send

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Send is a library for streaming files from the file system as a 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.

Looking to serve up entire folders mapped to URLs? Try serve-static.

Installation

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

``bash
$ npm install send
`

API

`js
var send = require('send')
`

$3

Create a new SendStream 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.

##### 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 actually 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.

##### 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.

#### Events

The SendStream is an event emitter and will emit the following events:

- error an error occurred (err)
- directory a directory was requested (res, path)
- file a file was requested (path, stat)
- headers the headers are about to be set on a file (res, path, stat)
- stream file streaming has started (stream)
- end streaming has completed

#### .pipe

The pipe method is used to pipe the response into the Node.js HTTP response
object, typically send(req, path, options).pipe(res).

Error-handling

By default when no error listeners are present an automatic response will be
made, otherwise you have full control over the response, aka you may show a 5xx
page etc.

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 __DEBUG__:

`
$ DEBUG=send node app
`

Running tests

`
$ npm install
$ npm test
`

Examples

$3

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

`js
var http = require('http')
var send = require('send')

var server = http.createServer(function onRequest (req, res) {
send(req, '/path/to/index.html')
.pipe(res)
})

server.listen(3000)
`

$3

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.

`js
var http = require('http')
var parseUrl = require('parseurl')
var send = require('send')

var server = http.createServer(function onRequest (req, res) {
send(req, parseUrl(req).pathname, { root: '/www/public' })
.pipe(res)
})

server.listen(3000)
`

$3

`js
var extname = require('path').extname
var http = require('http')
var parseUrl = require('parseurl')
var send = require('send')

var server = http.createServer(function onRequest (req, res) {
send(req, parseUrl(req).pathname, { root: '/www/public' })
.on('headers', function (res, path) {
switch (extname(path)) {
case '.x-mt':
case '.x-mtt':
// custom type for these extensions
res.setHeader('Content-Type', 'application/x-my-type')
break
}
})
.pipe(res)
})

server.listen(3000)
`

$3

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

`js
var http = require('http')
var fs = require('fs')
var parseUrl = require('parseurl')
var send = require('send')

// Transfer arbitrary files from within /www/example.com/public/*
// with a custom handler for directory listing
var server = http.createServer(function onRequest (req, res) {
send(req, parseUrl(req).pathname, { index: false, root: '/www/public' })
.once('directory', directory)
.pipe(res)
})

server.listen(3000)

// Custom directory handler
function directory (res, path) {
var stream = this

// redirect to trailing slash for consistent url
if (!stream.hasTrailingSlash()) {
return stream.redirect(path)
}

// get directory list
fs.readdir(path, function onReaddir (err, list) {
if (err) return stream.error(err)

// render an index for the directory
res.setHeader('Content-Type', 'text/plain; charset=UTF-8')
res.end(list.join('\n') + '\n')
})
}
`

$3

`js
var http = require('http')
var parseUrl = require('parseurl')
var send = require('send')

var server = http.createServer(function onRequest (req, res) {
// your custom error-handling logic:
function error (err) {
res.statusCode = err.status || 500
res.end(err.message)
}

// your custom headers
function headers (res, path, stat) {
// serve all files for download
res.setHeader('Content-Disposition', 'attachment')
}

// your custom directory handling logic:
function redirect () {
res.statusCode = 301
res.setHeader('Location', req.url + '/')
res.end('Redirecting to ' + req.url + '/')
}

// transfer arbitrary files from within
// /www/example.com/public/*
send(req, parseUrl(req).pathname, { root: '/www/public' })
.on('error', error)
.on('directory', redirect)
.on('headers', headers)
.pipe(res)
})

server.listen(3000)
``

License

MIT

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[github-actions-ci-url]: https://github.com/pillarjs/send/actions/workflows/ci.yml
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[npm-url]: https://npmjs.org/package/send
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