send
Last updated
Last updated
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.
This is a Node.js module available through the npm registry. Installation is done using the npm install
command:
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).
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 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 diable 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.
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
The pipe
method is used to pipe the response into the Node.js HTTP response object, typically send(req, path, options).pipe(res)
.
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).
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.
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 ;).
To enable debug()
instrumentation output export DEBUG:
This simple example will send a specific file to all requests.
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
.
This is a example of serving up a structure of directories with a custom function to render a listing of a directory.