79 lines
2.2 KiB
Ruby
79 lines
2.2 KiB
Ruby
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require 'set'
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module Liquid
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# A drop in liquid is a class which allows you to export DOM like things to liquid.
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# Methods of drops are callable.
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# The main use for liquid drops is to implement lazy loaded objects.
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# If you would like to make data available to the web designers which you don't want loaded unless needed then
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# a drop is a great way to do that.
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#
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# Example:
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#
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# class ProductDrop < Liquid::Drop
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# def top_sales
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# Shop.current.products.find(:all, :order => 'sales', :limit => 10 )
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# end
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# end
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#
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# tmpl = Liquid::Template.parse( ' {% for product in product.top_sales %} {{ product.name }} {%endfor%} ' )
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# tmpl.render('product' => ProductDrop.new ) # will invoke top_sales query.
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#
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# Your drop can either implement the methods sans any parameters
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# or implement the liquid_method_missing(name) method which is a catch all.
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class Drop
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attr_writer :context
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# Catch all for the method
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def liquid_method_missing(method)
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return nil unless @context && @context.strict_variables
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raise Liquid::UndefinedDropMethod, "undefined method #{method}"
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end
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# called by liquid to invoke a drop
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def invoke_drop(method_or_key)
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if self.class.invokable?(method_or_key)
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send(method_or_key)
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else
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liquid_method_missing(method_or_key)
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end
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end
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def key?(_name)
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true
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end
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def inspect
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self.class.to_s
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end
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def to_liquid
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self
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end
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def to_s
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self.class.name
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end
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alias_method :[], :invoke_drop
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# Check for method existence without invoking respond_to?, which creates symbols
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def self.invokable?(method_name)
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invokable_methods.include?(method_name.to_s)
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end
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def self.invokable_methods
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@invokable_methods ||= begin
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blacklist = Liquid::Drop.public_instance_methods + [:each]
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if include?(Enumerable)
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blacklist += Enumerable.public_instance_methods
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blacklist -= [:sort, :count, :first, :min, :max, :include?]
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end
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whitelist = [:to_liquid] + (public_instance_methods - blacklist)
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Set.new(whitelist.map(&:to_s))
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end
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end
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end
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end
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