August 12, 2007 by alex
If you change the images dimensions or introduce a new version for models using file column you need a way to update the existing ones. Here is a script that will regenerate all file column images and its version. We still look for a way to generate only new versions.
# recreates all file_column images in all needed sizes
class ImageUpdater
def update_all
update_model(:user, :photo)
update_model(:auto, :photo)
update_model(:photo, :file)
update_model(:group, :photo)
end
private
def update_model(class_name, attribute_name)
eval(class_name.to_s.capitalize).find(:all).each {|instance|
begin
dir = instance.send(attribute_name)
unless dir.blank?
instance.send("#{attribute_name}=", upload(dir))
instance.save!
end
rescue Exception => e
puts e.message
end
}
end
# copied from file_column/test_case.rb
def upload(path, content_type=:guess, type=:tempfile)
if content_type == :guess
case path
when /\.jpg$/ then content_type = "image/jpeg"
when /\.png$/ then content_type = "image/png"
else content_type = nil
end
end
uploaded_file(path, content_type, File.basename(path), type)
end
def uploaded_file(path, content_type, filename, type=:tempfile) # :nodoc:
if type == :tempfile
t = Tempfile.new(File.basename(filename))
FileUtils.copy_file(path, t.path)
else
if path
t = StringIO.new(IO.read(path))
else
t = StringIO.new
end
end
(class << t; self; end).class_eval do
alias local_path path if type == :tempfile
define_method(:local_path) { "" } if type == :stringio
define_method(:original_filename) {filename}
define_method(:content_type) {content_type}
end
return t
end
end