@otterhttp/content-disposition

content-disposition rewrite in TypeScript.

Create and parse HTTP Content-Disposition header

Install

pnpm i @otterhttp/content-disposition

API

import { contentDisposition, parse } from '@otterhttp/content-disposition'

contentDisposition(filename)

Create an attachment Content-Disposition header value using the given file name, if supplied. The filename is optional and if no file name is desired, but you want to specify options, set filename to undefined.

res.setHeader('Content-Disposition', contentDisposition('∫ maths.pdf'))

note HTTP headers are of the ISO-8859-1 character set. If you are writing this header through a means different from setHeader in Node.js, you'll want to specify the 'binary' encoding in Node.js.

Options

contentDisposition accepts these properties in the options object.

fallback

If the filename option is outside ISO-8859-1, then the file name is actually stored in a supplemental field for clients that support Unicode file names and a ISO-8859-1 version of the file name is automatically generated.

This specifies the ISO-8859-1 file name to override the automatic generation or disables the generation all together, defaults to true.

• A string will specify the ISO-8859-1 file name to use in place of automatic generation.
• false will disable including a ISO-8859-1 file name and only include the Unicode version (unless the file name is already ISO-8859-1).
• true will enable automatic generation if the file name is outside ISO-8859-1.

If the filename option is ISO-8859-1 and this option is specified and has a different value, then the filename option is encoded in the extended field and this set as the fallback field, even though they are both ISO-8859-1.

type

Specifies the disposition type, defaults to "attachment". This can also be "inline", or any other value (all values except inline are treated like attachment, but can convey additional information if both parties agree to it). The type is normalized to lower-case.

contentDisposition.parse(string)

contentDisposition.parse('attachment; filename="EURO rates.txt"; filename*=UTF-8\'\'%e2%82%ac%20rates.txt')

Parse a Content-Disposition header string. This automatically handles extended ("Unicode") parameters by decoding them and providing them under the standard parameter name. This will return an object with the following properties (examples are shown for the string 'attachment; filename="EURO rates.txt"; filename*=UTF-8\'\'%e2%82%ac%20rates.txt'):

• type: The disposition type (always lower case). Example: 'attachment'

• parameters: An object of the parameters in the disposition (name of parameter always lower case and extended versions replace non-extended versions). Example: {filename: "€ rates.txt"}

Example

This simple example shows how to use accepts to return a different typed respond body based on what the client wants to accept. The server lists it's preferences in order and will get back the best match between the client and server.

import { contentDisposition } from '@otterhttp/content-disposition'
import destroy from 'destroy'
import fs from 'node:fs'
import { createServer } from 'node:http'
import onFinished from 'on-finished'

const filePath = '/path/to/public/plans.pdf'

createServer((req, res) => {
  res.setHeader('Content-Type', 'application/pdf')
  res.setHeader('Content-Disposition', contentDisposition(filePath))

  const stream = fs.createReadStream(filePath)
  stream.pipe(res)
  onFinished(res, () => destroy(stream))
})