MongoDB::GridFS(3) User Contributed Perl Documentation MongoDB::GridFS(3)NAMEMongoDB::GridFS - A file storage utility
SYNOPSIS
use MongoDB::GridFS;
my $grid = $database->get_gridfs;
my $fh = IO::File->new("myfile", "r");
$grid->insert($fh, {"filename" => "mydbfile"});
There are two interfaces for GridFS: a file-system/collection-like
interface (insert, remove, drop, find_one) and a more general interface
(get, put, delete). Their functionality is the almost identical (get,
put and delete are always safe ops, insert, remove, and find_one are
optionally safe), using one over the other is a matter of preference.
SEE ALSO
Core documentation on GridFS: <http://dochub.mongodb.org/core/gridfs>.
ATTRIBUTES
chunk_size
The number of bytes per chunk. Defaults to 1048576.
prefix
The prefix used for the collections. Defaults to "fs".
files
Collection in which file metadata is stored. Each document contains
md5 and length fields, plus user-defined metadata (and an _id).
chunks
Actual content of the files stored. Each chunk contains up to 4Mb of
data, as well as a number (its order within the file) and a files_id
(the _id of the file in the files collection it belongs to).
METHODS
get($id)
my $file = $grid->get("my file");
Get a file from GridFS based on its _id. Returns a
MongoDB::GridFS::File.
put($fh, $metadata)
my $id = $grid->put($fh, {filename => "pic.jpg"});
Inserts a file into GridFS, adding a MongoDB::OID as the _id field if
the field is not already defined. This is a wrapper for
"MongoDB::GridFS::insert", see that method below for more information.
Returns the _id field.
delete($id)
$grid->delete($id)
Removes the file with the given _id. Will die if the remove is
unsuccessful. Does not return anything on success.
find_one ($criteria?, $fields?)
my $file = $grid->find_one({"filename" => "foo.txt"});
Returns a matching MongoDB::GridFS::File or undef.
remove ($criteria?, $options?)
$grid->remove({"filename" => "foo.txt"});
Cleanly removes files from the database. $options is a hash of options
for the remove. Possible options are:
just_one If true, only one file matching the criteria will be removed.
safe If true, each remove will be checked for success and die on
failure.
This method doesn't return anything.
insert ($fh, $metadata?, $options?)
my $id = $gridfs->insert($fh, {"content-type" => "text/html"});
Reads from a file handle into the database. Saves the file with the
given metadata. The file handle must be readable. $options can be
"{"safe" =" true}>, which will do safe inserts and check the MD5 hash
calculated by the database against an MD5 hash calculated by the local
filesystem. If the two hashes do not match, then the chunks already
inserted will be removed and the program will die.
Because "MongoDB::GridFS::insert" takes a file handle, it can be used
to insert very long strings into the database (as well as files). $fh
must be a FileHandle (not just the native file handle type), so you can
insert a string with:
# open the string like a file
my $basic_fh;
open($basic_fh, '<', \$very_long_string);
# turn the file handle into a FileHandle
my $fh = FileHandle->new;
$fh->fdopen($basic_fh, 'r');
$gridfs->insert($fh);
drop
@files = $grid->drop;
Removes all files' metadata and contents.
all
@files = $grid->all;
Returns a list of the files in the database.
AUTHOR
Kristina Chodorow <kristina@mongodb.org>
perl v5.14.2 2011-09-07 MongoDB::GridFS(3)
