andris9/grid-fs

Convenience wrappers around Mongodb GridFS

grid-fs

Convenience wrappers around MongoDB GridFS methods.

v1.0.0+ requires at least Node.js v6

Installation

npm install grid-fs --save

Usage

Require GridFs constructor and create a gridFs instance

const GridFs = require('grid-fs');
const gridFs = new GridFs(db[, collectionName]);

Where

• db is a opened database instance
• collectionName (optional, defaults to 'fs') is the collection name for the stored files

Example

const MongoClient = require('mongodb').MongoClient;
const GridFs = require('grid-fs');
MongoClient.connect('mongodb://127.0.0.1:27017/db', function(err, db) {
    let gridFs = new GridFs(db);
});

List file data

gridFs.listFile(filename, callback)

Where

• filename is the name of the file to list
• callback is the function to run with arguments (err, info). Info object contains the following properties
  • filename
  • contentType
  • uploadDate – Date object
  • length – length in bytes
  • metadata – metadata object used when creating the write stream
  • internalMd5 – MD5 hash of the contents

Example

gridFs.listFile('test.txt', (err, info) => {
    if(err){
        console.log('Error or file not found');
    }else{
        console.log('File uploaded: %s', info.uploadDate);
    }
});

List all files

List all files in the collection

gridFs.list(callback)

Where

• callback is the function to run when file list is fetched, uses arguments (err, list) where list is an array of file names

Example

gridFs.list((err, list) => {
    if(err){
        console.log(err);
    }else{
        list.forEach(filename => {
            console.log(filename);
        });
    }
});

Write files to GridFs

Create Writable stream

let stream = gridFs.createWriteStream(filename[, options]);

Where

• filename is the name of file to write to (overwrites existing file if present)
• options is the optional options object (metadata object property is probably most important)

Listen for the 'close' event to find out when the file has been stored to the GridFs

Example

let stream = gridFs.createWriteStream('test.txt', {
    metadata: {
        author: 'Andris'
    }
});
stream.end('text.txt');
stream.on('close', () => {
    console.log('File stored and closed');
});

Read files from GridFs

Create Readable stream

let stream = gridFs.createReadStream(filename);

Where

• filename is the name of the file to read from

Example

let stream = gridFs.createReadStream('test.txt');
stream.pipe(process.stdout);

Delete files from GridFs

Unlink a file with

gridFs.unlink(filename, callback);

Where

• filename is the name of the file to unlink
• callback is the function to run once the file is deleted

Example

gridFs.unlink('test.txt', err => {
    if(err){
        console.log('Unlink failed');
    }
});

License

MIT