originalname is not properly decoded

If uploaded file name contains special characters, the originalname will be set in encoded form.

Steps to repro:

• upload file named ‘file".ext’
• expected originalname = ‘file".ext’
• actual originalname = ‘file%22.ext’

Additional info from browser side:

Headers:
method: POST
content-type: multipart/form-data; boundary=----WebKitFormBoundaryBc2l7WXbILSFIgKL
...
Data:
------WebKitFormBoundaryBc2l7WXbILSFIgKL
Content-Disposition: form-data; name="file"; filename="file%22.ext"
...

[donghero]

this is my solution

const storage = multer.diskStorage({
  destination: function (req, file, cb) {
    cb(null, fullPath);
  },
  filename: function (req, file, cb) {
    let extname = path.extname(file.originalname);
    file.originalname = path.basename(
      Buffer.from(file.originalname, "latin1").toString("utf8"),
      extname
    );
    const uniqueSuffix = Date.now() + "-" + Math.round(Math.random() * 1e9);
    filename = file.fieldname + "-" + uniqueSuffix + extname;
    cb(null, filename);
  }
});

the important part is that Buffer.from(file.originalname, "latin1").toString("utf8")

[LinusU]

@donghero that’s great! From my understanding it seems like HTTP headers are latin1 unless otherwise specified

ref: https://www.jmix.io/blog/utf-8-in-http-headers/

It would probably be nice to add support for filename* as well though