Technical references: Perl Webpage status checker

How to check webpage status using Perl

We have several web pages that we needs to be monitored from outside of our work network especially after a maintenance window. I didn't want to do this manually (ever again), so I wrote a Perl script to run on my Linux server (laptop) from home.

This is the header portion. I imported these modules to be used by my script. Line 3 turns any expression that is deemed difficult to debug into error. And line 4 enabled optional warnings.

#!/usr/local/bin/perl
## to install modules, follow instruction from http://www.cpan.org/modules/INSTALL.html
use strict;
use warnings;
use WWW::Mechanize;
use HTTP::Cookies;
use IO::Socket::SSL;
use Email::Sender::Simple qw(sendmail);
use Email::Sender::Transport::SMTPS ();
use Email::Simple ();
use Email::Simple::Creator ();
use WWW::Wunderground::API;
use Try::Tiny;
binmode STDOUT, ':utf8'; # for degrees symbol

----
Below is to use Weather Underground API. You must obtain your own free API key to use.

my $weather = new WWW::Wunderground::API(
    location => 'pws:XXXXXXXXXX',
    api_key  => '1111111111111111',
    auto_api => 1,
);

---
In the below code, we paste Message of the Day to our email body and get a list of URLs from a file.

## For debugging purposes
#my $outfile = "/home/me/Documents/perl/output.htm";

## Message of day
my $motd = `exec /usr/games/fortune | /usr/games/cowsay -n`;

## List of websites to check from outside
my $filename = '/home/me/Documents/perl/serverlist.txt';
open(my $fh, '<:encoding(UTF-8)', $filename)
 or die "Could not open file '$filename' $!";

---
Below is the main section used to loop through the list of URLs and check their status using a function call (last block of codes below). In line 10, we also use the WeatherUnderground API to get our temperature.

my $emailbody = "webpage status codes\n";
while (my $text = <$fh>) {
 chomp $text;
 $emailbody = $emailbody  . "$text: ";  
 my $answer = get_answer($text);
  $emailbody = $emailbody  . "$answer\n"; 
}
$emailbody = $emailbody  . "$motd\n"; 

my $currentTemp = $weather->conditions->temp_f;
my $cTempString = "Current Temperature is $currentTemp degrees";
$emailbody = $emailbody  . "$cTempString\n";

##For debugging purposes
#print $emailbody;

---
The below block of code is to connect to my email service provider and send email to everyone in the address book.

## Put SMTP authentication information here
my $smtpserver = 'smtp.office365.com';
my $smtpport = 587;
my $smtpuser   = 'me@outlook.com';
my $smtppassword = 'xxxxxxxxxxxxxxxxxxxxxxxxxxxxx';
my $tousers='';
## List of email addresses
$filename = '/home/me/Documents/perl/addresses.txt';
open($fh, '<:encoding(UTF-8)', $filename)
  or die "Could not open file '$filename' $!";

while (my $row = <$fh>) {
   chomp $row;
   $tousers = $tousers  . "$row,";  
}
$tousers = $tousers  . "$smtpuser";

##setup the email server connection here
my $transport = Email::Sender::Transport::SMTPS->new({
   host => $smtpserver,
   port => $smtpport,
   ssl => "starttls",
   sasl_username => $smtpuser,
   sasl_password => $smtppassword,
});

##create email object
my $email = Email::Simple->create(
   header => [
      To      => $tousers,
      From    => $smtpuser,
      Subject => 'Status',
   ],
   body => $emailbody,
);

##send the email
sendmail($email, { transport => $transport });

---
The below code is my function that does the actual website checking. Notice the Try-Catch blocks, this is useful for checking webpage status because if the website is unreachable it is a Catch event. Also line 2 shows how we obtain the parameter value for this function call. Be sure to wrap the variable around ().

sub get_answer {
 my ($row) = @_;
 try{
  chomp $row;
  ##print "$row\n";
      my $mech=WWW::Mechanize->new(ssl_opts => {
         verify_hostname => 0,
      }); 
     $mech->cookie_jar(HTTP::Cookies->new());
     $mech->get($row);
     ##my $output_page = $mech->content();
     my $output_status = $mech->status();
     ##print $output_page; 
  chomp $output_status;
  return $output_status;
 }catch{
    my $output_status = "Fail";
  return $output_status;
 };
}

Technical references

Thursday, August 3, 2017

Perl Webpage status checker

How to check webpage status using Perl

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