Make AuthnRequest Signature and SigAlg optional

lib/saml/bindings/http_redirect.rb

@@ -5,7 +5,7 @@ class HTTPRedirect
 
       class << self
         def create_url(request_or_response, options = {})
-          options[:signature_algorithm] ||= 'http://www.w3.org/2000/09/xmldsig#rsa-sha1'
+          options[:signature_algorithm] ||= 'http://www.w3.org/2000/09/xmldsig#rsa-sha1' unless options[:exclude_signature]
           new(request_or_response, options).create_url
         end
 
@@ -42,13 +42,14 @@ def decode_message(message)
         end
       end
 
-      attr_accessor :request_or_response, :signature_algorithm, :relay_state, :signature
+      attr_accessor :request_or_response, :signature_algorithm, :relay_state, :signature, :exclude_signature
 
       def initialize(request_or_response, options = {})
         @request_or_response = request_or_response
         @signature_algorithm = options[:signature_algorithm]
         @relay_state         = options[:relay_state]
         @signature           = options[:signature]
+        @exclude_signature   = options[:exclude_signature]
       end
 
       def verify_signature(query)
@@ -61,7 +62,7 @@ def create_url
         url = request_or_response.destination
         delimiter = url.include?('?') ? '&' : '?'
 
-        [url, signed_params].join(delimiter)
+        [url, exclude_signature ? unsigned_params : signed_params].join(delimiter)
       end
 
       private
@@ -108,6 +109,10 @@ def signed_params
 
         "#{encoded_params}&Signature=#{encoded_signature}"
       end
+
+      def unsigned_params
+        encoded_params.to_s
+      end
     end
   end
 end

spec/lib/saml/bindings/http_redirect_spec.rb

@@ -115,6 +115,19 @@ def get_url(request = authn_request)
           expect(params["Signature"]).to eq(sha1_signature_mri)
         end
       end
+
+      context "with exclude_signature option" do
+        let(:url) do
+          described_class.create_url(authn_request,
+                                     exclude_signature: true
+          )
+        end
+
+        it "not add Signature and SigAlg params" do
+          expect(params["Signature"]).to eq nil
+          expect(params["SigAlg"]).to eq nil
+        end
+      end
     end
   end