I have integrated payment gateway now, on success URL I want to pass some data from one controller to another controller but it's not working properly it's showing null value sometimes so, What I have to use instead of Session or TempData.
public void Index(UserRegistreModel model)
{
TempData["model2"]= model;
redirecturl += "&return=" + ConfigurationManager.AppSettings["SuccessURL"].ToString();
}
public ActionResult AnotherControllerMethod(UserRegistreModel model)
{
UserRegistreModel add = (UserRegistreModel) TempData["model2"];
//not getting any values
}
Your are adding User type class to Temp Data but you are extracting UserRegistreModel type so, that's why this was empty, Use like this :-
public void Index(User model)
{
TempData["model2"]= model;
redirecturl += "&return=" +
ConfigurationManager.AppSettings["SuccessURL"].ToString();
}
public ActionResult AnotherControllerMethod(User model)
{
User add = (User) TempData["model2"];
//not getting any values
}
How u are Passing Data ? Is it a forward or redirect? Forward will take the current data of your Request Object as it is the same Request but ur URL will not be changed in client.
And If u are redirecting then its a new Request. In This case the response will go to the client first (browser) then come to your new controller. As it is a new request, it will not have the old data from your calling controller.
Spring Has a special type of pojo called RedirectAttributes for this. Where you can add FlashAttribute for this type of requirement. Check the similar thing in .net
Related
Scenario: How to update a model?
ASP MVC 6
I am trying to update a model. For passing the model information to the client(browser/app) I am using the DTO.
Question 1: For updating, should I post the whole object back?
Question 2: Is there a way I can easily pass only the information that is updated? If yes, how?
Question 3: Can I use JSON Patch for updation?
Question 2: Is there a way I can easily pass only the information that
is updated? If yes, how?
Yes. You should create a view model which should have only those properties needed for the view.
Let's assume your use case is to build a view which allows user to edit only their last name.
public class EditUserViewModel
{
public int Id {set;get;}
public string LastName {set;get;}
}
And in your Get
public ActionResult Edit(int id)
{
var user = yourUserRepository.GetUser(id);
if(user!=null)
{
var v = new EditUserViewModel { Id=id,LastName=user.LastName};
return View(v);
}
return View("NotFound");
}
And the view
#model EditUserViewModel
#using(Html.BeginForm())
{
#Html.TextBoxFor(s=>S.LastName)
#Html.HiddenFor(s=>s.Id)
<input type="submit" id="saveBtn" />
}
and your HttpPost action
[HttpPost]
public ActionResult Edit(EditUserViewModel model)
{
// Since you know you want to update the LastName only,
// read model.LastName and use that
var existingUser = yourUserRepository.GetUser(model.Id);
existingUser.LastName = model.LastName;
yourUserRepository.Save();
// TO DO: redirect to success page
}
Assuming yourUserRepository is an object of your data access classes abstraction.
Question 1: For updating, should I post the whole object back?
Depends on what you want from the end user. With this view model approach, It is going to post only the Id and LastName and that is our use case.
Can I use JSON Patch for updating?
Since you are only sending the data which needs to be updated (partial data), you should be fine.
If you want,you may simply serialize your form data(which has only Id and LastName) and use jQuery post method to send it to your server.
$(function(){
$("#saveBtn").click(function(e){
e.preventDefault(); //prevent default form submit
var _form=$(this).closest("form");
$.post(_form.attr("action"),_form.serialize(),function(res){
//do something with the response.
});
});
});
To prevent overposting, you can use a binding whitelist using Bind attribute on your HttpPost action method. But the safest strategy is to use a view model class that exactly matches what the client is allowed to send.
Instead of this
UpdateModel(model);
You now can call this
await TryUpdateModelAsync(model);
This is my controller code:
private string testVal;
public ActionResult Index()
{
testVal = "test";
return View();
}
public ActionResult NextView()
{
if (testVal == null)
Debug.WriteLine("testVal is null");
return View();
}
Is it possible to remeber values like testVal after changing page? It seems that when redirecting it resets values (testVal in NextVal is null).
Edit:
I try to save values to session but Session is null. I am using SignalR and when user is connected to page i use static event from hub to inform controller that user has connected - but inside method that runs on that event Session is unfortunetly null.
My controller code:
public ActionResult Index()
{
LoadingHub.userConnected += new EventHandler<IdEventArgs>(UserConnected);
return View();
}
private void UserConnected(object sender, IdEventArgs e)
{
Debug.WriteLine("User Connected with Id: " + e.Id);
if (Session == null)
Debug.WriteLine("Session is null");
}
My signalr hub:
public class LoadingHub : Hub
{
public static event EventHandler<IdEventArgs> userConnected;
//Function informs server that user has connected
public void Connected()
{
Debug.WriteLine("Hub Connected Method");
var id = Context.ConnectionId;
userConnected(this, new IdEventArgs(id));
}
}
Every time that you make a request a new instance of the controller is created so using a private field you will not be able to retain the value of this variable.
The easiest way for you to retain it it is to use a session. (if you want to retain this value per user base)
for example in your code
public ActionResult Index()
{
System.Web.HttpContext.Current.Session["testVal"] = "test";
return View();
}
public ActionResult NextView()
{
if (System.Web.HttpContext.Current.Session["testVal"] == null)
Debug.WriteLine("testVal is null");
return View();
}
you can use cookie or cache to replace the variable.
when you redirect to a webpage ，the controller will be newed ,so you cannot get the right testVal .but the cookie is stored in broswer .so you can set it and get .
You may use session or Pass the data to the controller
Have you looked into ASP.NET server side state management click here.
These are basically different ways to remember a value on the server once a new page has been loaded.
So a few server side techniques you could use to remember testVal are Session State or Application State. However Session State is more suitable for your scenario as it is only specific to the user's current session whereas Application State stores data that can be shared between sessions and would therefore be more ideal for global variables.
You can read the link I provided to read more on the differences though.
I would also like to warn you (as some say to use cookies), the user can delete or disable or manipulate them on the browser so this isn't an ideal solution.
I have an ASP.NET MVC4 front end as one project in my solution, and a separate ASP.NET Web API as another project in the same solution. The Web API will contain all of my CRUD operations.
2 questions
How do I call my Web API from my front end to perform CRUD operations? I have my entity data model defined in my Web API project, and I will need to bind my front end views to it, how would I do that?
Once this is deployed to my web servers, the front end will reside on one server, and the Web API will reside on another server (the server that holds most of our web services). So, I guess along the same lines, how would I call the Web API from my front end once deployed? I understand Web API's are simply called with an HTTP request, but in terms of passing my models (which are defined in my Web API project) into my Views (in my front end project), how can I do this?
While Kevin is right, I did this the non-Ajax way. Keep in mind that I am working with JSON data, so this is centered around JSON.
In your controller page, remove anything that has to do with DbContext, Entity Framework, etc. The reason is by default, the controller will want to perform CRUD operations by calling the DbContext, and we don't want this. We want to call the WebAPI instead to do this.
First and foremost, declare some member variables in your controller. The rest of your controller will utilize these:
HttpClient client = new HttpClient();
HttpResponseMessage response = new HttpResponseMessage();
Uri contactUri = null;
In your controller, create a constructor for your controller, as such:
public ContactController()
{
// set base address of WebAPI depending on your current environment
client.BaseAddress = new Uri("http://server/YourAPI/");
// Add an Accept header for JSON format.
client.DefaultRequestHeaders.Accept.Add(
new MediaTypeWithQualityHeaderValue("application/json"));
}
Replace the Index action's code with something like the following. Note that the only relevant pieces are the client.GetAsync() call and the var contacts assignment. Everything else is not necessary for the context of this problem. The value inside the client.GetAsync() should be the name of your controller, prepended by any custom routing you set up in your WebApiConfig.cs - in my case, I added the api part in my route to distinguish between API calls and normal calls:
public ActionResult Index()
{
response = client.GetAsync("api/contact").Result;
if (response.IsSuccessStatusCode)
{
var contacts = response.Content.ReadAsAsync<IEnumerable<Contact>>().Result;
return View(contacts);
}
else
{
// add something here to tell the user hey, something went wrong
return RedirectToAction("Index");
}
}
Replace the Create action (the HttpPost action) with something like the following. Again, the only important piece is the client.PostAsJsonAsync() part - this is what calls the WebAPI's POST action which takes care of, in my case, inserting a new record into the database:
[HttpPost]
[ValidateAntiForgeryToken]
public ActionResult Create(Contact contact)
{
// Create a new product
response = client.PostAsJsonAsync("api/contact", contact).Result;
if (response.IsSuccessStatusCode)
{
return RedirectToAction("Index");
}
else
{
// add something here to tell the user hey, something went wrong
return RedirectToAction("Index");
}
}
Replace the Edit action (the non-HttpPost action) with something like the following. This was a little tricky because in order to edit, you had to retrieve the record first, so basically, the HttpPost version of Edit will contain somewhat similar code, with an additional line of code that performs the edit POST (PUT). Below, we're getting the response from the WebAPI by passing it a specific record ID. So, just like for Index (GET), we are doing the same thing only passing in the ID so we only get back one record. Then, we cast the response to an actual object that can be operated on in the View:
public ActionResult Edit(int id = 0)
{
response = client.GetAsync(string.Format("api/contact/{0}", id)).Result;
Contact contact = response.Content.ReadAsAsync<Contact>().Result;
if (contact == null)
{
return HttpNotFound();
}
return View(contact);
}
Replace the Edit action (the HttpPost action) with something like the following. Below, we're getting the record to be edited by calling client.GetAsync() and passing in the primary key as a parameter (contact_id). Then, we're getting the RequestUri from that response and saving it. Then, we're calling client.PutAsJsonAsync() and passing in the Uri.PathAndQuery (what we just saved) as well as the object to be edited.
[HttpPost]
[ValidateAntiForgeryToken]
public ActionResult Edit(Contact contact)
{
response = client.GetAsync(string.Format("api/contact/{0}", contact.contact_id)).Result;
contactUri = response.RequestMessage.RequestUri;
response = client.PutAsJsonAsync(contactUri.PathAndQuery, contact).Result;
if (response.IsSuccessStatusCode)
{
return RedirectToAction("Index");
}
else
{
// add something here to tell the user hey, something went wrong
return RedirectToAction("Index");
}
}
Replace the Delete action (the non-HttpPost action) with something like the following. So again, we're getting the record from the database by simply calling client.GetAsync() and casting it to an actual object my app knows of.
public ActionResult Delete(int id = 0)
{
response = client.GetAsync(string.Format("api/contact/{0}", id)).Result;
Contact contact = response.Content.ReadAsAsync<Contact>().Result;
if (contact == null)
{
return HttpNotFound();
}
return View(contact);
}
Finally, replace the Delete action (the HttpPost action) with something like the following. Again, we're doing something similar to that of the Edit action. We are getting the record to be deleted, casting it to an object, and then passing that object into a client.DeleteAsync() call, as shown below.
[HttpPost, ActionName("Delete")]
[ValidateAntiForgeryToken]
public ActionResult DeleteConfirmed(int id)
{
response = client.GetAsync(string.Format("api/contact/{0}", id)).Result;
contactUri = response.RequestMessage.RequestUri;
response = client.DeleteAsync(contactUri).Result;
return RedirectToAction("Index");
}
You can call your Web API from the client using jQuery ajax method. But since you are calling from a site other than where the Web API is deployed you will have to use JSONP, instead of JSON. Take a look at this QA to see how you use JSONP with Web API. Your models will be passed as JSON which you will have to render on the client side, instead of using Razor to render it on the server side. I would use something like Knockout to create a View Model on the client that will bind your model to the HTML elements on the client.
I have a spring MVC based web application. Currently in my web page i am showing the user first name and last name after user logs in. The way i am doing this is, for every HttpServletRequest that comes into #Controller#RequestMapping, i get the Principal object and get the user details from it, then populate the ModelMap with firstname and lastname attribute. For example here is the sample code
#Autowired
private SecurityDetails securityDetails;
#RequestMapping(method = RequestMethod.GET)
public String showWelcomePage(HttpServletRequest request,
HttpServletResponse response, ModelMap model, Principal principal)
{
securityDetails.populateUserName(model, principal);
... lot of code here;
return "home";
}
public boolean populateUserName(ModelMap model, Principal principal) {
if (principal != null) {
Object ob = ((Authentication)principal).getPrincipal();
if(ob instanceof MyUserDetails)
{
MyUserDetails ud = (MyUserDetails)ob;
model.addAttribute("username", ud.getFirstName() + " " + ud.getLastName());
}
return true;
}
else
{
logger.debug("principal is null");
return false;
}
}
My problem is i am having to call the populateUserName method for every RequestMapping. Is there a elegant way, like populating this in Interceptor method, which will result in this method being called just in one place for entire application?
Its good that you want to prevent duplication of code. Here is how you can do it.
Create a custom HandlerInterceptor http://static.springsource.org/spring/docs/2.5.x/api/org/springframework/web/servlet/HandlerInterceptor.html
Post handle is the only method of interest for us, for the others return defaults.
In the post handle method, you have access to the model and view returned from your controller, go ahead and add whatever you want.
The Principal will not be available directly here, you will have to look it up using some code like SecurityContextHolder.getContext().getAuthentication().getPrincipal()
Wire the handler interceptor to intercept all or some of your controllers.
Hope this helps.
You can use either Servlet Filters or Spring Interceptors.
BTW, where do you populate the Principal from?
In any case, thats where you should do this populating stuff.
ASP.NET MVC 2.0 will now, by default, throw an exception when an action attempts to return JSON in response to a GET request. I know this can be overridden on a method by method basis by using JsonRequestBehavior.AllowGet, but is it possible to set on a controller or higher basis (possibly the web.config)?
Update: Per Levi's comment, this is what I ended up using-
protected override JsonResult Json(object data, string contentType, System.Text.Encoding contentEncoding)
{
return Json(data, contentType, JsonRequestBehavior.AllowGet);
}
This, like other MVC-specific settings, is not settable via Web.config. But you have two options:
Override the Controller.Json(object, string, Encoding) overload to call Json(object, string, Encoding, JsonRequestBehavior), passing JsonRequestBehavior.AllowGet as the last argument. If you want this to apply to all controllers, then do this inside an abstract base controller class, then have all your controllers subclass that abstract class.
Make an extension method MyJson(this Controller, ...) which creates a JsonResult and sets the appropriate properties, then call it from your controller via this.MyJson(...).
There's another option. Use Action Filters.
Create a new ActionFilterAttribute, apply it to your controller or a specific action (depending on your needs). This should suffice:
public class JsonRequestBehaviorAttribute : ActionFilterAttribute
{
private JsonRequestBehavior Behavior { get; set; }
public JsonRequestBehaviorAttribute()
{
Behavior = JsonRequestBehavior.AllowGet;
}
public override void OnResultExecuting(ResultExecutingContext filterContext)
{
var result = filterContext.Result as JsonResult;
if (result != null)
{
result.JsonRequestBehavior = Behavior;
}
}
}
Then apply it like this:
[JsonRequestBehavior]
public class Upload2Controller : Controller
MVC 2 block Json for GET requests for security reasons. If you want to override that behavior, check out the overload for Json that accepts a JsonRequestBehavior parameter.
public ActionResult Index()
{
return Json(data, JsonRequestBehavior.AllowGet)
}
I also got this error when I first use MVC 2.0 using my old code in MVC 1.0. I use fiddler to identify the cause of the error. See the steps on how to troubleshoot it using Fidder -
http://www.rodcerrada.com/post/2011/07/11/jQuery-getJSON()-does-not-tirgger-the-callback-in-ASPNET-MVC-2.aspx
Is this is the security issue MVC2 was trying to address?
http://haacked.com/archive/2009/06/25/json-hijacking.aspx
If so, it seems like the vulnerability is only an issue if you are trying to do a json call to an outside website. If your MVC2 app is only making json calls to your own website (to fill jqgrids for example), shouldn't you be able to safely override the Json call in your base controller to always allow get?
Just change JSON code from :
$.getJson("methodname/" + ID, null, function (data, textStatus)
to:
$.post("methodname/" + ID, null, function (data, textStatus)