1341 not receiving emails

[aharwood2]

This pull request refactors the email sending logic in EmailService.cs to simplify the SendEmail method and ensure that emails are sent individually to each recipient rather than as a group. The changes also introduce a delay between sending emails to different recipients and update logging for better clarity.

Email sending logic refactor:

• Changed SendEmail to accept a single recipient (string to) instead of a list, and updated its implementation to add only one recipient per email. Logging statements were also updated accordingly. [1] [2] [3]

• Updated all usages of SendEmail that previously passed a list of recipients to instead loop through each recipient and send emails individually, adding a 1-second delay between each send. [1] [2] [3]

Async improvements:

• Changed background email sending tasks to use async/await for better asynchronous handling.

[PhilBradbury]

Not sure the creation of an SMTP client for each email is particularly efficient (can it be wrapped in a Using statement, or is a fresh one each time to minimise issues?) but for the amount we're sending I guess it should be fine.

However, I did notice this whilst reviewing the code:

... which strikes me as being very manchester specific! Do we do that in case we don't have a registered email and we know that will work? I assume we'll have to remove it, but not sure what the backup will be.

[aharwood2]

Not sure the creation of an SMTP client for each email is particularly efficient (can it be wrapped in a Using statement, or is a fresh one each time to minimise issues?) but for the amount we're sending I guess it should be fine.

However, I did notice this whilst reviewing the code:

... which strikes me as being very manchester specific! Do we do that in case we don't have a registered email and we know that will work? I assume we'll have to remove it, but not sure what the backup will be.

Agreed. Will add a setting for "email domain" or something and then a setting to use "backup email logic" or something? Or do we just do this away altogether and say if there isn't an email in the system then they just don't get emails?

[PhilBradbury]

Agreed. Will add a setting for "email domain" or something and then a setting to use "backup email logic" or something? Or do we just do this away altogether and say if there isn't an email in the system then they just don't get emails?

Removing it altogether seems reasonable, IMO

[PhilBradbury]

@aharwood2 - removed the creation of the email using username@manchester.ac.uk. Also added a quick check to build and only send email if there is an address now.

[Copilot]

Pull request overview

This pull request updates EmailService to send emails per-recipient (instead of batching recipients into a single message), adds a delay between sends, and adjusts async usage for background email notification flows.

Changes:

• Refactors SendEmail to accept a single recipient (string to) and builds each MailMessage with one To address.
• Updates notification flows to loop over recipients and send emails individually with a 1-second delay between sends.
• Converts some Task.Run(...) usages to Task.Run(async () => ...) to support await Task.Delay(...) in those loops.

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[PhilBradbury]

Untested, but looks logical to me.