I have a problem with the my Controller code. GET works fine (both empty form + form populated from db), POST works fine only for creating new object, but doesn't work for editing. Part of my #Controller class:
#RequestMapping(value = "/vehicle_save.html", method = RequestMethod.GET)
public String setUpForm(#RequestParam(value="id", required = false) Long id, ModelMap model) {
Vehicle v;
if (id == null) {
v = new Vehicle();
} else {
v = vehicleManager.findVehicle(id);
}
model.addAttribute("vehicle", v);
return "vehicle_save";
}
#RequestMapping(value = "/vehicle_save.html", method = RequestMethod.POST)
public String save(#ModelAttribute("vehicle") Vehicle vehicle, BindingResult result, SessionStatus status) {
vehicleValidator.validate(vehicle, result);
if (result.hasErrors()) {
return "vehicle_save";
}
if(vehicle.getId() == null) {
vehicleManager.createVehicle(vehicle);
} else {
vehicleManager.updateVehicle(vehicle);
}
status.setComplete();
return "redirect:vehicle_list.html";
}
The first method creates a vehicle object (including its ID). But the second method gets the same object without the ID field (set to null).
What could I do: manually set vehicle.setID(id from parameters) and then save it to database. This causes JPAOptimisticLockException + I don't like that solution.
Is there a way to pass my Vehicle object with ID to the second method? BTW, I would like to avoid adding hidden ID field to the JSP.
the example you suggested is using session to store the value. the #SessionAttribute is to bind an existing model object to the session. Look at the source code the class is annotated with #SessionAttributes("pet").Which means your model attribute named "pet" is getting stored in session.Also look at the code in processSubmit method of EditPetForm class
#RequestMapping(method = { RequestMethod.PUT, RequestMethod.POST })
public String processSubmit(#ModelAttribute("pet") Pet pet, BindingResult result, SessionStatus status) {
new PetValidator().validate(pet, result);
if (result.hasErrors()) {
return "pets/form";
}
else {
this.clinic.storePet(pet);
status.setComplete(); //look at its documentation
return "redirect:/owners/" + pet.getOwner().getId();
}
}
I havnt used something like this before.But i guess putting ur id in session is the way
BTW, I would like to avoid adding hidden ID field to the JSP.
This is common solution. What's wrong with it ? You should create hidden input with id.
May be you can try using session, cause you cant store info between two request. But that will be uglier i guess.
Btw, Can you please explain a little why you want to avoid adding hidden fields? I'm little curious
Related
I have the following code in my receiving controller:
[Route("api/StudentUserId/{string}"), HttpGet]
public StudentDto StudentUserId(string userId)
{
StudentModel sm = new StudentModel(userId);
StudentDto dto = sm.ConvertToDto();
return dto;
}
After running this project, I have another project that I use to test the WebAPI controller calls. I use the following code to read a student record form the database using their userId:
protected T SendRequestToReadItemUsingString<T>(string resource, string userId) where T : new()
{
string resourceString = string.Format("{0}/{{userId}}", resource);
RestRequest request = new RestRequest(resourceString, Method.GET);
request.AddUrlSegment("userId", userId);
RestClient restClient = new RestClient(Service.Location);
var response = restClient.Execute<T>(request);
T retVal = response.Data;
return retVal;
}
Comparible code seems to work if I change the userId to an int Id in both the controller and calling code. I can't seem to get it to work with string. If I place a breakpoint in the controller code it never hits it and the calling code just returns a null.
Thanks for your help
Please note that WebApi works based on reflection this means that your curly braces {vars} must match the same name in your methods.
Therefore to match this api/StudentUserId/{string} your method needs to be declare like this:
[Route("api/StudentUserId/{userId}"), HttpGet]
public StudentDto StudentUserId(string userId)
return userId;
}
Where the parameter {string} was replaced by userId.
If you want to read more about this Routing Rules here is similar post on this;
WebApi Routing Configuration
I've my rest uri's as below
/leagues - Lists all the leagues organized so far
/leagues/{leagueName} - Details of the give leagueName
/leagues/{leagueName}/levels/ - Lists all the levels of a given league (For e.g. Playoffs, QF, SF etc)
Controllers
1.
#RequestMapping (value = "/leagues", method = RequestMethod.GET)
public String list(Model model)
{
return "/leagues/list";
}
2.
#RequestMapping (value = "/leagues/{leagueName}", method = RequestMethod.GET)
public String leagues(#PathVariable String leagueName, Model model)
{
return "/leagues/league";
}
3.
#RequestMapping (value = "/leagues/{leagueName}/levels", method = RequestMethod.GET)
public String levels(#PathVariable ("leagueName") String leagueName, Model model)
{
return "/leagues/levels/list";
}
The problem I am having is that the controller method for the (2) /leagues/{leagueName} is being invoked when I try (2) /leagues/levels/. Need help on how to fix this.
You forget to add the leguname to the url: use /leagues/SuperHero/levels/ instead (/leagues/levels/)
If you want to filter out /leagues/levels/`, then you can try to add an additional handler method:
#RequestMapping(value="/leagues/levels/")
for example, to return all levels of any league
The behavior is perfectly fine... The URL leagues/levels matches the second method's RequestMapping...
If you want to invoke the third method u need the URL as leagues/[some string]/levels
The website that I'm working on is heavily depending on ajax/json and knockout.js.
I would like to have a lot of my Controllers return view-tailored 'json objects', without wrapping them in a JsonResult when returning the method.
This would mean I could easily composite multiple calls into one parent object, but still be able to call the Actions separately too.
Simplified example:
public object Main(int groupId)
{
var viewModel = new
{
Persons = Employees(groupId),
Messages = AllMessages()
};
return viewModel;
}
public object Employees(int groupId)
{
return DatabaseContext.Employees.Where(e => e.GroupId == groupId).ToList();
}
public object AllMessages()
{
return DatabaseContext.Messages.ToList();
}
I was hoping I could capture the returned object in OnActionExecuted and at that point wrap the whole result up in a final JsonResult.
The result is already converted to a string and captured in a ContentResult though.
Any ideas? :) Thanks,
A good approach on this is to create helper methods for your entity calls. Or if you have those methods already somewhere, they can actually serve as the helper methods. In that manner you can return a list of strongly-typed Messages and Employees as well as returning your desired parent object. You can then have individual controller methods that returns json objects. In addition, you can extend the parent viewmodel to return additional fields.
The Parent ViewModel
public class ParentModel {
public Employee Persons {get;set;}
public Message Messages {get;set;}
}
The Helper Methods
The beauty of using helper methods similar to what is defined here is that you can apply a few more logic to your query, and more, and you don't have to change anything in your controller methods.
public ParentModel GetMain(int groupId)
{
var viewModel = new ParentModel
{
Persons = Employees(groupId),
Messages = AllMessages()
};
return viewModel;
}
public IEnumerable<Employee> Employees(int groupId)
{
return DatabaseContext.Employees.Where(e => e.GroupId == groupId).ToList();
}
public IEnumerable<Message> AllMessages()
{
return DatabaseContext.Messages.ToList();
}
The Controller Methods
public ActionResult GetParent(int groupId){
return Json(helperinstance.GetMain());
}
public ActionResult GetEmployees(int groupId){
return Json(helperinstance.Employees());
}
public ActionResult GetMessages(int groupId){
return Json(helperinstance.AllMessages());
}
Thanks for the answer. I'm not going for the solution of von v. because I like to keep the boilerplate as small as possible.
In the end I am trying out the following approach. It seems to work pretty well for now, but I still have to test it in real production.
If anyone has some (security) concerns with this, I'm happy to hear them in the comments.
// BaseController
protected override void OnActionExecuting(ActionExecutingContext filterContext)
{
var returnType = ((ReflectedActionDescriptor)filterContext.ActionDescriptor).MethodInfo.ReturnType;
// is the returnType not deriving from ActionResult? Automatically wrap it in a JsonResult
if ( !typeof(ActionResult).IsAssignableFrom(returnType) )
{
var result = filterContext.ActionDescriptor.Execute(filterContext, filterContext.ActionParameters);
filterContext.Result = Json( result );
}
}
Is it possible for a Controller method to handle all Posted items which derive from a particular base class? The idea is to be able to dispatch Commands by posting them to an endpoint. When I try the following, the "cmd" parameter in the Post method is always null.
Example
//the model:
public abstract class Command{
public int CommandId{get; set;}
}
public class CommandA:Command{
public string StringParam{get; set;}
}
public class CommandB:Command{
public DateTime DateParam{get; set;}
}
//and in the controller:
public HttpResponseMessage Post([FromBody]Command cmd)
{
//cmd parameter is always null when I Post a CommandA or CommandB
//it works if I have separate Post methods for each Command type
if (ModelState.IsValid)
{
if (cmd is CommandA)
{
var cmdA = (CommandA)cmd;
// do whatever
}
if (cmd is CommandB)
{
var cmdB = (CommandB)cmd;
//do whatever
}
//placeholder return stuff
var response = Request.CreateResponse(HttpStatusCode.Created);
var relativePath = "/api/ToDo/" + cmd.TestId.ToString();
response.Headers.Location = new Uri(Request.RequestUri, relativePath);
return response;
}
throw new HttpResponseException(HttpStatusCode.BadRequest);
}
Again, when I try this approach the Post method gets called, but the parameter is always null from the framework. However if I replace it with a Post method with a specific CommandA parameter type, it works.
Is what I'm attempting possible? Or does every message type need a separate handler method in the controller?
If you are sending data in Json format, then following blog gives more details about how hierarchies deserialization can be achieved in json.net:
http://dotnetbyexample.blogspot.com/2012/02/json-deserialization-with-jsonnet-class.html
I have the following code:
public ActionResult Index()
{
AdminPreRegUploadModel model = new AdminPreRegUploadModel()
{
SuccessCount = successAddedCount,
FailureCount = failedAddedCount,
AddedFailure = addedFailure,
AddedSuccess = addedSuccess
};
return RedirectToAction("PreRegExceUpload", new { model = model });
}
public ActionResult PreRegExceUpload(AdminPreRegUploadModel model)
{
return View(model);
}
but model is null when I breakpoint on PreRegExcelUpload. Why?
Instead of using the Session object in Evgeny Levin's answer I would suggest to use TempData. See http://rachelappel.com/when-to-use-viewbag-viewdata-or-tempdata-in-asp.net-mvc-3-applications about TempData.
You could also fix this by calling return PreRegExceUpload(model); instead of return RedirectToAction(..) in you Index function.
TempData is just a "smart" wrapper for the Session, under the hood it still acts the same way.
Since it's only 4 fields, i would pass them via querystring.
Always try and avoid session/tempdata where possible, for which in this scenario it certainly is.
Are you sure that's your full code? As it doesn't make sense.
If your POST'ing some data and saving it to the database (for example), usually you redirect to another action passing the unique identifier (which is usually generated after the save), fetch it back from the DB and return the view.
That is much better practice.
If you explain your scenario a bit more, and show the proper code your using, i can help further.
Use session to pass model to method:
public ActionResult Index()
{
AdminPreRegUploadModel model = new AdminPreRegUploadModel()
{
SuccessCount = successAddedCount,
FailureCount = failedAddedCount,
AddedFailure = addedFailure,
AddedSuccess = addedSuccess
};
Session["someKey"] = model;
return RedirectToAction("PreRegExceUpload");
}
public ActionResult PreRegExceUpload()
{
var model = (AdminPreRegUploadModel) Session["someKey"];
Session["someKey"] = null;
return View(model);
}
Method RedirectToAction() can't take non primitive types as parameters, because url parameters is string.