一个支持HTTP续传下载的PERL程序

#!/usr/bin/perl

use IO::Socket;

if ($#ARGV <= 0) {

print STDERR "usage: getright <URL> <FILENAME>\n\n";

print STDERR " <URL>: eg. http://www.server.dom:port/path/file.ext\n";

print STDERR "<FILENAME>: eg. filename.ext\n";

exit(0);

} else {

open(FILE, "+>>".$ARGV[1]) or die "Cannot open $ARGV[1] for append: $!";

($length = sysseek(FILE,0,2)) =~ s!.*([0-9]+).*!$1!g;

print STDERR "Attempting to resume $ARGV[1] from byte: $length\n";

}

if ($ARGV[0] =~ m!^ (?:http://)? (.*?) (?:\:([0-9]+))? (/.*)$!x)

{ ($server,$port,$path) = ($1, $2 || 80, $3); }

print "[$server] [$port] [$path]\n";

$socket = IO::Socket::INET->new(PeerAddr => $server,

PeerPort => $port,

Proto => 'tcp',

Type => SOCK_STREAM) or die "Cannot connect: $!";

print $socket "GET $path HTTP/1.0\n";

print $socket "Host: $server\n";

print $socket "Range: bytes=$length-\n";

print $socket "Connection: close\n\n";

if (!(($reply = <$socket>) =~ /HTTP\/1.[01] 206 Partial Content/)) {

$reply =~ s!(.*)\r\n!$1!;

print STDERR "Failed [$reply]\n";

print STDERR "Invalid URL/Unrecognized Reply/Resume Not Supported.\n";

close($socket); exit(0);

} else {

print STDERR "Received valid HTTP reply.\n";

}

while (($mime = <$socket>) =~ /\w+: /) {

if ($mime =~ /Content\-Range\:\sbytes\s([0-9]+)\-([0-9]+)\/([0-9]+)/)

{ ($start,$finish,$filesize) = ($1, $2, $3); }

if ($mime =~ /Content\-Length\:\s([0-9]+)/) { $total = $1; }

}

print STDERR "Receiving data: ";

while ($data = <$socket>) {

$recieved += length($data);

$percentage= int((($start+$recieved) / $filesize) * 100);

print STDERR $percentage."%"."\b"x(length($percentage)+1);

print FILE $data;

}

print STDERR "100%\n";

close(FILE);

close($socket);

# Example HTTP return header:

#

# HTTP/1.1 206 Partial content

# Date: Wed, 15 Nov 1995 06:25:24 GMT

# Last-modified: Wed, 15 Nov 1995 04:58:08 GMT

# Content-Range: bytes 21010-47021/47022

# Content-Length: 26012

# Content-Type: image/gif