Added support for upload progress indicators in Apache and lighttpd 1…

….4.x (won't work in WEBrick or lighttpd 1.3.x) #1475 [Sean Treadway]

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@1553 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

actionpack/lib/action_controller/cgi_ext/multipart_progress.rb

@@ -0,0 +1,167 @@
+# == Overview
+#
+# This module will extend the CGI module with methods to track the upload
+# progress for multipart forms for use with progress meters.  The progress is
+# saved in the session to be used from any request from any server with the
+# same session.  In other words, this module will work across application
+# instances.
+#
+# === Usage
+#
+# Just do your file-uploads as you normally would, but include an upload_id in
+# the query string of your form action.  Your form post action should look
+# like:
+#
+#   <form method="post" enctype="multipart/form-data" action="postaction?upload_id=SOMEIDYOUSET">
+#     <input type="file" name="client_file"/>
+#   </form>
+#
+# Query the upload state in a progress by reading the progress from the session
+#
+#   class UploadController < ApplicationController
+#     def upload_status
+#       render :text => "Percent complete: " + @session[:uploads]['SOMEIDYOUSET'].completed_percent"
+#     end
+#   end
+#
+# === Session options
+#
+# Upload progress uses the session options defined in 
+# ActionController::CgiRequest::DEFAULT_SESSION_OPTIONS.  If you are passing
+# custom session options to your dispatcher then please follow the
+# "recommended way to change session options":http://wiki.rubyonrails.com/rails/show/HowtoChangeSessionOptions
+#
+# === Update frequency
+#
+# During an upload, the progress will be written to the session every 2
+# seconds.  This prevents excessive writes yet maintains a decent picture of
+# the upload progress for larger files.  
+#
+# User interfaces that update more often that every 2 seconds will display the same results.
+# Consider this update frequency when designing your progress polling.
+#
+
+require 'cgi'
+
+# For integration with ActionPack
+require 'action_controller/base'
+require 'action_controller/cgi_process'
+require 'action_controller/upload_progress'
+
+class CGI #:nodoc:
+  class ProgressIO < SimpleDelegator #:nodoc:
+    MIN_SAVE_INTERVAL = 1.0         # Number of seconds between session saves
+
+    attr_reader :progress, :session
+
+    def initialize(orig_io, progress, session)
+      @session = session
+      @progress = progress
+
+      @start_time = Time.now
+      @last_save_time = @start_time
+      save_progress
+
+      super(orig_io)
+    end
+
+    def read(*args)
+      data = __getobj__.read(*args)
+
+      if data and data.size > 0
+        now = Time.now
+        elapsed =  now - @start_time
+        progress.update!(data.size, elapsed)
+
+        if now - @last_save_time > MIN_SAVE_INTERVAL
+          save_progress 
+          @last_save_time = now 
+        end
+      else
+        ActionController::Base.logger.debug("CGI::ProgressIO#read returns nothing when it should return nil if IO is finished: [#{args.inspect}], a cancelled upload or old FCGI bindings.  Resetting the upload progress")
+
+        progress.reset!
+        save_progress
+      end
+
+      data
+    end
+
+    def save_progress
+      @session.update 
+    end
+
+    def finish
+      @session.update
+      ActionController::Base.logger.debug("Finished processing multipart upload in #{@progress.elapsed_seconds.to_s}s")
+    end
+  end
+
+  module QueryExtension #:nodoc:
+    # Need to do lazy aliasing on the instance that we are extending because of the way QueryExtension
+    # gets included for each instance of the CGI object rather than on a module level.  This method is a 
+    # bit obtrusive because we are overriding CGI::QueryExtension::extended which could be used in the 
+    # future.  Need to research a better method
+    def self.extended(obj)
+      obj.instance_eval do
+        # unless defined? will prevent clobbering the progress IO on multiple extensions
+        alias :stdinput_without_progress :stdinput unless defined? stdinput_without_progress
+        alias :stdinput :stdinput_with_progress 
+      end
+    end
+
+    def stdinput_with_progress
+      @stdin_with_progress or stdinput_without_progress
+    end
+
+    private
+    # Bootstrapped on ActionController::UploadProgress::upload_status_for
+    def read_multipart_with_progress(boundary, content_length)
+      begin
+        begin
+          # Session disabled if the default session options have been set to 'false'
+          options = ActionController::CgiRequest::DEFAULT_SESSION_OPTIONS
+          raise RuntimeError.new("Multipart upload progress disabled, no session options") unless options
+
+          options = options.stringify_keys
+
+          #Controllers.const_load!(:ApplicationController, "application") unless Controllers.const_defined?(:ApplicationController)
+
+          # Assumes that @cookies has already been setup
+          # Raises nomethod if upload_id is not defined
+          @params = CGI::parse(read_params_from_query)
+          upload_id = @params[(options['upload_key'] || 'upload_id')].first
+          raise RuntimeError.new("Multipart upload progress disabled, no upload id in query string") unless upload_id
+
+          upload_progress = ActionController::UploadProgress::Progress.new(content_length)
+
+          session = Session.new(self, options)
+          session[:uploads] = {} unless session[:uploads]
+          session[:uploads].delete(upload_id) # in case the same upload id is used twice
+          session[:uploads][upload_id] = upload_progress
+
+          @stdin_with_progress = CGI::ProgressIO.new(stdinput_without_progress, upload_progress, session)
+          ActionController::Base.logger.debug("Multipart upload with progress (id: #{upload_id}, size: #{content_length})")
+        rescue
+          ActionController::Base.logger.debug("Exception during setup of read_multipart_with_progress: #{$!}")
+        end
+      ensure
+        begin
+          params = read_multipart_without_progress(boundary, content_length)
+          @stdin_with_progress.finish if @stdin_with_progress.respond_to? :finish
+        ensure
+          @stdin_with_progress = nil
+          session.close if session
+        end
+      end
+      params 
+    end
+
+    # Prevent redefinition of aliases on multiple includes
+    unless private_instance_methods.include?("read_multipart_without_progress")
+      alias_method :read_multipart_without_progress, :read_multipart 
+      alias_method :read_multipart, :read_multipart_with_progress
+    end
+
+  end
+end