Methods for sending files and streams to the browser instead of rendering.

Methods
S
Constants
DEFAULT_SEND_FILE_OPTIONS = { :type => 'application/octet-stream'.freeze, :disposition => 'attachment'.freeze, :stream => true, :buffer_size => 4096 }.freeze
 
Instance Protected methods
send_data(data, options = {})

Send binary data to the user as a file download. May set content type, apparent file name, and specify whether to show data inline or download as an attachment.

Options:

  • :filename - Suggests a filename for the browser to use.

  • :type - specifies an HTTP content type. Defaults to 'application/octet-stream'.

  • :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 OK'.

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.

Source: show 

# File rails/actionpack/lib/action_controller/streaming.rb, line 104
def send_data(data, options = {}) #:doc:
  logger.info "Sending data #{options[:filename]}" unless logger.nil?
  send_file_headers! options.merge(:length => data.size)
  @performed_render = false
  render :status => options[:status], :text => data
end
send_file(path, options = {})

Sends the file by streaming it 4096 bytes at a time. This way the whole file doesn’t need to be read into memory at once. This makes it feasible to send even large files.

Be careful to sanitize the path parameter if it coming from a web page. send_file(params) allows a malicious user to download any file on your server.

Options:

  • :filename - suggests a filename for the browser to use. Defaults to File.basename(path).

  • :type - specifies an HTTP content type. Defaults to 'application/octet-stream'.

  • :disposition - specifies whether the file will be shown inline or downloaded.

    Valid values are ‘inline’ and ‘attachment’ (default).

  • :stream - whether to send the file to the user agent as it is read (true) or to read the entire file before sending (false). Defaults to true.

  • :buffer_size - specifies size (in bytes) of the buffer used to stream the file. Defaults to 4096.

  • :status - specifies the status code to send with the response. Defaults to '200 OK'.

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', :status => 404

Read about the other Content-* HTTP headers if you’d like to provide the user with more information (such as Content-Description). www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.11

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 www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.9 for the Cache-Control header spec.

Source: show 

# File rails/actionpack/lib/action_controller/streaming.rb, line 58
def send_file(path, options = {}) #:doc:
  raise MissingFile, "Cannot read file #{path}" unless File.file?(path) and File.readable?(path)

  options[:length]   ||= File.size(path)
  options[:filename] ||= File.basename(path)
  send_file_headers! options

  @performed_render = false

  if options[:stream]
    render :status => options[:status], :text => Proc.new { |response, output|
      logger.info "Streaming file #{path}" unless logger.nil?
      len = options[:buffer_size] || 4096
      File.open(path, 'rb') do |file|
        while buf = file.read(len)
          output.write(buf)
        end
      end
    }
  else
    logger.info "Sending file #{path}" unless logger.nil?
    File.open(path, 'rb') { |file| render :status => options[:status], :text => file.read }
  end
end