Node.js MongoDB Driver API

Class: GridFSBucketReadStream

GridFSBucketReadStream

new GridFSBucketReadStream(chunks, files, readPreference, filter, options)

lib/gridfs-stream/download.js, line 27

A readable stream that enables you to read buffers from GridFS.

Do not instantiate this class directly. Use openDownloadStream() instead.

Name Type Description
chunks Collection

Handle for chunks collection
files Collection

Handle for files collection
readPreference Object

The read preference to use
filter Object

The query to use to find the file document
options Object optional

Optional settings.

Name Type Description
sort Number optional

Optional sort for the file find query
skip Number optional

Optional skip for the file find query
start Number optional

Optional 0-based offset in bytes to start streaming from
end Number optional

Optional 0-based offset in bytes to stop streaming before
Fires:

Extends

Methods

abort(callback)

lib/gridfs-stream/download.js, line 142

Marks this stream as aborted (will never push another data event)
and kills the underlying cursor. Will emit the 'end' event, and then
the 'close' event once the cursor is successfully killed.

Name Type Description
callback GridFSBucket~errorCallback optional

called when the cursor is successfully closed or an error occurred.
Fires:
  • GridFSBucketWriteStream#event:close
  • GridFSBucketWriteStream#event:end

end(end){GridFSBucketReadStream}

lib/gridfs-stream/download.js, line 125

Sets the 0-based offset in bytes to start streaming from. Throws
an error if this stream has entered flowing mode
(e.g. if you've already called on('data'))

Name Type Description
end Number

Offset in bytes to stop reading at
Returns:
to self

inherited pause(){null}

lib/cursor.js, line 1116

This method will cause a stream in flowing-mode to stop emitting data events. Any data that becomes available will remain in the internal buffer.

inherited pipe(destination, options){null}

lib/cursor.js, line 1122

This method pulls all the data out of a readable stream, and writes it to the supplied destination, automatically managing the flow so that the destination is not overwhelmed by a fast readable stream.

Name Type Description
destination Writable

The destination for writing data
options object optional

Pipe options

inherited read(size){String|Buffer|null}

lib/cursor.js, line 1096

The read() method pulls some data out of the internal buffer and returns it. If there is no data available, then it will return null.

Name Type Description
size number

Optional argument to specify how much data to read.

inherited resume(){null}

lib/cursor.js, line 1110

This method will cause the readable stream to resume emitting data events.

inherited setEncoding(encoding){null}

lib/cursor.js, line 1103

Call this function to cause the stream to return strings of the specified encoding instead of Buffer objects.

Name Type Description
encoding string

The encoding to use.

start(start){GridFSBucketReadStream}

lib/gridfs-stream/download.js, line 110

Sets the 0-based offset in bytes to start streaming from. Throws
an error if this stream has entered flowing mode
(e.g. if you've already called on('data'))

Name Type Description
start Number

Offset in bytes to start reading at
Returns:
to Self

inherited unpipe(destination){null}

lib/cursor.js, line 1130

This method will remove the hooks set up for a previous pipe() call.

Name Type Description
destination Writable optional

The destination for writing data

inherited unshift(chunk){null}

lib/cursor.js, line 1137

This is useful in certain cases where a stream is being consumed by a parser, which needs to "un-consume" some data that it has optimistically pulled out of the source, so that the stream can be passed on to some other party.

Name Type Description
chunk Buffer | string

Chunk of data to unshift onto the read queue.

inherited wrap(stream){null}

lib/cursor.js, line 1144

Versions of Node prior to v0.10 had streams that did not implement the entire Streams API as it is today. (See "Compatibility" below for more information.)

Name Type Description
stream Stream

An "old style" readable stream.

Events

close

lib/gridfs-stream/download.js, line 76

Fired when the stream is exhausted and the underlying cursor is killed

Type:
  • object

data

lib/gridfs-stream/download.js, line 62

Emitted when a chunk of data is available to be consumed.

Type:
  • object

end

lib/gridfs-stream/download.js, line 69

Fired when the stream is exhausted (no more data events).

Type:
  • object

error

lib/gridfs-stream/download.js, line 47

An error occurred

Type:
  • Error

file

lib/gridfs-stream/download.js, line 54

Fires when the stream loaded the file document corresponding to the
provided id.

Type:
  • object