Sample rake tasks

build.rb

require 'rexml/document'

@json_files
@xml_files

# This set of tasks assumes that some settings have been already
# been loaded in to globals called APP_SETTINGS and USER_SETTINGS.
# Pretty much everything will fail until that has been done, usually
# in a calling rakefile
desc "Default build task"
task :default => ['user_config','db:update_connection_strings'] do
end

task :clean => ['creator:clean']
task :clobber => ['creator:clean']

desc 'Update configuration files specific to a user'
task :user_config => ['creator:create_user_files'] do
	puts "Updating JSON configuration files"
	search_terms = USER_SETTINGS['servers']
	
	APP_SETTINGS['json_templates'].each do |name|
		target = name.ext('') # strip file extension
		cp name, target, :verbose => false
		text = File.read(target)
		
		search_terms.each do |s,r|
			text = text.gsub(s.upcase,r)
		end

		f = File.open(target, 'w')
		f.write(text)
	end
end

def load_file_lists
	@json_files = Array.new
	@json_files.concat(APP_SETTINGS['json_templates'])
	@xml_files = Array.new
	@xml_files.concat(APP_SETTINGS['xml_templates'])
end

namespace :creator do


	# This is kind of wacky - Rake can create a task-per-file. In this
	# case we first build a list of all of the files we want and THEN
	# build a task that collects all of the file copy activities
	# together. Sort of backwards to my way of thinking but it works.
	
	# What's really cool is that Rake keeps track of which files it's
	# already created, so you can call this multiple times and it'll
	# only copy files that don't yet exist. Of course, if you've changed
	# a file then you need to run the creator:clean task first to get
	# back to square one
	load_file_lists()

	FileList[@json_files, @xml_files].each do | source |
		target = source.ext('')
		file target => source do
			cp source, target, :verbose => false
		end
		desc 'Creates all of the user specific files from templates'
		task :create_user_files  => target

	end
	
	desc 'Remove user specific config files'
	task :clean do
		load_file_lists()
		delete_these = @json_files.map {|x| x.ext('') }
		delete_these.concat(@xml_files.map {|x| x.ext('') })
		puts "Deleting existing user configurations"
		rm_f FileList[delete_these], :verbose => false
	end

end

# Database specific stuff
namespace :db do

	desc 'Updates *.config files with valid database connection strings'
	task :update_connection_strings => ['creator:create_user_files'] do
		puts "Updating connection strings"
		@xml_files.each do | xml |
			doc = REXML::Document::new(File.open(xml.ext('')))
			doc.elements.each('connectionStrings/add') do | element |
				element.attributes["connectionString"] = USER_SETTINGS['database'][element.attributes['name'].to_s.downcase]
			end
			
			f = File.open(xml.ext(''), 'w')
			f.write(doc)
		
		end
	end

end