using gridfs-stream write string to gridfs

This page comes up first when searching for how to store a string data in Mongo GridFS using NodeJS. Since most of the answers here and elsewhere are based on deprecated API, I decided to post a code based on a more recent GridFSBucket. The code has an additional provision to overwrite existing files. If you don't need that - you can replace openUploadStreamWithId with openUploadStream which creates duplicates.

var mongo = require('mongodb');var stream = require('stream');var MongoClient = mongo.MongoClient;function getFileSystemItem(dbo, filename) {  var buf = new Buffer('');  return new Promise(function(resolve, reject) {    var bucket = new mongo.GridFSBucket(dbo);    var readstream = bucket.openDownloadStream(filename);    readstream.on('data', (chunk) => {      buf = Buffer.concat([buf, chunk]);    });    readstream.on('error', (err) => {        reject(err);    });    readstream.on('end', () => {        var res = buf.toString();        buf = null; // Clean up memory        readstream.destroy();        resolve(res);    });  });}function putFileSystemItem(dbo, filename, data) {  var putItemHelper = function(bucket, resolve, reject) {    var writeStream = bucket.openUploadStreamWithId(filename, filename);    var s = new stream.Readable();    s.push(data);    s.push(null); // Push null to end stream    s.pipe(writeStream);    writeStream.on('finish', resolve);    writeStream.on('error', reject);  };  return new Promise(function(resolve, reject) {    var bucket = new mongo.GridFSBucket(dbo);    bucket.find({_id: filename}).count(function(err, count) {      if (err) return reject(err);      if (count > 0) {          bucket.delete(filename, function() {          putItemHelper(bucket, resolve, reject);        }, reject)      } else {        putItemHelper(bucket, resolve, reject);      }    }, reject);  });}function test() {  var MongoUrl = 'mongodb://localhost:27017';  var dbName = 'test';  MongoClient.connect(MongoUrl, function(err, db) {    if (err) throw err;    var dbo = db.db(DbName);    putFileSystemItem(dbo, 'test', 'this is a test')    .then(function(a) {      console.log('Wrote a gridFS file with metadata:', a);      return getFileSystemItem(dbo, 'test')    })    .then(function(a) {      console.log('Got data back from a gridFS file:', a);      db.close();    })    .catch(function(e) {      console.log(e);      db.close();    })  });}test();

Credit: This is assembled from a dozen of other StackOverflow pages and MongoDB API help.

Even though it's been a while. I had this problem and solved it creating a stream from the string instead of a file.Like this:

  var writestream = gfs.createWriteStream({      filename: fileName  });  // Create stream with buffer to pipe to writestream  var s = new stream.Readable();  s.push(pic);  s.push(null); // Push null to end stream  s.pipe(writestream);  writestream.on('close', function (file) {    // Do anything with the file    cb(null, file.filename);  }).on('error', cb);

Got the stream idea from here

I was faced with the same problem. I just simply deleted the file using gfs.remove and then added the updated file to GridFS.

Also FYI. I used async.series to finish the delete operation first and then write the updated file to GridFS.

Hope this helps!