如何删除JavaScript / node.js中HTTP响应头中的无效字符？

Question

I have the following problem: When a client enters a certain URL it receives an .mp3 file back via sendFile() from Express. The name of the file is defined in the response header as follow:

var fileName = (JSON.stringify(data.videoTitle).replace(/["']/g, "") + fileType);

headers: {
        'x-timestamp': Date.now(),
        'x-sent': true,
        'Content-type': 'application/octet-stream',
        'Content-Disposition': 'attachment; filename="' + fileName + '"'
    }

The problem is that fileName is fetched from another website and I have no control over what the title of the file will be. So far it was no problem but it just happened to me that a file contained the character ú which lead to the following error:

throw new TypeError('The header content contains invalid characters');

This could potentially happen very often as there are many characters that the headers might not like. Is there any possibility that I only keep valid characters before setting the header? I assume a whitelist approach would be better than a blacklist approach as there are nearly infinite possibilities of invalid characters.

Thank you very much in advance

Answer 1

Here is an extended answer which basically tells you that only a subset of ASCII or ISO-8859-1 is allowed.

What character encoding should I use for a HTTP header?

And here is your solution: transliterate the filename into ASCII characters to make it safe for use in a header value:

https://www.npmjs.com/package/transliteration