package LWP::Protocol::ftp;
# Implementation of the ftp protocol (RFC 959). We let the Net::FTP
# package do all the dirty work.
use Carp ();
use HTTP::Status ();
use HTTP::Negotiate ();
use HTTP::Response ();
use LWP::MediaTypes ();
use File::Listing ();
require LWP::Protocol;
@ISA = qw(LWP::Protocol);
use strict;
eval {
package LWP::Protocol::MyFTP;
require Net::FTP;
Net::FTP->require_version(2.00);
use vars qw(@ISA);
@ISA=qw(Net::FTP);
sub new {
my $class = shift;
my $self = $class->SUPER::new(@_) || return undef;
my $mess = $self->message; # welcome message
$mess =~ s|\n.*||s; # only first line left
$mess =~ s|\s*ready\.?$||;
# Make the version number more HTTP like
$mess =~ s|\s*\(Version\s*|/| and $mess =~ s|\)$||;
${*$self}{myftp_server} = $mess;
#$response->header("Server", $mess);
$self;
}
sub http_server {
my $self = shift;
${*$self}{myftp_server};
}
sub home {
my $self = shift;
my $old = ${*$self}{myftp_home};
if (@_) {
${*$self}{myftp_home} = shift;
}
$old;
}
sub go_home {
my $self = shift;
$self->cwd(${*$self}{myftp_home});
}
sub request_count {
my $self = shift;
++${*$self}{myftp_reqcount};
}
sub ping {
my $self = shift;
return $self->go_home;
}
};
my $init_failed = $@;
sub _connect {
my($self, $host, $port, $user, $account, $password, $timeout) = @_;
my $key;
my $conn_cache = $self->{ua}{conn_cache};
if ($conn_cache) {
$key = "$host:$port:$user";
$key .= ":$account" if defined($account);
if (my $ftp = $conn_cache->withdraw("ftp", $key)) {
if ($ftp->ping) {
# save it again
$conn_cache->deposit("ftp", $key, $ftp);
return $ftp;
}
}
}
# try to make a connection
my $ftp = LWP::Protocol::MyFTP->new($host,
Port => $port,
Timeout => $timeout,
LocalAddr => $self->{ua}{local_address},
);
# XXX Should be some what to pass on 'Passive' (header??)
unless ($ftp) {
$@ =~ s/^Net::FTP: //;
return HTTP::Response->new(&HTTP::Status::RC_INTERNAL_SERVER_ERROR, $@);
}
unless ($ftp->login($user, $password, $account)) {
# Unauthorized. Let's fake a RC_UNAUTHORIZED response
my $mess = scalar($ftp->message);
$mess =~ s/\n$//;
my $res = HTTP::Response->new(&HTTP::Status::RC_UNAUTHORIZED, $mess);
$res->header("Server", $ftp->http_server);
$res->header("WWW-Authenticate", qq(Basic Realm="FTP login"));
return $res;
}
my $home = $ftp->pwd;
$ftp->home($home);
$conn_cache->deposit("ftp", $key, $ftp) if $conn_cache;
return $ftp;
}
sub request
{
my($self, $request, $proxy, $arg, $size, $timeout) = @_;
$size = 4096 unless $size;
# check proxy
if (defined $proxy)
{
return HTTP::Response->new(&HTTP::Status::RC_BAD_REQUEST,
'You can not proxy through the ftp');
}
my $url = $request->uri;
if ($url->scheme ne 'ftp') {
my $scheme = $url->scheme;
return HTTP::Response->new(&HTTP::Status::RC_INTERNAL_SERVER_ERROR,
"LWP::Protocol::ftp::request called for '$scheme'");
}
# check method
my $method = $request->method;
unless ($method eq 'GET' || $method eq 'HEAD' || $method eq 'PUT') {
return HTTP::Response->new(&HTTP::Status::RC_BAD_REQUEST,
'Library does not allow method ' .
"$method for 'ftp:' URLs");
}
if ($init_failed) {
return HTTP::Response->new(&HTTP::Status::RC_INTERNAL_SERVER_ERROR,
$init_failed);
}
my $host = $url->host;
my $port = $url->port;
my $user = $url->user;
my $password = $url->password;
# If a basic autorization header is present than we prefer these over
# the username/password specified in the URL.
{
my($u,$p) = $request->authorization_basic;
if (defined $u) {
$user = $u;
$password = $p;
}
}
# We allow the account to be specified in the "Account" header
my $account = $request->header('Account');
my $ftp = $self->_connect($host, $port, $user, $account, $password, $timeout);
return $ftp if ref($ftp) eq "HTTP::Response"; # ugh!
# Create an initial response object
my $response = HTTP::Response->new(&HTTP::Status::RC_OK, "OK");
$response->header(Server => $ftp->http_server);
$response->header('Client-Request-Num' => $ftp->request_count);
$response->request($request);
# Get & fix the path
my @path = grep { length } $url->path_segments;
my $remote_file = pop(@path);
$remote_file = '' unless defined $remote_file;
my $type;
if (ref $remote_file) {
my @params;
($remote_file, @params) = @$remote_file;
for (@params) {
$type = $_ if s/^type=//;
}
}
if ($type && $type eq 'a') {
$ftp->ascii;
}
else {
$ftp->binary;
}
for (@path) {
unless ($ftp->cwd($_)) {
return HTTP::Response->new(&HTTP::Status::RC_NOT_FOUND,
"Can't chdir to $_");
}
}
if ($method eq 'GET' || $method eq 'HEAD') {
if (my $mod_time = $ftp->mdtm($remote_file)) {
$response->last_modified($mod_time);
if (my $ims = $request->if_modified_since) {
if ($mod_time <= $ims) {
$response->code(&HTTP::Status::RC_NOT_MODIFIED);
$response->message("Not modified");
return $response;
}
}
}
# We'll use this later to abort the transfer if necessary.
# if $max_size is defined, we need to abort early. Otherwise, it's
# a normal transfer
my $max_size = undef;
# Set resume location, if the client requested it
if ($request->header('Range') && $ftp->supported('REST'))
{
my $range_info = $request->header('Range');
# Change bytes=2772992-6781209 to just 2772992
my ($start_byte,$end_byte) = $range_info =~ /.*=\s*(\d+)-(\d+)?/;
if ( defined $start_byte && !defined $end_byte ) {
# open range -- only the start is specified
$ftp->restart( $start_byte );
# don't define $max_size, we don't want to abort early
}
elsif ( defined $start_byte && defined $end_byte &&
$start_byte >= 0 && $end_byte >= $start_byte ) {
$ftp->restart( $start_byte );
$max_size = $end_byte - $start_byte;
}
else {
return HTTP::Response->new(&HTTP::Status::RC_BAD_REQUEST,
'Incorrect syntax for Range request');
}
}
elsif ($request->header('Range') && !$ftp->supported('REST'))
{
return HTTP::Response->new(&HTTP::Status::RC_NOT_IMPLEMENTED,
"Server does not support resume.");
}
my $data; # the data handle
if (length($remote_file) and $data = $ftp->retr($remote_file)) {
my($type, @enc) = LWP::MediaTypes::guess_media_type($remote_file);
$response->header('Content-Type', $type) if $type;
for (@enc) {
$response->push_header('Content-Encoding', $_);
}
my $mess = $ftp->message;
if ($mess =~ /\((\d+)\s+bytes\)/) {
$response->header('Content-Length', "$1");
}
if ($method ne 'HEAD') {
# Read data from server
$response = $self->collect($arg, $response, sub {
my $content = '';
my $result = $data->read($content, $size);
# Stop early if we need to.
if (defined $max_size)
{
# We need an interface to Net::FTP::dataconn for getting
# the number of bytes already read
my $bytes_received = $data->bytes_read();
# We were already over the limit. (Should only happen
# once at the end.)
if ($bytes_received - length($content) > $max_size)
{
$content = '';
}
# We just went over the limit
elsif ($bytes_received > $max_size)
{
# Trim content
$content = substr($content, 0,
$max_size - ($bytes_received - length($content)) );
}
# We're under the limit
else
{
}
}
return \$content;
} );
}
# abort is needed for HEAD, it's == close if the transfer has
# already completed.
unless ($data->abort) {
# Something did not work too well. Note that we treat
# responses to abort() with code 0 in case of HEAD as ok
# (at least wu-ftpd 2.6.1(1) does that).
if ($method ne 'HEAD' || $ftp->code != 0) {
$response->code(&HTTP::Status::RC_INTERNAL_SERVER_ERROR);
$response->message("FTP close response: " . $ftp->code .
" " . $ftp->message);
}
}
}
elsif (!length($remote_file) || ( $ftp->code >= 400 && $ftp->code < 600 )) {
# not a plain file, try to list instead
if (length($remote_file) && !$ftp->cwd($remote_file)) {
return HTTP::Response->new(&HTTP::Status::RC_NOT_FOUND,
"File '$remote_file' not found");
}
# It should now be safe to try to list the directory
my @lsl = $ftp->dir;
# Try to figure out if the user want us to convert the
# directory listing to HTML.
my @variants =
(
['html', 0.60, 'text/html' ],
['dir', 1.00, 'text/ftp-dir-listing' ]
);
#$HTTP::Negotiate::DEBUG=1;
my $prefer = HTTP::Negotiate::choose(\@variants, $request);
my $content = '';
if (!defined($prefer)) {
return HTTP::Response->new(&HTTP::Status::RC_NOT_ACCEPTABLE,
"Neither HTML nor directory listing wanted");
}
elsif ($prefer eq 'html') {
$response->header('Content-Type' => 'text/html');
$content = "<HEAD><TITLE>File Listing</TITLE>\n";
my $base = $request->uri->clone;
my $path = $base->path;
$base->path("$path/") unless $path =~ m|/$|;
$content .= qq(<BASE HREF="$base">\n</HEAD>\n);
$content .= "<BODY>\n<UL>\n";
for (File::Listing::parse_dir(\@lsl, 'GMT')) {
my($name, $type, $size, $mtime, $mode) = @$_;
$content .= qq( <LI> <a href="$name">$name</a>);
$content .= " $size bytes" if $type eq 'f';
$content .= "\n";
}
$content .= "</UL></body>\n";
}
else {
$response->header('Content-Type', 'text/ftp-dir-listing');
$content = join("\n", @lsl, '');
}
$response->header('Content-Length', length($content));
if ($method ne 'HEAD') {
$response = $self->collect_once($arg, $response, $content);
}
}
else {
my $res = HTTP::Response->new(&HTTP::Status::RC_BAD_REQUEST,
"FTP return code " . $ftp->code);
$res->content_type("text/plain");
$res->content($ftp->message);
return $res;
}
}
elsif ($method eq 'PUT') {
# method must be PUT
unless (length($remote_file)) {
return HTTP::Response->new(&HTTP::Status::RC_BAD_REQUEST,
"Must have a file name to PUT to");
}
my $data;
if ($data = $ftp->stor($remote_file)) {
my $content = $request->content;
my $bytes = 0;
if (defined $content) {
if (ref($content) eq 'SCALAR') {
$bytes = $data->write($$content, length($$content));
}
elsif (ref($content) eq 'CODE') {
my($buf, $n);
while (length($buf = &$content)) {
$n = $data->write($buf, length($buf));
last unless $n;
$bytes += $n;
}
}
elsif (!ref($content)) {
if (defined $content && length($content)) {
$bytes = $data->write($content, length($content));
}
}
else {
die "Bad content";
}
}
$data->close;
$response->code(&HTTP::Status::RC_CREATED);
$response->header('Content-Type', 'text/plain');
$response->content("$bytes bytes stored as $remote_file on $host\n")
}
else {
my $res = HTTP::Response->new(&HTTP::Status::RC_BAD_REQUEST,
"FTP return code " . $ftp->code);
$res->content_type("text/plain");
$res->content($ftp->message);
return $res;
}
}
else {
return HTTP::Response->new(&HTTP::Status::RC_BAD_REQUEST,
"Illegal method $method");
}
$response;
}
1;
__END__
# This is what RFC 1738 has to say about FTP access:
# --------------------------------------------------
#
# 3.2. FTP
#
# The FTP URL scheme is used to designate files and directories on
# Internet hosts accessible using the FTP protocol (RFC959).
#
# A FTP URL follow the syntax described in Section 3.1. If :<port> is
# omitted, the port defaults to 21.
#
# 3.2.1. FTP Name and Password
#
# A user name and password may be supplied; they are used in the ftp
# "USER" and "PASS" commands after first making the connection to the
# FTP server. If no user name or password is supplied and one is
# requested by the FTP server, the conventions for "anonymous" FTP are
# to be used, as follows:
#
# The user name "anonymous" is supplied.
#
# The password is supplied as the Internet e-mail address
# of the end user accessing the resource.
#
# If the URL supplies a user name but no password, and the remote
# server requests a password, the program interpreting the FTP URL
# should request one from the user.
#
# 3.2.2. FTP url-path
#
# The url-path of a FTP URL has the following syntax:
#
# <cwd1>/<cwd2>/.../<cwdN>/<name>;type=<typecode>
#
# Where <cwd1> through <cwdN> and <name> are (possibly encoded) strings
# and <typecode> is one of the characters "a", "i", or "d". The part
# ";type=<typecode>" may be omitted. The <cwdx> and <name> parts may be
# empty. The whole url-path may be omitted, including the "/"
# delimiting it from the prefix containing user, password, host, and
# port.
#
# The url-path is interpreted as a series of FTP commands as follows:
#
# Each of the <cwd> elements is to be supplied, sequentially, as the
# argument to a CWD (change working directory) command.
#
# If the typecode is "d", perform a NLST (name list) command with
# <name> as the argument, and interpret the results as a file
# directory listing.
#
# Otherwise, perform a TYPE command with <typecode> as the argument,
# and then access the file whose name is <name> (for example, using
# the RETR command.)
#
# Within a name or CWD component, the characters "/" and ";" are
# reserved and must be encoded. The components are decoded prior to
# their use in the FTP protocol. In particular, if the appropriate FTP
# sequence to access a particular file requires supplying a string
# containing a "/" as an argument to a CWD or RETR command, it is
# necessary to encode each "/".
#
# For example, the URL <URL:ftp://myname@host.dom/%2Fetc/motd> is
# interpreted by FTP-ing to "host.dom", logging in as "myname"
# (prompting for a password if it is asked for), and then executing
# "CWD /etc" and then "RETR motd". This has a different meaning from
# <URL:ftp://myname@host.dom/etc/motd> which would "CWD etc" and then
# "RETR motd"; the initial "CWD" might be executed relative to the
# default directory for "myname". On the other hand,
# <URL:ftp://myname@host.dom//etc/motd>, would "CWD " with a null
# argument, then "CWD etc", and then "RETR motd".
#
# FTP URLs may also be used for other operations; for example, it is
# possible to update a file on a remote file server, or infer
# information about it from the directory listings. The mechanism for
# doing so is not spelled out here.
#
# 3.2.3. FTP Typecode is Optional
#
# The entire ;type=<typecode> part of a FTP URL is optional. If it is
# omitted, the client program interpreting the URL must guess the
# appropriate mode to use. In general, the data content type of a file
# can only be guessed from the name, e.g., from the suffix of the name;
# the appropriate type code to be used for transfer of the file can
# then be deduced from the data content of the file.
#
# 3.2.4 Hierarchy
#
# For some file systems, the "/" used to denote the hierarchical
# structure of the URL corresponds to the delimiter used to construct a
# file name hierarchy, and thus, the filename will look similar to the
# URL path. This does NOT mean that the URL is a Unix filename.
#
# 3.2.5. Optimization
#
# Clients accessing resources via FTP may employ additional heuristics
# to optimize the interaction. For some FTP servers, for example, it
# may be reasonable to keep the control connection open while accessing
# multiple URLs from the same server. However, there is no common
# hierarchical model to the FTP protocol, so if a directory change
# command has been given, it is impossible in general to deduce what
# sequence should be given to navigate to another directory for a
# second retrieval, if the paths are different. The only reliable
# algorithm is to disconnect and reestablish the control connection.