send-transform
v0.15.1
Published
Better streaming static file server with transform, Range and conditional-GET support
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send-transform
Send-transform is a modified version of the send library for streaming files from the file system as a http response supporting partial responses (Ranges), conditional-GET negotiation, high test coverage, and granular events which may be leveraged to take appropriate actions in your application or framework.
This modified version of send supports specifying a transform function that takes the file stream as input, and produces a new (transformed) stream as ouput. See below for more information.
Looking to serve up entire folders mapped to URLs? Try serve-static.
Installation
$ npm install send-transform
API
var send = require('send-transform')
send(req, path, [options])
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 maxAge
option.
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 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
, unless the transform
option is set.
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.
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. Uses the file system's last modified
value.
Defaults to true
, unless the transform
option is set.
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.
transform
A function that consumes the file stream and produces a new (transformed) stream:
function(stream) {return stream.pipe(replaceStream('tobi', 'peter'))}
Multiple transformations are possible:
function(stream) {
return stream
.pipe(replaceStream('tobi', 'peter'))
.pipe(replaceStream('peter', 'hans'))
.pipe(...)
}
When a transform is specified, the lastModified
and etag
options default to
false
, but can be overridden when a transform on the file's stream is expected
to always generate the same result.
Events
The SendStream
is an event emitter and will emit the following events:
error
an error occurred(err)
directory
a directory was requestedfile
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)
.
.mime
The mime
export is the global instance of 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).
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
Small example
var http = require('http')
var parseUrl = require('parseurl')
var send = require('send-transform')
var app = http.createServer(function onRequest (req, res) {
send(req, parseUrl(req).pathname).pipe(res)
}).listen(3000)
Custom file types
var http = require('http')
var parseUrl = require('parseurl')
var send = require('send-transform')
// Default unknown types to text/plain
send.mime.default_type = 'text/plain'
// Add a custom type
send.mime.define({
'application/x-my-type': ['x-mt', 'x-mtt']
})
var app = http.createServer(function onRequest (req, res) {
send(req, parseUrl(req).pathname).pipe(res)
}).listen(3000)
Serving from a root directory with custom error-handling
var http = require('http')
var parseUrl = require('parseurl')
var send = require('send')
var app = 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/example.com/public'})
.on('error', error)
.on('directory', redirect)
.on('headers', headers)
.pipe(res);
}).listen(3000)