From: ahoward <ahoward@...>
Date: 2003-02-13T00:03:12+09:00
Subject: class MOD_FCGI < FCGI



rubyists-

i've collected some usefull examples and added some signal handling to the
fcgi package written by moon wolf.  if any one has experience using fcgi out
there i appreciate any comments.  highlights are

    * reload any application using 'kill -HUP pid' w/o hanging apache
    * gracefull shutdown from confusing SIGUSR1/SIGHUP combo sent by
      apache/mod_fastcgi to fcgi programs
    * clean exit on 'kill -TERM pid'
    * each method which provides a CGI object

eg of use

   MOD_FCGI.each('html3') do |cgi|
      content = ''
      cgi.env_table.each do |k,v|
	content << "#{k} -> #{v}<br>\n"
      end
      cgi.out { cgi.html { cgi.body { content } } }
  end


ps.  this is named MOD_FCGI because, AFAIK this signal handling is specific to
apache's mod_fastcgi


file : mod_fcgi.rb
----CUT----
require 'fcgi'
require 'cgi'
require 'ftools'


class MOD_FCGI < FCGI

  class Log < File
    def tmpnam basename = nil,
	       tmpdir = ENV['TMPDIR']||ENV['TMP']||ENV['TEMP']||'/tmp'
      if $SAFE > 0 and tmpdir.tainted?
	tmpdir = '/tmp'
      end
      basename ||= File.basename $0
      n = 0
      while true
	begin
	  path = sprintf('%s/%s%d.%d', tmpdir, basename, $$, n)
	  @_lock = path + '.lock'
	  unless File.exist?(path) or File.exist?(@_lock)
	    Dir.mkdir(@_lock)
	    break
	  end
	rescue
	  raise "cannot generate tempfile `%s'" % path if n >= 16
	end
	n += 1
      end
      path
    end
    def initialize path = tmpnam, mode = 'w+', &block
      super path, mode, &block
      Dir.rmdir(@_lock) if defined? @_lock
      self.sync = true
    end
  end

  # enable CGI to bootstrap off of an FCGI request
  class CGI < ::CGI
    class << self
      def remove_params
	if (const_defined?(:CGI_PARAMS))
	  remove_const(:CGI_PARAMS)
	  remove_const(:CGI_COOKIES)
	end
      end
    end
    def initialize(request, *args)
      self.class.remove_params
      @request = request
      super (*args)
      @args = *args
    end
    def args
      @args
    end
    def env_table
      @request.env
    end
    def stdinput
      @request.in
    end
    def stdoutput
      @request.out
    end
  end

  # initialize mod_fcgi
  @@handling_request = false
  @@exit_requested = false
  @@traps_installed = false
  @@signals = []


  class << self
    def handle_request
      @@handling_request = true
      yield if block_given?
      ensure
	@@handling_request = false
    end

    def install_traps
      return if @@traps_installed

      # user signal to reload application
      # does a clean shutdown after which
      # the fcgi_pm will reload of source file
      trap ('SIGHUP') do
	unless @@signals.size > 0
	  @@signals << 'SIGHUP'
	  if @@handling_request
	    @@exit_requested = true
	  else
	    @@server.close
	    exit
	  end
	end
      end

      # sent from apache to do clean shutdown
      # note that a sigterm could be sent from fcgi_pm
      # AFTER this!  we handle only one of them!
      trap ('SIGUSR1') do
	unless @@signals.size > 0
	  @@signals << 'SIGUSR1'
	  if @@handling_request
	    @@exit_requested = true
	  else
	    @@server.close
	    exit
	  end
	end
      end

      # see above note.
      # when no other signals pedning, simply exit quickly
      trap ('SIGTERM') do
	unless @@signals.size > 0
	  @@signals << 'SIGTERM'
	  @@server.close
	  exit
	end
      end

      # sent from mod_fcgi when client aborts request
      # we simply ignore this for now, although some smarts could be
      # added to abort the present request and resume accepting...
      trap ('SIGPIPE') do
	# nothing
      end

      @@traps_installed = true
    end

    def each (*args)
      install_traps
      while request = accept
	handle_request {
	  if block_given?
	    yield (CGI.new (request, *args))
	    request.finish
	  end
	}
	exit if @@exit_requested
      end
    end

    alias each_request each
  end
end
----CUT----

-a

-- 

 ====================================
 | Ara Howard
 | NOAA Forecast Systems Laboratory
 | Information and Technology Services
 | Data Systems Group
 | R/FST 325 Broadway
 | Boulder, CO 80305-3328
 | Email: ahoward@fsl.noaa.gov
 | Phone:  303-497-7238
 | Fax:    303-497-7259
 ====================================