Type of change

• 🌻 Feature
• 🐛 Bugfix
• 🗺️ Documentation
• 🤖 Supportability/Tests
• 💻 CI/Deployment
• 🧹 Tech Debt/Cleanup

Issue(s)

• #

Test Plan

• 💪 Manual
• ⚡ Unit test
• 💚 E2E

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[meain]

... with a small translator function which converts Postable to Messageable ...

This would be better. I personally would have done this conversion as there are more gotchas in the eml conversion. We could always separate it out in case we find that Postable is not a subset.

Looking at the interface, these seem to be the functions that are in Postable but not in Messageable:

GetConversationThreadId()(*string)
GetInReplyTo()(Postable)
GetNewParticipants()([]Recipientable)

I'll however leave that decision up to you. The PR looks good to me.

[pandeyabs]

Thanks @meain . I'll punt this for now. Here's a tech debt ticket. #5155

I had one question about the message -> EML code here.

	if data.GetSentDateTime() != nil {
		email.SetDate(ptr.Val(data.GetSentDateTime()).Format(dateFormat))
	}

Any reason we are using sent date time here and not received date time or last modified date time?
Asking because posts don't have sent date time field. So I am using received date time field as an alternative.

[meain]

The spec mentions it to be the "sent" datetime. The idea is to have the datetime where it was "created".

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3.6.1. The Origination Date Field

The origination date field consists of the field name "Date" followed
by a date-time specification.

orig-date = "Date:" date-time CRLF

The origination date specifies the date and time at which the creator
of the message indicated that the message was complete and ready to
enter the mail delivery system. For instance, this might be the time
that a user pushes the "send" or "submit" button in an application
program. In any case, it is specifically not intended to convey the
time that the message is actually transported, but rather the time at
which the human or other creator of the message has put the message
into its final form, ready for transport. (For example, a portable
computer user who is not connected to a network might queue a message
for delivery. The origination date is intended to contain the date
and time that the user queued the message, not the time when the user
connected to the network to send the message.)

[pandeyabs]

Thanks Abin! I'll change it to post.GetCreatedDateTime()

[sonarqubecloud]

Quality Gate failed

Failed conditions

37.4% Duplication on New Code (required ≤ 3%)

See analysis details on SonarCloud