mongo-ruby-driver/lib/mongo/gridfs/grid.rb

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# encoding: UTF-8
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# --
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# Copyright (C) 2008-2010 10gen Inc.
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#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
# ++
module Mongo
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# Implementation of the MongoDB GridFS specification. A file store.
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class Grid
include GridExt::InstanceMethods
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DEFAULT_FS_NAME = 'fs'
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# Initialize a new Grid instance, consisting of a MongoDB database
# and a filesystem prefix if not using the default.
#
# @core gridfs
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#
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# @see GridFileSystem
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def initialize(db, fs_name=DEFAULT_FS_NAME)
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raise MongoArgumentError, "db must be a Mongo::DB." unless db.is_a?(Mongo::DB)
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@db = db
@files = @db["#{fs_name}.files"]
@chunks = @db["#{fs_name}.chunks"]
@fs_name = fs_name
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@chunks.create_index([['files_id', Mongo::ASCENDING], ['n', Mongo::ASCENDING]], :unique => true)
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end
# Store a file in the file store. This method is designed only for writing new files;
# if you need to update a given file, first delete it using #Grid#delete.
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#
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# Note that arbitary metadata attributes can be saved to the file by passing
# them in as options.
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#
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# @param [String, #read] data a string or io-like object to store.
#
# @option opts [String] :filename (nil) a name for the file.
# @option opts [Hash] :metadata ({}) any additional data to store with the file.
# @option opts [ObjectId] :_id (ObjectId) a unique id for
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# the file to be use in lieu of an automatically generated one.
# @option opts [String] :content_type ('binary/octet-stream') If no content type is specified,
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# the content type will may be inferred from the filename extension if the mime-types gem can be
# loaded. Otherwise, the content type 'binary/octet-stream' will be used.
# @option opts [Integer] (262144) :chunk_size size of file chunks in bytes.
# @option opts [Boolean] :safe (false) When safe mode is enabled, the chunks sent to the server
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# will be validated using an md5 hash. If validation fails, an exception will be raised.
#
# @return [Mongo::ObjectId] the file's id.
def put(data, opts={})
filename = opts[:filename]
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opts.merge!(default_grid_io_opts)
file = GridIO.new(@files, @chunks, filename, 'w', opts=opts)
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file.write(data)
file.close
file.files_id
end
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# Read a file from the file store.
#
# @param [] id the file's unique id.
#
# @return [Mongo::GridIO]
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def get(id)
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opts = {:query => {'_id' => id}}.merge!(default_grid_io_opts)
GridIO.new(@files, @chunks, nil, 'r', opts)
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end
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# Delete a file from the store.
#
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# Note that deleting a GridFS file can result in read errors if another process
# is attempting to read a file while it's being deleted. While the odds for this
# kind of race condition are small, it's important to be aware of.
#
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# @param [] id
#
# @return [Boolean]
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def delete(id)
@files.remove({"_id" => id})
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@chunks.remove({"files_id" => id})
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end
private
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def default_grid_io_opts
{:fs_name => @fs_name}
end
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end
end