###############################################################################
# = gradesheet-server.rb
#
# WEBrick server to supply class gradesheet information.
# Copyright (C) 2005 by Allyn Dimock
#
# Produces a servlet processing https on the port given by the constant PORT
# with root given by the constant ROOT.
# Constant SHEETS is an array of hashes giving the information about the sheets
# that are available:
# * id => name to become part of URI 
#   e.g. "https://foo.bar.baz.com/OOCalcGradesheetDocs/301f03/"
#   if server is running on foo.bar.baz.com, ROOT="/OOCalcGradesheetDocs"
#   and id => "301f03"
# * file => name of OOCalc spresasheet file to be passed to 
#   StreadsheetContent.new
# * fixed_rows => array of integers showing rows in spreadsheet to be returned
#   along with the row for the query.
# * id_column => column in spreadsheet that contains an identifier that 
#   indicates the row to be returned.
#
###############################################################################

raise "Please, use ruby1.8.2 or later." if RUBY_VERSION < "1.8.2"

require 'webrick'
require 'webrick/https'
require 'gradesheet-rows'

include WEBrick

# Port number of server (default https port number = 443)
PORT_NUMBER = 8080

# URI doesn't use a real file name
ROOT = "/OOCalcGradesheetDocs"	

# Certificate: self-certified
CERTIFICATE = [ ["C","USA"],
                ["O","cs.uml.edu"],
                ["CN", "OocalcGradesheetViewer"] ]

#
# Gradesheets to serve:
# resource name, file name, rows to always return, id column
#
SHEETS =
  [
  {:id => '301f03', :file => "~/earth/grade301-F03/gradesheet.sxc", 
    :fixed_rows => [1,2,20,21], :id_column => 0},
  {:id => '531f03', :file => "~/earth/grade531-F03/roster.sxc",
    :fixed_rows => [1,35], :id_column => 1}
]

###############################################################################
#
# Define a HTTPS server  following model in "Gnome's Guide to WEBrick" by
# Yohanes Santoso.  Create new server, then yield to caller who can mount some
# services, then start server.
#
###############################################################################

def start_webrick(config={})	# Should we let caller set any config options? 
  config.update(:Port             => PORT_NUMBER)	# set port number
  config.update(:DocumentRoot     => ROOT)
  config.update(:SSLEnable        => true)
  config.update(:SSLVerifyClient  => ::OpenSSL::SSL::VERIFY_NONE)
  config.update(:SSLCertName      => CERTIFICATE)
  server = WEBrick::HTTPServer.new(config) # start server
  yield server if block_given?	# execute caller's block
#
# Set to trap INT, TERM signals and shut down cleanly on the signal
#
['INT','TERM'].each { |signal|
  trap(signal){ server.shutdown }
  }

  server.start
end

###############################################################################
#
# class OOCalcLinesServlet serves requests like
#
# GET /OOCalcGradesheetDocs/sheet_id/?id=123456789 HTTP/1.1
# From: myhost.mysubdomain.mydomain.com
#
# * if ?id=... not specified, replies with 412 (Precondition failed)
# * if no row is found for the id, replies with 404 (Not Found)
# * else replies with 200 (OK) and the payload from the students_html message
#   passed to the SpreadsheetContent object for sheet_id.
#
# Requests other than GET are not served!
###############################################################################

class OOCalcLinesServlet < HTTPServlet::AbstractServlet
  #############################################################################
  # 
  # Method do_GET handles a get request.
  #
  #############################################################################
  def do_GET(req,resp)
#    puts "in do_GET"
    if req.query['id']
      raise HTTPStatus::NotFound if req.query['id'] == ""
      begin
#	puts "processing " + '"' + req.query['id'] + '"'
	obj = @options[0]
	row = obj.students_row(req.query['id'])
      rescue Exception => exn
	puts "found some error " + exn.message
	print exn.backtrace.join("\n") + "\n"
#	puts "about to raise NotFound"
	raise HTTPStatus::NotFound
      end
      raise HTTPStatus::NotFound if row.nil?
      resp.body = obj.students_html(row)
#      puts "about to raise OK"
      raise HTTPStatus::OK
    else 
#      puts "about to raise PreconditionFailed"
      raise HTTPStatus::PreconditionFailed.new(
        "missing attribute 'id'")
    end				# if
  end				# def do_GET
end				# class OOCalcLinesServlet

###############################################################################
#
# Start the web service:
# Create SpreadsheetContent.new for each sheet in SHEETS,
# Start web server 
# Mount a resource for each gradesheet being serviced.
#
###############################################################################

def start_service() 
  sheets = []
  # initialize gradesheet info for each gradesheet served
  SHEETS.each { |sheet|
    sheets << {'id' => sheet[:id], 
      'obj' => SpreadsheetContent.new(sheet[:file],sheet[:fixed_rows],
				      sheet[:id_column])}
  }
  # start WEBrick HTTP server
  start_webrick() { |server|
    # mount a resource for each gradesheet served
    sheets.each { |sheet|
      server.mount(ROOT + '/' + sheet['id'], OOCalcLinesServlet, sheet['obj'])
    }				# sheets.each
  }				# block to start_webrick()
end				# start_service

start_service()