multer file upload - how to get a value from multer in route? - express

Question

I'm uploading a file using multer with Express.
I'd like access a value from multer's storage object inside the route.
How can I do that?
Multer configuration (right now I only know how to log the key):
const aws = require("aws-sdk");
const multer = require("multer");
const multerS3 = require("multer-s3");
function configureUpload () {
const s3 = new aws.S3({...my credentials...});
const upload = multer({
storage: multerS3({
s3: s3,
bucket: process.env.S3_BUCKET_NAME,
metadata: (req, file, cb) => cb(null, { fieldName: file.fieldname }),
key: (req, file, cb) => {
const key = `${new Date().toISOString()}-${file.originalname}`;
return cb(console.log("KEY: ", key), key); // The string I need to access in route
},
}),
});
return upload;
}
The route:
const express = require("express");
const Person = require("../../../db/models/person");
const configureUpload = require("../../../configureUpload ");
const router = express.Router();
// Saving to MongoDB with mongoose
router.post("/", configureUpload ().any(), async (req, res) => {
Person.create({
...req.body,
files: [] // I want to add the string in multer.storage.key to this array
})
.then((person) => {
...
})
.catch((err) => {
...
});
});
module.exports = router;

Answer 1

This an exapmle of what Tarique Akhtar Ansari already said. Adding your key to the req object so that you can access the key's value in your controller/route like so:
const aws = require("aws-sdk");
const multer = require("multer");
const multerS3 = require("multer-s3");
function configureUpload () {
const s3 = new aws.S3({...my credentials...});
const upload = multer({
storage: multerS3({
s3: s3,
bucket: process.env.S3_BUCKET_NAME,
metadata: (req, file, cb) => {cb(null, { fieldName: file.fieldname })},
key: (req, file, cb) => {
const key = `${new Date().toISOString()}-${file.originalname}`;
req.key = key; // added the key to req object
// return cb(console.log("KEY: ", key), key); // The string I need to access in route
},
}),
});
return upload;
}
Accessing the value of the key inside your controller or route
const express = require("express");
const Person = require("../../../db/models/person");
const configureUpload = require("../../../configureUpload ");
const router = express.Router();
// Saving to MongoDB with mongoose
router.post("/", configureUpload ().any(), async (req, res) => {
console.log('here is the value your key', req.key); // it's that simple.
Person.create({
...req.body,
files: [] // I want to add the string in multer.storage.key to this array
})
.then((person) => {
...
})
.catch((err) => {
...
});
});
module.exports = router;

Answer 2

you can simply add req.key = keyValue
then you can access in next route using req.key name
or you can also access req.file or req.files object in route
In express everything is a middleware so you can easily pass and access in next middleware