#!/usr/bin/perl
#
# Realtime Bandwidth checker "bw.cgi"
#
#   This script calculates the total bandwidth from 00:00 PST/PDT,
#   as well as total hits, and some estimates.
#
#   It writes "bwpos.txt" to preserve the last count and the file position
#   so that next time it will start counting from there, to be efficient.
#
#   It's a light weight tool, and can be used every now and then,
#   or placed in a crontab for hourly check 
#   or even a bit more often if desired.
#
#   Optionally, it can output only the total bandwidth, so that you can 
#   use this in a (shell) script to alert or take some actions 
#   if the bandwidth usage is getting closer to the limits.
#
#        WARNING: Please place this in a protected directory
#
# Usage: bw.cgi [-c]|[-q]
#        or http://yourdomaincom/protected/bw.cgi?
#
#  -c: This option force to check fron the top of the log file
#      DO NOT use this option unless you think you need to do it.
#
#  -q: When this option is turned on, the program will output 
#      total bandwidth in ascii only. (For using in shell script.)
#
#  These options are recognized in the CGI invocation, as well.
#
#  This script will create "bwpos.txt" in the same directory.
#  Do not modify/delete that file unless you are removing this script.
#
#  As this script is based on the records of log file,
#  if the log isn't accurate, the result will follow it, naturally.
#  Some servers of PowWeb may producing logs containing 20 to 30% less
#  than it should be for mnay maonths. (as of April/2005)
#
#
#  Additional note to  "PHP people": 
#    This script and all other normal CGI need permission of 700 (or 500).
#    CGI script can be placed and used in ANY directory (on PowWeb servers).
#
#
#  This script comes with NO GUARANTY what so ever.
#  It works for me, but maybe not for you,
#  especially if you are not nice person.
#  It's not my problem if you experience any problem with it.  
#
#  I totally neglected the design aspects of this script, as usuall.
#  Modify it to add colors and output formats if you like.
#
#  Be happy and don't worry about the bandwidth.
#  If you really need this tool, maybe it's time for you to look for
#  another host where you can get more bandwidth, hits, and so on.
#

$|=1;
$verbose = 1 if $ARGV[0] ne '-q';
if( $verbose){
  print "Content-type: text/html\n\n" ;
  print "<H1>THE Bandwidth checker (for PowWeb users)</H1><pre>";
}
$t=time();

print "Option specified: @ARGV\n" if $verbose and $ARGV[0];
$clean = 1 if grep(/\-c/,@ARGV);
print "'-c' option found. Strting from the top of the log\n" if $clean && $verbose;

$lid = $< - 500;
$fname = "/log/access/".substr($lid,0,1)."/${lid}_access_log";
#print "$fname\n";
$fpos = 'bwpos.txt';
open(FH,$fname) || die "Error: failed to open $fname\n";
read(FH,$line,64);
$line =~s/\n|\r/_/g;
seek(FH,0,0);

if((!$clean) && open(FPOS,$fpos)){
  chomp(@pos = <FPOS>);
  close(FPOS);
  if( $line eq $pos[3]){ # Check if we are dealing with the same log
    if( seek(FH,$pos[0],0)){ # if so, seek to the last position.
      print "Setting the starting file position to: $pos[0], and counter to: $pos[1]\n" if $verbose;
      $c = $pos[1];
      $h = $pos[2];
      $tt = $pos[4];
    }
  }else{ # if not, start from the top.
    print "$line\n$pos[3]\n-----\n" if $verbose;
  }
}else{
  $c = 0;
}
$l=0;

print "Counting ..." if $verbose;
while(<FH>){ # With 'g' option it's quicker, somehow.
  $cc += $1 if /\" [2-5][0-9][0-9] ([0-9]+)/og;
  $l++;
}
$c += $cc;
print "\nFinished !\n\n" if $verbose;
#print "cc=$cc, l=$l\n"; # Debug print
#print `ps uww`;
seek(FH,0,2);
$endpos = tell(FH);
close(FH);
$h += $l;
if(open(FPOSW,">$fpos")){
  print "writing following data to bwpos.txt:\n\t$endpos <== The end position of log file\n\t$c <== The total count at that point\n\t$h <== The Total hit count of the day\n\t$line <== The first 64 bytes of log (for identification)\n\n" if $verbose;
  print FPOSW "$endpos\n$c\n$h\n$line\n$t\n";
  close(FPOSW);
}else{
  print "Error: failed to open $fname for writing 'position file'\n";
}
if( $verbose){
  #printf("time=%d, t-tt=%d\n", time(), $t-$tt);
  ($sec,$min,$hour,$mday,$mon,$year,$wday, $yday, $isdst) =localtime(time);
  $now = localtime(time());
  $tn = ($hour*60 + $min)*60 +$sec;
  $td = $t - $tt;
  $td = $tn if $clean;
  print "It's $now (PST/PDT).  $tn seconds has passed since the midnight.\n\n";
  print "$cc bytes, and $l lines(hits) since last check ($td seconds ago), Total of $h hits, today.\n";
  print $c/$h , " bytes/hit average.\n" if $h > 0;
  if( $td > 0){
    $ctd = $cc/$td;
    $htd = $l/$td;
    print "\n$ctd bytes/sec, $htd hits/sec (since last check of $td seconds ago)\n";
    $hth = $htd*3600;
    $ctday = $ctd*360*24/1024/1024;
    printf( "Roughly translated into %d Megabytes/day, and  %d hits/hour at the current rate (since last check).\n", $ctday,$hth);
    print "Note. The estimate above isn't necessarily accurate if the last check was done shortly before.\n";
  }
  if($tn > 0){
    $ctn = $c/$tn;
    $htn = $h/$tn;
    print "\n$ctn bytes/sec, $htn hits/sec,  today (since 00:00 PST/PDT)\n";
    $hthn = $htn*3600;
    $ctdayn = $ctn*3600*24/1024/1024;
    printf( "Roughly translated into %d Megabytes/day, and  %d hits/hour at the current rate, today.\n", $ctdayn,$hthn);
  }
  print "\n'$c' bytes (Total Bandwidth in the logfile: $fname)\n";
  if( $c > 4*1024*1024*1024){
    print "\nIt's over 4GB, now. I'd start worrying a little.\n";
  }elsif( $c < 2*1024*1024*1024){
    print "\nYou don't have to worry about the bandwidth limit, yet...\nunless it's pretty early in the day...   :)\n" ;
  }elsif( $c > 8*1024*1024*1024){
    print "\nIt's over 8GB !!! \n";
  }else{
    print "\nIt's over 2GB ... but under 8GB, now...\n" ;
  }

}else{
  print $c;
}
 
1;