Add a StringSymbolOrProcSetting inspired by MethodProcHelper.render_or_call_method_or_proc_on

Author: varyonic

lib/active_admin/dynamic_setting.rb

@@ -1,8 +1,14 @@
 module ActiveAdmin
 
   class DynamicSetting
-    def self.build(setting)
-      new(setting)
+    def self.build(setting, type)
+      (type ? klass(type) : self).new(setting)
+    end
+
+    def self.klass(type)
+      klass = "#{type.to_s.camelcase}Setting"
+      raise ArgumentError, "Unknown type: #{type}" unless ActiveAdmin.const_defined?(klass)
+      ActiveAdmin.const_get(klass)
     end
 
     def initialize(setting)
@@ -14,4 +20,19 @@ def value(*_args)
     end
   end
 
+  # Many configuration options (Ex: site_title, title_image) could either be
+  # static (String), methods (Symbol) or procs (Proc). This wrapper takes care of
+  # returning the content when String or using instance_eval when Symbol or Proc.
+  #
+  class StringSymbolOrProcSetting < DynamicSetting
+    def value(context = self)
+      case @setting
+      when Symbol, Proc
+        context.instance_eval(&@setting)
+      else
+        @setting
+      end
+    end
+  end
+
 end

lib/active_admin/dynamic_settings_node.rb

@@ -5,22 +5,22 @@ module ActiveAdmin
 
   class DynamicSettingsNode < SettingsNode
     class << self
-      def register(name, value)
+      def register(name, value, type = nil)
         class_attribute "#{name}_setting"
         add_reader(name)
-        add_writer(name)
+        add_writer(name, type)
         send "#{name}=", value
       end
 
       def add_reader(name)
-        define_singleton_method(name) do
-          send("#{name}_setting").value
+        define_singleton_method(name) do |*args|
+          send("#{name}_setting").value(*args)
         end
       end
 
-      def add_writer(name)
+      def add_writer(name, type)
         define_singleton_method("#{name}=") do |value|
-          send("#{name}_setting=", DynamicSetting.build(value))
+          send("#{name}_setting=", DynamicSetting.build(value, type))
         end
       end
     end

spec/unit/dynamic_settings_spec.rb

@@ -0,0 +1,28 @@
+require 'rails_helper'
+
+RSpec.describe ActiveAdmin::DynamicSettingsNode do
+  subject { ActiveAdmin::DynamicSettingsNode.build }
+
+  context "StringSymbolOrProcSetting" do
+    before { subject.register :foo, 'bar', :string_symbol_or_proc }
+
+    it "should pass through a string" do
+      subject.foo = "string"
+      expect(subject.foo(self)).to eq "string"
+    end
+
+    it "should instance_exec if context given" do
+      ctx = Hash[i: 42]
+      subject.foo = proc { self[:i] += 1 }
+      expect(subject.foo(ctx)).to eq 43
+      expect(subject.foo(ctx)).to eq 44
+    end
+
+    it "should send message if symbol given" do
+      ctx = double
+      expect(ctx).to receive(:quux).and_return 'qqq'
+      subject.foo = :quux
+      expect(subject.foo(ctx)).to eq 'qqq'
+    end
+  end
+end