FindBy mixin, to search arrays ala processes.find_by_pid(123)

lib/rush.rb

@@ -13,6 +13,7 @@ module Rush::Connection; end
 require 'dir'
 require 'search_results'
 require 'head_tail'
+require 'find_by'
 require 'string_ext'
 require 'fixnum_ext'
 require 'array_ext'

lib/rush/array_ext.rb

@@ -13,5 +13,7 @@ def entries
 		self
 	end
 
+	include Rush::FindBy
+
 	include Rush::HeadTail
 end

lib/rush/find_by.rb

@@ -0,0 +1,37 @@
+# Generic find_by (returns first match) and find_all_by (returns all matches)
+# against arrays.
+#
+# Examples:
+#
+#   processes.find_by_pid(::Process.pid)
+#   processes.find_all_by_cmdline(/mongrel_rails/)
+#
+module Rush::FindBy
+	def method_missing(meth, *args)
+		if m = meth.to_s.match(/^find_by_([a-z_]+)$/)
+			find_by(m[1], args.first)
+		elsif m = meth.to_s.match(/^find_all_by_([a-z_]+)$/)
+			find_all_by(m[1], args.first)
+		end
+	end
+
+	def find_by(field, arg)
+		detect do |item|
+			item.respond_to?(field) and compare_or_match(item.send(field), arg)
+		end
+	end
+
+	def find_all_by(field, arg)
+		select do |item|
+			item.respond_to?(field) and compare_or_match(item.send(field), arg)
+		end
+	end
+
+	def compare_or_match(value, against)
+		if against.class == Regexp
+			value.match(against) ? true : false
+		else
+			value == against
+		end
+	end
+end

spec/find_by_spec.rb

@@ -0,0 +1,55 @@
+require File.dirname(__FILE__) + '/base'
+
+describe Rush::FindBy do
+	before do
+		class Foo
+			attr_accessor :bar
+
+			def initialize(bar)
+				@bar = bar
+			end
+		end
+
+		@one = Foo.new('one')
+		@two = Foo.new('two')
+		@three = Foo.new('three')
+
+		@list = [ @one, @two, @three ]
+	end
+
+	it "compare_or_match exact match success" do
+		@list.compare_or_match('1', '1').should == true
+	end
+
+	it "compare_or_match exact match failure" do
+		@list.compare_or_match('1', '2').should == false
+	end
+
+	it "compare_or_match regexp match success" do
+		@list.compare_or_match('123', /2/).should == true
+	end
+
+	it "compare_or_match regexp match failure" do
+		@list.compare_or_match('123', /x/).should == false
+	end
+
+	it "find_by_ extact match" do
+		@list.find_by_bar('two').should == @two
+	end
+
+	it "find_by_ regexp match" do
+		@list.find_by_bar(/.hree/).should == @three
+	end
+
+	it "find_all_by_ exact match" do
+		@list.find_all_by_bar('one').should == [ @one ]
+	end
+
+	it "find_all_by_ regexp match" do
+		@list.find_all_by_bar(/^...$/).should == [ @one, @two ]
+	end
+
+	it "find_by_ with field not recognized by objects raises no errors" do
+		@list.find_by_nothing('x')
+	end
+end