Configuring Express Multer Middleware and Checking File Information

Photo by Maksym Kaharlytskyi on Unsplash

Multer is a middleware that lets us process file uploads with our Express app.

In this article, we’ll look at the settings that we can change to upload files our way, and also check the file information.

Checking File Information

We can check the uploaded files’ information by looking at the req.file object for single file upload and the array entries of req.files for multiple file uploads.

These fields are available for each file:

• fieldname — field name specified in the form
• originalname — name of the file on the user’s computer
• encoding — encoding type of the file
• mimetype — MIME-type of the file
• size — size of the file in bytes
• destination — the folder where the file was saved on the server
• filename — name of the file stored in the destination
• path — the full path of the uploaded file
• buffer — Buffer object of the whole file

Options for File Upload

The multer function takes an options object that takes a variety of options.