allow mail rendering at delay time

[hqm42]

The current solution to delayed mail delivery renders the mail template at delivery time:

Notifier.delay.signup(@user)

This can lead to problems, if your data that is accessed by the mail template changed between delay time and delivery time.

When you try to explicitly delay delivery forcing rendering you will get an error:

Notifier.signup(@user).delay.deliver
# Use MyMailer.delay.mailer_action(args) to delay sending of emails.

The new approach will serialize the mail message at delay time using Mail::Message.encoded and deserialize using the constructor:

Notifier.signup(@user).delay.deliver
# works like expected (render message -> delay -> execute job -> deliver)

The old approach:

Notifier.delay.signup(@user)
# still works (delay -> execute job -> render message -> deliver)

[wgc-as]

+1 When will this be merged in?

[albus522]

My primary concern with this is that it seriously increases the risk of a silent serialization errors due to exceeding the handler size. We get a lot of confusion when databases like Mysql simply truncate the data and move one. Unfortunately I can't find the conversation about why this is a difficult problem, but the short version is that text fields are reported as unlimited length but they aren't actually unlimited.