Net::FTP::AutoReconnecUser Contributed Perl DocumentNet::FTP::AutoReconnect(3)NAMENet::FTP::AutoReconnect - FTP client class with automatic reconnect on
failure
SYNOPSIS
"Net::FTP::AutoReconnect" is a wrapper module around "Net::FTP". For
many commands, if anything goes wrong on the first try, it tries to
disconnect and reconnect to the server, restore the state to the same
as it was when the command was executed, then execute it again. The
state includes login credentials, authorize credentials, transfer mode
(ASCII or binary), current working directory, and any restart, passive,
or port commands sent.
DESCRIPTION
The goal of this method is to hide some implementation details of FTP
server systems from the programmer. In particular, many FTP systems
will automatically disconnect a user after a relatively short idle time
or after a transfer is aborted. In this case,
"Net::FTP::AutoReconnect" will simply reconnect, send the commands
necessary to return your session to its previous state, then resend the
command. If that fails, it will return the error.
It makes no effort to determine what sorts of errors are likely to
succeed when they're retried. Partly that's because it's hard to know;
if you're retreiving a file from an FTP site with several mirrors and
the file is not found, for example, maybe on the next try you'll
connect to a different server and find it. But mostly it's from
laziness; if you have some good ideas about how to determine when to
retry and when not to bother, by all means send patches.
This module contains an instance of "Net::FTP", which it passes most
method calls along to.
These methods also record their state: "alloc", "ascii", "authorize",
"binary", "cdup", "cwd", "hash", "login","restart", "pasv", "port".
Directory changing commands execute a "pwd" afterwards and store their
new working directory.
These methods are automatically retried: "alloc", "appe", "append",
"ascii", "binary", "cdup", "cwd", "delete", "dir", "get", "list", "ls",
"mdtm", "mkdir", "nlst", "pasv", "port", "put", "put_unique", "pwd",
"rename", "retr", "rmdir", "size", "stou", "supported".
These methods are tried just once: "abort", "authorize", "hash",
"login", "pasv_xfer", "pasv_xfer_unique", "pasv_wait", "quit",
"restart", "site", "unique_name". From "Net::Cmd": "code", "message",
"ok", "status". "restart" doesn't actually send any FTP commands
(they're sent along with the command they apply to), which is why it's
not restarted.
Any other commands are unimplemented (or possibly misdocumented); if I
missed one you'd like, please send a patch.
CONSTRUCTOR
new
All parameters are passed along verbatim to "Net::FTP", as well as
stored in case we have to reconnect.
METHODS
Most of the methods are those of Net::FTP. One additional method is
available:
reconnect()
Abandon the current FTP connection and create a new one, restoring all
the state we can.
disconnect()
Disconnect the current FTP connection abruptly. Mostly useful for
testing.
connect_count()
Return the number of times we have connected or reconnected to this
server. Mostly useful for testing.
AUTHOR
Scott Gifford <sgifford@suspectclass.com>
BUGS
We should really be smarter about when to retry.
We shouldn't be hardwired to use "Net::FTP", but any FTP-compatible
class; that would allow all modules similar to this one to be chained
together.
Much of this is only lightly tested; it's hard to find an FTP server
unreliable enough to test all aspects of it. It's mostly been tested
with a server that dicsonnects after an aborted transfer, and the
module seems to work OK.
SEE ALSO
Net::FTP.
COPYRIGHT
Copyright (c) 2006 Scott Gifford. All rights reserved. This program is
free software; you can redistribute it and/or modify it under the same
terms as Perl itself.
perl v5.14.2 2009-08-12 Net::FTP::AutoReconnect(3)
