SWF-765 throw an IllegalStateException if a redirect is requested on a portlet render request. Only the portlet action request supports redirects

spring-webflow-reference/src/portlet.xml

@@ -190,6 +190,12 @@ externalContext.requestMap.portletMode
 			<para>
 				The Portlet API only allows redirects to be requested from an action request.
 				Because views are rendered on the render request, views and <code>view-state</code>s cannot trigger a redirect.
+				The <code>externalRedirect:</code> view prefix is a convenience for Servlet based flows.
+				An <code>IllegalStateException</code> is thrown if a redirect is requested from a render request.
+			</para>
+			<para>
+				This limitation can be worked around for an <code>end-state</code> by implementing the <code>FlowHandler.handleExecutionOutcome</code> method.
+				This callback provides the <code>ActionResponse</code> object which supports redirects.
 			</para>
 		</sect2>
 		<sect2 id="portlet-issues-modes">

spring-webflow/src/main/java/org/springframework/webflow/context/portlet/PortletExternalContext.java

@@ -235,19 +235,31 @@ public class PortletExternalContext implements ExternalContext {
 	}
 
 	public void requestFlowExecutionRedirect() {
+		if (isRenderPhase()) {
+			throw new IllegalStateException("Redirects are not allowed durring the portlet render phase");
+		}
 		flowExecutionRedirectRequested = true;
 	}
 
 	public void requestExternalRedirect(String uri) {
+		if (isRenderPhase()) {
+			throw new IllegalStateException("Redirects are not allowed durring the portlet render phase");
+		}
 		externalRedirectUrl = uri;
 	}
 
 	public void requestFlowDefinitionRedirect(String flowId, MutableAttributeMap input) {
+		if (isRenderPhase()) {
+			throw new IllegalStateException("Redirects are not allowed durring the portlet render phase");
+		}
 		flowDefinitionRedirectFlowId = flowId;
 		flowDefinitionRedirectFlowInput = input;
 	}
 
 	public void requestRedirectInPopup() {
+		if (isRenderPhase()) {
+			throw new IllegalStateException("Redirects are not allowed durring the portlet render phase");
+		}
 		redirectInPopup = true;
 	}
 

spring-webflow/src/test/java/org/springframework/webflow/context/portlet/PortletExternalContextTests.java

@@ -22,6 +22,8 @@ import org.springframework.mock.web.portlet.MockActionResponse;
 import org.springframework.mock.web.portlet.MockPortletContext;
 import org.springframework.mock.web.portlet.MockPortletRequest;
 import org.springframework.mock.web.portlet.MockPortletResponse;
+import org.springframework.mock.web.portlet.MockRenderRequest;
+import org.springframework.mock.web.portlet.MockRenderResponse;
 import org.springframework.webflow.context.servlet.ServletExternalContext;
 
 /**
@@ -37,11 +39,20 @@ public class PortletExternalContextTests extends TestCase {
 
 	private PortletExternalContext context;
 
+	private MockPortletRequest renderRequest;
+
+	private MockPortletResponse renderResponse;
+
+	private PortletExternalContext renderContext;
+
 	protected void setUp() {
 		portletContext = new MockPortletContext();
 		request = new MockActionRequest();
 		response = new MockActionResponse();
 		context = new PortletExternalContext(portletContext, request, response);
+		renderRequest = new MockRenderRequest();
+		renderResponse = new MockRenderResponse();
+		renderContext = new PortletExternalContext(portletContext, renderRequest, renderResponse);
 	}
 
 	public void testGetContextPath() {
@@ -76,18 +87,45 @@ public class PortletExternalContextTests extends TestCase {
 		assertTrue(context.getFlowExecutionRedirectRequested());
 	}
 
+	public void testCommitExecutionRedirectRenderRequest() {
+		try {
+			renderContext.requestFlowExecutionRedirect();
+			fail("IllegalStateException expected");
+		} catch (IllegalStateException e) {
+			// we want this
+		}
+	}
+
 	public void testCommitFlowRedirect() {
 		context.requestFlowDefinitionRedirect("foo", null);
 		assertTrue(context.getFlowDefinitionRedirectRequested());
 		assertEquals("foo", context.getFlowRedirectFlowId());
 	}
 
+	public void testCommitFlowRedirectRenderRequest() {
+		try {
+			renderContext.requestFlowDefinitionRedirect("foo", null);
+			fail("IllegalStateException expected");
+		} catch (IllegalStateException e) {
+			// we want this
+		}
+	}
+
 	public void testCommitExternalRedirect() {
 		context.requestExternalRedirect("foo");
 		assertTrue(context.getExternalRedirectRequested());
 		assertEquals("foo", context.getExternalRedirectUrl());
 	}
 
+	public void testCommitExternalRedirectRenderRequest() {
+		try {
+			renderContext.requestExternalRedirect("foo");
+			fail("IllegalStateException expected");
+		} catch (IllegalStateException e) {
+			// we want this
+		}
+	}
+
 	public void testCommitExecutionRedirectPopup() {
 		context.requestFlowExecutionRedirect();
 		context.requestRedirectInPopup();
@@ -111,6 +149,15 @@ public class PortletExternalContextTests extends TestCase {
 		assertTrue(context.getRedirectInPopup());
 	}
 
+	public void testExecutionRedirectPopupRenderRequest() {
+		try {
+			renderContext.requestRedirectInPopup();
+			fail("IllegalStateException expected");
+		} catch (IllegalStateException e) {
+			// we want this
+		}
+	}
+
 	public void testResponseAllowed() {
 		assertFalse(context.isResponseAllowed());
 	}