The Perl Toolchain Summit needs more sponsors. If your company depends on Perl, please support this very important event.
MSCHILLI / Net-Google-Drive-Simple-0.02 / eg / google-drive-init 
#!/usr/local/bin/perl -w
# This script starts a web server on port 8082 on your local machine.
# When you point your browser at http://localhost:8082, you'll see a link
# that will lead you to Google Drive's login page, where you authenticate and 
# then allow the app (specified by client_id and client_secret below) access to 
# your Google Drive data. The script will then receive an access token
# from Google Drive and store it in ~/.google-drive.yml from where
# other scripts can pick it up and work on the data stored on the user's
# Google Drive account.
# Note that you need to obtain client_id and a client_secret below from
# https://developers.google.com/drive before you can use this script.

use strict;
use Mojolicious::Lite;
use YAML qw( DumpFile );
use Log::Log4perl qw(:easy);
use LWP::UserAgent;
use HTTP::Request::Common;
use JSON qw( from_json );
use URI;

  # You need to obtain a client_id and a client_secret from
  # https://developers.google.com/drive to use this.
my $client_id     = "XXX";
my $client_secret = "YYY";

my $scope    = 
  "https://www.googleapis.com/auth/drive";
my $listen   = "http://localhost:8082";
my($home)    = glob '~';
my $CFG_FILE = 
  "$home/.google-drive.yml";
my $redir_uri = "$listen/callback";

my $login_uri = URI->new( 
  "https://accounts.google.com" .
  "/o/oauth2/auth" );

$login_uri->query_form (
  response_type => "code",
  client_id     => $client_id,
  redirect_uri  => $redir_uri,
  scope         => $scope,
);

@ARGV = (qw(daemon --listen), $listen);

###########################################
get '/' => sub {
###########################################
  my ( $self ) = @_;

  $self->stash->{login_url} = 
      $login_uri->as_string();

} => 'index';

###########################################
get '/callback' => sub {
###########################################
  my ( $self ) = @_;

  my $code = $self->param( "code" );

  my( $access_token, $refresh_token, 
      $expires_in ) = 
    tokens_get( $self->param( "code" ) );

  umask 0177;
  DumpFile $CFG_FILE, { 
    access_token  => $access_token,
    refresh_token => $refresh_token,
    client_id     => $client_id,
    client_secret => $client_secret,
    expires => time() + $expires_in,
    code => $code 
  };

  $self->render_text( "Tokens saved.",
        layout => 'default' );
};

###########################################
sub tokens_get {
###########################################
  my( $code ) = @_;

  my $req = &HTTP::Request::Common::POST(
    'https://accounts.google.com/o/' .
    'oauth2/token',
    [
      code => $code,
      client_id => $client_id,
      client_secret => $client_secret,
      redirect_uri => $redir_uri,
      grant_type => 'authorization_code',
    ]
  );

  my $ua = LWP::UserAgent->new();
  my $resp = $ua->request($req);

  if( $resp->is_success() ) {
    my $data = 
      from_json( $resp->content() );

    return ( $data->{ access_token }, 
             $data->{ refresh_token },
             $data->{ expires_in } );
  }

  warn $resp->status_line();
  return undef;
}

app->start;

__DATA__
###########################################
@@ index.html.ep
% layout 'default';
<a href="<%= $login_url %>"
>Login on Google Drive</a>

@@ layouts/default.html.ep
<!doctype html><html>
  <head><title>Token Fetcher</title></head>
    <body>
      <pre>
      <%== content %>
      </pre>
    </body>
</html>