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openproject/lib/widget/base.rb

111 lines
3.0 KiB

#-- copyright
# ReportingEngine
#
# Copyright (C) 2010 - 2014 the OpenProject Foundation (OPF)
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License
# version 3.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
#++
require 'digest/sha1'
class Widget::Base < Widget
attr_reader :engine, :output
##
# Deactivate caching for certain widgets. If called on Widget::Base,
# caching is deactivated globally
def self.dont_cache!
@dont_cache = true
end
##
# Query whether this widget class should be cached.
def self.dont_cache?
@dont_cache or self != Widget::Base && Widget::Base.dont_cache?
end
def initialize(query)
@subject = query
@engine = query.class
@options = {}
end
##
# Write a string to the canvas. The string is marked as html_safe.
# This will write twice, if @cache_output is set.
def write(str)
str ||= ''
@output ||= ''.html_safe
@output = @output + '' if @output.frozen? # Rails 2 freezes tag strings
@output.concat str.html_safe
@cache_output.concat(str.html_safe) if @cache_output
str.html_safe
end
##
# Render this widget. Abstract method. Needs to call #write at least once
def render
raise NotImplementedError, "#render is missing in my subclass #{self.class}"
end
##
# Render this widget, passing options.
# Available options:
# :to => canvas - The canvas (streaming or otherwise) to render to. Has to respond to #write
def render_with_options(options = {}, &block)
set_canvas(options.delete(:to)) if options.has_key? :to
@options = options
render_with_cache(options, &block)
@output
end
def cache_key
@cache_key ||= Digest::SHA1::hexdigest begin
if subject.respond_to? :cache_key
"#{I18n.locale}/#{self.class.name.demodulize}/#{subject.cache_key}/#{@options.sort_by(&:to_s)}"
else
subject.inspect
end
end
end
def cached?
cache? && Rails.cache.exist?(cache_key)
end
private
def cache?
!self.class.dont_cache?
end
##
# Render this widget or serve it from cache
def render_with_cache(_options = {}, &block)
if cached?
write Rails.cache.fetch(cache_key)
else
render(&block)
Rails.cache.write(cache_key, @cache_output || @output) if cache?
end
end
##
# Set the canvas. If the canvas object isn't a string (e.g. cannot be cached easily),
# a @cache_output String is created, that will mirror what is being written to the canvas.
def set_canvas(canvas)
@cache_output = ''.html_safe
@output = canvas
end
end