C4/External/OverDrive.pm

   1 package C4::External::OverDrive;
   2
   3 # Copyright (c) 2013 ByWater
   4 #
   5 # This file is part of Koha.
   6 #
   7 # Koha is free software; you can redistribute it and/or modify it
   8 # under the terms of the GNU General Public License as published by
   9 # the Free Software Foundation; either version 3 of the License, or
  10 # (at your option) any later version.
  11 #
  12 # Koha is distributed in the hope that it will be useful, but
  13 # WITHOUT ANY WARRANTY; without even the implied warranty of
  14 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  15 # GNU General Public License for more details.
  16 #
  17 # You should have received a copy of the GNU General Public License
  18 # along with Koha; if not, see <http://www.gnu.org/licenses>.
  19
  20 use strict;
  21 use warnings;
  22
  23 use Koha;
  24 use JSON;
  25 use Koha::Cache;
  26 use HTTP::Request;
  27 use HTTP::Request::Common;
  28 use LWP::Authen::Basic;
  29 use LWP::UserAgent;
  30
  31 BEGIN {
  32     require Exporter;
  33     our $VERSION = 3.07.00.049;
  34     our @ISA = qw( Exporter ) ;
  35     our @EXPORT = qw(
  36         IsOverDriveEnabled
  37         GetOverDriveToken
  38     );
  39 }
  40
  41 sub _request {
  42     my ( $request ) = @_;
  43     my $ua = LWP::UserAgent->new( agent => "Koha " . $Koha::VERSION );
  44
  45     my $response;
  46     eval {
  47         $response = $ua->request( $request ) ;
  48     };
  49     if ( $@ )  {
  50         warn "OverDrive request failed: $@";
  51         return;
  52     }
  53
  54     return $response;
  55 }
  56
  57 =head1 NAME
  58
  59 C4::External::OverDrive - Retrieve OverDrive content availability information
  60
  61 =head2 FUNCTIONS
  62
  63 This module provides content search for OverDrive,
  64
  65 =over
  66
  67 =item IsOverDriveEnabled
  68
  69 Returns 1 if all of the necessary system preferences for OverDrive are set.
  70
  71 =back
  72
  73 =cut
  74
  75 sub IsOverDriveEnabled {
  76     return (
  77         C4::Context->preference( 'OverDriveClientKey' ) &&
  78         C4::Context->preference( 'OverDriveClientSecret' )
  79     );
  80 }
  81
  82 =over
  83
  84 =item GetOverDriveToken
  85
  86 Fetches an OAuth2 auth token for the OverDrive API, reusing an existing token in
  87 Memcache if possible.
  88
  89 Returns the token ( as "bearer ..." )  or undef on failure.
  90
  91 =back
  92
  93 =cut
  94
  95 sub GetOverDriveToken {
  96     my $key = C4::Context->preference( 'OverDriveClientKey' );
  97     my $secret = C4::Context->preference( 'OverDriveClientSecret' );
  98
  99     return unless ( $key && $secret ) ;
 100
 101     my $cache;
 102
 103     eval { $cache = Koha::Cache->get_instance() };
 104
 105     my $token;
 106     $cache and $token = $cache->get_from_cache( "overdrive_token" ) and return $token;
 107
 108     my $request = HTTP::Request::Common::POST( 'https://oauth.overdrive.com/token', [
 109         grant_type => 'client_credentials'
 110     ] ) ;
 111     $request->header( Authorization => LWP::Authen::Basic->auth_header( $key, $secret ) );
 112
 113     my $response = _request( $request ) or return;
 114     if ( $response->header('Content-Type') !~ m!application/json! ) {
 115         warn "Could not connect to OverDrive: " . $response->message;
 116         return;
 117     }
 118     my $contents = from_json( $response->decoded_content );
 119
 120     if ( !$response->is_success ) {
 121         warn "Could not log into OverDrive: " . ( $contents ? $contents->{'error_description'} : $response->decoded_content );
 122         return;
 123     }
 124
 125     $token = $contents->{'token_type'} . ' ' . $contents->{'access_token'};
 126
 127     # Fudge factor to prevent spurious failures
 128     $cache
 129       and $cache->set_in_cache( 'overdrive_token', $token,
 130         { expiry => $contents->{'expires_in'} - 5 } );
 131
 132     return $token;
 133 }
 134
 135 1;
 136 __END__
 137
 138 =head1 NOTES
 139
 140 =cut
 141
 142 =head1 AUTHOR
 143
 144 Jesse Weaver <pianohacker@gmail.com>
 145
 146 =cut