MongoDB数据库GridFS Wrapper
简单写了一个Perl版本的GriFS的wrapper：
package CZone::GridFS;
use strict;
use MongoDB::GridFS;
use Path::Class;
use Digest::file qw(digest_file_hex);
use Digest::MD5 qw(md5_hex);
use IO::File;
use Data::Dumper;
use Any::Moose;
has database => (
isa => ‘MongoDB::Database’,
is => ‘ro’,
required => 1
);
has _gridfs => (
isa => ‘MongoDB::GridFS’,
is => ‘ro’,
lazy => 1,
builder => ‘_build__gridfs’,
);
has _file_collection => (
isa => ‘MongoDB::Collection’,
is => ‘ro’,
lazy => 1,
builder => ‘_build__file_collection’
);
sub _build__gridfs {
my $self = shift;
return $self->database->get_gridfs;
}
sub _build__file_collection {
my $self = shift;
return $self->database->get_collection(‘fs.files’);
}
sub get_bytes {
my ($self, $id ) = @_;
my $file = $self->_gridfs->find_one({_id => $id });
my $bytes;
my $fh = new IO::File $bytes,’>';
$file->print($fh);
return $bytes;
}
sub store_file {
my ($self, $file_path) = @_;
my $file = file($file_path)->absolute;
return undef unless -e $file;
my $md5 = digest_file_hex($file,’MD5′);
my $fh = $file->open(‘r’) or return undef;
return $self->_store_fh($fh,$md5);
}
sub _store_fh {
my ($self,$fh,$md5) = @_;
# $grid_file isa MongoDB::GridFS::File
my $grid_file = $self->_gridfs->find_one({ ‘md5′ =>
$md5});
if ($grid_file) {
$self->_inc_refs($grid_file->info->{_id});
return $grid_file->info->{_id};
}
else {
my $oid = $self->_gridfs->insert($fh,{
refs => 1,
md5 => $md5,
});
return $oid;
}
}
sub store_bytes {
my ($self, $bytes) = @_;
my $md5 = md5_hex($bytes);
my $fh = new IO::File $bytes,’ # my $fh = FileHandle->new;
# $fh->open($bytes,’ return $self->_store_fh($fh,$md5);
}
sub unlink {
my ($self, $id ) = @_;
$self->_dec_refs(MongoDB::OID->new(value =>”$id”));
}
sub _inc_refs {
my ($self,$id) = @_;
$self->_file_collection->update({_id => $id },{ ‘$inc’
=> { refs => 1}});
}
sub _dec_refs {
my ($self,$id) = @_;
$self->_file_collection->update({_id => $id },{ ‘$inc’
=> { refs => -1}});
}
sub gc {
my $self = shift;
$self->_gridfs->remove({refs => 0});
}
no Any::Moose;
__PACKAGE__->meta->make_immutable;
1;
__END__
这是从czone项目中的PHP代码移植过来的。
方便将gridfs中的文件读写到scalar中。同时，通过检查存储文件的md5值，并记录相同文件的引用计数，相同文件只存储一个copy，节省空间。（BSON格式对于空间的需求是非常大的）
