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

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