In my grails project some of controllers' actions annotated with custom annotation, say CustomAnnotation.
Also, there is a filter that checks controllers' actions whether they annotated by CustomAnnotation or not.
I've tried two ways to perform this check:
1) Look for annotations of bean's class methods
def artefact = grailsApplication.getArtefactByLogicalPropertyName("Controller", controllerName)
def controller = applicationContext.getBean(artefact.clazz.name)
def actionMethod = controller.class.declaredMethods.find { it.name == actionName }
def isAnnotated = actionMethod.isAnnotationPresent(CustomAnnotation)
2) Look for annotations of artifact's clazz methods
def artefact = grailsApplication.getArtefactByLogicalPropertyName("Controller", controllerName)
def actionMethod = artefact.clazz.declaredMethods.find { it.name == actionName }
def isAnnotated = actionMethod.isAnnotationPresent(CustomAnnotation)
While the first way doesn't work for me, the second works well.
Why these classes are different and what is the difference?
Transforming the comment in answer, the difference can be clarified by printing the class of the controller:
In the first case, the bean class is a proxy:custom.package.CustomController$$EnhancerByCGLIB$$a131be82 you can notice that by the "EnhacerByCGLIB" part. In the second one the class is correct.
Related
Greeting everyone,
I am trying to pass a parameters from a URL to a findAll() method.
LINE3 I use findAll() to define mouse.
LINE2 def house will bring in the parameter DELAWARE when I go to the page: http://localhost:8080/TestApp/home/county/DELAWARE
House will only show one instance instead of a list.. is there anyway to pass the url instead of ["DELAWARE"]? (please see line 3) thanks :)
def county() {
def house = Home.findByCounty(params.id) //sends only user related address to view
def mouse = Home.findAll("from Home h where h.county= ?", ["DELAWARE"]);
if (!house) {
response.sendError(404)
} else {
[house:house, mouse:mouse ]
}
}
Working Code +1 #Danilo
def county() {
def house = Home.findAllByCounty (params.id) //sends only county specified thru URL e.g. http://localhost:8080/TestAPP/home/county/DELAWARE
if (!house) {
response.sendError(404)
} else {
[house:house ]
}
}
findBy* will return at most one row, if you want to get all rows use findAllBy*
In order to understand how the URL will be used by Grails you have to have a look at conf/UrlMappings.groovy. You may find something like this:
static mappings = {
"/$controller/$action?/$id?(.$format)?"{
}
}
this means that when you call TestApp/home/county/DELAWARE what Grails is trying to do is use the home controller (HomeController), invoking the county method (def county(){...}) and passing DELAWARE as id.
This should work correctly if inside county method of the HomeController you have:
def filteredInstances = Home.findAllByCounty(params.id)
Is there any useful hook in ASP.NET MVC (MVC4) which can let you access the Action method parameter (View model) before the action method becomes invoked, and then also (e.g. depending on the value of something you checked in the action method parameter) let you prevent the action method from being invoked, i.e. instead either forward the view model object (action method parameter) to another action method or directly to some view (i.e. without any further processing in an action method) ?
If you do not understand the question, please see the code example below which should illustrate the kind of code I am looking for...
(though I do not know if there actually exists such kind of interface and a possibility to hook an implementation into the MVC framework)
If this is indeed possible, I would like to see an answer with code example about how to do it (and not just a response with someone claiming that e.g. "try using method 'ActionFilterAttribute.OnActionExecuting' or 'IModelBinder.BindModel' " because I have already tried those and could not make it work).
Also, please respect that I do not want this thread to become a discussion about WHY to do it, but want to see HOW to do it.
(i.e. I am not interested in getting into discussions with responses such as "What are you actually trying to achieve?" or "There are probably better things of doing what you want to do...")
The question can be split into three subquestions/code examples as my own code samples below try to illustrate:
(but would like them "refactored" into REAL code with usage of real existing types)
(obviously, every type below which includes the substring "Some" is something I have made up, and I am looking for the corresponding real thing ...)
(1) Example of how to get access to (and potentially modify) view model objects (action method parameters) in a generic place before the actual action method is invoked with the view model object parameter.
The kind of code example I am looking for would probably be similar to below but do not know what kind of interface to use and how to register it to be able to do something like below:
public class SomeClass: ISomeInterface { // How to register this kind of hook in Application_Start ?
public void SomeMethodSomewhere(SomeActionMethodContext actionMethodContext, object actionMethodParameterViewModel) {
string nameOfTheControllerAboutToBeInvoked = actionMethodContext.ControllerName;
string nameOfTheActionMethodAboutToBeInvoked = actionMethodContext.MethodName;
// the above strings are not used below but just used for illustrating that the "context object" contains information about the action method to become invoked by the MVC framework
if(typeof(IMyBaseInterfaceForAllMyViewModels).IsAssignableFrom(actionMethodParameterViewModel.GetType())) {
IMyBaseInterfaceForAllMyViewModels viewModel = (IMyBaseInterfaceForAllMyViewModels) actionMethodParameterViewModel;
// check something in the view model:
if(viewModel.MyFirstGeneralPropertyInAllViewModels == "foo") {
// modify something in the view model before it will be passed to the target action method
viewModel.MySecondGeneralPropertyInAllViewModels = "bar";
}
}
}
}
(2) Example of how to prevent the targeted action method from being executed and instead invoke another action method.
The example might be an extension of the above example, with something like below:
public void SomeMethodSomewhere(SomeActionMethodContext actionMethodContext, object actionMethodParameterViewModel) {
... same as above ...
if(viewModel.MyFirstGeneralPropertyInAllViewModels == "foo") {
actionMethodContext.ControllerName = "SomeOtherController";
actionMethodContext.MethodName = "SomeOtherActionMethod";
// The above is just one example of how I imagine this kind of thing could be implemented with changing properties, and below is another example of doing it with a method invocation:
SomeHelper.PreventCurrentlyTargetedActionMethodFromBecomingExecutedAndInsteadExecuteActionMethod("SomeOtherController", "SomeOtherActionMethod", actionMethodParameterViewModel);
// Note that I do _NOT_ want to trigger a new http request with something like the method "Controller.RedirectToAction"
}
(3) Example of how to prevent the normal action method from being executed and instead forward the view model object directly to a view without any further processing.
The example would be an extension of the first above example, with something like below:
public void SomeMethodSomewhere(SomeActionMethodContext actionMethodContext, object actionMethodParameterViewModel) {
... same as the first example above ...
if(viewModel.MyFirstGeneralPropertyInAllViewModels == "foo") {
// the below used razor view must of course be implemented with a proper type for the model (e.g. interface 'IMyBaseInterfaceForAllMyViewModels' as used in first example above)
SomeHelper.PreventCurrentlyTargetedActionMethodFromBecomingExecutedAndInsteadForwardViewModelToView("SomeViewName.cshtml", actionMethodParameterViewModel);
}
You could use an action filter and override the OnActionExecuting event:
public class MyActionFilterAttribute : ActionFilterAttribute
{
public override void OnActionExecuting(ActionExecutingContext filterContext)
{
...
}
}
Now let's see what useful information you could extract from this filterContext argument that is passed to this method. The property you should be looking for is called ActionParameters and represents an IDictionary<string, object>. As its name suggests this property contains all the parameters that are passed to the controller action by name and value.
So let's suppose that you have the following controller action:
[MyActionFilter]
public ActionResult Index(MyViewModel model)
{
...
}
Here's how you could retrieve the value of the view model after model binding:
public class MyActionFilterAttribute : ActionFilterAttribute
{
public override void OnActionExecuting(ActionExecutingContext filterContext)
{
var model = filterContext.ActionParameters["model"] as MyViewModel;
// do something with the model
// You could change some of its properties here
}
}
Now let's see the second part of your question. How to shortcircuit the controller action and redirect to another action?
This could be done by assigning a value to the Result property:
public class MyActionFilterAttribute : ActionFilterAttribute
{
public override void OnActionExecuting(ActionExecutingContext filterContext)
{
... some processing here and you decide to redirect:
var routeValues = new RouteValueDictionary(new
{
controller = "somecontroller",
action = "someaction"
});
filterContext.Result = new RedirectToRouteResult(routeValues);
}
}
or for example you decide to shortcircuit the execution of the controller action and directly render a view:
public class MyActionFilterAttribute : ActionFilterAttribute
{
public override void OnActionExecuting(ActionExecutingContext filterContext)
{
var viewResult = new ViewResult
{
ViewName = "~/Views/FooBar/Baz.cshtml",
};
MyViewModel someModel = ... get the model you want to pass to the view
viewResult.ViewData.Model = model;
filterContext.Result = viewResult;
}
}
or you might decide to render a JSON result:
public class MyActionFilterAttribute : ActionFilterAttribute
{
public override void OnActionExecuting(ActionExecutingContext filterContext)
{
MyViewModel someModel = ... get the model you want to pass to the view
filterContext.Result = new JsonResult
{
Data = model,
JsonRequestBehavior = JsonRequestBehavior.AllowGet
};
}
}
So as you can see the possibilities are unlimited of what you can do.
I have experimented with the code in the answer provided by the user Darin Dimitrov, and the first and third parts of the answer are correct.
(Though, for others who might find this thread and be interested, I can clarify that in the first answer the "model" does not seem to
be a hardcoded keyword always used for the model but seems to have to correspond to the chosen name of the action method parameter.
In other words, if you instead have the method signature
public ActionResult Index(MyViewModel myViewModel)
then in your action filter you have to use
var model = filterContext.ActionParameters["myViewModel"] as MyViewModel;
)
Regarding the second answer, the usage of 'RedirectToRouteResult' will trigger a new http request (which was not desired as I mentioned in the second code example of mine).
I found another way of "changing" action method by actually invoking it explicitly:
var controller = new SomeController();
ActionResult result = controller.SomeAction(model);
filterContext.Result = result;
The above code actually seems to prevent the originally targeted action method from becoming invoked, i.e. when I put a breakpoint in the method annotated with '[MyActionFilter]' the execution never got into that method.
Typically, it is probably not desired to hardcode a controller like above, but instead reflection might be used, for example as below with the thirdpart library "fasterflect":
string nameOfController = ...
string nameOfActionMethod = ...
// both above variables might for example be derived by using some naming convention and parsing the refering url, depending on what you want to do ...
var theController = this.GetType().Assembly.CreateInstance(nameOfController);
ActionResult result = (ActionResult)theController.CallMethod(nameOfActionMethod, model);
filterContext.Result = result;
(for those who want to extract the names of the current target controller and action method, when implementing logic to determine the controller you want to invoke, you can use this code in the filter:
var routeValueDictionary = filterContext.RouteData.Values;
string nameOfTargetedController = routeValueDictionary["controller"].ToString();
string nameOfTargetedActionMethod = routeValueDictionary["action"].ToString();
)
I think it feels a bit awkward to instantiate and invoke controllers like above, and would prefer to change the target controller and action method in another way if possible ?
So, the remaining question is if there is still (in MVC 4 final version) no way of redirecting/forwarding execution "internally" (without a new http request being fired as with 'RedirectToAction') at the server ?
Basically, I think I am here just looking for something like "Server.Transfer" which was used with ASP.NET Web Forms (and also the old classic ASP I believe could use the same thing).
I have seen older question/answers on this issue with people implementing this behaviour themselves with some "TransferResult" class of their own, but it seems to tend to become broken i different MVC versions.
(for example, see here for MVC 4 beta: How to redirect MVC action without returning 301? (using MVC 4 beta) ).
Is there really still not a simple standard solution (implemented in MVC 4 final) about how to do an "internal redirect" without a new http request (as RedirectToAction does) ?
I have already posted this question, but i realised the aswer was not what i was looking for. Imagine this controller:
class exampleController{
def action1 = {
...
[lala: lala, lele: lele]}
...
}
def action15 = {
...
[lala: lala, lele: lele]
}
I want to be able to return in all the action in this controller the same params. Imagining this:
def book = Book.findAllByIsbn(Isbn.get(1))
[book: book]
Is there any way of doing this, besides writing all the same code on all the actions? I have tried this method and it isnt working:
def action5 = {getModel()}
private getModel() {
def book = Book.findAllByIsbn(Isbn.get(1))
[book: book]
}
}
It is not working because, and my thought is, he doest accept multiple [return1: aaa, return2: bbb]. Any suggestion please ? I have also tried filters like in here: Grails controllers repeated code for all actions
but i couldnt managed to make it work. I would apreciated a detailed explanaintion about any of the solutions if possible:p Thanks in advanced,
VA
So it's not the same model, but a model with a repeated part.
You should know that the return value is an ordinary Map.
So, return value can be constructed like return getCommonModel() + [book: currentBook] where getCommonModel() returns another Map.
If you want to return the same model from all your actions, this approach should work:
class ExampleController {
def action5 = {getModel()}
def action1 = {getModel()}
//etc.
private getModel() {
def book = Book.findAllByIsbn(Isbn.get(1))
[book: book]
}
}
If you want to return the same model and render the same view from all your actions, you could return the same ModelAndView from each action, but then I would ask why do you need separate actions if they're all doing exactly the same thing?
I don't really understand your hypothesis
It is not working because, and my thought is, he doest accept multiple [return1: aaa, return2: bbb]
If your suggesting that getModel() can only return a model with a single entry, I find that very hard to believe. Can you elaborate a bit on this, or post some more information (e.g. stacktrace, unit test) that shows how/why it's not working?
Update
After reading your comments below I think I finally understand what you want to achieve, which is to append the model returned by getModel() (above) to the model returned by various other actions. Does this work:
class ExampleController {
def action5 = {
def action5Model = [foo: 'bar']
return addBookModel(action5Model)
}
def action1 = {
def action1Model = [foo2: 'bar2']
return addBookModel(action1Model)
}
//etc.
private Map addBookModel(Map model) {
def book = Book.findAllByIsbn(Isbn.get(1))
model.book = book
return model
}
}
This approach will only work when you want to add the book model within a single controller. If you want to add the book model in several controllers you can do this by:
putting addBookModel in an abstract class that the controllers extend
putting addBookModel in a class that is mixed-in with the controllers (using #Mixin)
putting addBookModel in a filter that is executed after the controller actions
If you are using exact same model in multiple pages. I would recommend you use a taglib for it.
Is it possible to access the current controller instance from within a TagLib? For example:
class FooTagLib {
static namespace = 'foo'
def msg = { attrs, body ->
// Can I get a reference to the current controller here?
}
}
I want to do this because I store some data in a property of the controller and want to access it within the TagLib. I realise this may sound strange, but just humour me....
Inside your msg tagLib:
grailsApplication.getArtefactByLogicalPropertyName('Controller', pageScope.controllerName)
Like Views, you have access to the current controller and action through controllerName and actionName
Try something like this...
def ctl = grailsApplication.getArtefactByLogicalPropertyName('Controller', 'whateverController')
I am trying to set a variable for the current user (a POJO) in all views so I can get things like the user name and check their role on every view (including the default layout). How can I setup something (e.g. currentUser) in grails so that it is accessible in every grails view like so:
<div>${currentUser.name}</div>
or like this:
<g:if test="${currentUser.admin}">ADMIN</g:if>
You want to use a grails filter. Using a filter, you can specify which controllers and methods (using wild cards) you want to intercept using before/after and afterView methods.
This makes it easy to stuff a new variable into the model so it's available in a view. Here's an example that uses the acegi plugin authenticateService:
class SecurityFilters {
def authenticateService
def filters = {
all(controller:'*', action:'*') {
after = { model ->
def principal = authenticateService.principal()
if (principal != null && principal != 'anonymousUser') {
model?.loggedInUser = principal?.domainClass
log.debug("SecurityFilter: adding current user to model = $model")
} else {
log.debug("SecurityFilter: anonymous user, model = $model")
}
}
}
}
}
You can use the session scope to store the variable. Your calls would change to:
<div>${session.currentUser.name}</div>
and
<g:if test="${session.currentUser.admin}">ADMIN</g:if>
And you would set the variable like so in a controller:
session.currentUser = XXXXX