GRAILS-11576 - more flexible exception handling

Controller exception handler methods can now catch exceptions thrown during command object initialization.

Author: jeffscottbrown

grails-plugin-controllers/src/main/groovy/org/codehaus/groovy/grails/compiler/web/ControllerActionTransformer.java

@@ -354,7 +354,6 @@ private MethodNode convertToMethodAction(ClassNode classNode, MethodNode methodN
                 GrailsASTUtils.error(source, methodNode, formattedMessage);
             }
         }
-        wrapMethodBodyWithExceptionHandling(classNode, methodNode);
 
         MethodNode method = null;
         if (methodNode.getParameters().length > 0) {
@@ -376,9 +375,12 @@ private MethodNode convertToMethodAction(ClassNode classNode, MethodNode methodN
 
             GrailsASTUtils.copyAnnotations(methodNode, method);
             annotateActionMethod(classNode, parameters, method);
+            wrapMethodBodyWithExceptionHandling(classNode, method);
         } else {
             annotateActionMethod(classNode, parameters, methodNode);
         }
+        
+        wrapMethodBodyWithExceptionHandling(classNode, methodNode);
 
         return method;
     }

grails-plugin-controllers/src/main/groovy/org/codehaus/groovy/grails/plugins/web/api/ControllersApi.java

@@ -57,7 +57,6 @@
 import org.codehaus.groovy.runtime.InvokerHelper;
 import org.grails.databinding.CollectionDataBindingSource;
 import org.grails.databinding.DataBindingSource;
-import org.grails.databinding.bindingsource.DataBindingSourceCreationException;
 import org.springframework.beans.factory.config.AutowireCapableBeanFactory;
 import org.springframework.context.ApplicationContext;
 import org.springframework.http.HttpMethod;
@@ -495,7 +494,11 @@ public Object initializeCommandObject(final Object controllerInstance, final Cla
                     bindData(controllerInstance, commandObjectInstance, commandObjectBindingSource, Collections.EMPTY_MAP, null);
                 }
             }
-        } catch (DataBindingSourceCreationException e) {
+        } catch (Exception e) {
+            final Method exceptionHandlerMethodFor = getExceptionHandlerMethodFor(controllerInstance, e.getClass());
+            if(exceptionHandlerMethodFor != null) {
+                throw e;
+            }
             commandObjectInstance = type.newInstance();
             final Object o = GrailsMetaClassUtils.invokeMethodIfExists(commandObjectInstance, "getErrors");
             if(o instanceof BindingResult) {

grails-test-suite-web/src/test/groovy/org/codehaus/groovy/grails/web/binding/json/JsonBindingWithExceptionHandlerSpec.groovy

@@ -0,0 +1,64 @@
+package org.codehaus.groovy.grails.web.binding.json
+
+import grails.artefact.Artefact
+import grails.test.mixin.TestFor
+
+import org.grails.databinding.bindingsource.DataBindingSourceCreationException
+
+import spock.lang.Specification
+
+
+@TestFor(BindingWithExceptionHandlerMethodController)
+class JsonBindingWithExceptionHandlerSpec extends Specification {
+
+    void 'test binding malformed JSON'() {
+        given:
+        request.contentType = JSON_CONTENT_TYPE
+        request.method = 'POST'
+        request.JSON = '{"mapData": {"name":"Jeff{{{"'
+
+        when:
+        controller.bindWithCommandObject()
+        
+        then:
+        response.status == 400
+        model.errorMessage == 'caught a DataBindingSourceCreationException'
+        view == '/bindingProblems'
+    }
+
+    void 'test binding valid JSON'() {
+        given:
+        request.contentType = JSON_CONTENT_TYPE
+        request.method = 'POST'
+        request.JSON = '{"name":"Jeff"}'
+
+        when:
+        def model = controller.bindWithCommandObject()
+        
+        then:
+        response.status == 200
+        flash.message == null
+        model.command.name == 'Jeff'
+        
+    }
+}
+
+@Artefact('Controller')
+class BindingWithExceptionHandlerMethodController {
+    
+    def bindWithCommandObject(SomeCommandObject co) {
+        [command: co]
+    }
+    
+    def handleDataBindingException(DataBindingSourceCreationException e) {
+        response.status = 400
+        render view: '/bindingProblems', model: [errorMessage: 'caught a DataBindingSourceCreationException']
+    }
+} 
+
+class SomeCommandObject {
+    String name
+    static constraints = {
+        name matches: /[A-Z].*/
+    }
+}