(experimental) added framework for filtering all sorts of internals in discourse and consuming by plugins

lib/plugin/filter.rb

@@ -0,0 +1,18 @@
+require_dependency 'plugin/filter_manager'
+# this concept is borrowed straight out of wordpress
+module Plugin
+  class Filter
+    def self.manager
+      @manager ||= FilterManager.new
+    end
+
+    def self.register(name, &blk)
+      manager.register(name, &blk)
+    end
+
+    def self.apply(name, context, result)
+      manager.apply(name, context, result)
+    end
+
+  end
+end

lib/plugin/filter_manager.rb

@@ -0,0 +1,23 @@
+module Plugin
+  class FilterManager
+
+    def initialize
+      @map = {}
+    end
+
+    def register(name, &blk)
+      raise ArgumentException unless blk && blk.arity == 2
+      filters = @map[name] ||= []
+      filters << blk
+    end
+
+    def apply(name, context, result)
+      if filters = @map[name]
+        filters.each do |blk|
+          result = blk.call(context, result)
+        end
+      end
+      result
+    end
+  end
+end