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