Update multiple dokuwiki installations via a ruby script

upgrade_dokuwiki.rb

#! /usr/bin/env ruby
=begin
  This script backups and updates all dokuwiki installations on this server
  Copyright (c) 2010 by Johannes Thönes <johannes.thoenes@googlemail.com>
  Licensed under the MIT license: http://www.opensource.org/licenses/mit-license.php
=end

# Library Requirements
require 'net/http' # for download of the files
require 'open-uri' # for download of the files
require 'fileutils' # for file operation
include FileUtils
require 'tmpdir' # for Dir.tmpdir
require 'date' # for time

require 'rubygems' # Rubygems for the following libs
require 'libarchive_ruby' # for archive extraction

# Definition of existing installation
INSTALLATIONS = [
  '/path/to/docu/wiki/installation1',
  '/path/to/docu/wiki/installation2'
].freeze

# Files to remove Gist
OLD_FILES_URL = 'http://www.dokuwiki.org/_export/code/install:upgrade?codeblock=7'

# Helper Function (change here, if you want to customize something)
def backup_folder_base 
  @backup_folder_base ||= "#{Dir.tmpdir}/dokuwiki_backup_#{DateTime.now.strftime('%Y%m%d-%H%M%S')}"
end

def download_location uri
  "#{Dir.tmpdir}/#{release_package_name(uri)}"
end

def release_package_name uri
  uri.path.split('/').last
end

def release_name uri
  release_package_name(uri).split('.').first
end

def walk_archive location
  Archive.read_open_filename(location) do |archive| 
    while entry = archive.next_header
      location = entry.pathname.split('/').reject{|dirname| dirname =~ /dokuwiki-(rc?)\d{4}-\d{2}-\d{2}/}
			data = archive.read_data
      yield(location, entry, data)
    end
  end
end

def apply_to_installation_path rel_path
  INSTALLATIONS.each do |inst|
    yield("#{inst}/#{rel_path}")
  end
end

def create_data_folder_if_not_exists rel_path
  apply_to_installation_path(rel_path) do |path|
	  unless File.directory?(path)
		  raise "'#{path}' exists but is not a directory" if File.exists?(path)
			mkdir path
			chown_R 'www-data', 'www-data', path
			chmod_R 664, path
		end
	end
end

def create_folder_if_not_exists rel_path, entry
  apply_to_installation_path(rel_path) do |path|
	  unless File.directory?(path)
		  raise "'#{path}' exists but is not a directory" if File.exists?(path)
			mkdir path
			chmod entry.mode, path
	  end
  end
end

def copy_file rel_path, entry, data
  apply_to_installation_path(rel_path) do |path|
		File.open(path, 'w', entry.mode) {|f| f.write(data)}
  end
end

def delete_file_if_exists rel_path
  apply_to_installation_path(rel_path) do |path|
    rm(path) if File.exists?(path)
  end
end

# Parameter extraction
raise "You need to supply the current dokuwiki release download" if ARGV.first.nil?
package_uri = URI.parse(ARGV.first)


# Backup existing locations to a folder in tempdir
raise "Backup Folder '#{backup_folder_base}' already exists" if File.exists?(backup_folder_base)
mkdir backup_folder_base
INSTALLATIONS.each do |installation|
  cp_r installation, backup_folder_base
end

# Downloading the newest dokuwiki package
archive_loc = download_location(package_uri)
Net::HTTP.start(package_uri.host) do |http|
  response = http.get(package_uri.path)
  File.open(download_location(package_uri), 'w') {|f| f.write(response.body)}
end

# Copy the new package (except the /data folder) into the the directories
walk_archive(archive_loc) do |location, entry, data|
  if (location.first == 'data')
	  create_data_folder_if_not_exists(location.join('/')) if entry.directory?
  else
		create_folder_if_not_exists(location.join('/'), entry) if entry.directory?
		copy_file(location.join('/'), entry, data) unless entry.directory?
  end
end

# Delete old files
open(OLD_FILES_URL) do |f|
  f.each_line do |rel_path|
    if rel_path !~ /^#/ and rel_path.strip.length != 0
      delete_file_if_exists(rel_path)
    end
  end
end