Bug Fixing : Browse shelves not displaying results
[koha.git] / opac / opac-detail.pl
index 76429f4..a95329f 100755 (executable)
@@ -19,7 +19,8 @@
 
 
 use strict;
-require Exporter;
+use warnings;
+
 use CGI;
 use C4::Auth;
 use C4::Branch;
@@ -32,9 +33,8 @@ use C4::Circulation;
 use C4::Tags qw(get_tags);
 use C4::Dates qw/format_date/;
 use C4::XISBN qw(get_xisbns get_biblionumber_from_isbn get_biblio_from_xisbn);
-use C4::Amazon;
+use C4::External::Amazon;
 use C4::Review;
-use C4::Serials;
 use C4::Members;
 use C4::XSLT;
 
@@ -57,11 +57,16 @@ my ( $template, $borrowernumber, $cookie ) = get_template_and_user(
 );
 
 my $biblionumber = $query->param('biblionumber') || $query->param('bib');
+
+$template->param( 'AllowOnShelfHolds' => C4::Context->preference('AllowOnShelfHolds') );
+$template->param( 'ItemsIssued' => CountItemsIssued( $biblionumber ) );
+
+my $record       = GetMarcBiblio($biblionumber);
 $template->param( biblionumber => $biblionumber );
 # XSLT processing of some stuff
-if (C4::Context->preference("XSLTResultsDisplay") ) {
-    my $newxmlrecord = XSLTParse4Display($biblionumber,C4::Context->config('opachtdocs')."/prog/en/xslt/MARC21slim2OPACDetail.xsl");
-    $template->param('XSLTBloc' => $newxmlrecord);
+if (C4::Context->preference("XSLTDetailsDisplay") ) {
+    $template->param(
+        'XSLTBloc' => XSLTParse4Display($biblionumber, $record, 'Detail') );
 }
 
 # change back when ive fixed request.pl
@@ -81,12 +86,11 @@ if (!$dat) {
     print $query->redirect("/cgi-bin/koha/errors/404.pl");
     exit;
 }
-my $imgdir = getitemtypeimagesrc();
 my $itemtypes = GetItemTypes();
 # imageurl:
 my $itemtype = $dat->{'itemtype'};
 if ( $itemtype ) {
-    $dat->{'imageurl'}    = $imgdir."/".$itemtypes->{$itemtype}->{'imageurl'};
+    $dat->{'imageurl'}    = getitemtypeimagelocation( 'opac', $itemtypes->{$itemtype}->{'imageurl'} );
     $dat->{'description'} = $itemtypes->{$itemtype}->{'description'};
 }
 my $shelflocations =GetKohaAuthorisedValues('items.location',$dat->{'frameworkcode'});
@@ -96,7 +100,7 @@ my $collections =  GetKohaAuthorisedValues('items.ccode',$dat->{'frameworkcode'}
 my $subscriptionsnumber = CountSubscriptionFromBiblionumber($biblionumber);
 my @subscriptions       = GetSubscriptions( $dat->{title}, $dat->{issn}, $biblionumber );
 my @subs;
-$dat->{'serial'}=1 if $subscriptionsnumber;
+$dat->{'serials'}=1 if $subscriptionsnumber;
 foreach my $subscription (@subscriptions) {
     my %cell;
     $cell{subscriptionid}    = $subscription->{subscriptionid};
@@ -111,38 +115,40 @@ foreach my $subscription (@subscriptions) {
 
 $dat->{'count'} = scalar(@items);
 
-#adding RequestOnOpac filter to allow or not the display of plce reserve button
-# FIXME - use me or delete me.
-my $RequestOnOpac;
-if (C4::Context->preference("RequestOnOpac")) {
-    $RequestOnOpac = 1;
-}
-
-my $biblio_authorised_value_images = C4::Items::get_authorised_value_images( C4::Biblio::get_biblio_authorised_values( $biblionumber ) );
+my $biblio_authorised_value_images = C4::Items::get_authorised_value_images( C4::Biblio::get_biblio_authorised_values( $biblionumber, $record ) );
 
 my $norequests = 1;
 my $branches = GetBranches();
 my %itemfields;
 for my $itm (@items) {
-     $norequests = 0 && $norequests
+    $norequests = 0
        if ( (not $itm->{'wthdrawn'} )
-         || (not $itm->{'itemlost'} )
-         || (not $itm->{'itemnotforloan'} )
-         || ($itm->{'itemnumber'} ) );
+         && (not $itm->{'itemlost'} )
+         && ($itm->{'itemnotforloan'}<0 || not $itm->{'itemnotforloan'} )
+                && (not $itemtypes->{$itm->{'itype'}}->{notforloan} )
+         && ($itm->{'itemnumber'} ) );
+
+    if ( defined $itm->{'publictype'} ) {
+        # I can't actually find any case in which this is defined. --amoore 2008-12-09
         $itm->{ $itm->{'publictype'} } = 1;
-    $itm->{datedue} = format_date($itm->{datedue});
+    }
+    $itm->{datedue}      = format_date($itm->{datedue});
     $itm->{datelastseen} = format_date($itm->{datelastseen});
 
-    #get collection code description, too
-       my $ccode= $itm->{'ccode'};
-       $itm->{'ccode'} = $collections->{$ccode} if(defined($collections) && exists($collections->{$ccode}));
-    $itm->{'location_description'} = $shelflocations->{$itm->{'location'} };
-    $itm->{'imageurl'}    = $imgdir."/".$itemtypes->{ $itm->{itype} }->{'imageurl'};     
-    $itm->{'description'} = $itemtypes->{$itemtype}->{'description'};
-       $itemfields{ccode} = 1 if($itm->{ccode});
-       $itemfields{enumchron} = 1 if($itm->{enumchron});
-       $itemfields{copynumber} = 1 if($itm->{copynumber});
-       $itemfields{itemnotes} = 1 if($itm->{itemnotes});
+    # get collection code description, too
+    if ( my $ccode = $itm->{'ccode'} ) {
+        $itm->{'ccode'} = $collections->{$ccode} if ( defined($collections) && exists( $collections->{$ccode} ) );
+    }
+    if ( defined $itm->{'location'} ) {
+        $itm->{'location_description'} = $shelflocations->{ $itm->{'location'} };
+    }
+    if (exists $itm->{itype} && defined($itm->{itype}) && exists $itemtypes->{ $itm->{itype} }) {
+        $itm->{'imageurl'}    = getitemtypeimagelocation( 'opac', $itemtypes->{ $itm->{itype} }->{'imageurl'} );
+        $itm->{'description'} = $itemtypes->{ $itm->{itype} }->{'description'};
+    }
+    foreach (qw(ccode enumchron copynumber itemnotes uri)) {
+        $itemfields{$_} = 1 if ($itm->{$_});
+    }
 
      # walk through the item-level authorised values and populate some images
      my $item_authorised_value_images = C4::Items::get_authorised_value_images( C4::Items::get_item_authorised_values( $itm->{'itemnumber'} ) );
@@ -154,9 +160,13 @@ for my $itm (@items) {
          $itm->{'lostimagelabel'} = $lostimageinfo->{ 'label' };
      }
 
+     if( $itm->{'count_reserves'}){
+          if( $itm->{'count_reserves'} eq "Waiting"){ $itm->{'waiting'} = 1; }
+          if( $itm->{'count_reserves'} eq "Reserved"){ $itm->{'onhold'} = 1; }
+     }
     
      my ( $transfertwhen, $transfertfrom, $transfertto ) = GetTransfers($itm->{itemnumber});
-     if ( $transfertwhen ne '' ) {
+     if ( defined( $transfertwhen ) && $transfertwhen ne '' ) {
         $itm->{transfertwhen} = format_date($transfertwhen);
         $itm->{transfertfrom} = $branches->{$transfertfrom}{branchname};
         $itm->{transfertto}   = $branches->{$transfertto}{branchname};
@@ -166,7 +176,6 @@ for my $itm (@items) {
 ## get notes and subjects from MARC record
 my $dbh              = C4::Context->dbh;
 my $marcflavour      = C4::Context->preference("marcflavour");
-my $record           = GetMarcBiblio($biblionumber);
 my $marcnotesarray   = GetMarcNotes   ($record,$marcflavour);
 my $marcauthorsarray = GetMarcAuthors ($record,$marcflavour);
 my $marcsubjctsarray = GetMarcSubjects($record,$marcflavour);
@@ -181,9 +190,10 @@ my $subtitle         = C4::Biblio::get_koha_field_from_marc('bibliosubtitle', 's
                      MARCSERIES              => $marcseriesarray,
                      MARCURLS                => $marcurlsarray,
                      norequests              => $norequests,
-                     RequestOnOpac           => $RequestOnOpac,
+                     RequestOnOpac           => C4::Context->preference("RequestOnOpac"),
                      itemdata_ccode          => $itemfields{ccode},
                      itemdata_enumchron      => $itemfields{enumchron},
+                     itemdata_uri            => $itemfields{uri},
                      itemdata_copynumber     => $itemfields{copynumber},
                      itemdata_itemnotes          => $itemfields{itemnotes},
                      authorised_value_images => $biblio_authorised_value_images,
@@ -191,17 +201,12 @@ my $subtitle         = C4::Biblio::get_koha_field_from_marc('bibliosubtitle', 's
     );
 
 foreach ( keys %{$dat} ) {
-    $template->param( "$_" => $dat->{$_} . "" );
+    $template->param( "$_" => defined $dat->{$_} ? $dat->{$_} : '' );
 }
 
 # COinS format FIXME: for books Only
-my $coins_format;
-my $fmt = substr $record->leader(), 6,2;
-my $fmts;
-$fmts->{'am'} = 'book';
-$coins_format = $fmts->{$fmt};
 $template->param(
-       ocoins_format => $coins_format,
+    ocoins => GetCOinSBiblio($biblionumber),
 );
 
 my $reviews = getreviews( $biblionumber, 1 );
@@ -213,6 +218,7 @@ foreach ( @$reviews ) {
     $_->{surname}   = $borrowerData->{'surname'};
     $_->{firstname} = $borrowerData->{'firstname'};
     $_->{userid}    = $borrowerData->{'userid'};
+    $_->{cardnumber}    = $borrowerData->{'cardnumber'};
     $_->{datereviewed} = format_date($_->{datereviewed});
     if ($borrowerData->{'borrowernumber'} eq $borrowernumber) {
                $_->{your_comment} = 1;
@@ -237,6 +243,8 @@ $template->param(
 
 sub isbn_cleanup ($) {
        my $isbn=shift;
+    ($isbn) = $isbn =~ /([\d-]*[X]*)/;
+    $isbn =~ s/-//g;
        if (
                $isbn =~ /\b(\d{13})\b/ or
                $isbn =~ /\b(\d{10})\b/ or 
@@ -249,8 +257,9 @@ sub isbn_cleanup ($) {
 
 # XISBN Stuff
 my $xisbn=$dat->{'isbn'};
-$xisbn =~ /(\d*[X]*)/;
-$template->param(amazonisbn => $1);            # FIXME: so it is OK if the ISBN = 'XXXXX' ?
+(my $aisbn) = $xisbn =~ /([\d-]*[X]*)/;
+$aisbn =~ s/-//g;
+$template->param(amazonisbn => $aisbn);                # FIXME: so it is OK if the ISBN = 'XXXXX' ?
 my ($clean,$clean2);
 # these might be overkill, but they are better than the regexp above.
 if ($clean = isbn_cleanup($xisbn)){
@@ -267,100 +276,167 @@ if (C4::Context->preference("OPACFRBRizeEditions")==1) {
     if ($@) { warn "XISBN Failed $@"; }
 }
 # Amazon.com Stuff
-if ( C4::Context->preference("OPACAmazonContent") == 1 ) {
+if ( C4::Context->preference("OPACAmazonEnabled") ) {
+    $template->param( AmazonTld => get_amazon_tld() );
+}
+if ( C4::Context->preference("OPACAmazonEnabled") && C4::Context->preference("OPACAmazonSimilarItems") ) {
     my $similar_products_exist;
-    my $amazon_details = &get_amazon_details( $xisbn );
-    my $item_attributes = \%{$amazon_details->{Items}->{Item}->{ItemAttributes}};
-    my $customer_reviews = \@{$amazon_details->{Items}->{Item}->{CustomerReviews}->{Review}};
-    for my $one_review (@$customer_reviews) {
-        $one_review->{Date} = format_date($one_review->{Date});
-    }
-    my @similar_products;
-    for my $similar_product (@{$amazon_details->{Items}->{Item}->{SimilarProducts}->{SimilarProduct}}) {
-        # do we have any of these isbns in our collection?
-        my $similar_biblionumbers = get_biblionumber_from_isbn($similar_product->{ASIN});
-        # verify that there is at least one similar item
-        $similar_products_exist++ if ${@$similar_biblionumbers}[0];
-        push @similar_products, +{ similar_biblionumbers => $similar_biblionumbers, title => $similar_product->{Title}, ASIN => $similar_product->{ASIN}  };
+    my $amazon_reviews  = C4::Context->preference("AmazonReviews");
+    my $amazon_similars = C4::Context->preference("AmazonSimilarItems");
+    my @services;
+    my $amazon_details = &get_amazon_details( $dat->{isbn}, $record, $marcflavour, \@services );
+
+    if ( $amazon_reviews ) {
+       
+        my $item = $amazon_details->{Items}->{Item}->[0];
+        my $customer_reviews = \@{ $item->{CustomerReviews}->{Review} };
+        for my $one_review ( @$customer_reviews ) {
+            $one_review->{Date} = format_date($one_review->{Date});
+        }
+        my $editorial_reviews = \@{ $item->{EditorialReviews}->{EditorialReview} };
+        my $average_rating = $item->{CustomerReviews}->{AverageRating} || 0;
+        $template->param( amazon_average_rating    => $average_rating * 20);
+        $template->param( AMAZON_CUSTOMER_REVIEWS  => $customer_reviews );
+        $template->param( AMAZON_EDITORIAL_REVIEWS => $editorial_reviews );
     }
-    my $editorial_reviews = \@{$amazon_details->{Items}->{Item}->{EditorialReviews}->{EditorialReview}};
-    my $average_rating = $amazon_details->{Items}->{Item}->{CustomerReviews}->{AverageRating};
-    $template->param( OPACAmazonSimilarItems => $similar_products_exist );
-    $template->param( amazon_average_rating => $average_rating * 20);
-    $template->param( AMAZON_CUSTOMER_REVIEWS    => $customer_reviews );
-    $template->param( AMAZON_SIMILAR_PRODUCTS => \@similar_products );
-    $template->param( AMAZON_EDITORIAL_REVIEWS    => $editorial_reviews );
+    if ( $amazon_similars ) {
+        my $item = $amazon_details->{Items}->{Item}->[0];
+        my @similar_products;
+        for my $similar_product (@{ $item->{SimilarProducts}->{SimilarProduct} }) {
+            # do we have any of these isbns in our collection?
+            my $similar_biblionumbers = get_biblionumber_from_isbn($similar_product->{ASIN});
+            # verify that there is at least one similar item
+            if (scalar(@$similar_biblionumbers)){
+                $similar_products_exist++ if ($similar_biblionumbers && $similar_biblionumbers->[0]);
+                push @similar_products, +{ similar_biblionumbers => $similar_biblionumbers, title => $similar_product->{Title}, ASIN => $similar_product->{ASIN}  };
+            }
+        }
+       $template->param( OPACAmazonSimilarItems => $similar_products_exist );
+       $template->param( AMAZON_SIMILAR_PRODUCTS => \@similar_products );
+    }    
+    
 }
-# Shelf Browser Stuff
-if (C4::Context->preference("OPACShelfBrowser")) {
-# pick the first itemnumber unless one was selected by the user
-my $starting_itemnumber = $query->param('shelfbrowse_itemnumber'); # || $items[0]->{itemnumber};
-$template->param( OpenOPACShelfBrowser => 1) if $starting_itemnumber;
-# find the right cn_sort value for this item
-my ($starting_cn_sort, $starting_homebranch, $starting_location);
-my $sth_get_cn_sort = $dbh->prepare("SELECT cn_sort,homebranch,location from items where itemnumber=?");
-$sth_get_cn_sort->execute($starting_itemnumber);
-while (my $result = $sth_get_cn_sort->fetchrow_hashref()) {
-    $starting_cn_sort = $result->{'cn_sort'};
-    $starting_homebranch->{code} = $result->{'homebranch'};
-    $starting_homebranch->{description} = $branches->{$result->{'homebranch'}}{branchname};
-    $starting_location->{code} = $result->{'location'};
-    $starting_location->{description} = GetAuthorisedValueDesc('','',   $result->{'location'} ,'','','LOC');
 
+# Babelthèque
+if ( C4::Context->preference("Babeltheque") ) {
+    $template->param( 
+        Babeltheque => 1,
+    );
 }
 
-## List of Previous Items
-# order by cn_sort, which should include everything we need for ordering purposes (though not
-# for limits, those need to be handled separately
-my $sth_shelfbrowse_previous = $dbh->prepare("SELECT * FROM items WHERE CONCAT(cn_sort,itemnumber) <= ? AND homebranch=? AND location=? ORDER BY CONCAT(cn_sort,itemnumber) DESC LIMIT 3");
-$sth_shelfbrowse_previous->execute($starting_cn_sort.$starting_itemnumber, $starting_homebranch->{code}, $starting_location->{code});
-my @previous_items;
-while (my $this_item = $sth_shelfbrowse_previous->fetchrow_hashref()) {
-    my $sth_get_biblio = $dbh->prepare("SELECT biblio.*,biblioitems.isbn AS isbn FROM biblio LEFT JOIN biblioitems ON biblio.biblionumber=biblioitems.biblionumber WHERE biblio.biblionumber=?");
-    $sth_get_biblio->execute($this_item->{biblionumber});
-    while (my $this_biblio = $sth_get_biblio->fetchrow_hashref()) {
-        $this_item->{'title'} = $this_biblio->{'title'};
-               if ($clean2 = isbn_cleanup($this_biblio->{'isbn'})) {
-               $this_item->{'isbn'} = $clean2;
-               } else { 
-                       $this_item->{'isbn'} = $this_biblio->{'isbn'};
-               }
+# Shelf Browser Stuff
+if (C4::Context->preference("OPACShelfBrowser")) {
+    # pick the first itemnumber unless one was selected by the user
+    my $starting_itemnumber = $query->param('shelfbrowse_itemnumber'); # || $items[0]->{itemnumber};
+    $template->param( OpenOPACShelfBrowser => 1) if $starting_itemnumber;
+    # find the right cn_sort value for this item
+    my ($starting_cn_sort, $starting_homebranch, $starting_location);
+    my $sth_get_cn_sort = $dbh->prepare("SELECT cn_sort,homebranch,location from items where itemnumber=?");
+    $sth_get_cn_sort->execute($starting_itemnumber);
+    while (my $result = $sth_get_cn_sort->fetchrow_hashref()) {
+        $starting_cn_sort = $result->{'cn_sort'};
+        $starting_homebranch->{code} = $result->{'homebranch'};
+        $starting_homebranch->{description} = $branches->{$result->{'homebranch'}}{branchname};
+        $starting_location->{code} = $result->{'location'};
+        $starting_location->{description} = GetAuthorisedValueDesc('','',   $result->{'location'} ,'','','LOC');
+    
     }
-    unshift @previous_items, $this_item;
-}
-my $throwaway = pop @previous_items;
-## List of Next Items
-my $sth_shelfbrowse_next = $dbh->prepare("SELECT * FROM items WHERE CONCAT(cn_sort,itemnumber) >= ? AND homebranch=? AND location=? ORDER BY CONCAT(cn_sort,itemnumber) ASC LIMIT 3");
-$sth_shelfbrowse_next->execute($starting_cn_sort.$starting_itemnumber, $starting_homebranch->{code}, $starting_location->{code});
-my @next_items;
-while (my $this_item = $sth_shelfbrowse_next->fetchrow_hashref()) {
-    my $sth_get_biblio = $dbh->prepare("SELECT biblio.*,biblioitems.isbn AS isbn FROM biblio LEFT JOIN biblioitems ON biblio.biblionumber=biblioitems.biblionumber WHERE biblio.biblionumber=?");
-    $sth_get_biblio->execute($this_item->{biblionumber});
-    while (my $this_biblio = $sth_get_biblio->fetchrow_hashref()) {
-        $this_item->{'title'} = $this_biblio->{'title'};
-               if ($clean2 = isbn_cleanup($this_biblio->{'isbn'})) {
-               $this_item->{'isbn'} = $clean2;
-               } else { 
-                       $this_item->{'isbn'} = $this_biblio->{'isbn'};
-               }
+    
+    ## List of Previous Items
+    # order by cn_sort, which should include everything we need for ordering purposes (though not
+    # for limits, those need to be handled separately
+    my $sth_shelfbrowse_previous;
+    if (defined $starting_location->{code}) {
+      $sth_shelfbrowse_previous = $dbh->prepare("
+        SELECT *
+        FROM items
+        WHERE
+            ((cn_sort = ? AND itemnumber < ?) OR cn_sort < ?) AND
+            homebranch = ? AND location = ?
+        ORDER BY cn_sort DESC, itemnumber LIMIT 3
+        ");
+      $sth_shelfbrowse_previous->execute($starting_cn_sort, $starting_itemnumber, $starting_cn_sort, $starting_homebranch->{code}, $starting_location->{code});
+    } else {
+      $sth_shelfbrowse_previous = $dbh->prepare("
+        SELECT *
+        FROM items
+        WHERE
+            ((cn_sort = ? AND itemnumber < ?) OR cn_sort < ?) AND
+            homebranch = ?
+        ORDER BY cn_sort DESC, itemnumber LIMIT 3
+        ");
+      $sth_shelfbrowse_previous->execute($starting_cn_sort, $starting_itemnumber, $starting_cn_sort, $starting_homebranch->{code});
+    }
+    my @previous_items;
+    while (my $this_item = $sth_shelfbrowse_previous->fetchrow_hashref()) {
+        my $sth_get_biblio = $dbh->prepare("SELECT biblio.*,biblioitems.isbn AS isbn FROM biblio LEFT JOIN biblioitems ON biblio.biblionumber=biblioitems.biblionumber WHERE biblio.biblionumber=?");
+        $sth_get_biblio->execute($this_item->{biblionumber});
+        while (my $this_biblio = $sth_get_biblio->fetchrow_hashref()) {
+            $this_item->{'title'} = $this_biblio->{'title'};
+            if ($clean2 = isbn_cleanup($this_biblio->{'isbn'})) {
+                $this_item->{'isbn'} = $clean2;
+            } else { 
+                $this_item->{'isbn'} = $this_biblio->{'isbn'};
+            }
+        }
+        unshift @previous_items, $this_item;
+    }
+    
+    ## List of Next Items; this also intentionally catches the current item
+    my $sth_shelfbrowse_next;
+    if (defined $starting_location->{code}) {
+      $sth_shelfbrowse_next = $dbh->prepare("
+        SELECT *
+        FROM items
+        WHERE
+            ((cn_sort = ? AND itemnumber >= ?) OR cn_sort > ?) AND
+            homebranch = ? AND location = ?
+        ORDER BY cn_sort, itemnumber LIMIT 3
+        ");
+      $sth_shelfbrowse_next->execute($starting_cn_sort, $starting_itemnumber, $starting_cn_sort, $starting_homebranch->{code}, $starting_location->{code});
+    } 
+    else {
+      $sth_shelfbrowse_next = $dbh->prepare("
+        SELECT *
+        FROM items
+        WHERE
+            ((cn_sort = ? AND itemnumber >= ?) OR cn_sort > ?) AND
+            homebranch = ?
+        ORDER BY cn_sort, itemnumber LIMIT 3
+        ");
+      $sth_shelfbrowse_next->execute($starting_cn_sort, $starting_itemnumber, $starting_cn_sort, $starting_homebranch->{code});
+    }
+    my @next_items;
+    while (my $this_item = $sth_shelfbrowse_next->fetchrow_hashref()) {
+        my $sth_get_biblio = $dbh->prepare("SELECT biblio.*,biblioitems.isbn AS isbn FROM biblio LEFT JOIN biblioitems ON biblio.biblionumber=biblioitems.biblionumber WHERE biblio.biblionumber=?");
+        $sth_get_biblio->execute($this_item->{biblionumber});
+        while (my $this_biblio = $sth_get_biblio->fetchrow_hashref()) {
+            $this_item->{'title'} = $this_biblio->{'title'};
+            if ($clean2 = isbn_cleanup($this_biblio->{'isbn'})) {
+                $this_item->{'isbn'} = $clean2;
+            } else { 
+                $this_item->{'isbn'} = $this_biblio->{'isbn'};
+            }
+        }
+        push @next_items, $this_item;
     }
-    push @next_items, $this_item;
-}
 
-# alas, these won't auto-vivify, see http://www.perlmonks.org/?node_id=508481
-my $shelfbrowser_next_itemnumber = $next_items[-1]->{itemnumber} if @next_items;
-my $shelfbrowser_next_biblionumber = $next_items[-1]->{biblionumber} if @next_items;
 
-$template->param(
-    starting_homebranch => $starting_homebranch->{description},
-    starting_location => $starting_location->{description},
-    shelfbrowser_prev_itemnumber => $previous_items[0]->{itemnumber},
-    shelfbrowser_next_itemnumber => $shelfbrowser_next_itemnumber,
-    shelfbrowser_prev_biblionumber => $previous_items[0]->{biblionumber},
-    shelfbrowser_next_biblionumber => $shelfbrowser_next_biblionumber,
-    PREVIOUS_SHELF_BROWSE => \@previous_items,
-    NEXT_SHELF_BROWSE => \@next_items,
-);
+    # alas, these won't auto-vivify, see http://www.perlmonks.org/?node_id=508481
+    my $shelfbrowser_next_itemnumber = $next_items[-1]->{itemnumber} if @next_items;
+    my $shelfbrowser_next_biblionumber = $next_items[-1]->{biblionumber} if @next_items;
+    
+    $template->param(
+        starting_homebranch => $starting_homebranch->{description},
+        starting_location => $starting_location->{description},
+        starting_itemnumber => $starting_itemnumber,
+        shelfbrowser_prev_itemnumber => (@previous_items ? $previous_items[0]->{itemnumber} : 0),
+        shelfbrowser_next_itemnumber => $shelfbrowser_next_itemnumber,
+        shelfbrowser_prev_biblionumber => (@previous_items ? $previous_items[0]->{biblionumber} : 0),
+        shelfbrowser_next_biblionumber => $shelfbrowser_next_biblionumber,
+        PREVIOUS_SHELF_BROWSE => \@previous_items,
+        NEXT_SHELF_BROWSE => \@next_items,
+    );
 }
 
 if (C4::Context->preference("BakerTaylorEnabled")) {