Class: Mongo::GridIO

Inherits:

Object

• Object
• Mongo::GridIO

show all

Includes:

WriteConcern

Defined in:

lib/mongo/gridfs/grid_io.rb

Overview

Constant Summary

DEFAULT_CHUNK_SIZE =

256 * 1024

DEFAULT_CONTENT_TYPE =

'binary/octet-stream'

PROTECTED_ATTRS =

[:files_id, :file_length, :client_md5, :server_md5]

Instance Attribute Summary (collapse)

• - (Object) chunk_size readonly

  Returns the value of attribute chunk_size.

• - (Object) client_md5 readonly

  Returns the value of attribute client_md5.

• - (Object) content_type readonly

  Returns the value of attribute content_type.

• - (Object) file_length readonly

  Returns the value of attribute file_length.

• - (Object) file_position readonly

  Returns the value of attribute file_position.

• - (Object) filename readonly

  Returns the value of attribute filename.

• - (Object) files_id readonly

  Returns the value of attribute files_id.

• - (Object) metadata readonly

  Returns the value of attribute metadata.

• - (Object) server_md5 readonly

  Returns the value of attribute server_md5.

• - (Object) upload_date readonly

  Returns the value of attribute upload_date.

Attributes included from WriteConcern

#legacy_write_concern

Instance Method Summary (collapse)

• - (Object) [](key)
• - (Object) []=(key, value)
• - (BSON::ObjectId) close

  Creates or updates the document from the files collection that stores the chunks' metadata.

• - (Mongo::GridIO) each { ... }

  Read a chunk of the data from the file and yield it to the given block.

• - (Boolean) eof (also: #eof?)

  Return a boolean indicating whether the position pointer is at the end of the file.

• - (String) getc

  Return the next byte from the GridFS file.

• - (String) gets(separator = "\n", length = nil)

  Return the next line from a GridFS file.

• - (GridIO) initialize(files, chunks, filename, mode, opts = {}) constructor

  Create a new GridIO object.

• - (Object) inspect
• - (String) read(length = nil) (also: #data)

  Read the data from the file.

• - (Integer) rewind

  Rewind the file.

• - (Integer) seek(pos, whence = IO::SEEK_SET)

  Position the file pointer at the provided location.

• - (Integer) tell (also: #pos)

  The current position of the file.

• - (Integer) write(io)

  Write the given string (binary) data to the file.

Methods included from WriteConcern

#get_write_concern, gle?, #write_concern_from_legacy

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# File 'lib/mongo/gridfs/grid_io.rb', line 40

def initialize(files, chunks, filename, mode, opts={})
  @files          = files
  @chunks         = chunks
  @filename       = filename
  @mode           = mode
  opts            = opts.dup
  @query          = opts.delete(:query) || {}
  @query_opts     = opts.delete(:query_opts) || {}
  @fs_name        = opts.delete(:fs_name) || Grid::DEFAULT_FS_NAME
  @write_concern  = get_write_concern(opts)
  @local_md5      = Digest::MD5.new if Mongo::WriteConcern.gle?(@write_concern)
  @custom_attrs   = {}

  case @mode
    when 'r' then init_read
    when 'w' then init_write(opts)
    else
      raise GridError, "Invalid file mode #{@mode}. Mode should be 'r' or 'w'."
  end
end

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# File 'lib/mongo/gridfs/grid_io.rb', line 14

def chunk_size
  @chunk_size
end

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# File 'lib/mongo/gridfs/grid_io.rb', line 14

def client_md5
  @client_md5
end

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# File 'lib/mongo/gridfs/grid_io.rb', line 14

def content_type
  @content_type
end

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# File 'lib/mongo/gridfs/grid_io.rb', line 14

def file_length
  @file_length
end

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# File 'lib/mongo/gridfs/grid_io.rb', line 14

def file_position
  @file_position
end

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# File 'lib/mongo/gridfs/grid_io.rb', line 14

def filename
  @filename
end

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# File 'lib/mongo/gridfs/grid_io.rb', line 14

def files_id
  @files_id
end

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# File 'lib/mongo/gridfs/grid_io.rb', line 14

def metadata
  @metadata
end

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# File 'lib/mongo/gridfs/grid_io.rb', line 14

def server_md5
  @server_md5
end

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# File 'lib/mongo/gridfs/grid_io.rb', line 14

def upload_date
  @upload_date
end

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# File 'lib/mongo/gridfs/grid_io.rb', line 61

def [](key)
  @custom_attrs[key] || instance_variable_get("@#{key.to_s}")
end

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# File 'lib/mongo/gridfs/grid_io.rb', line 65

def []=(key, value)
  if PROTECTED_ATTRS.include?(key.to_sym)
    warn "Attempting to overwrite protected value."
    return nil
  else
    @custom_attrs[key] = value
  end
end

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# File 'lib/mongo/gridfs/grid_io.rb', line 219

def close
  if @mode[0] == ?w
    if @current_chunk['n'].zero? && @chunk_position.zero?
      warn "Warning: Storing a file with zero length."
    end
    @upload_date = Time.now.utc
    id = @files.insert(to_mongo_object)
  end
  id
end

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# File 'lib/mongo/gridfs/grid_io.rb', line 239

def each
  return read_all unless block_given?
  while chunk = read(chunk_size) 
    yield chunk
    break if chunk.empty?
  end
  self
end

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# File 'lib/mongo/gridfs/grid_io.rb', line 173

def eof
  raise GridError, "file not opened for read #{@mode}" unless @mode[0] == ?r
  @file_position >= @file_length
end

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# File 'lib/mongo/gridfs/grid_io.rb', line 207

def getc
  read_length(1)
end

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# File 'lib/mongo/gridfs/grid_io.rb', line 192

def gets(separator="\n", length=nil)
  if separator.nil?
    read_all
  elsif separator.is_a?(Integer)
    read_length(separator)
  elsif separator.length > 1
    read_to_string(separator, length)
  else
    read_to_character(separator, length)
  end
end

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# File 'lib/mongo/gridfs/grid_io.rb', line 248

def inspect
  "#<GridIO _id: #{@files_id}>"
end

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# File 'lib/mongo/gridfs/grid_io.rb', line 81

def read(length=nil)
  return '' if @file_length.zero?
  if length == 0
    return ''
  elsif length.nil? && @file_position.zero?
    read_all
  else
    read_length(length)
  end
end

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# File 'lib/mongo/gridfs/grid_io.rb', line 164

def rewind
  raise GridError, "file not opened for read" unless @mode[0] == ?r
  seek(0)
end

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# File 'lib/mongo/gridfs/grid_io.rb', line 132

def seek(pos, whence=IO::SEEK_SET)
  raise GridError, "Seek is only allowed in read mode." unless @mode == 'r'
  target_pos = case whence
               when IO::SEEK_CUR
                 @file_position + pos
               when IO::SEEK_END
                 @file_length + pos
               when IO::SEEK_SET
                 pos
               end

  new_chunk_number = (target_pos / @chunk_size).to_i
  if new_chunk_number != @current_chunk['n']
    save_chunk(@current_chunk) if @mode[0] == ?w
    @current_chunk = get_chunk(new_chunk_number)
  end
  @file_position  = target_pos
  @chunk_position = @file_position % @chunk_size
  @file_position
end

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# File 'lib/mongo/gridfs/grid_io.rb', line 156

def tell
  @file_position
end

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# File 'lib/mongo/gridfs/grid_io.rb', line 100

def write(io)
  raise GridError, "file not opened for write" unless @mode[0] == ?w
  if io.is_a? String
    if Mongo::WriteConcern.gle?(@write_concern)
      @local_md5.update(io)
    end
    write_string(io)
  else
    length = 0
    if Mongo::WriteConcern.gle?(@write_concern)
      while(string = io.read(@chunk_size))
        @local_md5.update(string)
        length += write_string(string)
      end
    else
      while(string = io.read(@chunk_size))
        length += write_string(string)
      end
    end
    length
  end
end