Feature request: alternative name for Date: header attribute

[UffeJakobsen]

Feature request: alternative name for Date: header field

Hi

It would be nice with an option to rename or prepend a prefix to the Date: header attribute

Reasoning:

The way we use mailmerge is by generating output to a spool-file (using --output-format raw)
That enables to do extensive review of what actually is generated before sending out emails.
Once we are satisfied with the generated spool-file - the individual emails in the spoo-lfile are split (by a simple shell script) and sent via sendmail (postfix incarnation). As postfix (sendmail) adds its own "Date:" attr at the actual queuing time it would be useful to let the the generated Date: attr be know by another name - as it represents the date of the generation (rendering) and not the queueing - which in theory could be many days apart.

[awdeorio]

In a typical use case, mailmerge would generate a message including a Date field and send it right away. Your use case seems a bit unusual, where you generate a message, do some post-processing, and send it later using sendmail. I wonder if it makes sense for you to strip the Date header in your post-processing step. If there's another common use case that I'm missing, I'm open to adding a feature to support it.

[UffeJakobsen]

In my production environment - I cannot connect to any mail server via socket (TCP) the only way to get the email sent is to queue the message via pipe through the local sendmail binary

I've created a PR #164 with a suggestion to a possible solution :-)

[awdeorio]

I see that you're using templating aspects of mailmerge but not the sendmail part. I wonder if it would be useful to add a config option for a dummy SMTP server.

[UffeJakobsen]

I see that you're using templating aspects of mailmerge but not the sendmail part. I wonder if it would be useful to add a config option for a dummy SMTP server.

I'm not entirely sure what the implications are by this suggestion - and if it would solve my issue/challenges - but is sounds like an interesting solution - and I guess that it could be useful for lots of other use-cases 👍 :-)

[awdeorio]

It sounds like Date handling might be best handled near the time of sendmail() call in sendmail_client.py. I think you're idea to have an option to leave it out is fine. I'm hesitant to implement it with the "if it's blank then ..." logic, which could confuse users.

Here's a more thought-out suggestion for your consideration.

1. Add a member function to TemplateMessage that adds a Date header. Throw an exception if a Date header already exists.
2. Add a configuration parameter to MailmergeConfig called date
3. Edit SendmailClient to check the date config
   i. If date is None or auto, automatically add a Date via member function described above.
   ii. Else if date is manual do nothing
   iii. Else throw an exception about badly formed config