#----------------------------------------------------------------#
 # Use for-loop to allow two tries on red alerts.                 #
 #----------------------------------------------------------------#
 for (my $n=1; $n<=$retry; $n++)
 {
   @http_err = ""; # Reinitialize every time through.
   $ua       = ""; #      ''
   $response = ""; #      ''
   $request  = ""; #      ''
   $headers  = ""; #      ''
   $body     = ""; #      ''
   $code     = ""; #      ''
   $desc     = ""; #      ''
   #----------------------------------------------------------#
   # If serialization of the URL requested, append hostname   #
   # and seconds (from time() function) patameters.           #
   #----------------------------------------------------------#
   if ($opt_s or $serialize)
   {
     sleep(2);
     $url        = "$http_cmd";
     $url_suffix = "hostname=$host&seqnumber=" . time();
     $url .= ($url =~ /\?/) ? "\&${url_suffix}" : "\?${url_suffix}";
   }

   $ua = LWP::UserAgent->new();
   $ua->env_proxy(); # Check proxy settings.

   echo("$n. Checking connection to $uiPID\n");

   echo("\$ua->agent('DMC $0/%I%')\n");
          $ua->agent("DMC $0/%I%");

   echo("\$response = \$ua->timeout($timeout)\n");
          $response =  $ua->timeout($timeout);
   ($opt_v or $URL_opt_v) && print "${sp}\$response=|$response|\n";

   #----------------------------------------------------------------#
   # Wrap this in alarm trap to (hopefully) kill hanging            #
   # requests.                                                      #
   #                                                                #
   $http_OK = 1; # Hope for the best.                               #
   $msg = "Alarm Timeout! ($url)";                                  #
   local $SIG{ALRM} = sub {                                         #
                            echo("$msg [\$@=|$@|]\n");              #
                            $http_OK = 0;                           #
                          };                                        #
   $timeout_alarm = $timeout + 5;                                   #
   ($opt_v or $URL_opt_v) && echo("alarm($timeout_alarm)\n");       #
                                   alarm($timeout_alarm);           #
                                                                    #
     echo("\$request  = new HTTP::Request('GET', '$url')\n");       #
            $request  = new HTTP::Request("GET", "$url");           #
     ($opt_v or $URL_opt_v) && print "${sp}\$request=|$request|\n"; #
                                                                    #
     echo("\$response = \$ua->request($request)\n");                #
            $response =  $ua->request($request);                    #
                                                                    #
   ($opt_v or $URL_opt_v) && echo("alarm(0)\n");                    #
                                   alarm(0); # Halt alarm.          #
                                                                    #
   if ($@) # Propagate any errors (if any).                         #
   {                                                                #
     @http_err = "$@";                                              #
     foreach (@http_err) # Propagate any errors (if any).
       { print "${sp}\$@=|$_|\n"; }                                 #
     $@ = "";                                                       #
   } # if ($@)                                                      #
   #                                                                #
   #----------------------------------------------------------------#

   $null_n = $response =~ s/\x00//g; # Strip nulls
   $null_n ||= 0;
   if ($null_n)
   {
     $msg  = "${sp}Removed $null_n nulls from \$response\n";
     $len  = length($response);
     $msg .= "${sp}\$response now $len bytes\n";
     $subject = "$surname: NOTICE Nulls In HTTP Response";
     email("$subject", "$msg", $support);
     if ($opt_v)
     {
       print "${sp}Removed $null_n nulls from \$response\n";
       $len = length($response);
       print "${sp}\$response now at $len bytes\n";
     }
   }

   ($opt_v or $URL_opt_v) && print "${sp}\$response=|$response|\n";

   #----------------------------------------------------------#
   # In case of Alarm Timeout, $http_OK will be zero.  We'll  #
   # still try to capture the following info, but we'll also  #
   # be testing both $http_OK and $response_OK before giving  #
   # our blessing for the connectivity test.                  #
   #----------------------------------------------------------#
   $response_OK = ($response->is_success);

   echo("\$code     = \$response->code\n");
          $code     =  $response->code;
   ($opt_v or $URL_opt_v) && print "${sp}\$code     = |$code|\n";

   echo("\$desc     = HTTP::Status::status_message($code)\n");
          $desc     = HTTP::Status::status_message($code);
   ($opt_v or $URL_opt_v) && print "${sp}\$desc     = |$desc|\n";

   #----------------------------------------------------------#
   # Get headers                                              #
   #----------------------------------------------------------#
   echo("\$headers  = \$response->headers_as_string\n");
          $headers  =  $response->headers_as_string;

   if ($opt_v or $URL_opt_v)
   {
     @headers = split(/\n/,$headers); # Split on newlines
     foreach (@headers)
     {
       print "${sp}headers=$_\n";
     }
   }

   #--------------------------------------------------------------#
   # $http_OK means we didn't alarm() out.  $response_OK is from  #
   # "$response_OK = ($response->is_success);" above.   If both   #
   # of these look good, then we check next for any HTTP output   #
   # we're supposed to find.                                      #
   #--------------------------------------------------------------#
   if ($http_OK and $response_OK)
   {
     #----------------------------------------------------------#
     # If we have expected or alternate responses, then check   #
     # them before sounding the "All clear."                    #
     #----------------------------------------------------------#
     if (
          (defined($expd_response) and $expd_response ne "")
        or
          (defined($alt_response ) and $alt_response  ne "")
        )
     {
       #----------------------------------------------------#
       # Get body -- print as needed.                       #
       #----------------------------------------------------#
       echo("\$body     = \$response->content\n");
              $body     =  $response->content;
       @body = split(/\n/,$body); # Split body on newlines
       if ($opt_v or $URL_opt_v)
       {
         foreach (@body)
         {
           print "${sp}content=$_\n"
         }
       } # if ($opt_v or $URL_opt_v)

       @grep_response = grep(/$expd_response/, @body);
       $response_n    = @grep_response;
       #----------------------------------------------------#
       # If 1st response found, look for any optional/add'l.#
       #----------------------------------------------------#
       if (
              $response_n > 0
           &&
              defined($addl_response)
           &&
              $addl_response ne ""
          )
       {
         @grep_response = grep(/$addl_response/, @body);
         $response_n    = @grep_response;
       }

       #----------------------------------------------------#
       # Response not found, any alternate response?        #
       #----------------------------------------------------#
       if ($response_n == 0)
       {
         if (defined($alt_response) and $alt_response ne "")
         {
           @grep_response = grep(/$alt_response/, @body);
           $response_n    = @grep_response;
         }
       }

       #----------------------------------------------------#
       # Neither expected nor alternate response found.     #
       #----------------------------------------------------#
       if ($response_n == 0)
       {
         if ($n > 1) # for (my $n=1; $n<=$retry; $n++)
         {
           $epage_msg = "$host: Web connection to $uiPID "
             . "failed (expected response not found)";
           notify_support(); # Modifies $epage_msg
           $msg       = "$host|$uiPID|$url|$alert|$epage_msg";
           no strict 'refs';
             ${$alert}++;
           use strict 'refs';
           ELS_Agent("$msg");
         }
         next; # Iterate "for (my $n=1; $n<=$retry; $n++)"
       }
     } # if (defined($expd_response) and ..

     #------------------------------------------------------#
     # Else, $http_OK is sufficient for "All clear."        #
     #------------------------------------------------------#
     $shortdesc = "Successful web connection to $uiPID";
     $n++; # Incr $n--no need to try again; it was successful.
     $msg = "$host|$uiPID|$url|green|$shortdesc|";
     $green++;
     ELS_Agent("$msg");

     echo("$0: $shortdesc\n");
     last; # for (my $n=0; $n<=1; $n++)
   } # if ($http_OK)
   elsif ($n > ($retry - 1)) # Something's amuck.
   {
     $epage_msg = "$host: Web connection to $uiPID failed";
     if (@http_err)
     {
       $epage_msg .= " [";
       foreach (@http_err) { $epage_msg .= "$_ "; }
       $epage_msg =~ s/\s+$/\]/;
     }

     notify_support(); # Modifies $epage_msg (appends to it).
     $msg = "$host|$uiPID|$url|$alert|$epage_msg";
     no strict 'refs';
       ${$alert}++;
     use strict 'refs';
     ELS_Agent("$msg");
   } # if ($http_OK); elsif ($n > 1)
   else
   {
     sleep(2);
   } # if ($http_OK); elsif ($n > 1); else
 } # for (my $n=0; $n<=1; $n++)