Скачать или смотреть How to Upload Different Types of Files with Different Sizes in Express using Multer

Learn how to use `Multer` in `Express` to upload various file types with specific size limits, ensuring efficient file management in your applications.
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This video is based on the question https://stackoverflow.com/q/65955884/ asked by the user 'Sudhir S Pawar' ( https://stackoverflow.com/u/1951530/ ) and on the answer https://stackoverflow.com/a/65962531/ provided by the user 'Mohammad Yaser Ahmadi' ( https://stackoverflow.com/u/9689193/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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Upload Different Types of Files with Different Sizes in Express using Multer

Uploading files through a web application can often be a complex task, especially when you want to restrict the types and sizes of files that users can upload. This is where the power of Express and Multer comes into play. In this guide, we'll explore how to upload different types of files while enforcing specific size limits, ensuring a smooth user experience and maintaining server integrity.

Understanding the Problem

Multer is a middleware for handling multipart/form-data, which is primarily used for uploading files in Node.js applications. However, you may encounter situations where you want to set different size limits based on the file type. For example:

PDF files should be under 1 MB.

Image files (like PNG, JPEG, and JPG) should be under 4 MB.

To achieve this using Multer, we need to implement a solution that involves both file filtering and size validation.

Setting Up Your Environment

First, ensure that you have the necessary packages installed. You can do this using npm:

[[See Video to Reveal this Text or Code Snippet]]

Code Implementation

Here’s how to create a file upload service with specific size limits using Multer:

[[See Video to Reveal this Text or Code Snippet]]

Explanation of the Code

Dependencies: We import Express, Multer, and some utilities to help with file management.

File Types: We define constants for acceptable file types and their extensions to handle.

Multer Configuration:

Storage: We specify how Multer should store files, generating unique filenames using UUIDs.

File Size Limits: Within the fileFilter, we check the size of files using req.rawHeaders.size and validate against our defined limits.

Error Handling: An error will be triggered if a file doesn't meet the specified criteria.

Conclusion

By utilizing Express and Multer, you can effectively manage file uploads in your Node.js applications with customized restrictions based on file type and size. This not only improves user experience but also enhances the security and organization of your server.

Feel free to adapt this example to fit additional requirements for your specific project. Happy coding!