NAME
POE::Component::Client::SimpleFTP - A simple FTP client library for POE
VERSION
This document describes v0.003 of POE::Component::Client::SimpleFTP - released May 04, 2011 as part of POE-Component-Client-SimpleFTP.
SYNOPSIS
# A simple FTP client logging in to a server
use POE qw( Component::Client::SimpleFTP );
POE::Session->create(
inline_states => {
_start => sub {
POE::Component::Client::SimpleFTP->new(
alias => "ftp",
remote_addr => "invalid.addr",
username => "myuser",
password => "mypassword",
);
return;
},
authenticated => sub {
print "LOGGED ON!\n";
$_[KERNEL]->post( "ftp", "quit" );
return;
}
},
);
POE::Kernel->run;
DESCRIPTION
This is a simple FTP client to use in a POE application. It's a complete
rewrite of the old POE::Component::Client::FTP codebase and makes it
easier to use. Most of the API/event flow is compatible, so you should
have few problems porting your code to this module.
You start by creating the ftp object and wait for it to send you events.
By default the caller session will get all the events directed to it, no
need to "register" for events or anything like that. Events are sent to
you in the generic form of $command or "${command}_error" events. This
module will parse the FTP reply codes and determine if it is an error or
not, and dispatch it to the appropriate event.
An important thing to keep in mind is that there is no command queueing
done in this module. It is up to the user to know what state they are in
and to dispatch events at the right time. If a command is sent while
this module is processing one, an exception will be thrown. Fortunately,
due to the way events are named, it should be easy to keep track of the
event flow.
Initial Connection
When the object is created, it attempts to make a connection to the
server specified in the attributes. It will automatically login with the
provided credentials. Additionally, it will enable TLS mode if you
enabled the attributes "tls_cmd" and "tls_data". There is a timeout
timer on the initial connection that you can tweak via setting
"timeout".
The following events may be sent to your session:
authenticated
This event is sent when the entire login procedure is done. At this
point you can send commands to the server.
No arguments.
connect_error
This event is sent when there's an error connecting to the server. The
component will automatically destroy itself at this point, so if you
want to retry the connection, you have to make a new object.
The first argument is the error code, and the 2nd argument is the error
string.
The code "0" is used here, because we never got a reply from the server.
However, it is nice to have consistency with the other event handlers,
so it is supplied.
Example code: 0
Example reply: timedout
login_error
This event is sent when there's an error trying to login to the server.
The component will automatically destroy itself at this point, so if you
want to retry the connection, you have to make a new object.
The first argument is the error code, and the 2nd argument is the error
string.
Example code: 530
Example reply: Login incorrect.
Simple Commands
This is a class of commands that can be sent to the server after
receiving the "authenticated" event. They perform identically, and will
send the same replies back to your session. Some commands require
arguments, others don't.
Normally the events will include at least 2 arguments: the FTP return
code and the actual reply line from the server. If the command included
arguments, it will be supplied in the event to make identifying actions
easier.
Some commands is an alias for the actual command ( cd vs cwd ) but the
event name will follow the aliased command. If a cwd event is sent, the
error event is "cwd_error". If a cd event is sent, the error event is
"cd_error".
# send the cd command in an event handler somewhere
$ftp->yield( 'cd', '/foobar' );
# handler for the resulting event received from this component
sub cd {
my( $code, $reply, $path ) = @_[ ARG0 .. ARG2 ];
# $code probably is 250
# $reply probably is "Directory successfully changed."
# $path will be "/foobar"
}
sub cd_error {
my( $code, $reply, $path ) = @_[ ARG0 .. ARG2 ];
# $code probably is 550
# $reply probably is "Failed to change directory."
# $path will be "/foobar"
}
cwd
Changes the working directory.
Arguments: the path to change to ( required )
Example code: 250
Example reply: Directory successfully changed.
cd
An alias for "cwd"
dele
Deletes a file.
Arguments: the file to delete ( required )
Example code: 250
Example reply: Delete operation successful.
delete
An alias for "dele"
mkd
Creates a directory.
Arguments: the directory path to create ( required )
You can supply an absolute path or a relative path. It is up to the
server to figure out where to create the directory. It's easier to use
absolute paths so you are sure that the server is creating the directory
in the right place!
Remember, the FTP protocol doesn't support recursive directory creation!
If "/foo" exists but "/foo/bar" doesn't, then you cannot create
"/foo/bar/baz"!
Example code: 257
Example reply: "/foo" created
mkdir
An alias for "mkd"
rmd
Removes a directory.
Arguments: the directory path to delete ( required )
You can supply an absolute path or a relative path. It is up to the
server to figure out where to delete the directory. It's easier to use
absolute paths so you are sure that the server is deleting the right
directory!
Example code: 250
Example reply: Remove directory operation successful.
rmdir
An alias for "rmd"
cdup
Changes the working directory to the parent.
Remember, there might be symlinks or other bizarre stuff going on behind
the scenes! It's best to supply full pathnames to "cwd" to be safe.
Arguments: none
Example code: 250
Example reply: Directory successfully changed.
pwd
Prints the current working directory.
Arguments: none
Example code: 257
Example reply: "/"
rename
Renames a target file to a new name.
Arguments: the old filename and the new filename
Remember, the pathnames must exist and is a valid target. Best to send
absolute paths!
Example code: 250
Example reply: Rename successful.
mv
An alias for "rename"
quit
Disconnects from the server. Behaves differently depending on the
context when this command is received. After this command is sent, this
module will destroy itself and not send any more events to your session.
If this module isn't processing anything it will send the QUIT command
and gracefully shutdown when it receives the server reply.
If this module is processing a command it will disconnect immediately,
killing any command processing/data transfers that is happening.
If you want to force immediate shutdown, use the "shutdown" event.
Arguments: none
disconnect
An alias for "quit"
shutdown
Forces a shutdown of the component and kills everything.
Arguments: none
noop
Executes a no-operation command. Useful to keep the connection open or
to get the round-trip latency, or whatever :)
Arguments: none
Example code: 200
Example reply: NOOP ok.
quot
Sends a quoted command to the server. Useful for sending commands that
this module doesn't support.
Arguments: the actual command + arguments to send.
$ftp->yield( 'quot', 'CRAZYCMD', @crazy_args );
quote
An alias for "quot"
help
Gets the server's help output for a command.
Arguments: optional command to ask for help
Example code: 214
Example reply:
The following commands are recognized.
ABOR ACCT ALLO APPE CDUP CWD DELE EPRT EPSV FEAT HELP LIST MDTM MKD
MODE NLST NOOP OPTS PASS PASV PORT PWD QUIT REIN REST RETR RMD RNFR
RNTO SITE SIZE SMNT STAT STOR STOU STRU SYST TYPE USER XCUP XCWD XMKD
XPWD XRMD
Help OK.
site
Executes a specific command that the server supports. Consult your ftp
administrator or the document for the ftpd software for more
information.
Arguments: the command to execute + any optional arguments.
Example code: 500
Example reply: Unknown SITE command.
stat
Receives some informational text about the current status of the
connection.
BEWARE: While the RFC says this command can be sent while a data
transfer is in progress, this is unimplemented!
Arguments: none
Example code: 211
Example reply:
FTP server status:
Connected to 192.168.0.199
Logged in as apoc
TYPE: ASCII
No session bandwidth limit
Session timeout in seconds is 300
Control connection is plain text
Data connections will be plain text
At session startup, client count was 1
vsFTPd 2.2.0 - secure, fast, stable
End of status
syst
Gets the system information of the server.
Arguments: none
Example code: 215
Example reply: UNIX Type: L8
acct
Send the account information for your login. Generally not used, but if
your server requires it you should send this immediately after getting
the "authenticated" event.
Arguments: your account information
Example code: 502
Example reply: ACCT not implemented.
smnt
Mounts a different filesystem volume on your account. Generally not
used.
Arguments: a pathname to mount or system-specific string
Example code: 502
Example reply: SMNT not implemented.
mdtm
Gets the modification time of a file. Not supported by all servers! (
RFC 3659 )
Arguments: the file to query
Example code: 213
Example reply: 20110502230157
You can use the "mdtm_parser" in
POE::Component::Client::SimpleFTP::Utils function to convert it into a
DateTime object.
size
Gets the size of a file in bytes. Not supported by all servers! ( RFC
3659 )
Arguments: the file to query
Example code: 213
Example reply: 48
feat
Queries the FEAT capabilities of the server. Not supported by all
servers! ( RFC 2389 )
Arguments: none
Example code: 211
Example reply:
Features:
EPRT
EPSV
MDTM
PASV
REST STREAM
SIZE
TVFS
UTF8
End
You can use the "feat_parser" in
POE::Component::Client::SimpleFTP::Utils function to convert it into an
array of features.
features
An alias for "feat"
opts
Sets an option for the current session. Not supported by all servers! (
RFC 2389 )
Arguments: the option to set
Example code: 501
Example reply: Option not understood.
options
An alias for "opts"
Complex Commands
This class of commands is called complex because they require opening a
new data connection to the server. The requested data is transferred
over this connection, and the result is sent back to your session. All
of the commands behave the same except for the "upload" types.
Please look at the "examples" directory included in this distribution
for code samples.
The typical flow of this command is as follows:
$ftp->yield( 'get', "/myfile.txt" );
# receive a "get_connected" event
# args is: "/myfile.txt"
# at this point you prepare to process the incoming data
# receive a "get_data" event
# args is: $chunk, "/myfile.txt"
# at this point you should write out the data to the terminal, a file, or whatever!
# ... keep receiving "get_data" until the server finish sending
# receive a "get" event
# args is: $code, $reply, "/myfile.txt"
# at this point the transfer is complete
# if at any point there is an error, a "get_error" event is sent
# args is: $code, $reply, "/myfile.txt"
For the "upload" events where you are sending data to the server, the
flow is:
$ftp->yield( 'put', '/myfile.txt' );
# receive a "put_connected" event
# args is: "/myfile"
# at this point you should get the data to send to the server
# from your local filesystem, from a database server, or whatever!
# send a chunk of data to the server
# the chunk size should depend on your application - a reasonable default is 10240 bytes
$ftp->yield( 'put_data', $chunk );
# receive a "put_flushed" event
# args is: "/myfile"
# at this point, you can either send another chunk or signal EOF
$ftp->yield( 'put_close' );
# receive a "put" event
# args is: $code, $reply, "/myfile"
# at this point the transfer is complete
# if at any point there is an error, a "put_error" event is sent
# args is: $code, $reply, "/myfile"
list
Receives a directory list. The data is sent in a format similar to the
UNIX "ls" command, but can be anything!
Arguments: the optional path to query ( defaults to current working
directory )
Example data:
drwxr-xr-x 4 1000 1000 4096 May 02 18:24 a
drwxr-xr-x 4 1000 1000 4096 May 02 18:24 b
drwxr-xr-x 4 1000 1000 4096 May 02 18:24 c
-rw-r--r-- 1 1000 1000 0 May 02 20:26 foo.txt
ls
An alias for list
nlst
Receives a directory list. Differs from list in that only the names are
received.
Arguments: the optional path to query ( defaults to current working
directory )
Example data:
a
b
c
foo.txt
dir
An alias for "nlst"
retr
Retrieves a file from the server.
Arguments: the filename to receive
get
An alias for "get"
stor
Transmits a file to the server. This uses the "upload" command flow
explained in "Complex Commands"!
Arguments: the filename to put
stou
Transmits a file to the server. This differs from "stor" in that the ftp
server is required to store the file in a unique way. This uses the
"upload" command flow explained in "Complex Commands"!
Arguments: the filename to put
put
An alias for "stor"
ATTRIBUTES
alias
The alias this component will use. You can send commands to the ftpd in
2 ways:
my $ftp = POE::Component::Client::SimpleFTP->new( alias => "ftp", ... );
$poe_kernel->post( 'ftp', 'cd', 'foobar' );
# Or, you can use the yield sub:
$ftp->yield( 'cd', 'foobar' );
The default is: ftp
username
The FTP username you will be sending to the server.
required.
password
The FTP password you will be sending to the server.
required.
remote_addr
The IP address of the FTP server to connect to. Can be a DNS hostname or
IPv4/6 string.
required.
remote_port
The port of the FTP server to connect to.
The default is: 21
local_addr
The local IP address to bind to for all connections to the server.
The default is: INADDR_ANY ( let the OS decide )
local_port
The local port to bind to for the control connection to the server. If
you need to change the data connection's port, please change the
"local_data_port" attribute.
The default is: 0 ( let the OS decide )
local_data_port
The local port to bind to for the data connection to the server. Must be
a different port than the "local_port" attribute!
The default is: 0 ( let the OS decide )
tls_cmd
A boolean value to enable/disable TLS encryption of the command
connection. If you want to use this, you must have
POE::Component::SSLify installed!
The default is: false
tls_data
A boolean value to enable/disable TLS encryption of the data connection.
If you want to use this, you must have POE::Component::SSLify installed!
The default is: false
timeout
A value specifying the timeout in seconds for the initial connection to
the FTP server.
The default is: 120
connection_mode
Determine what connection mode we will be using when opening the data
connection to the server. In "active" mode, the server will be
connecting to us. In "passive" mode we will be connecting to the server.
You usually need "passive" mode if you are behind a firewall.
The default is: passive
FUNCTIONS
DEBUG
Enable this if you want to get debugging output. Do it like this:
sub POE::Component::Client::SimpleFTP::DEBUG () { 1 }
use POE::Component::Client::SimpleFTP;
The default is: false
yield
This method provides an alternative object based means of posting events
to the component. First argument is the event to post, following
arguments are sent as arguments to the resultant post.
my $ftp = POE::Component::Client::SimpleFTP->new( ... );
$ftp->yield( 'cd', 'foobar' );
# equivalent to:
$poe_kernel->post( $ftp->alias, 'cd', 'foobar' );
TLS support
TLS encryption is available if you want. You would need to enable the
"tls_cmd" and "tls_data" attributes and have POE::Component::SSLify
installed in order to use it. It should work with a lot of servers and
commands. However, not the entire specification is implemented! If you
encounter problems when using TLS on a server, please let me know by
filing a bug report!
Unimplemented Commands/Actions/Features
Those are the ideas that probably will be implemented in a future
version. Some of them require core changes to this module, while others
can be done in user-space but should be implemented here to make it
"simpler" :)
* full TLS support - check the RFCs
* FXP ( server<->server ) transfers
* intelligent NAT detection
* full ipv6 compatibility
* restart/abort/append a transfer
* bandwidth throttling for data connection
* support for "mkdir -p" where this module automatically creates all directories needed
* passing a filename/filehandle/whatever to put/get so this module automatically does the reading/writing
* directory mirroring ( ala rsync )
* use POE::Filter::Ls for parsing ( need to improve it first hah )
* encoded pathnames ( translate \012 in filename to \000 as per RFC 959 )
* security stuff - http://cr.yp.to/ftp/security.html
* event prefix ( so you get ftp_cd events instead of cd ) for easier event management
* strict command validation ( we don't check if the command requires 0, 1, or N args )
RFC 959 "FILE TRANSFER PROTOCOL (FTP)"
* REIN ( not allowed, as it generally screws up - just reconnect! )
* STRU ( default file type is always a good idea )
* MODE ( default stream type is always a good idea )
* APPE ( should be easy to implement, but im lazy )
* ALLO ( it is generally unused and obsolete? )
* REST ( a bit tricky to implement, maybe later )
* ABOR ( not allowed, as it generally screws up - just disconnect! )
* PASV ( this module automatically does it )
* PORT ( this module automatically does it )
* TYPE ( this module automatically does it )
* STAT ( implemented, but not allowed while a transfer is in progress as it generally screws things up )
RFC 2228 "FTP Security Extensions"
* AUTH ( only AUTH TLS is supported now )
* PROT/PBSZ is supported with the default options if you enable tls_cmd/tls_data
* ADAT ( not needed for AUTH TLS? )
* CCC ( not needed with TLS? )
* MIC ( not needed with TLS? )
* CONF ( not needed with TLS? )
* ENC ( not needed with TLS? )
RFC 2389 "Feature negotiation mechanism for the File Transfer Protocol"
* The entire RFC is implemented
RFC 2428 "FTP Extensions for IPv6 and NATs"
* EPRT
* EPSV
RFC 2577 "FTP Security Considerations"
* unimplemented
RFC 2640 "Internationalization of the File Transfer Protocol"
* unimplemented
RFC 3659 "Extensions to FTP"
* REST ( same reason as the RFC 959 one )
* MLST
* MLSD
RFC 4217 "Securing FTP with TLS"
* unimplemented except for what is implemented in 2228 :)
RFC 5796 "FTP Command and Extension Registry"
* No need to implement this, it is for servers only
SUPPORT
Perldoc
You can find documentation for this module with the perldoc command.
perldoc POE::Component::Client::SimpleFTP
Websites
The following websites have more information about this module, and may
be of help to you. As always, in addition to those websites please use
your favorite search engine to discover more resources.
* Search CPAN
The default CPAN search engine, useful to view POD in HTML format.
<http://search.cpan.org/dist/POE-Component-Client-SimpleFTP>
* RT: CPAN's Bug Tracker
The RT ( Request Tracker ) website is the default bug/issue tracking
system for CPAN.
<http://rt.cpan.org/NoAuth/Bugs.html?Dist=POE-Component-Client-Simpl
eFTP>
* AnnoCPAN
The AnnoCPAN is a website that allows community annonations of Perl
module documentation.
<http://annocpan.org/dist/POE-Component-Client-SimpleFTP>
* CPAN Ratings
The CPAN Ratings is a website that allows community ratings and
reviews of Perl modules.
<http://cpanratings.perl.org/d/POE-Component-Client-SimpleFTP>
* CPAN Forum
The CPAN Forum is a web forum for discussing Perl modules.
<http://cpanforum.com/dist/POE-Component-Client-SimpleFTP>
* CPANTS
The CPANTS is a website that analyzes the Kwalitee ( code metrics )
of a distribution.
<http://cpants.perl.org/dist/overview/POE-Component-Client-SimpleFTP
>
* CPAN Testers
The CPAN Testers is a network of smokers who run automated tests on
uploaded CPAN distributions.
<http://www.cpantesters.org/distro/P/POE-Component-Client-SimpleFTP>
* CPAN Testers Matrix
The CPAN Testers Matrix is a website that provides a visual way to
determine what Perls/platforms PASSed for a distribution.
<http://matrix.cpantesters.org/?dist=POE-Component-Client-SimpleFTP>
* CPAN Testers Dependencies
The CPAN Testers Dependencies is a website that shows a chart of the
test results of all dependencies for a distribution.
<http://deps.cpantesters.org/?module=POE::Component::Client::SimpleF
TP>
Email
You can email the author of this module at "APOCAL at cpan.org" asking
for help with any problems you have.
Internet Relay Chat
You can get live help by using IRC ( Internet Relay Chat ). If you don't
know what IRC is, please read this excellent guide:
<http://en.wikipedia.org/wiki/Internet_Relay_Chat>. Please be courteous
and patient when talking to us, as we might be busy or sleeping! You can
join those networks/channels and get help:
* irc.perl.org
You can connect to the server at 'irc.perl.org' and join this
channel: #perl-help then talk to this person for help: Apocalypse.
* irc.freenode.net
You can connect to the server at 'irc.freenode.net' and join this
channel: #perl then talk to this person for help: Apocal.
* irc.efnet.org
You can connect to the server at 'irc.efnet.org' and join this
channel: #perl then talk to this person for help: Ap0cal.
Bugs / Feature Requests
Please report any bugs or feature requests by email to
"bug-poe-component-client-simpleftp at rt.cpan.org", or through the web
interface at
<http://rt.cpan.org/NoAuth/ReportBug.html?Queue=POE-Component-Client-Sim
pleFTP>. You will be automatically notified of any progress on the
request by the system.
Source Code
The code is open to the world, and available for you to hack on. Please
feel free to browse it and play with it, or whatever. If you want to
contribute patches, please send me a diff or prod me to pull from your
repository :)
<http://github.com/apocalypse/perl-poe-component-simpleftp>
git clone git://github.com/apocalypse/perl-poe-component-simpleftp.git
AUTHOR
Apocalypse <APOCAL@cpan.org>
COPYRIGHT AND LICENSE
This software is copyright (c) 2011 by Apocalypse.
This is free software; you can redistribute it and/or modify it under
the same terms as the Perl 5 programming language system itself.
The full text of the license can be found in the LICENSE file included
with this distribution.
DISCLAIMER OF WARRANTY
BECAUSE THIS SOFTWARE IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY
FOR THE SOFTWARE, TO THE EXTENT PERMITTED BY APPLICABLE LAW. EXCEPT WHEN
OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES
PROVIDE THE SOFTWARE "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER
EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE
ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE SOFTWARE IS WITH
YOU. SHOULD THE SOFTWARE PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL
NECESSARY SERVICING, REPAIR, OR CORRECTION.
IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR
REDISTRIBUTE THE SOFTWARE AS PERMITTED BY THE ABOVE LICENCE, BE LIABLE
TO YOU FOR DAMAGES, INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL, OR
CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OR INABILITY TO USE THE
SOFTWARE (INCLUDING BUT NOT LIMITED TO LOSS OF DATA OR DATA BEING
RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD PARTIES OR A
FAILURE OF THE SOFTWARE TO OPERATE WITH ANY OTHER SOFTWARE), EVEN IF
SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
DAMAGES.