Added better error messaging. Shows full path of invalid param

Author: sumocoder

lib/rails_param/param.rb

@@ -4,7 +4,20 @@ module Param
     DEFAULT_PRECISION = 14
 
     class InvalidParameterError < StandardError
-      attr_accessor :param, :options
+      attr_accessor :param, :options, :full_path_array
+
+      def initialize(msg)
+        super(msg)
+        @full_path_array = []
+      end
+
+      def full_path
+        str = ""
+        full_path_array.each_with_index do |a, index|
+          str += (index == 0) ? a : "[#{a}]"
+        end
+        str
+      end
     end
 
     class MockController
@@ -13,6 +26,8 @@ class MockController
     end
 
     def param!(name, type, options = {}, &block)
+      evaluating_index = nil # used to keep track of array indexes
+
       # keep index for validating elements if integer
       name = name.to_s unless name.is_a? Integer
 
@@ -46,6 +61,7 @@ def param!(name, type, options = {}, &block)
           if type == Array
             params[name].each_with_index do |element, i|
               if element.is_a?(Hash)
+                evaluating_index = i
                 recurse element, &block
               else
                 # supply index as key unless value is hash
@@ -59,6 +75,10 @@ def param!(name, type, options = {}, &block)
         params[name]
 
       rescue InvalidParameterError => exception
+        unless evaluating_index.nil?
+          exception.full_path_array.unshift(evaluating_index)
+        end
+        exception.full_path_array.unshift(name)
         exception.param ||= name
         exception.options ||= options
         raise exception

spec/rails_param/param_spec.rb

@@ -477,5 +477,84 @@ def self.validate!(value)
         end
       end
     end
+
+    describe 'exception full_path_array' do
+      it 'has the proper full path with single param check' do
+        allow(controller).to receive(:params).and_return({"price" => "abc"})
+        begin
+          controller.param! :price, Integer, required: true
+        rescue RailsParam::Param::InvalidParameterError => e
+          expect(e.full_path_array).to eql ["price"]
+        end
+      end
+
+      it 'has the proper full path when using arrays with hashes' do
+        params = {
+          'array' => [
+            {'object'=>{ 'num' => '1', 'float' => '1.4' }},
+            {'object'=>{ 'num' => '2', 'float' => 'abc' }}
+          ]
+        }
+        allow(controller).to receive(:params).and_return(params)
+        begin
+          controller.param! :array, Array do |a|
+            a.param! :object, Hash do |h|
+              h.param! :num, Integer, required: true
+              h.param! :float, Float, required: true
+            end
+          end
+        rescue RailsParam::Param::InvalidParameterError => e
+          expect(e.full_path_array).to eql  ["array", 1, "object", "float"]
+        end
+      end
+
+      it 'has the proper full path when using arrays with primitive types' do
+        params = {
+          'array' => ["abc"]
+        }
+        allow(controller).to receive(:params).and_return(params)
+        begin
+          controller.param! :array, Array do |array, index|
+            array.param! index, Integer, :required => true
+          end
+        rescue RailsParam::Param::InvalidParameterError => e
+          expect(e.full_path_array).to eql ['array', 0]
+        end
+      end
+
+      it 'has the proper full path when using hashes' do
+        params = {
+          'hash' => {
+            'hash2'=> {'integers' => ['123', 'abc'] }
+          }
+        }
+        allow(controller).to receive(:params).and_return(params)
+        begin
+          controller.param! :hash, Hash do |a|
+            a.param! :hash2, Hash do |h|
+              h.param! :integers, Array do |array, index|
+                array.param! index, Integer
+              end
+            end
+          end
+        rescue RailsParam::Param::InvalidParameterError => e
+          expect(e.full_path_array).to eql ["hash", "hash2", "integers", 1]
+        end
+      end
+    end
+
+    describe 'full_path' do
+      it 'has the correct full path for root level item' do
+        e = RailsParam::Param::InvalidParameterError.new('error')
+        e.full_path_array = ["price"]
+        expect(e.full_path).to eql "price"
+      end
+
+      it 'has the correct full path for nested item' do
+        e = RailsParam::Param::InvalidParameterError.new('error')
+        e.full_path_array = ["hash", "hash2", "integers", 1]
+        expect(e.full_path).to eql "hash[hash2][integers][1]"
+      end
+    end
   end
 end