package Catalyst::Controller::Atompub::Collection; use strict; use warnings; use Atompub::DateTime qw(datetime); use Atompub::MediaType qw(media_type); use Atompub::Util qw(is_acceptable_media_type is_allowed_category); use Catalyst::Utils; use File::Slurp; use HTTP::Status; use NEXT; use POSIX qw(strftime); use Text::CSV; use Time::HiRes qw(gettimeofday); use URI; use URI::Escape; use XML::Atom::Entry; use base qw(Catalyst::Controller::Atompub::Base); __PACKAGE__->mk_accessors(qw(edited)); my %COLLECTION_METHOD = ( GET => '_list', HEAD => '_list', POST => '_create', ); my %RESOURCE_METHOD = ( GET => '_read', HEAD => '_read', POST => '_create', PUT => '_update', DELETE => '_delete', ); sub auto :Private { my($self, $c) = @_; $self->{resources} = []; 1; } # access to the collection sub default :Private { my($self, $c) = @_; my $method = $COLLECTION_METHOD{ uc $c->req->method }; unless ($method) { $c->res->headers->allow('GET, HEAD, POST'); return $self->error($c, RC_METHOD_NOT_ALLOWED); } $self->$method($c); } sub edit_uri :LocalRegex('^([^-?&#][^?&#]*)') { my($self, $c) = @_; my $method = $RESOURCE_METHOD{ uc $c->req->method }; unless ($method) { $c->res->headers->allow('GET, HEAD, PUT, DELETE'); return $self->error($c, RC_METHOD_NOT_ALLOWED); } $self->$method($c); } sub resource { my($self, $rc) = @_; if ($rc) { push @{ $self->{resources} }, $rc; } else { [ grep { $_ } @{ $self->{resources} } ]->[0]; } } *rc = \&resource; my @ACCESSORS = ( [ 'collection_resource', 'feed', 'is_collection' ], [ 'entry_resource', 'entry', 'is_entry' ], [ 'media_resource', undef, 'is_media' ], [ 'media_link_entry', 'entry', 'is_entry' ], ); for my $accessor (@ACCESSORS) { no strict 'refs'; ## no critic my($method, $type, $is) = @$accessor; *{$method} = sub { my($self, $rc) = @_; if ($rc) { $rc->type(media_type($type)) if $type; push @{ $self->{resources} }, $rc; } else { return [ grep { !$_->type || $_->$is } grep { $_ } @{ $self->{resources} } ]->[0]; } }; } sub make_edit_uri { my($self, $c, @args) = @_; my $collection_uri = $self->info->get($c, $self)->href; my $basename; if (my $slug = $c->req->slug) { my $slug = uri_unescape $slug; $slug =~ s/^\s+//; $slug =~ s/\s+$//; $slug =~ s/[.\s]+/_/; $basename = uri_escape lc $slug; } else { my($sec, $usec) = gettimeofday; $basename = join '-', strftime('%Y%m%d-%H%M%S', localtime($sec)), sprintf('%06d', $usec); } my @media_types = map { media_type($_) } ('entry', @args); my @uris; for my $media_type (@media_types) { my $ext = $media_type->extension || 'bin'; my $name = join '.', $basename, $ext; push @uris, join '/', $collection_uri, $name; } wantarray ? @uris : $uris[0]; } for my $operation qw(list create read update delete) { no strict 'refs'; ## no critic *{"do_$operation"} = sub { my($self, $c, @args) = @_; return $self->error($c, RC_METHOD_NOT_ALLOWED) unless UNIVERSAL::isa($self->{handler}{$operation}, 'CODE'); $self->{handler}{$operation}($self, $c, @args); }; } sub _list { my($self, $c) = @_; my $feed = XML::Atom::Feed->new; my $title = $self->info->get($c, $self)->title; $feed->title($title); if ($self->{author}) { my $author = XML::Atom::Person->new; $self->{author}{$_} and $author->$_($self->{author}{$_}) for qw(name email uri); $feed->author($author); } $feed->updated(datetime->w3c); my($uri) = $c->req->uri =~ m{^(https?://[^/]+/[^?&#]+)}; $feed->id(_make_id($uri)); $feed->self_link($uri); $self->collection_resource( Catalyst::Controller::Atompub::Collection::Resource->new({ uri => $uri, body => $feed, }) ); $self->do_list($c) or return $self->error($c, RC_INTERNAL_SERVER_ERROR, "Cannot list collection: $uri"); return unless $self->collection_resource; $c->res->content_type($self->collection_resource->type) unless $c->res->content_type; $c->res->body($self->collection_resource->serialize) unless $c->res->body; } sub _create { my($self, $c) = @_; my $media_type = media_type($c->req->content_type) || media_type('application/octet-stream'); my $coll = $self->info->get($c, $self); return $self->error($c, RC_UNSUPPORTED_MEDIA_TYPE, "Unsupported media type: $media_type") unless is_acceptable_media_type($coll, $media_type); $self->edited(datetime); if ($media_type->is_a('entry')) { my($uri) = $self->make_edit_uri($c); my $entry = $self->_fixup_entry($c, $uri) or return $self->error($c); $self->entry_resource( Catalyst::Controller::Atompub::Collection::Resource->new({ uri => $uri, body => $entry, }) ); } else { my($entry_uri, $media_uri) = $self->make_edit_uri($c, $media_type); return $self->error($c, RC_BAD_REQUEST, 'No body') unless $c->req->body; my $entry = $self->_create_media_link_entry($c, $entry_uri, $media_uri) or return $self->error($c); my $media = read_file($c->req->body, binmode => ':raw'); $self->media_link_entry( Catalyst::Controller::Atompub::Collection::Resource->new({ uri => $entry_uri, body => $entry, }) ); $self->media_resource( Catalyst::Controller::Atompub::Collection::Resource->new({ uri => $media_uri, body => $media, type => $media_type, }) ); } $self->do_create($c) or return $self->error($c, RC_INTERNAL_SERVER_ERROR, 'Cannot create new resource: '.$self->info->get($c, $self)->href); $c->res->status(RC_CREATED); if (!defined $c->res->etag || !$c->res->last_modified) { my %ret = $self->find_version($c, $self->entry_resource->uri); $c->res->etag($ret{etag}) if !defined $c->res->etag && defined $ret{etag}; $c->res->last_modified($ret{last_modified}) if !$c->res->last_modified && $ret{last_modified}; } return unless $self->entry_resource; $c->res->redirect($self->entry_resource->uri, RC_CREATED) unless $c->res->redirect; $c->res->content_type($self->entry_resource->type) unless $c->res->content_type; $c->res->body($self->entry_resource->serialize) unless $c->res->body; } sub _read { my($self, $c) = @_; return $c->res->status(RC_NOT_MODIFIED) unless $self->_is_modified($c); my $uri = $c->req->uri->no_query; my @accepts = $self->info->get($c, $self)->accepts; my $media_type = @accepts == 0 ? media_type('entry') : @accepts == 1 && $accepts[0] !~ /\*/ ? media_type($accepts[0]) : undef; $self->rc( Catalyst::Controller::Atompub::Collection::Resource->new({ uri => $uri, type => $media_type, }) ); $self->do_read($c) or return $self->error( $c, RC_INTERNAL_SERVER_ERROR, "Cannot read resource: $uri" ); if (!defined $c->res->etag || !$c->res->last_modified) { my %ret = $self->find_version($c, $uri); $c->res->etag($ret{etag}) if !defined $c->res->etag && defined $ret{etag}; $c->res->last_modified($ret{last_modified}) if !$c->res->last_modified && $ret{last_modified}; } return unless $self->rc; $c->res->content_type($self->rc->type) unless $c->res->content_type; return if $c->req->method eq 'HEAD'; $c->res->body($self->rc->serialize) unless $c->res->body; } sub _update { my($self, $c) = @_; return $self->error($c, RC_PRECONDITION_FAILED, 'Missing If-match header') if $self->_is_modified($c); my $media_type = media_type($c->req->content_type) || media_type('application/octet-stream'); my $coll = $self->info->get($c, $self); return $self->error($c, RC_UNSUPPORTED_MEDIA_TYPE, "Unsupported media type: $media_type") if !is_acceptable_media_type($coll, $media_type) && !$media_type->is_a('entry'); $self->edited(datetime); my $uri = $c->req->uri->no_query; my $body; if ($media_type->is_a('entry')) { $media_type = media_type('entry'); $body = $self->_fixup_entry($c, $uri) or return $self->error($c); } else { return $self->error($c, RC_BAD_REQUEST, 'No body') unless $c->req->body; $body = read_file($c->req->body, binmode => ':raw'); } $self->rc( Catalyst::Controller::Atompub::Collection::Resource->new({ uri => $uri, body => $body, type => $media_type, }) ); $self->do_update($c) or return $self->error($c, RC_INTERNAL_SERVER_ERROR, "Cannot update resource: $uri"); if (!defined $c->res->etag || !$c->res->last_modified) { my %ret = $self->find_version($c, $uri); $c->res->etag($ret{etag}) if !defined $c->res->etag && defined $ret{etag}; $c->res->last_modified($ret{last_modified}) if !$c->res->last_modified && $ret{last_modified}; } return unless $self->rc; return if $c->res->status eq RC_NO_CONTENT; $c->res->content_type($self->rc->type) unless $c->res->content_type; $c->res->body($self->rc->serialize) unless $c->res->body; } sub _delete { my($self, $c) = @_; # If-Match nor If-Unmodified-Since header is not required on DELETE # return $self->error($c, RC_PRECONDITION_FAILED) # if $self->_is_modified($c); my $uri = $c->req->uri->no_query; $self->rc( Catalyst::Controller::Atompub::Collection::Resource->new({ uri => $uri, }) ); $c->res->status(RC_NO_CONTENT); $self->do_delete($c) or return $self->error($c, RC_INTERNAL_SERVER_ERROR, "Cannot delete resource: $uri"); } sub find_version {} sub _is_modified { my($self, $c) = @_; my $method = $c->req->method; my %ret = $self->find_version($c, $c->req->uri->no_query); my $etag = $ret{etag}; my $last_modified = $ret{last_modified}; return $method eq 'GET' ? 1 : 0 if !defined $etag && !$last_modified; # if don't check version my $match = $method eq 'GET' ? $c->req->if_none_match : $c->req->if_match; $match =~ s/^['"](.+)['"]$/$1/ if $match; #" unquote return 1 if defined $etag && (!defined $match || $etag ne $match); my $since = $method eq 'GET' ? $c->req->if_modified_since : $c->req->if_unmodified_since; return 1 if $last_modified && (!$since || datetime($last_modified) != datetime($since)); return 0; } sub _fixup_entry { my($self, $c, $uri) = @_; my $entry = XML::Atom::Entry->new($c->req->body) or return $self->error($c, RC_BAD_REQUEST, XML::Atom::Entry->errstr); return $self->error($c, RC_BAD_REQUEST, 'Forbidden category') unless is_allowed_category($self->info->get($c, $self), $entry->category); $entry->edited($self->edited->w3c); $entry->updated($self->edited->w3c) unless $entry->updated; $entry->id(_make_id($uri)) unless $entry->id; $entry->edit_link($uri); # XXX check edit-media link if (!$entry->author) { my $author = XML::Atom::Person->new; $author->name(''); $entry->author($author); } elsif (!$entry->author->name) { $entry->author->name(''); } $entry->title('') unless defined $entry->title; $entry; } sub _make_id { my($uri) = @_; $uri = URI->new($uri); my $path = $uri->path; $path =~ s{#}{/}g; my $dt = datetime->dt; 'tag:'.$uri->authority.','.$dt->ymd.':'.$path; } sub _create_media_link_entry { my($self, $c, $entry_uri, $media_uri) = @_; my $entry = XML::Atom::Entry->new; $entry->edited($self->edited->w3c); $entry->updated($self->edited->w3c) unless $entry->updated; my $link = XML::Atom::Link->new; $link->rel('edit-media'); $link->href($media_uri); $entry->add_link($link); $link = XML::Atom::Link->new; $link->rel('edit'); $link->href($entry_uri); $entry->add_link($link); $entry->id($entry_uri); $entry->title(uri_unescape $c->req->slug || ''); my $content = XML::Atom::Content->new; $content->src($media_uri); $content->type($c->req->content_type); $entry->content($content); $entry->summary(''); $entry; } sub create_action { my($self, %args) = @_; # %args: namespace, name, reverse, class, attributes, code my $attr = lc $args{attributes}{Atompub}[0]; my $code = $args{code}; my $csv = Text::CSV->new({ allow_whitespace => 1 }); $csv->parse($attr); for ($csv->fields) { $self->{handler}{$_} = $code if length $_; # %args = (); # removes 'Loaded Private actions' message in initialization } $self->NEXT::create_action(%args); } sub URI::no_query { [ split /[?&]/, shift->canonical ]->[0] } package Catalyst::Controller::Atompub::Collection::Resource; use Atompub::MediaType qw(media_type); use base qw(Class::Accessor::Fast); __PACKAGE__->mk_accessors(qw(uri type body)); sub new { my($class, $args) = @_; $args ||= {}; bless $args, $class; } sub is_collection { my($self) = @_; my $media_type = media_type($self->type) or return; return $media_type->is_a('feed'); } sub is_entry { my($self) = @_; my $media_type = media_type($self->type) or return; return $media_type->is_a('entry'); } sub is_media { my($self) = @_; my $media_type = media_type($self->type) or return; return !$media_type->is_a('application/atom+xml'); } sub serialize { my($self) = @_; my $body = $self->body; UNIVERSAL::can($body, 'as_xml') ? $body->as_xml : $body; } 1; __END__ =head1 NAME Catalyst::Controller::Atompub::Collection - A Catalyst controller for the Atom Collection Resources =head1 SYNOPSIS # Use the Catalyst helper $ perl script/myatom_create.pl controller MyCollection Atompub::Collection # And edit lib/MyAtom/Controller/MyCollection.pm package MyAtom::Controller::MyCollection; use base 'Catalyst::Controller::Atompub::Collection'; # List resources in a Feed Document, which must be implemented in # the mehtod with "Atompub(list)" attribute sub get_feed :Atompub(list) { my($self, $c) = @_; # Skeleton of the Feed (XML::Atom::Feed) was prepared by # C::C::Atompub my $feed = $self->collection_resource->body; # Retrieve Entries sorted in descending order my $rs = $c->model('DBIC::Entries')->search({}, { order_by => 'edited desc', }); # Add Entries to the Feed while (my $entry_resource = $rs->next) { my $entry = XML::Atom::Entry->new(\$entry_resource->xml); $feed->add_entry($entry); } # Return true on success 1; } # Create new Entry in the method with "Atompub(create)" attribute sub create_entry :Atompub(create) { my($self, $c) = @_; # URI of the new Entry, which was determined by C::C::Atompub my $uri = $self->entry_resource->uri; # app:edited element, which was assigned by C::C::Atompub, # is coverted into ISO 8601 format like '2007-01-01 00:00:00' my $edited = $self->edited->iso; # POSTed Entry (XML::Atom::Entry) my $entry = $self->entry_resource->body; # Create new Entry $c->model('DBIC::Entries')->create({ uri => $uri, edited => $edited, xml => $entry->as_xml, }); # Return true on success 1; } # Search the requested Entry in the method with "Atompub(read)" # attribute sub get_entry :Atompub(read) { my($self, $c) = @_; my $uri = $c->entry_resource->uri; # Retrieve the Entry my $rs = $c->model('DBIC::Entries')->find({ uri => $uri }); # Set the Entry my $entry = XML::Atom::Entry->new(\$rs->xml); $self->entry_resource->body($entry); # Return true on success 1; } # Update the requested Entry in the method with "Atompub(update)" # attribute sub update_entry :Atompub(update) { my($self, $c) = @_; my $uri = $c->entry_resource->uri; # app:edited element, which was assigned by C::C::Atompub, # is coverted into ISO 8601 format like '2007-01-01 00:00:00' my $edited = $self->edited->iso; # PUTted Entry (XML::Atom::Entry) my $entry = $self->entry_resource->body; # Update the Entry $c->model('DBIC::Entries')->find({ uri => $uri })->update({ uri => $uri, edited => $edited, xml => $entry->as_xml, }); # Return true on success 1; } # Delete the requested Entry in the method with "Atompub(delete)" # attribute sub delete_entry :Atompub(delete) { my($self, $c) = @_; my $uri = $c->entry_resource->uri; # Delete the Entry $c->model('DBIC::Entries')->find({ uri => $uri })->delete; # Return true on success 1; } # Access to http://localhost:3000/mycollection and get Feed Document =head1 DESCRIPTION Catalyst::Controller::Atompub::Collection provides the following features: =over 4 =item * Pre-processing requests L pre-processes the HTTP requests. All you have to do is just writing CRUD operations in the subroutines with I attribute. =item * Media Resource support Media Resources (binary data) as well as Entry Resources are supported. A Media Link Entry, which has an I element to the newly created Media Resource, is given by L. =item * Media type check L checks a media type of the POSTed/PUTted resource based on collection configuration. =item * Category check L checks I elements in the POSTed/PUTted Entry Document based on collection configuration. =item * Cache controll and versioning Cache controll and versioning are enabled just by overriding C method, which returns I and/or I header. =item * Naming resources by I header Resource URIs are determined based on I header if exists. If the I header is "Entry 1", the resource URI will be like: http://localhost:3000/mycollection/entry_1.atom The default naming rules can be changed by overriding C method. =back =head1 SUBCLASSING One or more subclasses are required in your Atompub server implementation. In the subclasses, methods with the following attributes must be defined. =head2 sub xxx :Atompub(list) Lists resources in a Feed Document. This method is expected to add Entries and other elements to a skeleton of the Feed. The following accessors can be used. =over 2 =item - $controller->collection_resource->uri URI of Collection =item - $controller->collection_resource->body Skeleton of Feed (L) =back Returns true on success, false otherwise. =head2 sub xxx :Atompub(create) Creates new resource. =over 4 =item * In Collections with Entry Resources The implementation is expected to insert the new Entry to your model, such as L. The following accessors can be used. =over 2 =item - $controller->entry_resource->uri URI of New Entry =item - $controller->entry_resource->edited I element of New Entry =item - $controller->entry_resource->body New Entry (L) =back =item * In Collections with Media Resources The implementation is expected to insert new Media Link Entry as well as new Media Resource to your model, such as L. The following accessors can be used for the Media Resource. =over 2 =item - $controller->media_resource->uri URI of New Media Resource =item - $controller->media_resource->edited I element of New Media Resource =item - $controller->media_resource->type Media type of New Media Resource =item - $controller->media_resource->body New Media Resource (a byte string) =back The following accessors can be used for Media Link Entry. =over 2 =item - $controller->media_link_entry->uri URI of New Media Link Entry =item - $controller->media_link_entry->edited I element of New Media Link Entry =item - $controller->media_link_entry->body New Media Link Entry (L) =back =back Returns true on success, false otherwise. =head2 sub xxx :Atompub(read) Searchs the requested resource. =over 4 =item * In Collections with Entry Resources The implementation is expected to search the Entry, which must be stored in C accessor described below. The following accessors can be used. =over 2 =item - $controller->entry_resource->body Entry (L) =back =item * In Collections with Media Resources The implementation is expected to search Media Resource or Media Link Entry, which must be stored in C accessor described below. The following accessors can be used for the Media Resource. =over 2 =item - $controller->media_resource->type Media type of Media Resource =item - $controller->media_resource->body Media Resource (a byte string) =back The following accessors can be used for the Media Link Entry. =over 2 =item - $controller->media_link_entry->body Media Link Entry (L) =back =back Returns true on success, false otherwise. =head2 sub xxx :Atompub(update) Updates the requested resource. =over 4 =item * In Collections with Entry Resources The implementation is expected to update the Entry. The following accessors can be used. =over 2 =item - $controller->entry_resource->uri URI of Entry =item - $controller->entry_resource->edited I element of Entry =item - $controller->entry_resource->body Entry (L) =back =item * In Collections with Media Resources The implementation is expected to update the Media Resource or the Media Link Entry. The following accessors can be used for the Media Resource. =over 2 =item - $controller->media_resource->uri URI of Media Resource =item - $controller->media_resource->edited I element of Media Resource =item - $controller->media_resource->type Media type of Media Resource =item - $controller->media_resource->body Media Resource (a byte string) =back The following accessors can be used for the Media Link Entry. =over 2 =item - $controller->media_link_entry->uri URI of Media Link Entry =item - $controller->media_link_entry->edited I element of Media Link Entry =item - $controller->media_link_entry->body Media Link Entry (L) =back =back Returns true on success, false otherwise. =head2 sub xxx :Atompub(delete) Deletes the requested resource. The implementation is expected to delete the resource. If the collection contains Media Resources, corresponding Media Link Entry must be deleted at once. Returns true on success, false otherwise. =head1 METHODS The following methods can be overridden to change the default behaviors. =head2 $controller->find_version($uri) By overriding C method, cache control and versioning are enabled. The implementation is expected to return I and/or I value of the requested URI: package MyAtom::Controller::MyCollection; sub find_version { my($self, $c, $uri) = @_; # Retrieve ETag and/or Last-Modified of $uri return (etag => $etag, last_modified => $last_modified); } When a resource of the URI does not exist, the implementation must return an empty array. The behavior of Atompub server will be changed in the following manner: =over 4 =item * On GET request Status code of 304 (Not Modified) will be returned, if the requested resource has not been changed. =item * On PUT request Status code of 412 (Precondition Failed) will be returned, if the current version of the resource that a client is modifying is not the same as the version that the client is basing its modifications on. =back =head2 $controller->make_edit_uri($c, [@args]) By default, if the I header is "Entry 1", the resource URI will be like: http://localhost:3000/mycollection/entry_1.atom This default behavior can be changed by overriding C method: package MyAtom::Controller::MyCollection; sub make_edit_uri { my($self, $c, @args) = @_; my @uris = $self->SUPER::make_edit_uri($c, @args); # Modify @uris as you like return @uris; } Arguments @args are media types of POSTed resources. This method returns an array of resource URIs; the first element is a URI of the Entry Resource (including Media Link Entry), and the second one is a URI of the Media Resource if exists. =head2 $controller->default($c) =head2 $controller->edit_uri($c) The collection URI can be changed, by overriding C and C methods and modify the attributes. In the following example, the collection URI is changed like /mycollection/ by overriding C and C methods. The new parameter can be obtained by $c->req->captures->[0] . package MyAtom::Controller::MyCollection; sub default :LocalRegex('^(\w+)$') { my ($self, $c) = @_; $self->NEXT::default($c); } sub edit_uri :LocalRegex('^(\w+)/(\w+)$') { my ($self, $c) = @_; $self->NEXT::edit_uri($c); } =head2 $controller->do_list =head2 $controller->do_create =head2 $controller->do_read =head2 $controller->do_update =head2 $controller->do_delete =head1 ACCESSORS =head2 $controller->resource =head2 $controller->rc An accessor for a resource object except Media Link Entry. =head2 $controller->collection_resource An accessor for a Collection Resource object. =head2 $controller->entry_resource An accessor for an Entry Resource objecgt. =head2 $controller->media_resource An accessor for a Media Resource object. =head2 $controller->media_link_entry An accessor for a Media Link Entry object. =head2 $controller->edited An accessor for a app:edited, which is applied for the POSTed/PUTted Entry Resource. =head1 INTERNAL INTERFACES =head2 $controller->auto =head2 $controller->_list =head2 $controller->_create =head2 $controller->_read =head2 $controller->_update =head2 $controller->_delete =head2 $controller->_is_modified =head2 $controller->create_action =head1 FEED PAGING This module does not provide paging of Feed Documents. Paging mechanism should be implemented in a method with "Atompub(list)" attribute. =head1 CONFIGURATION By default (no configuration), Collections accept Entry Documents (application/atom+xml) and any I element. Acceptable I elements can be set like: Controller::EntryCollection: collection: title: Diary categories: - fixed: yes scheme: http://example.com/cats/big3 category: - term: animal label: animal - term: vegetable label: vegetable - term: mineral scheme: http://example.com/dogs/big3 label: mineral Acceptable media types is configured like: Controller::MediaCollection: collection: title: Photo accept: - image/png - image/jpeg - image/gif =head1 ERROR HANDLING See ERROR HANDLING in L. =head1 SAMPLES See SAMPLES in L. =head1 SEE ALSO L L L L =head1 AUTHOR Takeru INOUE C<< >> =head1 LICENCE AND COPYRIGHT Copyright (c) 2007, Takeru INOUE C<< >>. All rights reserved. This module is free software; you can redistribute it and/or modify it under the same terms as Perl itself. See L. =head1 DISCLAIMER OF WARRANTY BECAUSE THIS SOFTWARE IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY FOR THE SOFTWARE, TO THE EXTENT PERMITTED BY APPLICABLE LAW. EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES PROVIDE THE SOFTWARE "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE SOFTWARE IS WITH YOU. SHOULD THE SOFTWARE PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING, REPAIR, OR CORRECTION. IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR REDISTRIBUTE THE SOFTWARE AS PERMITTED BY THE ABOVE LICENCE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OR INABILITY TO USE THE SOFTWARE (INCLUDING BUT NOT LIMITED TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD PARTIES OR A FAILURE OF THE SOFTWARE TO OPERATE WITH ANY OTHER SOFTWARE), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.