# File::Fetch - man - phpman

## NAME
    [File::Fetch](https://www.chedong.com/phpMan.php/perldoc/File%3A%3AFetch/markdown) - A generic file fetching mechanism

## SYNOPSIS
        use [File::Fetch](https://www.chedong.com/phpMan.php/perldoc/File%3A%3AFetch/markdown);

        ### build a [File::Fetch](https://www.chedong.com/phpMan.php/perldoc/File%3A%3AFetch/markdown) object ###
        my $ff = [File::Fetch](https://www.chedong.com/phpMan.php/perldoc/File%3A%3AFetch/markdown)->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](https://www.chedong.com/phpMan.php/perldoc/File%3A%3AFetch/markdown) is a generic file fetching mechanism.

    It allows you to fetch any file pointed to by a "ftp", "http", "file", "git" or "rsync" uri by a
    number of different means.

    See the "HOW IT WORKS" section further down for details.

## ACCESSORS
    A "[File::Fetch](https://www.chedong.com/phpMan.php/perldoc/File%3A%3AFetch/markdown)" 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->file_default
        The name of the default local file, that $ff->output_file falls back to if it would
        otherwise return no filename. For example when fetching a URI like <http://www.abc.net.au/>
        the contents retrieved may be from a remote file called 'index.html'. The default value of
        this attribute is literally 'file_default'.

    $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](https://www.chedong.com/phpMan.php/perldoc/File%3A%3AFetch/markdown)->new( uri => '<http://some.where.com/dir/file.txt>' );
    Parses the uri and creates a corresponding [File::Fetch::Item](https://www.chedong.com/phpMan.php/perldoc/File%3A%3AFetch%3A%3AItem/markdown) 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, and false on failure.

  $ff->error([BOOL])
    Returns the last encountered error as string. Pass it a true value to get the "[Carp::longmess](https://www.chedong.com/phpMan.php/perldoc/Carp%3A%3Alongmess/markdown)()"
    output instead.

## HOW IT WORKS
    [File::Fetch](https://www.chedong.com/phpMan.php/perldoc/File%3A%3AFetch/markdown) 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, [HTTP::Tiny](https://www.chedong.com/phpMan.php/perldoc/HTTP%3A%3ATiny/markdown), wget, curl, lftp, fetch, [HTTP::Lite](https://www.chedong.com/phpMan.php/perldoc/HTTP%3A%3ALite/markdown), lynx, iosock
        ftp     => LWP, [Net::FTP](https://www.chedong.com/phpMan.php/perldoc/Net%3A%3AFTP/markdown), wget, curl, lftp, fetch, ncftp, ftp
        rsync   => rsync
        git     => git

    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.

    The "fetch" utility is available on FreeBSD. NetBSD and Dragonfly BSD may also have it from
    "pkgsrc". We only check for "fetch" on those three platforms.

    "iosock" is a very limited [IO::Socket::INET](https://www.chedong.com/phpMan.php/perldoc/IO%3A%3ASocket%3A%3AINET/markdown) based mechanism for retrieving "http" schemed urls.
    It doesn't follow redirects for instance.

    "git" only supports "git://" style urls.

    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](https://www.chedong.com/phpMan.php/perldoc/File%3A%3AFetch/markdown) can be altered by changing the following global variables:

  $[File::Fetch::FROM_EMAIL](https://www.chedong.com/phpMan.php/perldoc/File%3A%3AFetch%3A%3AFROMEMAIL/markdown)
    This is the email address that will be sent as your anonymous ftp password.

    Default is "<File-Fetch@example.com>".

  $[File::Fetch::USER_AGENT](https://www.chedong.com/phpMan.php/perldoc/File%3A%3AFetch%3A%3AUSERAGENT/markdown)
    This is the useragent as "LWP" will report it.

    Default is "[File::Fetch](https://www.chedong.com/phpMan.php/perldoc/File%3A%3AFetch/markdown)/$VERSION".

  $[File::Fetch::FTP_PASSIVE](https://www.chedong.com/phpMan.php/perldoc/File%3A%3AFetch%3A%3AFTPPASSIVE/markdown)
    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](https://www.chedong.com/phpMan.php/perldoc/File%3A%3AFetch%3A%3ATIMEOUT/markdown)
    When set, controls the network timeout (counted in seconds).

    Default value is 0.

  $[File::Fetch::WARN](https://www.chedong.com/phpMan.php/perldoc/File%3A%3AFetch%3A%3AWARN/markdown)
    This variable controls whether errors encountered internally by "[File::Fetch](https://www.chedong.com/phpMan.php/perldoc/File%3A%3AFetch/markdown)" 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](https://www.chedong.com/phpMan.php/perldoc/File%3A%3AFetch%3A%3ADEBUG/markdown)
    This enables debugging output when calling commandline utilities to fetch files. This also
    enables "[Carp::longmess](https://www.chedong.com/phpMan.php/perldoc/Carp%3A%3Alongmess/markdown)" 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](https://www.chedong.com/phpMan.php/perldoc/File%3A%3AFetch%3A%3ABLACKLIST/markdown)
    This is an array ref holding blacklisted modules/utilities for fetching files with.

    To disallow the use of, for example, "LWP" and "[Net::FTP](https://www.chedong.com/phpMan.php/perldoc/Net%3A%3AFTP/markdown)", you could set $[File::Fetch::BLACKLIST](https://www.chedong.com/phpMan.php/perldoc/File%3A%3AFetch%3A%3ABLACKLIST/markdown)
    to:

        $[File::Fetch::BLACKLIST](https://www.chedong.com/phpMan.php/perldoc/File%3A%3AFetch%3A%3ABLACKLIST/markdown) = [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](https://www.chedong.com/phpMan.php/perldoc/File%3A%3AFetch%3A%3AMETHODFAIL/markdown)
    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
        [HTTP::Lite](https://www.chedong.com/phpMan.php/perldoc/HTTP%3A%3ALite/markdown)  => httplite
        [HTTP::Tiny](https://www.chedong.com/phpMan.php/perldoc/HTTP%3A%3ATiny/markdown)  => httptiny
        [Net::FTP](https://www.chedong.com/phpMan.php/perldoc/Net%3A%3AFTP/markdown)    => netftp
        wget        => wget
        lynx        => lynx
        ncftp       => ncftp
        ftp         => ftp
        curl        => curl
        rsync       => rsync
        lftp        => lftp
        fetch       => fetch
        [IO::Socket](https://www.chedong.com/phpMan.php/perldoc/IO%3A%3ASocket/markdown)  => iosock

## FREQUENTLY ASKED QUESTIONS
  So how do I use a proxy with [File::Fetch](https://www.chedong.com/phpMan.php/perldoc/File%3A%3AFetch/markdown)?
    "[File::Fetch](https://www.chedong.com/phpMan.php/perldoc/File%3A%3AFetch/markdown)" currently only supports proxies with [LWP::UserAgent](https://www.chedong.com/phpMan.php/perldoc/LWP%3A%3AUserAgent/markdown). 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](https://www.chedong.com/phpMan.php/perldoc/LWP%3A%3AUserAgent/markdown) 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 'successful' 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](https://www.chedong.com/phpMan.php/perldoc/File%3A%3AFetch/markdown)" 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](https://www.chedong.com/phpMan.php/perldoc/URI%3A%3AEscape/markdown)" module
    from CPAN, and pre-encode your URI before passing it to "[File::Fetch](https://www.chedong.com/phpMan.php/perldoc/File%3A%3AFetch/markdown)". 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.