#-------------------------------------------------------------
#-------------------------------------------------------------

use Socket;

#-----------------------------------------------------------------
#-----------------------------------------------------------------
sub open_tcp {
    my ($FS, $dest, $port) = @_;

    my $proto = getprotobyname ('tcp');
    socket ($FS, PF_INET, SOCK_STREAM, $proto);
    my $sin = sockaddr_in ($port, inet_aton ($dest));
    connect ($FS, $sin) || return undef;

    my $old_fh = select ($FS);
    $| = 1; # unbuffer
    select ($old_fh);
    1;
}    

#-------------------------------------------------------------
# Given a URL, get the data from that URL by querying the
# associated web server.
# 
# Returns: the (usually html) text.
#-------------------------------------------------------------
sub url_get {
    my ($url, $include_header_info) = @_;
    my @lines;
    my $rc = 0;

    # Break the URL into a remote host name and a target 
    # directory.

    my ($service, $remote, $target) = split_url ($url);

    if (! defined ($service)) {
	$rc = 1;
	return $rc;
    }

    $cmd = "GET $target HTTP/1.0\nHost: $remote\n\n";

    #--------------------------------------------------------
    # Establish socket connection to the http server.
    #--------------------------------------------------------

    if (! defined open_tcp (SOCK, $remote, 80)) {
	print "Error connecting to server at $url\n";
	return undef;
    }

    # Request and receive the page.
    print SOCK $cmd;
    $in_header = 1;
    while (<SOCK>) {
	if ($in_header == 0) {
	    push @lines, $_;
	}
	elsif ($_ =~ /^\s*\r?\n$/) {
	    $in_header = 0;
	}
	else {
	    chop;
	    # Process header fields
	    if ($in_header == 1) {
		($http, $respcode, $other) = split (' ', $_);
		$in_header = 2;
	    }
	    else {
		$colonpos = index ($_, ":");
		if ($colonpos >= 1) {
		    $key = substr ($_, 0, $colonpos);
		    $value = substr ($_, $colonpos+1);
		    $value =~ s/^\s+//;
		    $value =~ s/\s+$//;
		    $header{"$key"} = $value;
		}
	    }
		    
	}
    }
    close SOCK;

#    print "RESPONSE CODE = $respcode\n";
    foreach $val (keys %header) {
#	print $val . " = " . $header{$val} . "\n";
    }

    # Page redirect: recursively try again.
    if ($respcode == 302) {
#	print "Trying again...\n";
	($rc, @lines) = url_get ($header{"Location"}, $include_header_info);
    }

    return ($rc, @lines);
}

#-----------------------------------------------------------------
# Break the URL into a remote host name and a target 
# directory.
#-----------------------------------------------------------------
sub split_url {
    my ($url) = @_;

    if ($url =~ "^([^:]+)://([^/]+)(/?.*)") {
	$service = $1;
	$remote = $2;
	$target = $3;
    }
    if (! defined ($remote)) {
	return undef;
    }
    if ($service eq "") {
	$service = "??";
    }
    if ($target eq "") {
	$target = "/";
    }
    
    return ($service, $remote, $target);

}
    
1;