check exist file before upload multer - node.js

I am using Multer for upload files using Nodejs. Problem is that I cannot verify exist file on server before it deliver to server.
I will check original name, mime type and file size to make sure it is same.
fileFilter: async function (req, file, callback) {
//but file here return only `original name` and `mime type`.
}
The files are sent to server successfully, multer return in req.files but files uploaded. It is not middleware anymore.

Related

Audio Upload with Expressjs

I am working on a music app,how can i upload audio file in my expressjs using cloudinary or any other way?
I tried using thesame format for image upload but didnt work
enter image description here
To upload audio using Express JS, you will need to use the multer middleware. Here is an example of how you can set up the multer middleware and use it to handle audio file uploads:
First, install the multer package:
npm install multer
Next, require the multer package in your Express app:
const multer = require('multer')
Set up the multer middleware by specifying where you want the uploaded audio files to be stored. For example:
const storage = multer.diskStorage({
destination: function (req, file, cb) {
cb(null, 'uploads/audio/')
},
filename: function (req, file, cb) {
cb(null, file.originalname)
}
})
Use the multer middleware in your route handling function to handle the audio file upload. For example:
app.post('/upload-audio', multer({ storage }).single('audio'), (req, res) => {
// req.file contains the uploaded audio file
// Do something with the audio file, such as save it to a database or storage service
res.send('Audio file successfully uploaded!')
})
In your HTML form for uploading audio, make sure to include the enctype="multipart/form-data" attribute and specify the name of the file input as audio. For example:
<form action="/upload-audio" method="post" enctype="multipart/form-data">
<input type="file" name="audio" accept="audio/*">
<button type="submit">Upload Audio</button>
</form>
I hope this helps!
To add to Jack's answer, there is a Cloudinary storage engine for Multer you can use to send your files to Cloudinary rather than keeping the assets on disk.
https://www.npmjs.com/package/multer-storage-cloudinary
When initializing the CloudinaryStorage object you can pass parameters to Cloudinary, including the resource_type. If you set that to auto (default is image if none is provided) then Cloudinary assigns the appropriate resource_type once it processes the upload request. For audio files, it will assign resource_type: "video" because audio files fall under this and for images, it'll assign "image". If you were to upload text files and you used resource_type: "auto" in your request, then Cloudinary will assign "raw" as the resource_type.
You will just need to store (e.g. in your database) the resource_type, type and public_id fields returned in the response to a successful upload and you can then refer to any of your files on Cloudinary.
The reason you want to save the 'resource_type' and 'type' and not only the 'public_id' is because, in Cloudinary, an asset is only unique if in combination with the 'resource_type' and 'type'. E.g. the below assets with the same public_id (sample) are different entities because of a different 'resource_type' and/or 'type':
image/upload/sample
image/private/sample
video/upload/sample
video/authenticated/sample
References:
https://cloudinary.com/documentation/upload_images#asset_types

How to create file uploading web service using node js with jwt Authentication?

I want to create file uploading web service with jwt Authentication such that peoples can upload there files to /upload route and I will use cloudinary service in my server to actually store them. User can also get their files using filename with /getfile route. Is there something else I should add in my project?
In order for the express server to be able to take a file as an input I would use the package Express file-upload in order to achieve this. The docs are super simple for this one.
Inside of your server.js file:
// setting temp files location
app.use(fileUpload({
useTempFiles : true,
tempFileDir : '/tmp/'
}));
upload route:
app.post('/upload', function(req, res) {
console.log(req.files.foo); // the uploaded file object
res.download('/report-12345.pdf')
});
This file obeject caqn then be used to save the file wherever you desire.
For sending the file back to the user Express also has a feature for this which is documented here
getfile route:
app.get('/getfile', function(req, res) {
// whatever file to be downloaded here
res.download('/report-12345.pdf')
});
Hope that's what you were asking for. Thanks!

Why multer should upload files before any operation?

They way Multer works on top of express is wired!, why Multer should precede the controller in the chain of Middlewares, which which by design causes the server to upload stuff before the DB operation is even checked?
For instance if there was a post operation to articles, and it contains a bunch of fields one of them is a file.
articleModel{title:String,image:String};
router.post('/', multer, articleController.createArticle);
now at the time the request hits, first thing in the chain is to upload the file in the request, but what if an error happened at the execution of the record to the DB like validation or even duplicates, what if I am going to update the article title only? the old files will be uploaded again?
How to make multer upload the files in the response of the http operation callback?
You can indeed make all kind of stuff before Multer actually process the image:
var upload = multer({
dest: 'uploads/',
fileFilter: function (req, file, cb) {
// only images are allowed
var filetypes = /jpeg|jpg|png/;
var mimetype = filetypes.test(file.mimetype);
var extname = filetypes.test(path.extname(file.originalname).toLowerCase());
if (mimetype && extname) {
return cb(null, true);
}
cb("Error");
}
}).single('localImg');
app.post('/api/file', checkBody, auth, uploadFile, controller.aController);
Take this code for example, you can make all kind of middleware actions BEFORE multer process your file, but multer is a library to process multipart/form-data, not files only, people use multipart for sending files mainly but you can send all kind of data too and it will append them to the body (req.body)
Your question is: "Why multer should upload files before any operation?"
You can execute multer when ever you want, but multer will process the request and get your data into the body. Unless you don't need the body data first hand, you need multer to be in the first middleware.
Your other question is: "what if I am going to update the article title only? the old files will be uploaded again?"
No, it will be uploaded once, if there is any problem with the database, any error or reject, you can always use the filesystem (fs) to remove the file from your server, if you already upload it to a third party system, you can delete it.
Hope it helps

How to use multer upload file without middleware

I'm new to NodeJS, I'm developing app where I have created registeration form. To upload images, I'm using multer. And for form validation I'm using express-validator. The issue with me is that, before form validation, file has upload. So, if user hasn't created account because of some validation errors, but file goes upload. The problem is that I get file upload for each form submition no matter, account has successfully created or not.
What I want to do?
I want save file only when user has successfully created account. So, is there anyway to use multer inside callback, so when my form validations are done, then files goes upload. I can't use express-validation middleware between multer midleware and final callback, because express-validation passes it's errors to next call back.
Here is my some code
router.post('/registeration', multerMiddleware, validationMiddleware, finalCallback)
validationMiddleware is an array.
var multer = require('multer');
var multerMiddleware= multer({dest: './profile-images', fileFilter: userRegisteration.fileFilter}).single('profileImage');
var validationMiddleware = [check(...), check(...),...]
var finalCallback = function (req, res, next) {
// code is here
}
Express router executes the middlewares in the same sequence you mount
them
router.post('/registeration', multerMiddleware, validationMiddleware, finalCallback)
So, your multerMiddleware is executed ( and hence saved the file ) before your validationMiddleware has done the validation.
Change the code to:
router.post('/registeration', validationMiddleware,multerMiddleware, finalCallback)
So, multerMiddleware will only save file once the request is validated

Can we configure multer to not store files locally and only for using req.files.image.path?

My application's need is as follows:
I upload the image to Cloudinary and store the url of image in my mongodb database.
To upload the image to cloudinary, I needed to give the file path, and for that, I am using multer.I use the statement:
app.use(multer({ dest: './uploads/'}));
The problem I face is that, everytime I upload an image from my local system to the database on Cloudinary, a local copy gets created in './uploads/'.I want this to not happen, since my images are there on Cloudinary.
I read the documentation of multer where it says:
Multer accepts an options object, the most basic of which is the dest property, which tells Multer where to upload the files. In case you omit the options object, the file will be renamed and uploaded to the temporary directory of the system.
I am unable to make out if that temporary upload space needs cleaning or if it is taken care of.My images are uploaded on Cloudinary.I used multer only for getting :
req.files.photo.path
to work.Is there any other way to do the same or if multer can be configured in a way to not store images to my local system?
July 2018:
So if you want to store an image into some sort of database, you probably want to convert it into a buffer, and then insert buffer into the database. If you are using multer to process the multipart form (in this case the image file you want to upload), you can use multer's memoryStorage to get the buffer of the image directly. In other words:
var storage = multer.memoryStorage();
var upload = multer({ storage: storage });
to get the buffer:
When using memory storage, the file info will contain a field called buffer that contains the entire file.
that means you can get the buffer from command like req.files[0].buffer
I updated a simple repo demonstrating upload images to database without making a copy to local in this repo
From Multer info page at
https://www.npmjs.com/package/multer
If the inMemory option is true - no data is written to
disk but data is kept in a buffer accessible in the file object.
Prior to 14-07-2016 you could not configure multer to store files locally.
But multer is just a wrapper of busboy. So, we can try use busboy directly if we want to avoid hitting the disk.
Connect-bubsboy will help us:
app.use(busboy());
// request handler
req.busboy.on('file', function(fieldname, file, filename, encoding, mimetype) {
file.on('end', function() {
// do stuff with req.files[fieldname]
});
});
Update 14-07-2016
Now multer has MemoryStorage to store files in memory as Buffer.
var storage = multer.memoryStorage()
var upload = multer({ storage: storage })
You can also delete the file once it's uploaded to Cloudinary.
// used to delete images from local directory
const fs = require('fs'); // gain access to file system
const util = require('util');
const deleteFile = util.promisify(fs.unlink); // unlink will delete the file
// in your post request
app.post('/images', upload.single('myFile'), async function(req, res) {
const file = req.file; // multer gives access to the file object in the request
// code to upload the file to Cloudinary
await deleteFile(file.path); // remove locally stored image by passing the file's path
});
If you're storing images with Cloudinary then try using multer-storage-cloudinary

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