@fastify/send

Send is a library for streaming files from the file system as an HTTP response supporting partial responses (Ranges), conditional-GET negotiation (If-Match, If-Unmodified-Since, If-None-Match, If-Modified-Since), high test coverage, and granular events which may be leveraged to take appropriate actions in your application or framework.

Installation

This is a Node.js module available through the npm registry. Installation is done using the npm install command:

1$ npm install @fastify/send

TypeScript

@types/mime@3 must be used if wanting to use TypeScript; @types/mime@4 removed the mime types.

1$ npm install -D @types/mime@3

API

1const send = require('@fastify/send')

send(req, path, [options])

Provide statusCode, headers, and stream for the given path to send to a res. The req is the Node.js HTTP request and the path is a urlencoded path to send (urlencoded, not the actual file-system path).

Options

acceptRanges

Enable or disable accepting ranged requests, defaults to true. Disabling this will not send Accept-Ranges and ignore the contents of the Range request header.

cacheControl

Enable or disable setting Cache-Control response header, defaults to true. Disabling this will ignore the immutable and maxAge options.

contentType

By default, this library uses the mime module to set the Content-Type of the response based on the file extension of the requested file.

To disable this functionality, set contentType to false. The Content-Type header will need to be set manually if disabled.

dotfiles

Set how "dotfiles" are treated when encountered. A dotfile is a file or directory that begins with a dot ("."). Note this check is done on the path itself without checking if the path exists on the disk. If root is specified, only the dotfiles above the root are checked (i.e. the root itself can be within a dotfile when set to "deny").

• 'allow' No special treatment for dotfiles.
• 'deny' Send a 403 for any request for a dotfile.
• 'ignore' Pretend like the dotfile does not exist and 404.

The default value is similar to 'ignore', with the exception that this default will not ignore the files within a directory that begins with a dot, for backward-compatibility.

end

Byte offset at which the stream ends, defaults to the length of the file minus 1. The end is inclusive in the stream, meaning end: 3 will include the 4th byte in the stream.

etag

Enable or disable etag generation, defaults to true.

extensions

If a given file doesn't exist, try appending one of the given extensions, in the given order. By default, this is disabled (set to false). An example value that will serve extension-less HTML files: ['html', 'htm']. This is skipped if the requested file already has an extension.

immutable

Enable or disable the immutable directive in the Cache-Control response header, defaults to false. If set to true, the maxAge option should also be specified to enable caching. The immutable directive will prevent supported clients from making conditional requests during the life of the maxAge option to check if the file has changed.

index

By default send supports "index.html" files, to disable this set false or to supply a new index pass a string or an array in preferred order.

lastModified

Enable or disable Last-Modified header, defaults to true. Uses the file system's last modified value.

maxAge

Provide a max-age in milliseconds for HTTP caching, defaults to 0. This can also be a string accepted by the ms module.

maxContentRangeChunkSize

Specify the maximum response content size, defaults to the entire file size. This will be used when acceptRanges is true.

root

Serve files relative to path.

start

Byte offset at which the stream starts, defaults to 0. The start is inclusive, meaning start: 2 will include the 3rd byte in the stream.

highWaterMark

When provided, this option sets the maximum number of bytes that the internal buffer will hold before pausing reads from the underlying resource. If you omit this option (or pass undefined), Node.js falls back to its built-in default for readable binary streams.

.mime

The mime export is the global instance of the mime npm module.

This is used to configure the MIME types that are associated with file extensions as well as other options for how to resolve the MIME type of a file (like the default type to use for an unknown file extension).

Caching

It does not perform internal caching, you should use a reverse proxy cache such as Varnish for this, or those fancy things called CDNs. If your application is small enough that it would benefit from single-node memory caching, it's small enough that it does not need caching at all ;).

Debugging

To enable debug() instrumentation output export NODE_DEBUG:

$ NODE_DEBUG=send node app

Running tests

$ npm install
$ npm test

Examples

Serve a specific file

This simple example will send a specific file to all requests.

1const http = require('node:http')
2const send = require('send')
3
4const server = http.createServer(async function onRequest (req, res) {
5  const { statusCode, headers, stream } = await send(req, '/path/to/index.html')
6  res.writeHead(statusCode, headers)
7  stream.pipe(res)
8})
9
10server.listen(3000)

Serve all files from a directory

This simple example will just serve up all the files in a given directory as the top-level. For example, a request GET /foo.txt will send back /www/public/foo.txt.

1const http = require('node:http')
2const parseUrl = require('parseurl')
3const send = require('@fastify/send')
4
5const server = http.createServer(async function onRequest (req, res) {
6  const { statusCode, headers, stream } = await send(req, parseUrl(req).pathname, { root: '/www/public' })
7  res.writeHead(statusCode, headers)
8  stream.pipe(res)
9})
10
11server.listen(3000)

Custom file types

1const http = require('node:http')
2const parseUrl = require('parseurl')
3const send = require('@fastify/send')
4
5// Default unknown types to text/plain
6send.mime.default_type = 'text/plain'
7
8// Add a custom type
9send.mime.define({
10  'application/x-my-type': ['x-mt', 'x-mtt']
11})
12
13const server = http.createServer(function onRequest (req, res) {
14  const { statusCode, headers, stream } = await send(req, parseUrl(req).pathname, { root: '/www/public' })
15  res.writeHead(statusCode, headers)
16  stream.pipe(res)
17})
18
19server.listen(3000)

Custom directory index view

This is an example of serving up a structure of directories with a custom function to render a listing of a directory.

1const http = require('node:http')
2const fs = require('node:fs')
3const parseUrl = require('parseurl')
4const send = require('@fastify/send')
5
6// Transfer arbitrary files from within /www/example.com/public/*
7// with a custom handler for directory listing
8const server = http.createServer(async function onRequest (req, res) {
9  const { statusCode, headers, stream, type, metadata } = await send(req, parseUrl(req).pathname, { index: false, root: '/www/public' })
10  if(type === 'directory') {
11    // get directory list
12    const list = await readdir(metadata.path)
13    // render an index for the directory
14    res.writeHead(200, { 'Content-Type': 'text/plain; charset=utf-8' })
15    res.end(list.join('\n') + '\n')
16  } else {
17    res.writeHead(statusCode, headers)
18    stream.pipe(res)
19  }
20})
21
22server.listen(3000)

Serving from a root directory with custom error-handling

1const http = require('node:http')
2const parseUrl = require('parseurl')
3const send = require('@fastify/send')
4
5const server = http.createServer(async function onRequest (req, res) {
6  // transfer arbitrary files from within
7  // /www/example.com/public/*
8  const { statusCode, headers, stream, type, metadata } = await send(req, parseUrl(req).pathname, { root: '/www/public' })
9  switch (type) {
10    case 'directory': {
11      // your custom directory handling logic:
12      res.writeHead(301, {
13        'Location': metadata.requestPath + '/'
14      })
15      res.end('Redirecting to ' + metadata.requestPath + '/')
16      break
17    }
18    case 'error': {
19      // your custom error-handling logic:
20      res.writeHead(metadata.error.status ?? 500, {})
21      res.end(metadata.error.message)
22      break
23    }
24    default: {
25      // your custom headers
26      // serve all files for download
27      res.setHeader('Content-Disposition', 'attachment')
28      res.writeHead(statusCode, headers)
29      stream.pipe(res)
30    }
31  }
32})
33
34server.listen(3000)

License

Licensed under MIT.