Clear interface for mail class

Francesco Bochicchio bieffe62 at gmail.com
Wed Oct 14 16:55:42 CEST 2009


On Oct 14, 2:39 pm, Benedict Verheyen <benedict.verhe... at gmail.com>
wrote:
> Hi,
>
> I'm trying to come up with a decent interface for my email class.
> Basically, i have one email function but it has many (too many?) variables:
>
>     send_mail(self, send_from, send_to, send_cc, subject, text, separate_emails = False, files=[], inline_files=[], server="localhost",
> charset="iso-8859-1")
>
> I'm thinking on how i could simplify it and make it look nicer and more easy to use.
> I can reduce the number of arguments by adding functions for the less common tasks
> like adding attachement, inline files and so on.
> Then i would end up with functions like this:
>
> def __init__(self):
>     """
>     """
>     self._files=[]
>     self._inline_files=[]
> ...
>
> def add_files(self, files=[]):
>     assert type(files)==list
>     self._files=files
> ...
>
> When sending an email, i could check if files where specified and if so, send them too.
>
> But it doesn't feel right to just have a bunch of small functions to set variables.
> Calling the function would change from:
>  (where m is the mail class)
>  m.send_mail( "from_me at work",
>               "to_ at work",
>               [],
>               "Test emailmodule ",
>               MSG,
>               separate_emails = True,
>               files=["attached_pic.png"],
>               inline_files=["inline_pic.png"],
>               server="mysmtpserver")
>
> to:
>
> m.add_files(["attached_pic.png"])
> m.add_inline_files(["inline_pic.png"])
> m.smtp_server("mysmtpserver")
> m.send_mail( "from_me at work",
>              "to_ at work",
>              [],
>              "Test emailmodule "",
>              MSG)
>
> It looks already better and i could set the smtp server as a class variable,
> but i'm not sure this will present me with the most natural interface to use.
>
> Or should i make 1 general function that sets vars according to a type?
> For instance: add_header("To",[list_of_recipients])
>
> This kind of problems seems to happen sometimes: i need to fix something quickly,
> build a script for it, and then i realise that the code i've written is not the best in
> terms of reusability and has some "not so great" functions or classes.
> Speedy development eh.
>
> Any ideas are welcome.
>
> Thanks,
> Benedict

I would add a server class, maybe subclassing something in standard
library, and add to it the 'send' method, so that sending a mail would
be
something like:

myserver = MyMailServer("mysmtpserver", "localhost", ) # this only
needs to be done once, not for each mail

m = MyMail( subject, text, separate_emails = False, files=[],
inline_files=[] ) # mail creation

myserver.send( m, from= "from_me at work", # mail sending
               to = "to_ at work",
               cc_to= None  )

Note that I put sender and destination senders in the send method, not
as attributes  of the mail object. It makes more sense to me, and yopu
can reuse
the same object if you want to send the same mail to many addresses
( and/or via different servers ).

IN general, un case like yours I use a lot default parameters, as you
did already. Having separate methods to setting specific part of an
object only makes
sens (to me) if you need  first to create an object and later change
some of the attributes. Also, if you are just going to change the
attributes, you do not
need a method: just use the object.attribute = value syntax. If you
are going to need later to do more complex thing, you can always
transform your
attribute in a property.







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