Upload file with React - reactjs

Question

I want to make a simple file upload form on the front end. Then, on the backend, I would pass the information about that file to an API.
Here is my front-end code where I call a specific function on the back end and pass the data:
import React from 'react';
import Axios from 'axios';
const Upload = () => {
// a local state to store the currently selected file.
const [selectedFile, setSelectedFile] = React.useState(null);
const handleSubmit = async (event) => {
event.preventDefault()
//Got all the Infos about my file
console.log(selectedFile)
const formData = new FormData();
formData.append("selectedFile", selectedFile);
//Empty result
console.log(formData)
Axios.get("http://localhost:3001/upload", {
//I will pass the data to a function in the backend
params: {
data: formData,
},
})
.then((Response) => {
console.log(Response)
})
.catch(function (error) {
console.log(error);
});
}
const handleFileSelect = (event) => {
setSelectedFile(event.target.files[0])
}
return (
<form onSubmit={handleSubmit}>
<input type="file" onChange={handleFileSelect}/>
<input type="submit" value="Upload File" />
</form>
)
};
export default Test
On the back-end side, a route call the method
router.get('/upload?', Upload);
Then finally the function in the backend to process
const ApiProcess = (req, res) => {
var axios = require('axios');
var data = req.query
console.log(req.query)
//All the API Stuff
}
But the problem is that I receive empty data in the Backend. What's wrong with my code?
Thanks
EDIT
On backend side I use multer and add 'app.use(multer().any())' on top of index file. That help cause now I cant access in backend to a simple formData. Now my function that receive the data log this '[Object: null prototype] {}'
Any idea ?

Answer 1

This is because your file is not getting forwarded from frontend
use FileReader instead
<input type="submit" value="Upload File" onChange={(e) =>
setFile(e.target.files)} />
const data = new FormData();
data.append(file[0])
and then you can access the file data on file[0] index and after storing the data you can forward it to the backend

Answer 2

there are some problems in your code.
first of all an upload request usually is a post type. and also you should send Content-Type header with your request. so:
Axios.post("http://localhost:3001/upload", formData {
headers: {
'Content-Type': 'Multipart/formData',
},
})
when you log formData it's always empty. you can use some methods like formData.keys() or formData.values() to see inside it.

Answer 3

Ok I got the solution. I missed a piece of middleware to process Multipart/formdata on Express Side :
const router = express.Router();
const multer = require("multer");
//Set the destination folder and Naming of the file that is upload
const storage = multer.diskStorage({
destination: function (req, file, cb) {
cb(null, 'uploads/')
},
filename: function (req, file, cb) {
cb(null, file.originalname)
}
})
const upload = multer({ storage: storage })
Then I process the formData with the files
router.post('/upload', upload.array("file"),Upload);
Thanks a lot for your help