Add url_by_request_host option @lleirborras @MirkoMignini

README.md

@@ -74,6 +74,19 @@ Other configuration options:
         extra_info
       }
     ```
+  * `url_by_request_host` - Optional. Hash keyed by request host, to use
+    different CAS Server URLs depending on the request host. *Requires* `url`
+    or `host` to be set anyway, that'll be used as defaults if no host
+    matches.
+
+    ```ruby
+    provider :cas,
+             url: 'https://cas.example.org',
+             url_by_request_host: {
+               'host1.example.org' => 'https://host1.cas.example.org',
+               'host2.example.org' => 'https://host2.cas.example.org',
+             }
+    ```
 
 Configurable options for values returned by CAS:
 

lib/omniauth/strategies/cas.rb

@@ -121,14 +121,27 @@ def single_sign_out_phase
       def cas_url
         extract_url if options['url']
         validate_cas_setup
-        @cas_url ||= begin
-          uri = Addressable::URI.new
-          uri.host = options.host
-          uri.scheme = options.ssl ? 'https' : 'http'
-          uri.port = options.port
-          uri.path = options.path
-          uri.to_s
-        end
+
+        by_host_cas_url || static_cas_url
+      end
+
+      def by_host_cas_url
+        return unless options.url_by_request_host && \
+          options.url_by_request_host.respond_to?(:fetch)
+
+        uri = options.url_by_request_host.fetch(request.host, nil)
+        return unless uri
+
+        Addressable::URI.parse(uri).to_s
+      end
+
+      def static_cas_url
+        uri = Addressable::URI.new
+        uri.host = options.host
+        uri.scheme = options.ssl ? 'https' : 'http'
+        uri.port = options.port
+        uri.path = options.path
+        uri.to_s
       end
 
       def extract_url

spec/omniauth/strategies/cas_spec.rb

@@ -80,6 +80,42 @@
         expect(provider.options).to include path:'/a/path'
       end
     end
+
+    context 'with a URL by host mapping' do
+      let(:params) { super().merge(
+        url: 'https://default.cas.host',
+        url_by_request_host: {
+          'host1.example.org': 'https://host1.cas.host',
+          'host2.example.org': 'https://host2.cas.host',
+        })
+      }
+
+      let(:request_host) { nil }
+
+      before do
+        allow_any_instance_of(MyCasProvider)
+          .to receive(:request)
+          .and_return(Rack::Request.new('HTTP_HOST' => request_host))
+      end
+
+      it { true }
+
+      context 'and an host in the map' do
+        let(:request_host) { 'host1.example.org' }
+
+        it 'returns the corresponding CAS host in the map' do
+          expect(subject).to eq('https://host1.cas.host')
+        end
+      end
+
+      context 'and an host not in the map' do
+        let(:request_host) { 'foo.bar' }
+
+        it 'returns the default CAS host' do
+          expect(subject).to eq('https://default.cas.host')
+        end
+      end
+    end
   end
 
   describe 'defaults' do