module ActionController #:nodoc:
# Methods for sending arbitrary data and for streaming files to the browser,
# instead of rendering.
module Streaming
extend ActiveSupport::Concern
include ActionController::Rendering
DEFAULT_SEND_FILE_OPTIONS = {
:type => 'application/octet-stream'.freeze,
:disposition => 'attachment'.freeze,
:stream => true,
:buffer_size => 4096,
:x_sendfile => false
}.freeze
X_SENDFILE_HEADER = 'X-Sendfile'.freeze
protected
# Sends the file, by default 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. You can optionally turn off streaming
# and send the whole file at once.
#
# Be careful to sanitize the path parameter if it is coming from a web
# page. <tt>send_file(params[:path])</tt> allows a malicious user to
# download any file on your server.
#
# Options:
# * <tt>:filename</tt> - suggests a filename for the browser to use.
# Defaults to <tt>File.basename(path)</tt>.
# * <tt>:type</tt> - specifies an HTTP content type. Defaults to 'application/octet-stream'. You can specify
# either a string or a symbol for a registered type register with <tt>Mime::Type.register</tt>, for example :json
# * <tt>:length</tt> - used to manually override the length (in bytes) of the content that
# is going to be sent to the client. Defaults to <tt>File.size(path)</tt>.
# * <tt>:disposition</tt> - specifies whether the file will be shown inline or downloaded.
# Valid values are 'inline' and 'attachment' (default).
# * <tt>:stream</tt> - 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+.
# * <tt>:buffer_size</tt> - specifies size (in bytes) of the buffer used to stream the file.
# Defaults to 4096.
# * <tt>:status</tt> - specifies the status code to send with the response. Defaults to '200 OK'.
# * <tt>:url_based_filename</tt> - set to +true+ if you want the browser guess the filename from
# the URL, which is necessary for i18n filenames on certain browsers
# (setting <tt>:filename</tt> overrides this option).
# * <tt>:x_sendfile</tt> - uses X-Sendfile to send the file when set to +true+. This is currently
# only available with Lighttpd/Apache2 and specific modules installed and activated. Since this
# uses the web server to send the file, this may lower memory consumption on your server and
# it will not block your application for further requests.
# See http://blog.lighttpd.net/articles/2006/07/02/x-sendfile and
# http://tn123.ath.cx/mod_xsendfile/ for details. Defaults to +false+.
#
# 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) in
# http://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
# http://www.mnot.net/cache_docs/ for an overview of web caching and
# http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.9
# for the Cache-Control header spec.
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) unless options[:url_based_filename]
send_file_headers! options
@performed_render = false
if options[:x_sendfile]
head options[:status], X_SENDFILE_HEADER => path
else
if options[:stream]
# TODO : Make render :text => proc {} work with the new base
render :status => options[:status], :text => Proc.new { |response, output|
len = options[:buffer_size] || 4096
File.open(path, 'rb') do |file|
while buf = file.read(len)
output.write(buf)
end
end
}
else
File.open(path, 'rb') { |file| render :status => options[:status], :text => file.read }
end
end
end
# Sends the given binary data to the browser. This method is similar to
# <tt>render :text => data</tt>, 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 apparent file name, and other things.
#
# Options:
# * <tt>:filename</tt> - suggests a filename for the browser to use.
# * <tt>:type</tt> - specifies an HTTP content type. Defaults to 'application/octet-stream'. You can specify
# either a string or a symbol for a registered type register with <tt>Mime::Type.register</tt>, for example :json
# * <tt>:disposition</tt> - specifies whether the file will be shown inline or downloaded.
# Valid values are 'inline' and 'attachment' (default).
# * <tt>:status</tt> - 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.
#
# <b>Tip:</b> if you want to stream large amounts of on-the-fly generated
# data to the browser, then use <tt>render :text => proc { ... }</tt>
# instead. See ActionController::Base#render for more information.
def send_data(data, options = {}) #:doc:
send_file_headers! options.merge(:length => data.bytesize)
render :status => options[:status], :text => data
end
private
def send_file_headers!(options)
options.update(DEFAULT_SEND_FILE_OPTIONS.merge(options))
[:length, :type, :disposition].each do |arg|
raise ArgumentError, ":#{arg} option required" if options[arg].nil?
end
disposition = options[:disposition].dup || 'attachment'
disposition <<= %(; filename="#{options[:filename]}") if options[:filename]
content_type = options[:type]
if content_type.is_a?(Symbol)
raise ArgumentError, "Unknown MIME type #{options[:type]}" unless Mime::EXTENSION_LOOKUP.key?(content_type.to_s)
self.content_type = Mime::Type.lookup_by_extension(content_type.to_s)
else
self.content_type = content_type
end
headers.merge!(
'Content-Length' => options[:length].to_s,
'Content-Disposition' => disposition,
'Content-Transfer-Encoding' => 'binary'
)
response.sending_file = true
# Fix a problem with IE 6.0 on opening downloaded files:
# If Cache-Control: no-cache is set (which Rails does by default),
# IE removes the file it just downloaded from its cache immediately
# after it displays the "open/save" dialog, which means that if you
# hit "open" the file isn't there anymore when the application that
# is called for handling the download is run, so let's workaround that
response.cache_control[:public] ||= false
end
end
end
