Re: surveying the dead

[Sean O Riordain]

S wrote:
> 
> >From the naive:
>         What is the most efficacious method of pinging a web server URL for its 
>status
> regarding the viability of a specific page ?
> 
>         appreciatively,
>         scott

Alternatively you could do something like below... note that this is a
cut down version but most of what you want is there...

cheers
Sean



use strict;

# not sure how many of these are really needed here...
use Carp;
use Fcntl qw(:DEFAULT :flock);
use MIME::Base64;

use POSIX qw(uname);
use Socket;

use Mail::Mailer;

use LWP::UserAgent;
use HTTP::Request;
use HTTP::Response;

#######################################################
#
# sub fpget($URL) - fetch URL or else complain...
#
sub fpget($$) {
    my $URL= shift;
    my $redirect_url = shift;

    my $URL_timeout = 30;
    my $URL_retries = 3;
    my $URL_email_list = "<fred\@silly.net>, <john\@silly.net>";

    # create the user agent object
    my $ua = new LWP::UserAgent;
    $ua->agent("daft_agent/1.0 " . $ua->agent);
    $ua->timeout($URL_timeout); # seconds

# if a proxy is needed then it would go something like...
#    $ua->proxy('http', 'http://proxy.silly.net:8080/');
#    $ua->no_proxy('silly.net');

    # create the request
    my $req = HTTP::Request->new(GET => $URL);
    $req->header('Connection' => 'Close');

    my $res;
    my $for_res;

    for (my $i=0; $i < $URL_retries; $i++) {
        $res =  $ua->request($req);
        if ($res->is_success) {
            $for_res = $res->content;
            last;
        } else {
            warn "The HTTP GET($URL) failed!\n\n";
        }
    }

    unless ($res->is_success) {
        warn "URL failed " . $URL_retries .
            " times, mailing $URL_email_list now.";

        # as per recipe 17.8 from the Ram book. get the
        # fully qualified name of this machine
        # my $hostname = hostname();
        my $hostname = (uname)[1];
        my $address = gethostbyname($hostname)
            or warn "Couldn't resolve $hostname: $!";
        $hostname = gethostbyaddr($address, AF_INET)
            or warn "Couldn't re-resolve $hostname : $!";

        # send a mail to the appropriate people warning them about
        # this problem....
        my $mailer = Mail::Mailer->new("sendmail");
        $mailer->open({ From => "wibble\@silly.net",
                        To => $URL_email_list,
                        Subject => "URL GET Failure",})
            or die "Can't open: $!\n";
        print $mailer "At ". scalar(gmtime) . " GMT, URL fetch
failed\n";
        print $mailer "from $hostname after " . $URL_retries . "
attempts\n";
        print $mailer "trying to fetch using url:\n";
        print $mailer "$URL\n";
        return "Temporarily unavailable";
    }
    # here we mung the page for our own purposes...
    return $for_res;
}