So im new on using expressjs, usually i choose Laravel as my backend. but because some certain consideration, i choose expressjs.
On Laravel, when we handling file upload, we can write upload logic everywhere, its your freedom to do that. You can encapsulate it inside your model function, or put it on service, or anywhere you want.
But when i use expressjs, so many articles on internet that recommend us to use multer for upload your file. As my background is using Laravel previously, i found its weird to use multer. Its because multer is a middleware. Why on earth we use middleware to upload our images/files.
With this i cant encapsulate my business logic into one service and its make the code separated and with this thats mean i need to maintain one business logic from multiple place.
Could you explain me why everyone choose multer ?
why dont just upload it to our local storage manually ?( actually for now i dont know how to do this ).
What is pros on mins from using this library ?
multer is a body parsing middleware that handles content type multipart/form-data
That means it parses the raw http request data which are primarily used for file upload, and makes it more accessible (storing on disk / in memory /...) for further processing.
Without multer, you would have to parse the raw data yourself if you want to access the file.
With this i cant encapsulate my business logic into one service and
its make the code separated and with this thats mean i need to
maintain one business logic from multiple place. Could you explain me
why everyone choose multer ?
multer, just like other middlewares, can be used at the root for all routes, but can also be put on only specific routes too.
More on express middleware
First of all, Express/body-parser does not handle file uploads natively, so that is why you see other libraries being loaded to handle them. They are all going to be loaded as middleware so they can be injected into the request and handle that a file was actually uploaded.
Coming from a Symfony background, I understand where you are coming from with wanting to handle things more manually, as I do the same. There are other alternatives to multer; for example I use express-fileupload which allows you to load the the uploading middleware for your entire app, and then you can use req.files to handle your uploads. For example:
// load the file upload library as app middleware
const fileUpload = require('express-fileupload');
app.use(fileUpload({
limits: { fileSize: 50 * 1024 * 1024 },
}));
Then let's say you have a file input named 'foo':
<input name="foo" type="file" />
In your route you would handle it like so:
// now handle a file upload
app.post('/upload', function(req, res) {
console.log(req.files.foo); // the uploaded file object
});
The file-upload documentation has examples for the req.files object as well as options you can pass to the middleware itself.
Related
I want to build a NodeJS server that accepts a .wav file (1Mb) sent to its single endpoint, then changes the file through AudioContext API and then sends back the response with the result?
The server shouldn't store anything, so, no database required.
How can I achieve this? (or, please correct me if don't understand how things work)
I would do this with express: https://expressjs.com/
and as middleware add express-fileuplaod: https://www.npmjs.com/package/express-fileupload
app.post('/upload', function(req, res) {
console.log(req.files.foo); // the uploaded file object
});
instead of the console.log(); you'd make a readable stream / buffer and then use it in the
AudioContext API
here is also a interesting Article explaining to use this:
https://www.russellgood.com/process-uploaded-file-web-audio-api/
Im making a web app, using node.js, express.js and mongodb and trying get my contact form done. I would like site visitors to contact me via the form where they can put their name, email and message, along with an uploadable file image so they can show me what they want to be done as a sample through an image.
It seems like every websites have this functionailiry but I cant seem to find the answer Im looking for. Any help and guides would be appreciated.
i think you could use this library i've just found for uploading files with Javascript by using a file dialog: https://fineuploader.com/demos.
I think your issue is pretty much solved after that because for what concerns the form, you may easily create the input tags in HTML and then get data from them by using NodeJS.
To upload files you need to use a form-data handler. I use multer:
npm i multer
You upload a file like this:
const multer = require('multer')
const upload = multer({ dest: 'uploads' })
app.post('/profile', upload.single('image'), (req, res)) {
//Now the image is uploaded in uploads folder you just need to send it back
}
Note that image is a form's input name.
For infroamtion on how to send the image see this
Look also at the docs for multer
If you don't want to store image you can use then fs module to delete it.
Early on in my Express app, I define Multer middleware to be used like this:
const multer = require('multer');
app.post('*', multer({ storage: multer.memoryStorage() }).any());
I'm using multer for file uploads.
The majority of my post request to my app will not require any file uploads and so that middleware is mostly useless most of the time.
Is there any downside or danger to using it like this, or is there some reason why I should just be applying the middleware to post requests that require file uploads?
I would suggest you to not use multer as a middleware for the whole app.
Using multer as a middleware would just be acting as a security threat for your app.
For example. You had two routes:
i. /register (requires an image upload as avatar)
ii. /login (doesnt require any file upload)
Any malicious user could easily use /login to upload malicious files into your destination folder in the app and could possibly act as a huge threat.
Only using the multer middleware in routes where you would do a file upload helps mitigate the risk to uploading unwanted and/or malicious files into the server.
Hope this helps.
I should implement an upload form
I thought of using bodyparser but I read
http://andrewkelley.me/post/do-not-use-bodyparser-with-express-js.html
so what's the way to upload a file with express using the mean stack ?
may be formidable or other modules ?
That warning is specifically against adding the express.bodyparser middleware to your entire stack as it adds express.multipart to all POST endpoints and therefore file uploads are automatically accepted at all POST endpoints. By default the framework automatically saves any uploaded files to /tmp and so unless you are cleaning them up an attacker could flood your disk with uploaded files.
If you want to avoid using additional modules, what you should do is implement express.multipart on the endpoint(s) where you want to allow file uploads. Here's what I'm talking about:
var express = require("express")
, app = express();
// middleware (no bodyparser here)
app.use(express.json());
app.use(express.urlencoded());
// average GET endpoint
app.get("/", function(req,res) {
res.send('ok');
});
// average POST endpont
app.post("/login", function(req,res) {
res.send('ok');
});
// File upload POST endpoint
app.post('/upload', express.multipart, function(req, res) {
//File upload logic here
//Make sure to delete or move the file accordingly here, otherwise files will pile up in `/tmp`
});
Note the inclusion of express.multipart in the file upload endpoint. This endpoint will now process multipart file uploads, and assuming you handle them correctly they won't be a threat.
Now, having told you all of this, Connect is moving to deprecate multipart due to this exact issue, but there don't seem to be any plans to add a stream based file upload replacement. What they instead recommend is that you use node-multiparty which uses streams to avoid ever placing a file on disk. However, there don't seem to be any good references I can find for using multiparty as a middleware without saving files though, so you'll have to contact the author of multiparty or take a closer look at the API for implementing it with Express.
I created an example that uses Express & Multer - very simple, avoids all Connect warnings
https://github.com/jonjenkins/express-upload
I want to be able to add image uploads to a site I'm working on, but I don't know how that is supposed to work with meteorjs. Is there a way to accept multipart forms on meteorjs? i.e. image uploads?
I could always rackup a small sinatra app for file uploads but I'd rather not.
You need to write a middleware to accept such requests.
WebApp.connectHandlers.stack.splice(0, 0, {
route: '/your/url/for/inputs',
handle: function(req, res, next) {
// Handle request and response
// just like you would do in node.js.
// Make sure to wrap your db calls in Fibers.
// Use next() if you change your mind
// and don't want to handle this request after all.
},
});
Looks like eventminded has a file upload package you could use.
https://www.eventedmind.com/posts/meteor-build-a-file-upload-package