class Rhcf::Utils::DownloadCache

Public Class Methods

hit_fname?(fname, ttl) click to toggle source
# File lib/rhcf/utils/download_cache.rb, line 52
def self.hit_fname?(fname, ttl)
  
  if File.exist?(fname) and !File.zero?(fname)
    if ttl
      File::Stat.new(fname).ctime > Time.now - ttl
    else 
      true
    end
  else
    false
  end
end
new(cache_id= 'default', ttl = nil, root_path = nil) click to toggle source
# File lib/rhcf/utils/download_cache.rb, line 12
def initialize(cache_id= 'default', ttl = nil, root_path = nil)
  @cache_id = cache_id
  @ttl = ttl
  @root_path ||= "/tmp/#{self.class.name}"
end

Public Instance Methods

download!(url, outfile) click to toggle source
# File lib/rhcf/utils/download_cache.rb, line 26
def download!(url, outfile)
  uri = URI(url)
  expected_file_size = nil
  Net::HTTP.start(uri.host) do |http|
   resp = http.get(uri.path)
   fail(DownloadError, resp.code) if resp.code != '200'

    expected_file_size = resp.body.size
    mkdir_p(File.dirname(outfile))
    File.open(outfile, 'wb') do |fd|
      fd.write(resp.body)
    end
  end

  if expected_file_size != File.size(outfile)
    raise "Different file size expected: '%d' bytes got: '%d' bytes " % [expected_file_size, File.size(outfile)]
  end
  raise "Empty file" if File.zero?(outfile)
  outfile
end
filename_for(url) click to toggle source
# File lib/rhcf/utils/download_cache.rb, line 65
def filename_for(url)
  hash =  Digest::MD5.hexdigest(url)
  uri = URI(url)
  basename = File.basename(uri.path)
  File.join(@root_path, @cache_id, hash_tree(hash), basename) 
end
get(url) click to toggle source
# File lib/rhcf/utils/download_cache.rb, line 19
def get(url)
  outfile = filename_for(url)
  return outfile if self.class.hit_fname?(outfile, @ttl) # here goes the cache
  download!(url, outfile)
end
hash_tree(hash) click to toggle source
# File lib/rhcf/utils/download_cache.rb, line 72
def hash_tree(hash)
  [*(hash[0,3].split('')) ,hash].join('/')
end
hit?(url) click to toggle source
# File lib/rhcf/utils/download_cache.rb, line 47
def hit?(url)
  outfile = filename_for(url)
  self.class.hit_fname?(outfile, @ttl) # here goes the cache
end