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::Caches;
  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 @ISA = qw( Exporter ) ;
  34     our @EXPORT = qw(
  35         IsOverDriveEnabled
  36         GetOverDriveToken
  37     );
  38 }
  39
  40 sub _request {
  41     my ( $request ) = @_;
  42     my $ua = LWP::UserAgent->new( agent => "Koha " . $Koha::VERSION );
  43
  44     my $response;
  45     eval {
  46         $response = $ua->request( $request ) ;
  47     };
  48     if ( $@ )  {
  49         warn "OverDrive request failed: $@";
  50         return;
  51     }
  52
  53     return $response;
  54 }
  55
  56 =head1 NAME
  57
  58 C4::External::OverDrive - Retrieve OverDrive content availability information
  59
  60 =head2 FUNCTIONS
  61
  62 This module provides content search for OverDrive,
  63
  64 =over
  65
  66 =item IsOverDriveEnabled
  67
  68 Returns 1 if all of the necessary system preferences for OverDrive are set.
  69
  70 =back
  71
  72 =cut
  73
  74 sub IsOverDriveEnabled {
  75     return (
  76         C4::Context->preference( 'OverDriveClientKey' ) &&
  77         C4::Context->preference( 'OverDriveClientSecret' )
  78     );
  79 }
  80
  81 =over
  82
  83 =item GetOverDriveToken
  84
  85 Fetches an OAuth2 auth token for the OverDrive API, reusing an existing token in
  86 Memcache if possible.
  87
  88 Returns the token ( as "bearer ..." )  or undef on failure.
  89
  90 =back
  91
  92 =cut
  93
  94 sub GetOverDriveToken {
  95     my $key = C4::Context->preference( 'OverDriveClientKey' );
  96     my $secret = C4::Context->preference( 'OverDriveClientSecret' );
  97
  98     return unless ( $key && $secret ) ;
  99
 100     my $cache;
 101
 102     eval { $cache = Koha::Caches->get_instance() };
 103
 104     my $token;
 105     $cache and $token = $cache->get_from_cache( "overdrive_token" ) and return $token;
 106
 107     my $request = HTTP::Request::Common::POST( 'https://oauth.overdrive.com/token', [
 108         grant_type => 'client_credentials'
 109     ] ) ;
 110     $request->header( Authorization => LWP::Authen::Basic->auth_header( $key, $secret ) );
 111
 112     my $response = _request( $request ) or return;
 113     if ( $response->header('Content-Type') !~ m!application/json! ) {
 114         warn "Could not connect to OverDrive: " . $response->message;
 115         return;
 116     }
 117     my $contents = from_json( $response->decoded_content );
 118
 119     if ( !$response->is_success ) {
 120         warn "Could not log into OverDrive: " . ( $contents ? $contents->{'error_description'} : $response->decoded_content );
 121         return;
 122     }
 123
 124     $token = $contents->{'token_type'} . ' ' . $contents->{'access_token'};
 125
 126     # Fudge factor to prevent spurious failures
 127     $cache
 128       and $cache->set_in_cache( 'overdrive_token', $token,
 129         { expiry => $contents->{'expires_in'} - 5 } );
 130
 131     return $token;
 132 }
 133
 134 1;
 135 __END__
 136
 137 =head1 NOTES
 138
 139 =cut
 140
 141 =head1 AUTHOR
 142
 143 Jesse Weaver <pianohacker@gmail.com>
 144
 145 =cut