NAME
File::Fetch - A generic file fetching mechanism
SYNOPSIS
use File::Fetch;
### build a File::Fetch object ###
my $ff = File::Fetch->new(uri => 'http://some.where.com/dir/a.txt');
### fetch the uri to cwd() ###
my $where = $ff->fetch() or die $ff->error;
### fetch the uri to /tmp ###
my $where = $ff->fetch( to => '/tmp' );
### parsed bits from the uri ###
$ff->uri;
$ff->scheme;
$ff->host;
$ff->path;
$ff->file;DESCRIPTION
File::Fetch is a generic file fetching mechanism.
It allows you to fetch any file pointed to by a ftp, http, file, or rsync uri by a number of different means.
See the HOW IT WORKS section further down for details.
ACCESSORS
A File::Fetch object has the following accessors
- $ff->uri
-
The uri you passed to the constructor
- $ff->scheme
-
The scheme from the uri (like 'file', 'http', etc)
- $ff->host
-
The hostname in the uri, will be empty for a 'file' scheme.
- $ff->path
-
The path from the uri, will be at least a single '/'.
- $ff->file
-
The name of the remote file. For the local file name, the result of $ff->output_file will be used.
- $ff->output_file
-
The name of the output file. This is the same as $ff->file, but any query parameters are stripped off. For example:
http://example.com/index.html?x=ywould make the output file be
index.htmlrather thanindex.html?x=y.
METHODS
$ff = File::Fetch->new( uri => 'http://some.where.com/dir/file.txt' );
Parses the uri and creates a corresponding File::Fetch::Item object, that is ready to be fetched and returns it.
Returns false on failure.
$ff->fetch( [to => /my/output/dir/] )
Fetches the file you requested. By default it writes to cwd(), but you can override that by specifying the to argument.
Returns the full path to the downloaded file on success, and false on failure.
$ff->error([BOOL])
Returns the last encountered error as string. Pass it a true value to get the Carp::longmess() output instead.
HOW IT WORKS
File::Fetch is able to fetch a variety of uris, by using several external programs and modules.
Below is a mapping of what utilities will be used in what order for what schemes, if available:
file => LWP, file
http => LWP, wget, curl, lynx
ftp => LWP, Net::FTP, wget, curl, ncftp, ftp
rsync => rsyncIf you'd like to disable the use of one or more of these utilities and/or modules, see the $BLACKLIST variable further down.
If a utility or module isn't available, it will be marked in a cache (see the $METHOD_FAIL variable further down), so it will not be tried again. The fetch method will only fail when all options are exhausted, and it was not able to retrieve the file.
A special note about fetching files from an ftp uri:
By default, all ftp connections are done in passive mode. To change that, see the $FTP_PASSIVE variable further down.
Furthermore, ftp uris only support anonymous connections, so no named user/password pair can be passed along.
/bin/ftp is blacklisted by default; see the $BLACKLIST variable further down.
GLOBAL VARIABLES
The behaviour of File::Fetch can be altered by changing the following global variables:
$File::Fetch::FROM_EMAIL
This is the email address that will be sent as your anonymous ftp password.
Default is File-Fetch@example.com.
$File::Fetch::USER_AGENT
This is the useragent as LWP will report it.
Default is File::Fetch/$VERSION.
$File::Fetch::FTP_PASSIVE
This variable controls whether the environment variable FTP_PASSIVE and any passive switches to commandline tools will be set to true.
Default value is 1.
Note: When $FTP_PASSIVE is true, ncftp will not be used to fetch files, since passive mode can only be set interactively for this binary
$File::Fetch::TIMEOUT
When set, controls the network timeout (counted in seconds).
Default value is 0.
$File::Fetch::WARN
This variable controls whether errors encountered internally by File::Fetch should be carp'd or not.
Set to false to silence warnings. Inspect the output of the error() method manually to see what went wrong.
Defaults to true.
$File::Fetch::DEBUG
This enables debugging output when calling commandline utilities to fetch files. This also enables Carp::longmess errors, instead of the regular carp errors.
Good for tracking down why things don't work with your particular setup.
Default is 0.
$File::Fetch::BLACKLIST
This is an array ref holding blacklisted modules/utilities for fetching files with.
To disallow the use of, for example, LWP and Net::FTP, you could set $File::Fetch::BLACKLIST to:
$File::Fetch::BLACKLIST = [qw|lwp netftp|]The default blacklist is [qw|ftp|], as /bin/ftp is rather unreliable.
See the note on MAPPING below.
$File::Fetch::METHOD_FAIL
This is a hashref registering what modules/utilities were known to fail for fetching files (mostly because they weren't installed).
You can reset this cache by assigning an empty hashref to it, or individually remove keys.
See the note on MAPPING below.
MAPPING
Here's a quick mapping for the utilities/modules, and their names for the $BLACKLIST, $METHOD_FAIL and other internal functions.
LWP => lwp
Net::FTP => netftp
wget => wget
lynx => lynx
ncftp => ncftp
ftp => ftp
curl => curl
rsync => rsyncFREQUENTLY ASKED QUESTIONS
So how do I use a proxy with File::Fetch?
File::Fetch currently only supports proxies with LWP::UserAgent. You will need to set your environment variables accordingly. For example, to use an ftp proxy:
$ENV{ftp_proxy} = 'foo.com';Refer to the LWP::UserAgent manpage for more details.
I used 'lynx' to fetch a file, but its contents is all wrong!
lynx can only fetch remote files by dumping its contents to STDOUT, which we in turn capture. If that content is a 'custom' error file (like, say, a 404 handler), you will get that contents instead.
Sadly, lynx doesn't support any options to return a different exit code on non-200 OK status, giving us no way to tell the difference between a 'successfull' fetch and a custom error page.
Therefor, we recommend to only use lynx as a last resort. This is why it is at the back of our list of methods to try as well.
Files I'm trying to fetch have reserved characters or non-ASCII characters in them. What do I do?
File::Fetch is relatively smart about things. When trying to write a file to disk, it removes the query parameters (see the output_file method for details) from the file name before creating it. In most cases this suffices.
If you have any other characters you need to escape, please install the URI::Escape module from CPAN, and pre-encode your URI before passing it to File::Fetch. You can read about the details of URIs and URI encoding here:
http://www.faqs.org/rfcs/rfc2396.htmlTODO
AUTHORS
This module by Jos Boumans <kane@cpan.org>.
COPYRIGHT
This module is copyright (c) 2003-2007 Jos Boumans <kane@cpan.org>. All rights reserved.
This library is free software; you may redistribute and/or modify it under the same terms as Perl itself.
1 POD Error
The following errors were encountered while parsing the POD:
- Around line 1056:
You forgot a '=back' before '=head1'