


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


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



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           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.

   $where = $ff->fetch( [to => /my/output/dir/ | \$scalar] )
       Fetches the file you requested and returns the full path
       to the file.

       By default it writes to "cwd()", but you can override that
       by specifying the "to" argument:

           ### file fetch to /tmp, full path to the file in $where
           $where = $ff->fetch( to => '/tmp' );

           ### file slurped into $scalar, full path to the file in $where
           ### file is downloaded to a temp directory and cleaned up at exit time
           $where = $ff->fetch( to => \$scalar );

       Returns the full path to the downloaded file on success,



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       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, lftp, file
           http    => LWP, wget, curl, lftp, lynx
           ftp     => LWP, Net::FTP, wget, curl, lftp, 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".



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


   $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



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       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
           lftp        => lftp

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.



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       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.


































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