MongoDB GridFSBucket upload stream doesn't return length of base64 image stream - mongodb

Question

I'm refactoring my team code to remove Deprecation Warnings from MongoDB.
I removed gridfs-stream library and I'm using GridFSBucket instead
But there is a problem: upload stream using GridFSBucket doesn't return the length of base64 image, instead it returns 0. This breaks one of the tests in our code.
This is the code using GridFSBucket:
function getGrid() {
return new mongoose.mongo.GridFSBucket(conn.db);
}
module.exports.store = function(id, contentType, metadata, stream, options, callback) {
... // unrelated things
var strMongoId = mongoId.toHexString(); // http://stackoverflow.com/a/27176168
var opts = {
contentType: contentType,
metadata: metadata
};
options = options || {};
if (options.filename) {
opts.filename = options.filename;
}
if (options.chunk_size) {
var size = parseInt(options.chunk_size, 10);
if (!isNaN(size) && size > 0 && size < 255) {
opts.chunkSizeBytes = chunk_size * size;
}
}
var gfs = getGrid();
var writeStream = gfs.openUploadStreamWithId(strMongoId, opts.filename, opts);
writeStream.on('finish', function(file) {
console.log(file) // <== Notice the log for this line below
return callback(null, file);
});
writeStream.on('error', function(err) {
return callback(err);
});
stream.pipe(writeStream);
};
The result for console.log(file) is:
{
"_id": "5ea7a3ffbc7dd36e7df4561e",
"length": 0, // <== Notice length is 0 here
"chunkSize": 10240,
"uploadDate": "2020-04-28T03:33:19.734Z",
"filename": "default_profile.png",
"md5": "d41d8cd98f00b204e9800998ecf8427e",
"contentType": "image/png",
"metadata": {
"name": "default_profile.png",
"creator": {
"objectType": "user",
"id": "5ea7a3febc7dd36e7df4560a"
}
}
}
This is the old code using gridfs-stream:
var Grid = require('gridfs-stream');
...
function getGrid() {
return new Grid(mongoose.connection.db, mongoose.mongo);
}
module.exports.store = function(id, contentType, metadata, stream, options, callback) {
... // unrelated things
var strMongoId = mongoId.toHexString(); // http://stackoverflow.com/a/27176168
var opts = {
_id: strMongoId,
mode: 'w',
content_type: contentType
};
options = options || {};
if (options.filename) {
opts.filename = options.filename;
}
if (options.chunk_size) {
var size = parseInt(options.chunk_size, 10);
if (!isNaN(size) && size > 0 && size < 255) {
opts.chunk_size = chunk_size * size;
}
}
opts.metadata = metadata;
var gfs = getGrid();
var writeStream = gfs.createWriteStream(opts);
writeStream.on('close', function(file) {
console.log(file) // <== Notice the log for this line below
return callback(null, file);
});
writeStream.on('error', function(err) {
return callback(err);
});
stream.pipe(writeStream);
};
And here is the result of console.log(file):
{
"_id": "5ea7a43a5d6eea73e0a3c8b1",
"filename": "default_profile.png",
"contentType": "image/png",
"length": 634, // <== We have the length here
"chunkSize": 10240,
"uploadDate": "2020-04-28T03:34:18.069Z",
"metadata": {
"name": "default_profile.png",
"creator": {
"objectType": "user",
"id": "5ea7a4395d6eea73e0a3c89d"
}
},
"md5": "c37659eb6a9e741656a8d0348765c668"
}
So how can I get the length using GridFSBucket?
Thank you!
UPDATE:
This is the log of variable stream in both cases:
{
"contentType": "image/png",
"fileName": "default_profile.png",
"transferEncoding": "base64",
"contentDisposition": "attachment",
"generatedFileName": "default_profile.png",
"contentId": "216d9aab57544410901f8ba7981e63aa#mailparser",
"stream": {
"_events": {},
"_eventsCount": 0,
"writable": true,
"checksum": {
"_handle": {},
"writable": true,
"readable": true
},
"length": 0,
"current": ""
}
}