#!/usr/bin/perl
use DBI;

print "Content-type:text/html\n\n";

$dbh = DBI->connect( "dbi:mysql:products", "webserver", "", {RaiseError=>1,AutoCommit=>1} ) or &dienice("Can't connect: $DBI::errstr");

$uri = $ENV{'REQUEST_URI'};
if ($uri eq "") {
    exit;			# don't update a blank counter.
}

# remove index.html from the end of the URI, so that "/class/ch18/index.html"
# becomes "/class/ch18/".
if ($uri =~ /(.*)index.html/i) {  
    $uri = $1;
}

$sth = $dbh->prepare("select count from counts where pagename=\"$uri\"");
$sth->execute  or db_err("Unable to execute query", $dbh->errstr);

($count) = $sth->fetchrow;
if ($count > 0) {
   $count++;
   $sth = $dbh->do("update counts set count=count+1 where
pagename=\"$uri\"")  or db_err("Unable to execute query", $dbh->errstr);
} else {
   $count = 1;
   $sth = $dbh->do("insert into counts values(\"$uri\",1)")  or db_err("Unable to execute query", $dbh->errstr);
}

print "You are visitor number $count.\n";

sub dienice {
    ($msg) = @_;
    print "<h2>Error</h2>\n";
    print $msg;
    exit;
}