102 lines
3.1 KiB
Ruby
102 lines
3.1 KiB
Ruby
# --
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# Copyright (C) 2008-2010 10gen Inc.
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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# ++
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module Mongo
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# A file store built on the GridFS specification featuring
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# an API and behavior similar to that of a traditional file system.
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class GridFileSystem < Grid
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# Initialize a new Grid instance, consisting of a MongoDB database
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# and a filesystem prefix if not using the default.
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#
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# @param [Mongo::DB] db a MongoDB database.
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# @param [String] fs_name A name for the file system. The default name, based on
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# the specification, is 'fs'.
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def initialize(db, fs_name=Grid::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
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@files = @db["#{fs_name}.files"]
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@chunks = @db["#{fs_name}.chunks"]
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@fs_name = fs_name
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@files.create_index([['filename', 1], ['uploadDate', -1]])
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@default_query_opts = {:sort => [['filename', 1], ['uploadDate', -1]], :limit => 1}
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end
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# Open a file for reading or writing.
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#
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# @param [String] filename the name of the file.
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# @param [String] mode either 'r' or 'w' for reading from
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# or writing to the file.
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#
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# @example
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#
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# # Store the text "Hello, world!" in the grid file system.
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# @grid = GridFileSystem.new(@db)
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# @grid.open('filename', 'w') do |f|
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# f.write "Hello, world!"
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# end
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#
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# # Output "Hello, world!"
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# @grid = GridFileSystem.new(@db)
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# @grid.open('filename', 'r') do |f|
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# puts f.read
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# end
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#
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# # Write a file on disk to the GridFileSystem
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# @file = File.open('image.jpg')
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# @grid = GridFileSystem.new(@db)
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# @grid.open('image.jpg, 'w') do |f|
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# f.write @file
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# end
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def open(filename, mode, opts={})
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opts.merge!(default_grid_io_opts(filename))
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file = GridIO.new(@files, @chunks, filename, mode, opts)
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return file unless block_given?
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result = nil
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begin
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result = yield file
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ensure
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file.close
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end
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result
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end
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# Delete the file with the given filename. Note that this will delete
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# all versions of the file.
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#
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# @param [String] filename
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#
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# @return [Boolean]
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def delete(filename)
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files = @files.find({'filename' => filename}, :fields => ['_id'])
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files.each do |file|
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@files.remove({'_id' => file['_id']})
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@chunks.remove({'files_id' => file['_id']})
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end
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end
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alias_method :unlink, :delete
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private
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def default_grid_io_opts(filename=nil)
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{:fs_name => @fs_name, :query => {'filename' => filename}, :query_opts => @default_query_opts}
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end
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end
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end
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