I am using mongoskin in my nodejs based application. I have used GridFS to uplaod the file. I am able to upload and read it back using the "filename" however I want to read it back using _id. How can i do? Following are code details.
Working code to read the file based on filename:
exports.previewFile = function (req, res) {
var contentId = req.params.contentid;
var gs = DBModule.db.gridStore('69316_103528209714703_155822_n.jpg', 'r');
gs.read(function (err, data) {
if (!err) {
res.setHeader('Content-Type', gs.contentType);
res.end(data);
} else {
log.error({err: err}, 'Failed to read the content for id '+contentId);
res.status(constants.HTTP_CODE_INTERNAL_SERVER_ERROR);
res.json({error: err});
}
});
};
How this code can be modified to make it work based on id?
After few hit & trial following code works. This is surprise bcz input parameter seems searching on all the fields.
//view file from database
exports.previewContent = function (req, res) {
var contentId = new DBModule.BSON.ObjectID(req.params.contentid);
console.log('Calling previewFile inside FileUploadService for content id ' + contentId);
var gs = DBModule.db.gridStore(contentId, 'r');
gs.read(function (err, data) {
if (!err) {
//res.setHeader('Content-Type', metadata.contentType);
res.end(data);
} else {
log.error({err: err}, 'Failed to read the content for id ' + contentId);
res.status(constants.HTTP_CODE_INTERNAL_SERVER_ERROR);
res.json({error: err});
}
});
};
Related
I am new to MongoDB . I have written code in which I am searching the data from the database ,
it works fine for the first search and gives the result but after the result is achieved then if I again perform some query then it do not works that is it keeps on rendering the page in which query is being made .
Below is the code snippet .
app.get('/problems/:a?',(req,res)=>{
var getpath = req.params.a;
problemModel.find({path:getpath},function(err,data){
if(err) throw err;
res.render(''+getpath,{record:data[0]});
conn.close();
});
});
Please help me out .
Here's your solution. Using async/await operators, instead of callbacks, the code is cleaner.
app.get('/problems/:path', async (req, res) => {
const { path } = req.params; // Equal to "const path = req.params.path"
try {
const data = await problemModel.find({ path: path });
res.render(path, { record: data[0] });
} catch (e) {
res.render('path-to-error-page');
}
});
Forgive me I'm still learning. I'm trying to download some mp3 files that I have stored in a table. I can download files directly from the file system like this:
if (fs.existsSync(filename)) {
res.setHeader('Content-disposition', 'attachment; filename=' + filename);
res.setHeader('Content-Type', 'application/audio/mpeg3');
var rstream = fs.createReadStream(filename);
rstream.pipe(res);
I have stored the data in the table using pg-promise example in the docs like so:
const rs = fs.createReadStream(filename);
function receiver(_, data) {
function source(index) {
if (index < data.length) {
return data[index];
}
}
function dest(index, data) {
return this.none('INSERT INTO test_bin (utterance) VALUES($1)', data);
}
return this.sequence(source, {dest});
} // end receiver func
rep.tx(t => {
return streamRead.call(t, rs, receiver);
})
.then(data => {
console.log('DATA:', data);
})
.catch(error => {
console.log('ERROR: ', error);
});
But now I want to take that data out of the table and download it to the client. The example in the docs of taking data out of binary converts it to JSON and then prints it to the console like this:
db.stream(qs, s => {
s.pipe(JSONStream.stringify()).pipe(process.stdout)
})
and that works. So the data is coming out of the database ok. But I can't seem to send it to the client. It seems that the data is already a stream so I have tried:
db.stream(qs, s => {
s.pipe(res);
});
But I get a typeerror: First argument must be a string or Buffer
Alternatively, I could take that stream and write it to the file system, and then serve it as in the top step above, but that seems like a workaround. I wish there was an example of how to save to a file in the docs.
What step am I missing?
I'm trying to send emails using sendgrid mail API.
Everything works fine. However, I want my emails to have a specific name.
Not the prefix of the sender's address, which is coming up by default.
I changed the From value to "MY_email_name <sender#example.com>". But it didn't work.
I have set the From_Name field to "MY_email_name". That too didn't work.
However, it's working when I not read the html content from an external file and instead give some inline. In that case it is sending me the email_name.
Any idea about how I can do this with reading the content.
Thanks.
var sendgrid = require('sendgrid')('MY_APP_SECRET');
var fs = require('fs');
var content;
// First I want to read the file
fs.readFile(__dirname+'/email.html', function read(err, data) {
if (err) {
throw err;
}
content = data;
// Invoke the next step here however you like
//console.log(content); // Put all of the code here (not the best solution)
processFile(); // Or put the next step in a function and invoke it
});
function processFile() {
console.log(content);
}
module.exports = function sendMail(mailObject){
return new Promise(function (resolve, reject){
// create a new email instance
var email = new sendgrid.Email();
email.addTo('some1#example.com');
email.setFrom('sender#example.com');
email.setSubject('My-Email-body');
email.setFromName("Email-Name");
email.setHtml(content);
email.addHeader('X-Sent-Using', 'SendGrid-API');
email.addHeader('X-Transport', 'web');
email.setASMGroupID(835);
//send mail
sendgrid.send(email, function(err, json) {
//if something went wrong
if (err) { reject({
error:err,
res : json,
}); }
//else
resolve({
statusText: 'OK',
res : json
});
});
})
}
Anyone knows why the "rename" function (and all other multer callbacks) are not working?
var express = require('express');
var multer = require('multer');
var app = express();
app.use(multer({
dest: 'uploads/',
rename: function (fieldname, filename) {
return new Date().getTime();
},
onFileUploadStart: function (file) {
console.log(file.name + ' is starting ...');
},
onFileUploadComplete: function (file, req, res) {
console.log(file.name + ' uploading is ended ...');
console.log("File name : "+ file.name +"\n"+ "FilePath: "+ file.path)
},
onError: function (error, next) {
console.log("File uploading error: => "+error)
next(error)
},
onFileSizeLimit: function (file) {
console.log('Failed: ', file.originalname +" in path: "+file.path)
fs.unlink(path.join(__dirname, '../tmpUploads/') + file.path) // delete the partially written file
}
}).array('photos', 12));
app.listen(8080,function(){
console.log("Working on port 8080");
});
app.get('/',function(req,res){
res.sendFile(__dirname + "/index.html");
});
app.post('/photos/upload', function (req, res, next) {
// req.files is array of `photos` files
// req.body will contain the text fields, if there were any
//console.log(req.files);
//console.log(req.body);
res.json(req.files)
});
It seems the usage has been changed over time. Currently, multer constructor only accepts following options (https://www.npmjs.com/package/multer#multer-opts):
dest or storage - Where to store the files
fileFilter - Function to control which files are accepted
limits - Limits of the uploaded data
So, for example the renaming is to be solved by configuring appropriate storage (https://www.npmjs.com/package/multer#storage).
var storage = multer.diskStorage({
destination: function (req, file, cb) {
cb(null, '/tmp/my-uploads'); // Absolute path. Folder must exist, will not be created for you.
},
filename: function (req, file, cb) {
cb(null, file.fieldname + '-' + Date.now());
}
})
var upload = multer({ storage: storage });
app.post('/profile', upload.single('fieldname'), function (req, res, next) {
// req.body contains the text fields
});
The fieldname must match the field name in the request body. That is, in case of HTML form post, the form upload element input name.
Also have a look for other middleware functions like array and fields - https://www.npmjs.com/package/multer#single-fieldname which provide a a little different functionality.
Also you may be interested in the limits (https://www.npmjs.com/package/multer#limits) and file filter (https://www.npmjs.com/package/multer#filefilter)
And also - source is the single source of truth - have a peek!(https://github.com/expressjs/multer/blob/master/index.js)
Its a windows issue. Date as ISOString used as file name is not allowed in windows and violates some CORS policy. So for that there is a node package called uuid which does the job.
I am new to Node.js. Can anyone provide me an example of how to use GridFS for storing and retrieving binary data, such as images, using Node.js and Mongoose? Do I need to directly access GridFS?
I was not satisfied with the highest rated answer here and so I'm providing a new one:
I ended up using the node module 'gridfs-stream' (great documentation there!) which can be installed via npm.
With it, and in combination with mongoose, it could look like this:
var fs = require('fs');
var mongoose = require("mongoose");
var Grid = require('gridfs-stream');
var GridFS = Grid(mongoose.connection.db, mongoose.mongo);
function putFile(path, name, callback) {
var writestream = GridFS.createWriteStream({
filename: name
});
writestream.on('close', function (file) {
callback(null, file);
});
fs.createReadStream(path).pipe(writestream);
}
Note that path is the path of the file on the local system.
As for my read function of the file, for my case I just need to stream the file to the browser (using express):
try {
var readstream = GridFS.createReadStream({_id: id});
readstream.pipe(res);
} catch (err) {
log.error(err);
return next(errors.create(404, "File not found."));
}
Answers so far are good, however, I believe it would be beneficial to document here how to do this using the official mongodb nodejs driver instead of relying on further abstractions such as "gridfs-stream".
One previous answer has indeed utilized the official mongodb driver, however they use the Gridstore API; which has since been deprecated, see here. My example will be using the new GridFSBucket API.
The question is quite broad as such my answer will be an entire nodejs program. This will include setting up the express server, mongodb driver, defining the routes and handling the GET and POST routes.
Npm Packages Used
express (nodejs web application framework to simplify this snippet)
multer (for handling multipart/form-data requests)
mongodb (official mongodb nodejs driver)
The GET photo route takes a Mongo ObjectID as a parameter to retrieve the image.
I configure multer to keep the uploaded file in memory. This means the photo file will not be written to the file system at anytime, and instead be streamed straight from memory into GridFS.
/**
* NPM Module dependencies.
*/
const express = require('express');
const photoRoute = express.Router();
const multer = require('multer');
var storage = multer.memoryStorage()
var upload = multer({ storage: storage, limits: { fields: 1, fileSize: 6000000, files: 1, parts: 2 }});
const mongodb = require('mongodb');
const MongoClient = require('mongodb').MongoClient;
const ObjectID = require('mongodb').ObjectID;
let db;
/**
* NodeJS Module dependencies.
*/
const { Readable } = require('stream');
/**
* Create Express server && Routes configuration.
*/
const app = express();
app.use('/photos', photoRoute);
/**
* Connect Mongo Driver to MongoDB.
*/
MongoClient.connect('mongodb://localhost/photoDB', (err, database) => {
if (err) {
console.log('MongoDB Connection Error. Please make sure that MongoDB is running.');
process.exit(1);
}
db = database;
});
/**
* GET photo by ID Route
*/
photoRoute.get('/:photoID', (req, res) => {
try {
var photoID = new ObjectID(req.params.photoID);
} catch(err) {
return res.status(400).json({ message: "Invalid PhotoID in URL parameter. Must be a single String of 12 bytes or a string of 24 hex characters" });
}
let bucket = new mongodb.GridFSBucket(db, {
bucketName: 'photos'
});
let downloadStream = bucket.openDownloadStream(photoID);
downloadStream.on('data', (chunk) => {
res.write(chunk);
});
downloadStream.on('error', () => {
res.sendStatus(404);
});
downloadStream.on('end', () => {
res.end();
});
});
/**
* POST photo Route
*/
photoRoute.post('/', (req, res) => {
upload.single('photo')(req, res, (err) => {
if (err) {
return res.status(400).json({ message: "Upload Request Validation Failed" });
} else if(!req.body.name) {
return res.status(400).json({ message: "No photo name in request body" });
}
let photoName = req.body.name;
// Covert buffer to Readable Stream
const readablePhotoStream = new Readable();
readablePhotoStream.push(req.file.buffer);
readablePhotoStream.push(null);
let bucket = new mongodb.GridFSBucket(db, {
bucketName: 'photos'
});
let uploadStream = bucket.openUploadStream(photoName);
let id = uploadStream.id;
readablePhotoStream.pipe(uploadStream);
uploadStream.on('error', () => {
return res.status(500).json({ message: "Error uploading file" });
});
uploadStream.on('finish', () => {
return res.status(201).json({ message: "File uploaded successfully, stored under Mongo ObjectID: " + id });
});
});
});
app.listen(3005, () => {
console.log("App listening on port 3005!");
});
I wrote a blog post on this subject; is is an elaboration of my answer. Available here
Further Reading/Inspiration:
NodeJs Streams: Everything you need to know
Multer NPM docs
Nodejs MongoDB Driver
I suggest taking a look at this question: Problem with MongoDB GridFS Saving Files with Node.JS
Copied example from the answer (credit goes to christkv):
// You can use an object id as well as filename now
var gs = new mongodb.GridStore(this.db, filename, "w", {
"chunk_size": 1024*4,
metadata: {
hashpath:gridfs_name,
hash:hash,
name: name
}
});
gs.open(function(err,store) {
// Write data and automatically close on finished write
gs.writeBuffer(data, true, function(err,chunk) {
// Each file has an md5 in the file structure
cb(err,hash,chunk);
});
});
It looks like the writeBuffer has since been deprecated.
/Users/kmandrup/private/repos/node-mongodb-native/HISTORY:
82 * Fixed dereference method on Db class to correctly dereference Db reference objects.
83 * Moved connect object onto Db class(Db.connect) as well as keeping backward compatibility.
84: * Removed writeBuffer method from gridstore, write handles switching automatically now.
85 * Changed readBuffer to read on Gridstore, Gridstore now only supports Binary Buffers no Strings anymore.
remove the fileupload library
and if it is giving some multi-part header related error than remove the content-type from the headers