module ActionController::DataStreaming
Action Controller Data Streaming¶ ↑
Methods for sending arbitrary data and for streaming files to the browser, instead of rendering.
Private Instance Methods
Sends the given binary data to the browser. This method is similar to render plain: data
, but also allows you to specify whether the browser should display the response as a file attachment (i.e. in a download dialog) or as inline data. You may also set the content type, the file name, and other things.
Options:
-
:filename
- suggests a filename for the browser to use. -
:type
- specifies an HTTP content type. Defaults toapplication/octet-stream
. You can specify either a string or a symbol for a registered type withMime::Type.register
, for example:json
. If omitted, type will be inferred from the file extension specified in:filename
. If no content type is registered for the extension, the default typeapplication/octet-stream
will be used. -
:disposition
- specifies whether the file will be shown inline or downloaded. Valid values are"inline"
and"attachment"
(default). -
:status
- specifies the status code to send with the response. Defaults to 200.
Generic data download:
send_data buffer
Download a dynamically-generated tarball:
send_data generate_tgz('dir'), filename: 'dir.tgz'
Display an image Active Record in the browser:
send_data image.data, type: image.content_type, disposition: 'inline'
See send_file
for more information on HTTP Content-*
headers and caching.
# File actionpack/lib/action_controller/metal/data_streaming.rb, line 111 def send_data(data, options = {}) # :doc: send_file_headers! options render options.slice(:status, :content_type).merge(body: data) end
Sends the file. This uses a server-appropriate method (such as X-Sendfile
) via the Rack::Sendfile
middleware. The header to use is set via config.action_dispatch.x_sendfile_header
. Your server can also configure this for you by setting the X-Sendfile-Type
header.
Be careful to sanitize the path parameter if it is coming from a web page. send_file(params[:path])
allows a malicious user to download any file on your server.
Options:
-
:filename
- suggests a filename for the browser to use. Defaults toFile.basename(path)
. -
:type
- specifies an HTTP content type. You can specify either a string or a symbol for a registered type withMime::Type.register
, for example:json
. If omitted, the type will be inferred from the file extension specified in:filename
. If no content type is registered for the extension, the default typeapplication/octet-stream
will be used. -
:disposition
- specifies whether the file will be shown inline or downloaded. Valid values are"inline"
and"attachment"
(default). -
:status
- specifies the status code to send with the response. Defaults to 200. -
:url_based_filename
- set totrue
if you want the browser to guess the filename from the URL, which is necessary for i18n filenames on certain browsers (setting:filename
overrides this option).
The default Content-Type
and Content-Disposition
headers are set to download arbitrary binary files in as many browsers as possible. IE versions 4, 5, 5.5, and 6 are all known to have a variety of quirks (especially when downloading over SSL).
Simple download:
send_file '/path/to.zip'
Show a JPEG in the browser:
send_file '/path/to.jpeg', type: 'image/jpeg', disposition: 'inline'
Show a 404 page in the browser:
send_file '/path/to/404.html', type: 'text/html; charset=utf-8', disposition: 'inline', status: 404
You can use other Content-*
HTTP headers to provide additional information to the client. See MDN for a list of HTTP headers.
Also be aware that the document may be cached by proxies and browsers. The Pragma
and Cache-Control
headers declare how the file may be cached by intermediaries. They default to require clients to validate with the server before releasing cached responses. See www.mnot.net/cache_docs/ for an overview of web caching and RFC 9111 for the Cache-Control
header spec.
# File actionpack/lib/action_controller/metal/data_streaming.rb, line 71 def send_file(path, options = {}) # :doc: raise MissingFile, "Cannot read file #{path}" unless File.file?(path) && File.readable?(path) options[:filename] ||= File.basename(path) unless options[:url_based_filename] send_file_headers! options self.status = options[:status] || 200 self.content_type = options[:content_type] if options.key?(:content_type) response.send_file path end