Strange problem with Mail::Send

[Ken Miller <kl...@shetlandsoftware.com>]

My web app sends notification emails when a task transitions from one 
part of the work flow to another.  I use Mail::Send to send mail, using 
a smtp server to transfer the mail.  The code looks something like this:

    my $mail = Mail::Send->new( Subject => 'a subject', To => 
'someone@example.com );
    my $fh = $mail->open( 'smtp', Server => 'some.host.name' );
    print $fh "A message\n";
    $fh->close;

To ensure that the recipient receives the mail from a recognizeable 
email address, I set the MAILADDRESS environment variable as follows:

    use constant FROM_ADDRESS => 'somebody@example.com';

and then, just before the above code to send the mail, I do this:

    local $ENV{ MAILADDRESS } = FROM_ADDRESS

This all works fine, except for one situation:

Ocassionally, the 'From' email address is not the constant address as 
shown above.  Instead, it's the 'from' email address from another part 
of the application completely unrelated to this notification email.  The 
code that sends this email uses this paradigm:

eval {
    local $ENV{ MAILADDRESS } = $some_other_email_address;
    (same mail boiler plate as above);
};

It almost seems that the mail address is getting stuck.

I don't have my mod-perl book handy right now, but I seem to remember 
that %ENV is restored after each request to the server startup state - 
is this correct?  If so, i should not need 'local' in front of the 
environment assignment, assuming that I'm not worries about the ENV 
changing during a request (which I'm not).

Is there some strange interplay going on between eval, local, and 
mod_perl that could cause this behaviour?  I've been unable to duplicate 
the problem in my test environment, so I'm just taking shots in the dark 
hoping to hit something.

Suggestions?

Cheers!

    -klm.

Re: Strange problem with Mail::Send

[Stas Bekman <st...@stason.org>]

Ken Miller wrote:
> My web app sends notification emails when a task transitions from one 
> part of the work flow to another.  I use Mail::Send to send mail, using 
> a smtp server to transfer the mail.  The code looks something like this:
> 
>    my $mail = Mail::Send->new( Subject => 'a subject', To => 
> 'someone@example.com );
>    my $fh = $mail->open( 'smtp', Server => 'some.host.name' );
>    print $fh "A message\n";
>    $fh->close;
> 
> To ensure that the recipient receives the mail from a recognizeable 
> email address, I set the MAILADDRESS environment variable as follows:
> 
>    use constant FROM_ADDRESS => 'somebody@example.com';
> 
> and then, just before the above code to send the mail, I do this:
> 
>    local $ENV{ MAILADDRESS } = FROM_ADDRESS
> 
> This all works fine, except for one situation:
> 
> Ocassionally, the 'From' email address is not the constant address as 
> shown above.  Instead, it's the 'from' email address from another part 
> of the application completely unrelated to this notification email.  The 
> code that sends this email uses this paradigm:
> 
> eval {
>    local $ENV{ MAILADDRESS } = $some_other_email_address;
>    (same mail boiler plate as above);
> };
> 
> It almost seems that the mail address is getting stuck.
> 
> I don't have my mod-perl book handy right now, but I seem to remember 
> that %ENV is restored after each request to the server startup state - 
> is this correct?  If so, i should not need 'local' in front of the 
> environment assignment, assuming that I'm not worries about the ENV 
> changing during a request (which I'm not).
> 
> Is there some strange interplay going on between eval, local, and 
> mod_perl that could cause this behaviour?  I've been unable to duplicate 
> the problem in my test environment, so I'm just taking shots in the dark 
> hoping to hit something.
> 
> Suggestions?

1) which mod_perl version are you using, Ken?

2) why do you use %ENV to pass the 'from' address, rather than pass it 
expicitly?

local() has the effect only for the block you defined it in, but if you've 
created a closure later on (not in %ENV at all), it may be the reason. 
just add debug prints to test it. I have a feeling that that's exactly 
what you are doing: creating a closure.

If you want us to look at it, please reduce the problematic code to the 
very minimum and post it here.


-- 
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