gridfs-express

Provide an API REST which support upload/download files to/from a modgodb grid. This package enable the user to define the API on a given Express router.

A complete example of a service using this package can be found at example-gridfs-express

Installation

npm install gridfs-express

Usage

const express = require('express');
const mongodb = require('mongodb');
const bodyParser = require('body-parser');
const expressListRoutes = require('express-list-routes');
const gridfs = require('gridfs-express');
 
const app = express();
 
const url = "mongodb://localhost:27017/gridfs_test";
 
let db;
 
const routerAPI = express.Router();
 
gridfs(routerAPI, {
  getDb: () => db,
  getKeyMetadata: (req) => ({id: req.query.id}),
  getOtherMetadata: (req) => req.body,
  fsCollections: [
    'input',
    'output'
  ]
});
 
app.use(bodyParser.json());
app.use('/api/gridfs', routerAPI);
expressListRoutes({prefix: '/api/gridfs'}, 'API:', routerAPI);
 
mongodb.MongoClient.connect(url, function(err, database) {
  if(err) throw err;
 
  db = database;
  // Start the application after the database connection is ready
  app.listen(3000);
});

The function gridfs define the following API on the given router object.

route	verb	URL parameters	description
/api/gridfs	GET	fs=[string]	get all files info
/api/gridfs/:id	GET	fs=[string] key=['filename','id']	get a single file
/api/gridfs/:id/info	GET	fs=[string] key=['filename','id']	get a sigle file, include a metadata field
/api/gridfs	POST	fs=[string]	upload a new file
/api/gridfs/:id	DELETE	fs=[string] key=['filename','id']	delete a single file
/api/gridfs/:id/metadata	PATCH	fs=[string] key=['filename','id']	modify the metadata field

The parameter :id is considered either as an identifier or filename depending on the value of query parameter key which could take on of the values id or filename respectively.

Note that the path /api/gridfs depends on the user election.

Options

The second argument to the function gridfs is an object with options to configure the endpoints. It is required to provide a function member to get the mongodb connection:

{
  getDb: () => {return db}
}

Other members which are optional are:

• maxFileSize: the maximum file size allowed. The default limit is 200MB.
• fsCollections: it is an array of string which contains the allowed collection names to be used in the query parameter fs. This array is used to validate the query parameter fs.
• getKeyMetadata: it is a function which should return an object. This object will be associated to the file in the gridfs collection. The filename will be unique for that object value. This objects is stored within the metadata for the file in the gridfs. The function will receive as argument the request object req. For instance, the following function build the key object from the url query parameter id:

function getKeyMetadata(req) {
  return {id: req.query.id};
}

• getMetadata: it is a function which should return an object, this object will be stored within the metadata for the file. The function will receive as argument the request object req. The returned object should not contain the keys returned from getKeyMetadata, they will be discarded. For instance, the following function build the an extra metadata object from the query parameters tag1 and tag2:

function getOtherMetadata(req) {
  return {
    tag1: req.query.tag1,
    tag2: req.query.tag1
  };
}

Tests

npm test

Contributing

In lieu of a formal style guide, take care to maintain the existing coding style. Add unit tests for any new or changed functionality. Lint and test your code.