NAME
    Parallel::Downloader - simply download multiple files at once

VERSION
    version 0.130530

SYNOPSIS
        use HTTP::Request::Common qw( GET POST );
        use Parallel::Downloader 'async_download';

        # simple example
        my @requests = map GET( "http://google.com" ), ( 1..15 );
        my @responses = async_download( requests => \@requests );

        # complex example
        my @complex_reqs = ( ( map POST( "http://google.com", [ type_id => $_ ] ), ( 1..60 ) ),
                           ( map POST( "http://yahoo.com", [ type_id => $_ ] ), ( 1..60 ) ) );

        my $downloader = Parallel::Downloader->new(
            requests => \@complex_reqs,
            workers => 50,
            conns_per_host => 12,
            aehttp_args => {
                timeout => 30,
                on_prepare => sub {
                    print "download started ($AnyEvent::HTTP::ACTIVE / $AnyEvent::HTTP::MAX_PER_HOST)\n"
                }
            },
            debug => 1,
            logger => sub {
                my ( $downloader, $message ) = @_;
                print "downloader sez [$message->{type}]: $message->{msg}\n";
            },
        );
        my @complex_responses = $downloader->run;

DESCRIPTION
    This is not a library to build a parallel downloader on top of. It is a
    downloading client build on top of AnyEvent::HTTP.

    Its goal is not to be better, faster, or smaller than anything else. Its
    goal is to provide the user with a single function they can call with a
    bunch of HTTP requests and which gives them the responses for them with
    as little fuss as possible and most importantly, without downloading
    them in sequence.

    It handles the busywork of grouping requests by hosts and limiting the
    amount of simultaneous requests per host, separate from capping the
    amount of overall connections. This allows the user to maximize their
    own connection without abusing remote hosts.

    Of course, there are facilities to customize the exact limits employed
    and to add logging and such; but "async_download" is the premier piece
    of API and should be enough for most uses.

FUNCTIONS
  async_download
    Can be requested to be exported, will instantiate a Parallel::Downloader
    object with the given parameters, run it and return the results. Its
    parameters are as follows:

   requests (required)
    Reference to an array of HTTP::Request objects, all of which will be
    downloaded.

   aehttp_args
    A reference to a hash containing arguments that will be passed to
    AnyEvent::HTTP::http_request.

    Default is an empty hashref.

   conns_per_host
    Sets the number of connections allowed per host by changing the
    corresponding AnyEvent::HTTP package variable.

    Default is '4'.

   debug
    A boolean that determines whether logging operations are a NOP or
    actually run. Set to any true value to activate the logging.

    Default is '0'.

   logger
    A reference to a sub that will receive a hash containing logging
    information. Whether that sub then prints them to screen or into a
    database or other targets is up to the user.

    Default is a sub that prints to the screen.

   workers
    The amount of workers to be used for downloading. Useful for controlling
    the global amount of connections your machine will try to establish.

    Default is '10'.

   build_response
    A reference to a sub that will be called on completion of a request to
    build the response variable that will be returned for this request. It
    receives as parameters the body of the response, a hash ref of the
    response headers and the original request.

    Default is a sub that returns the parameters wrapped in an array
    reference.

   sorted
    A boolean that determines whether the returned responses are sorted in
    the same order as the input requests. Can be useful to disable if
    build_response was overridden to not return an array or not return the
    request as the third element of the response array.

    Default is '1'.

METHODS
  run
    Runs the downloads for the given parameters and returns an array of
    array references, each containing the decoded contents, the headers and
    the HTTP::Request object.

SUPPORT
  Bugs / Feature Requests
    Please report any bugs or feature requests through the issue tracker at
    <http://rt.cpan.org/Public/Dist/Display.html?Name=Parallel-Downloader>.
    You will be notified automatically of any progress on your issue.

  Source Code
    This is open source software. The code repository is available for
    public review and contribution under the terms of the license.

    <https://github.com/wchristian/parallel-downloader>

      git clone https://github.com/wchristian/parallel-downloader.git

AUTHOR
    Christian Walde <walde.christian@googlemail.com>

COPYRIGHT AND LICENSE
    Christian Walde has dedicated the work to the Commons by waiving all of
    his or her rights to the work worldwide under copyright law and all
    related or neighboring legal rights he or she had in the work, to the
    extent allowable by law.

    Works under CC0 do not require attribution. When citing the work, you
    should not imply endorsement by the author.

