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File::Fetch(3pm)       Perl Programmers Reference Guide       File::Fetch(3pm)




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 if host was originally
           'localhost' for a 'file://' url.

       $ff->vol
           On operating systems with the concept of a volume the second
           element of a file:// is considered to the be volume specification
           for the file.  Thus on Win32 this routine returns the volume, on
           other operating systems this returns nothing.

           On Windows this value may be empty if the uri is to a network
           share, in which case the 'share' property will be defined.
           Additionally, volume specifications that use '|' as ':' will be
           converted on read to use ':'.

           On VMS, which has a volume concept, this field will be empty
           because VMS file specifications are converted to absolute UNIX
           format and the volume information is transparently included.

       $ff->share
           On systems with the concept of a network share (currently only
           Windows) returns the sharename from a file://// url.  On other
           operating systems returns empty.

       $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=y

           would make the output file be "index.html" rather than
           "index.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 "fetch"ed 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   => rsync

       If 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       => rsync


FREQUENTLY 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.html


TODO

       Implement $PREFER_BIN
           To indicate to rather use commandline tools than modules


BUG REPORTS

       Please report bugs or other issues to <bug-file-fetch@rt.cpan.org<gt>.


AUTHOR

       This module by Jos Boumans <kane@cpan.org>.


COPYRIGHT

       This library is free software; you may redistribute and/or modify it
       under the same terms as Perl itself.



perl v5.10.0                      2007-12-18                  File::Fetch(3pm)

Mac OS X 10.6 - Generated Thu Sep 17 20:12:02 CDT 2009
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