Perl read a file and send e-mail - perl

Question

I have a log file of below format
D12345 joe#gmail.com
C67890 mary#gmail.com
B45678 don#gmail.com
A12309 joe#gmail.com
F45670 mary#gmail.com
F45470 joe#gmail.com
Currently I'm able to send e-mail to everyone with below e-mail body content
your Product id: $product_id
($product_id is D12345, A12309, F45470 , C67890, F45670)
Problem is 'N' e-mails are sent to an user if their e-mail id is present N times in the log file.
Example :
2 e-mails are sent to mary#gmail.com and 3 e-mails are sent to joe#gmail.com
I want to send only one e-mail to the users but having all their product ids, if single e-mail id occurs multiple times in the output file, like
your Product ids: C67890, F45670 to mary#gmail.com
and
your Product ids: D12345, A12309, F45470 to joe#gmail
My current code snippet
open my $fh, '<', "output.txt" or die "could not open file: $!";
while (my $line = <$fh>) {
my ($product_id, $to_email) = $line =~ /(\w\d+)\t(\S+)/;
my $MailFrom = 'myemail#domain.com';
my $subject = "PRODUCT ID DETAILS";
my $message = "your Product ids: $product_id";
%mail = (
To => $to_email,
From => $MailFrom,
Subject => $subject,
Message => $message
);
$mail{Smtp} = 'mail.myorg.com';
sendmail(%mail)or die $Mail::Sendmail::error;
}
close $fh;
Suggestions are really appreciated. Thanks in advance.

Answer 1

You must aggregate the information from the log file into a hash before sending the mails
Here's some example code which dumps the %mail hash instead of calling sendmail so that you can see the results
use strict;
use warnings 'all';
use Data::Dump;
my %users;
{
open my $fh, '<', "output.txt" or die "could not open file: $!";
while ( <$fh> ) {
my ($prod, $user) = split;
push #{ $users{$user} }, $prod;
}
}
# Convert arrays of product codes into comma-separated strings
#
$_ = join ', ', #$_ for values %users;
while ( my ($user, $prods) = each %users ) {
my %mail = (
To => $user,
From => 'myemail#domain.com',
Subject => 'PRODUCT ID DETAILS',
Message => "Your product IDs: $prods",
Smtp => 'mail.myorg.com',
);
dd \%mail
#sendmail(%mail) or die $Mail::Sendmail::error;
}
output
{
From => "myemail\#domain.com",
Message => "Your product IDs: D12345, A12309, F45470",
Smtp => "mail.myorg.com",
Subject => "PRODUCT ID DETAILS",
To => "joe\#gmail.com",
}
{
From => "myemail\#domain.com",
Message => "Your product IDs: B45678",
Smtp => "mail.myorg.com",
Subject => "PRODUCT ID DETAILS",
To => "don\#gmail.com",
}
{
From => "myemail\#domain.com",
Message => "Your product IDs: C67890, F45670",
Smtp => "mail.myorg.com",
Subject => "PRODUCT ID DETAILS",
To => "mary\#gmail.com",
}

Answer 2

This is not a perl question, just how to do basic coding.
I would preprocess the data to fit your needs i.e. create a hash of arrays using the email id as the key and push the product into the array.
You will end up with something like:
{
joe#gmail.com: ['D12345', 'A12309', 'F45470'],
mary#gmail.com: ['C67890', 'F45670'],
don#gmail.com: ['B45678']
}
Once you've created that data structure form your log file it should be simple enough the iterate over each key and create an email with the values.