parse.rb

require 'net/http'
require 'rexml/document'
require 'rubygems'

# gem install xmlsimple
require 'xmlsimple'


def ParseSemester(year, season)
	# for the loops (they are mostly hash iterators) ,  k stands for key and v stand for value

	# Build the URLs
    # ex:	semester = "2011/spring"
	semester = year + "/" + season
	base_url = "http://courses.illinois.edu/cis/" + semester 
	url = base_url + "/schedule/index.xml"

	# Grab the response from the URL as a string
	xml_data = Net::HTTP.get_response(URI.parse(url)).body

	xml_data = "spring2011.xml"
	# Turn the string into a hash of data 
	catalog = XmlSimple.xml_in(xml_data)

	# Iterate through the subjects found in the hash
	catalog['subject'].each do |subject|
		print "-------\nSubject\n-------\n\n"

		# Build a url based off of the current subject code
		subjectURL = base_url + "/schedule/" + subject['subjectCode'].to_s + "/index.xml"
		
		# Fetch the courses for the subject and decrypt the data from the url
		subjectXML_data = Net::HTTP.get_response(URI.parse(subjectURL)).body
		subjectCourses = XmlSimple.xml_in(subjectXML_data)	

		# Iterate through the courses offered in the class 
		subjectCourses['subject'][0].each do |k, v|
			# Found a course tag, get all the information about the course
			if k == "course"
				v.each do |course|
					print "-------\nCourse START\n-------\n\n"
					course.each do |k, v|
						if k == "section"
							print "-------\nSection\n-------\n\n"
							v.each do |section|
								section.each do |k, v|
									print "\t\t\t<" + k + ">"+ v.to_s + "</"+ k+ ">\n"
								end
							end
							print "-------\nSection END\n-------\n\n"
						else
							print "\t\t<" + k + ">"+ v.to_s + "</"+ k+ ">\n"
						end
					end
					print "-------\nCourse END\n-------\n\n"
				end
			end
		end

		# iterate through the elements of the subject 
		# -General information about each subject/major
		subject.each do |k,v|
			print "<" + k + ">"+ v.to_s + "</"+ k+ ">\n"
		end

		print "\n"
	#	puts subject['subjectCode']
	end
end

ParseSemester( "2011", "spring")