vendor/rails/actionpack/lib/action_controller/streaming.rb

   1 module ActionController #:nodoc:
   2   # Methods for sending arbitrary data and for streaming files to the browser,
   3   # instead of rendering.
   4   module Streaming
   5     DEFAULT_SEND_FILE_OPTIONS = {
   6       :type         => 'application/octet-stream'.freeze,
   7       :disposition  => 'attachment'.freeze,
   8       :stream       => true,
   9       :buffer_size  => 4096,
  10       :x_sendfile   => false
  11     }.freeze
  12
  13     X_SENDFILE_HEADER = 'X-Sendfile'.freeze
  14
  15     protected
  16       # Sends the file, by default streaming it 4096 bytes at a time. This way the
  17       # whole file doesn't need to be read into memory at once. This makes it
  18       # feasible to send even large files. You can optionally turn off streaming
  19       # and send the whole file at once.
  20       #
  21       # Be careful to sanitize the path parameter if it is coming from a web
  22       # page. <tt>send_file(params[:path])</tt> allows a malicious user to
  23       # download any file on your server.
  24       #
  25       # Options:
  26       # * <tt>:filename</tt> - suggests a filename for the browser to use.
  27       #   Defaults to <tt>File.basename(path)</tt>.
  28       # * <tt>:type</tt> - specifies an HTTP content type. Defaults to 'application/octet-stream'. You can specify
  29       #   either a string or a symbol for a registered type register with <tt>Mime::Type.register</tt>, for example :json
  30       # * <tt>:length</tt> - used to manually override the length (in bytes) of the content that
  31       #   is going to be sent to the client. Defaults to <tt>File.size(path)</tt>.
  32       # * <tt>:disposition</tt> - specifies whether the file will be shown inline or downloaded.
  33       #   Valid values are 'inline' and 'attachment' (default).
  34       # * <tt>:stream</tt> - whether to send the file to the user agent as it is read (+true+)
  35       #   or to read the entire file before sending (+false+). Defaults to +true+.
  36       # * <tt>:buffer_size</tt> - specifies size (in bytes) of the buffer used to stream the file.
  37       #   Defaults to 4096.
  38       # * <tt>:status</tt> - specifies the status code to send with the response. Defaults to '200 OK'.
  39       # * <tt>:url_based_filename</tt> - set to +true+ if you want the browser guess the filename from
  40       #   the URL, which is necessary for i18n filenames on certain browsers
  41       #   (setting <tt>:filename</tt> overrides this option).
  42       # * <tt>:x_sendfile</tt> - uses X-Sendfile to send the file when set to +true+. This is currently
  43       #   only available with Lighttpd/Apache2 and specific modules installed and activated. Since this
  44       #   uses the web server to send the file, this may lower memory consumption on your server and
  45       #   it will not block your application for further requests.
  46       #   See http://blog.lighttpd.net/articles/2006/07/02/x-sendfile and
  47       #   http://tn123.ath.cx/mod_xsendfile/ for details. Defaults to +false+.
  48       #
  49       # The default Content-Type and Content-Disposition headers are
  50       # set to download arbitrary binary files in as many browsers as
  51       # possible.  IE versions 4, 5, 5.5, and 6 are all known to have
  52       # a variety of quirks (especially when downloading over SSL).
  53       #
  54       # Simple download:
  55       #
  56       #   send_file '/path/to.zip'
  57       #
  58       # Show a JPEG in the browser:
  59       #
  60       #   send_file '/path/to.jpeg', :type => 'image/jpeg', :disposition => 'inline'
  61       #
  62       # Show a 404 page in the browser:
  63       #
  64       #   send_file '/path/to/404.html', :type => 'text/html; charset=utf-8', :status => 404
  65       #
  66       # Read about the other Content-* HTTP headers if you'd like to
  67       # provide the user with more information (such as Content-Description) in
  68       # http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.11.
  69       #
  70       # Also be aware that the document may be cached by proxies and browsers.
  71       # The Pragma and Cache-Control headers declare how the file may be cached
  72       # by intermediaries.  They default to require clients to validate with
  73       # the server before releasing cached responses.  See
  74       # http://www.mnot.net/cache_docs/ for an overview of web caching and
  75       # http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.9
  76       # for the Cache-Control header spec.
  77       def send_file(path, options = {}) #:doc:
  78         raise MissingFile, "Cannot read file #{path}" unless File.file?(path) and File.readable?(path)
  79
  80         options[:length]   ||= File.size(path)
  81         options[:filename] ||= File.basename(path) unless options[:url_based_filename]
  82         send_file_headers! options
  83
  84         @performed_render = false
  85
  86         if options[:x_sendfile]
  87           logger.info "Sending #{X_SENDFILE_HEADER} header #{path}" if logger
  88           head options[:status], X_SENDFILE_HEADER => path
  89         else
  90           if options[:stream]
  91             render :status => options[:status], :text => Proc.new { |response, output|
  92               logger.info "Streaming file #{path}" unless logger.nil?
  93               len = options[:buffer_size] || 4096
  94               File.open(path, 'rb') do |file|
  95                 while buf = file.read(len)
  96                   output.write(buf)
  97                 end
  98               end
  99             }
 100           else
 101             logger.info "Sending file #{path}" unless logger.nil?
 102             File.open(path, 'rb') { |file| render :status => options[:status], :text => file.read }
 103           end
 104         end
 105       end
 106
 107       # Sends the given binary data to the browser. This method is similar to
 108       # <tt>render :text => data</tt>, but also allows you to specify whether
 109       # the browser should display the response as a file attachment (i.e. in a
 110       # download dialog) or as inline data. You may also set the content type,
 111       # the apparent file name, and other things.
 112       #
 113       # Options:
 114       # * <tt>:filename</tt> - suggests a filename for the browser to use.
 115       # * <tt>:type</tt> - specifies an HTTP content type. Defaults to 'application/octet-stream'. You can specify
 116       #   either a string or a symbol for a registered type register with <tt>Mime::Type.register</tt>, for example :json
 117       # * <tt>:disposition</tt> - specifies whether the file will be shown inline or downloaded.
 118       #   Valid values are 'inline' and 'attachment' (default).
 119       # * <tt>:status</tt> - specifies the status code to send with the response. Defaults to '200 OK'.
 120       #
 121       # Generic data download:
 122       #
 123       #   send_data buffer
 124       #
 125       # Download a dynamically-generated tarball:
 126       #
 127       #   send_data generate_tgz('dir'), :filename => 'dir.tgz'
 128       #
 129       # Display an image Active Record in the browser:
 130       #
 131       #   send_data image.data, :type => image.content_type, :disposition => 'inline'
 132       #
 133       # See +send_file+ for more information on HTTP Content-* headers and caching.
 134       #
 135       # <b>Tip:</b> if you want to stream large amounts of on-the-fly generated
 136       # data to the browser, then use <tt>render :text => proc { ... }</tt>
 137       # instead. See ActionController::Base#render for more information.
 138       def send_data(data, options = {}) #:doc:
 139         logger.info "Sending data #{options[:filename]}" if logger
 140         send_file_headers! options.merge(:length => data.size)
 141         @performed_render = false
 142         render :status => options[:status], :text => data
 143       end
 144
 145     private
 146       def send_file_headers!(options)
 147         options.update(DEFAULT_SEND_FILE_OPTIONS.merge(options))
 148         [:length, :type, :disposition].each do |arg|
 149           raise ArgumentError, ":#{arg} option required" if options[arg].nil?
 150         end
 151
 152         disposition = options[:disposition].dup || 'attachment'
 153
 154         disposition <<= %(; filename="#{options[:filename]}") if options[:filename]
 155
 156         content_type = options[:type]
 157         if content_type.is_a?(Symbol)
 158           raise ArgumentError, "Unknown MIME type #{options[:type]}" unless Mime::EXTENSION_LOOKUP.has_key?(content_type.to_s)
 159           content_type = Mime::Type.lookup_by_extension(content_type.to_s)
 160         end
 161         content_type = content_type.to_s.strip # fixes a problem with extra '\r' with some browsers
 162
 163         headers.merge!(
 164           'Content-Length'            => options[:length],
 165           'Content-Type'              => content_type,
 166           'Content-Disposition'       => disposition,
 167           'Content-Transfer-Encoding' => 'binary'
 168         )
 169
 170         # Fix a problem with IE 6.0 on opening downloaded files:
 171         # If Cache-Control: no-cache is set (which Rails does by default),
 172         # IE removes the file it just downloaded from its cache immediately
 173         # after it displays the "open/save" dialog, which means that if you
 174         # hit "open" the file isn't there anymore when the application that
 175         # is called for handling the download is run, so let's workaround that
 176         headers['Cache-Control'] = 'private' if headers['Cache-Control'] == 'no-cache'
 177       end
 178   end
 179 end