Node.js MongoDB Driver API

Class: GridFSBucketWriteStream

GridFSBucketWriteStream

new GridFSBucketWriteStream(bucket, filename, options){GridFSBucketWriteStream}

lib/gridfs-stream/upload.js, line 29

A writable stream that enables you to write buffers to GridFS.

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

Name Type Default Description
bucket GridFSBucket

Handle for this stream's corresponding bucket
filename string

The value of the 'filename' key in the files doc
options object null optional

Optional settings.

Name Type Default Description
id string | number | object null optional

Custom file id for the GridFS file.
chunkSizeBytes number null optional

The chunk size to use, in bytes
w number null optional

The write concern
wtimeout number null optional

The write concern timeout
j number null optional

The journal write concern
Fires:
Returns:
GridFSBucketWriteStream instance.

Methods

abort(callback){Promise}

lib/gridfs-stream/upload.js, line 108

Places this write stream into an aborted state (all future writes fail)
and deletes all chunks that have already been written.

Name Type Description
callback GridFSBucket~errorCallback

called when chunks are successfully removed or error occurred
Returns:
no callback specified
Example
// Aborting an upload

var MongoClient = require('mongodb').MongoClient,
  test = require('assert');
MongoClient.connect('mongodb://localhost:27017/test', function(err, db) {
  var bucket = new GridFSBucket(db,
    { bucketName: 'gridfsabort', chunkSizeBytes: 1 });
  var CHUNKS_COLL = 'gridfsabort.chunks';
  var FILES_COLL = 'gridfsabort.files';
  var uploadStream = bucket.openUploadStream('test.dat');

  var id = uploadStream.id;
  var query = { files_id: id };
  uploadStream.write('a', 'utf8', function(error) {
    test.equal(error, null);
    db.collection(CHUNKS_COLL).count(query, function(error, c) {
      test.equal(error, null);
      test.equal(c, 1);
      uploadStream.abort(function(error) {
        test.equal(error, null);
        db.collection(CHUNKS_COLL).count(query, function(error, c) {
          test.equal(error, null);
          test.equal(c, 0);
          uploadStream.write('b', 'utf8', function(error) {
            test.equal(error.toString(),
              'Error: this stream has been aborted');
            uploadStream.end('c', 'utf8', function(error) {
              test.equal(error.toString(),
                'Error: this stream has been aborted');
              // Fail if user tries to abort an aborted stream
              uploadStream.abort().then(null, function(error) {
                test.equal(error.toString(),
                  'Error: Cannot call abort() on a stream twice');
              });
            });
          });
        });
      });
    });
  });
});

end(chunk, encoding, callback)

lib/gridfs-stream/upload.js, line 140

Tells the stream that no more data will be coming in. The stream will
persist the remaining data to MongoDB, write the files document, and
then emit a 'finish' event.

Name Type Description
chunk Buffer

Buffer to write
encoding String

Optional encoding for the buffer
callback function

Function to call when all files and chunks have been persisted to MongoDB

write(chunk, encoding, callback){Boolean}

lib/gridfs-stream/upload.js, line 92

Write a buffer to the stream.

Name Type Description
chunk Buffer

Buffer to write
encoding String

Optional encoding for the buffer
callback function

Function to call when the chunk was added to the buffer, or if the entire chunk was persisted to MongoDB if this chunk caused a flush.
Returns:
if this write required flushing a chunk to MongoDB. True otherwise.

Events

error

lib/gridfs-stream/upload.js, line 67

An error occurred

Type:
  • Error

finish

lib/gridfs-stream/upload.js, line 74

end() was called and the write stream successfully wrote the file
metadata and all the chunks to MongoDB.

Type:
  • object