Custom Validation attribute is not firing when the model property is called - asp.net-mvc

I have made a custom attribute which checks the password complexity, the issue is that it called when i first run the code, after that if i change the complexity it does not register that attribute even if the session is refreshed.
i am calling it on property named password
in UserModel.
[ComplexPassword()]
public String Password { get; set; }
The custom attribute is here.
public class ComplexPassword : RegularExpressionAttribute
{
public ComplexPassword()
: base(GetRegex())
{
T = Localizer.CaptionInstance;
}
private Localizer.CaptionDelegate T { get; set; }
Some Logic here...
}
the Password property is used in the changed password form which is using user model. i think view code is not necessary to show. Can anyone guide how to fire it at every at every call of Password property.

I believe the Data Annotations get cached on a model. So if you are doing something behind the scenes so that GetRegex() changes depending on something you do in the app, it might not be reflected in any new validation attempts on the model. You might need to create your own MetadataProvider that cusotmizes the behavior of DataAnnotationsModelMetadataProvider

Related

Disable remote validation

I have a model that uses remote validation. The model also acts as a parent class to a child class. How would i disable remote validation in the view for a particular field?
Model code
public user
{
[Remote("Validateemail","User",etc)]
public string Email {get; set;}
}
public edituser:user
{
public int userid {get; set;}
public edituser(int userid,string email)
{
userid=userid;
Email=email;
}
}
My aim is to remove the remove validation in the edituser class in the view.
im assuming that you just need to display the email field and all the data in it as it is in editView because by defauflt a user cannot edit his/her email..
to so this you can just change the code in the view from
Html.EditorFor() to Html.DisplayFor()
this is the perfect case for viewmodel. create a different viewmodel for edit (as a matter-effect view should not be linked directly to domain models in most of the cases)
or you can use IValidatableObject or fluentvalidation , or you can use DataAnnotationsModelValidatorProvider for manually attaching attribute condition based if it applies in your case.

MVC Partial Model Updates

I often find myself in the situation where I only want to present and edit some fields from my model. Let's say I have a model that represts an address, perhaps I just want the form to update the city and post code fields (bad example, but hopefully it explains the scenario).
I know of two methods:
1) Persist the unwanted fields in hidden input elements on the form, or...
2) Create a dedicated view model that just defines the fields I need.
I favour option #2, but I don't have a nice clean way of merging the data from the view model back into the 'real' model within the controller action. At the moment, I follow this approach...
1) Store the record I'd in a hidden field on the view model
2) When the page posts back, the controller retrieves the original record and I manually assign each field from the view model to the real model
3) Save the real model back to the data store.
This works, but it is quite a lot of work and very easy to miss an assignment/reassignment and I was wondering if anyone knew of another approach?
Use the System.ComponentModel.DataAnnotations.MetadataType.
Something like:
public class BaseClassOfProperties
{
public string Name { get; set; }
}
public interface INameViewableProperties
{
[Display(name = "Your Name")]
string Name { get; set; }
}
public interface INameHiddenProperties
{
//[scaffoldColumn(false)] this completely hides the fields
[UIHint("Hidden")] // i think...
string Name { get; set; }
}
[MetadataType(typeof(INameViewableProperties)]
public class NameViewAbleProperties : BaseClassOfProperties
{
}
[MetadataType(typeof(INameHiddenProperties)]
public class NameHiddenProperties : BaseClassOfProperties
{
}

Remote attribute in asp.net mvc – in some situations restricts our model

I’ve got an unexpected situation when using Remote Attribute in ASP.NET MVC3.
The model type I used:
using System;
using System.Web.Mvc;
using System.ComponentModel.DataAnnotations;
namespace dTweets.Models
{
// at first time, user should create his account with unique username
// as in twitter.com, user do
public class UserMetadata
{
[HiddenInput]
internal int Identity { get; set; }
[Remote("IsUserExist", "Account")] // at any HttpPost, username should
// be unique – not appropriate if
// updating/editing this model later
[Required(ErrorMessage = "username should be unique")]
public string UserName { get; set; } // user cannot change it, later
[DataType(DataType.Password)]
public string Password { get; set; } // user can also change password, later
[DataType(DataType.MultilineText)]
public string About { get; set; } // Optional field – user can edit it later
}
[MetadataType(typeof(UserMetadata))]
[Bind(Include="UserName, Password, About")]
public partial class User
{
}
}
Remote attribute validates user unique name at account creation time. But when later user wants to update/change his account, Remote attribute did not allow to update model if keeping user unique name the same one.
This is not appropriate result because rarely user changes their unique user name. They just change other fields like About field or password etc.
[Note: at account creation time, I want to check user unique name so I used Remote attribute here, but at later time when updating user account I no longer need Remote attribute]
I must remove Remote attribute for updating this model later.
I want to update/change this model without changing user unique name (remote attribute is applied to this unique name).
one way to do this is to send ID value of this record in AdditionalFields named parameter like
[Remote("IsUserExist", "Account",AdditionalFields = "Identity")]
and then you can check for uniqueness across all rows except the ones that belong to current user. and don't forget to change signature of IsUserEsists action result to receive Identity like
public ActionResutl IsUserExists(string UserName, int Identity)
{
}
Can't you just change server side validation method to something like:
public ActionResult IsUserExists(string userName)
{
if (!UserService.UserNameExists(userName) || (CurrentUser.UserName == userName))
{
return "Yeah. Is it valid.";
}
}
You have current user, because he is logged in. As long as user can only edit his data, this will work.
This is one place where buddy metadata falls short.
Edit/Add scenarios require their own view models. One size fits all scenario validation attributes only work in very trivial business CRUD apps. Add and Edit actions happen in totally different contexts and are only transiently related. This concept is very similar to the DDD bounded context idea.

ASP.NET MVC validation of uniqueness

Rails has a very convenient uniqueness validation.
ASP.NET MVC doesn't.
I need to make sure that the e-mail address a user has entered hasn't been registered by anyone yet.
I can see only one way of doing this kind of validation: create a new data context object in the UniqueAttribute class.
But I'm afraid that wasting memory on a new data context object just for one validation is dangerous.
Am I wrong? Is there a better way to do that?
Update
This is what I got so far
public class UniqueEmailAttribute : ValidationAttribute {
public override bool IsValid(object value) {
DataContext db = new DataContext();
var userWithTheSameEmail = db.Users.SingleOrDefault(
u => u.Email == (string)value);
return userWithTheSameEmail == null;
}
}
// Usage
[UniqueEmail(ErrorMessage="This e-mail is already registered")]
public string Email { get; set; }
There are two problems.
It would be good to have just one UniqueAttribute class, not separate classes for e-mails, usernames etc. How can I do that?
Creating a new data context every time you need to validate a single attribute.
SOLUTION
So in the end I created a unique constraint on the table and now I just have to intercept SqlException in Users repository. Works great and is probably more efficient than searching for the same node in the whole table. Thanks!
Mvc 3 Relaease candidate has new New Validation Attributes as a remotevalidation -where you can register a method for validation on clientside(jquery).
see below example-
RemoteAttribute
The new RemoteAttribute validation attribute takes advantage of the jQuery Validation plug-in's remote validator, which enables client-side validation to call a method on the server that performs the actual validation logic.
In the following example, the UserName property has the RemoteAttribute applied. When editing this property in an Edit view, client validation will call an action named UserNameAvailable on the UsersController class in order to validate this field.
public class User {
[Remote("UserNameAvailable", "Users")]
public string UserName { get; set; }
}
The following example shows the corresponding controller.
public class UsersController {
public bool UserNameAvailable(string username) {
return !MyRepository.UserNameExists(username);
}
}
Mvc 3
UPDATE
public bool UserNameAvailable(string Propertyname)
{
if (Request.QueryString[0]= "UserName")
{
//validate username
}
elseif (Request.QueryString[0]= "Email")
{
//Validate Email
}
}
ASP.Net does have a feature that can automatically check the uniqueness of a user's email address when a user registers. It is the ASP.Net Membership service and you can use it to do what you want even if you don't use all of the features of it.
If you are not using the full Membership feature in your MVC application, then all you need to do is use
Membership.FindUsersByEmail(emailYouAreLookingFor);
If any values come back, you know that the address is not unique. If you ARE using the Membership service to create users, then the Membership service will check AUTOMATICALLY and return a code to you if the user's email address is not unique.
The Membership service sits in the System.Web.Security area so you would need a
using System.Web.Security;
reference in your controller.
Here is an example
MembershipCreateStatus createStatus = MembershipService.CreateUser(UserName, Password, Email);
if (createStatus == MembershipCreateStatus.DuplicateEmail)
{
//do something here
}
else
{
//do something here
}
I hope this helps!
The right way to make a generic remote unique validator in MVC can be found in this MVC forum. by counsellorben. It's based on my MVC unique remote validator article http://msdn.microsoft.com/en-us/library/gg508808(VS.98).aspx
A foolproof way of doing this is to create a validation attribute that would query the database for the email address. It would certainly add latency.
An alternative would be to create a unique constraint on the table and intercept SqlException.

Where should be the validation in a ASP.Net MVC scenario having Repository, Service Layer and using Model Binder?

Related: What’s the best way to implement field validation using ASP.NET MVC?
Let's suppose a solution with the following projects:
Foo; // the MVC web project
Foo.Models;
Foo.Repositories;
Foo.Services;
Foo.Models is the domain of the application with all the entities, doesn't matter if using EF, NH, POCO or whatever. Here's an example:
public class User
{
public string Username { get; set; }
public string Email { get; set; }
public string Password { get; set; }
}
In Foo.Repositories there is a UserRepository and in Foo.Services there is a UserService.
In the web application let's consider a model binder like following:
public class UserBinder : DefaultModelBinder
{
//...
}
I see three different options on where to put the validation:
In Foo.Models like the following:
public class User
{
public string Username { get; set; }
public string Email { get; set; }
public string Password { get; set; }
public ICollection<KeyValuePair<string, string>> ValidateErrors()
{
//Validate if Username, Email and Password has been passed
}
}
In Foo.Services like:
public class UserService
{
public ICollection<KeyValuePair<string, string>> ValidateErrors()
{
//Validate if Username, Email and Password has been passed
}
}
In Foo inside the model binder:
public class UserBinder : DefaultModelBinder
{
protected override void OnModelUpdated(ControllerContext controllerContext, ModelBindingContext bindingContext)
{
var user = (User)bindingContext.Model;
// validate everything here
base.OnModelUpdated(controllerContext, bindingContext);
}
}
Another thing to notice is that considering the first 2 options [Model and Service] there is another decision to make: ValidateErrors method can be called directly on the controller or inside the Binder.
I have 2 questions on the scenario:
Should the validation be:
In the Model being called from the controller?
In the Model being called from the binder?
In the Service being called from the controller?
In the Service being called from the binder?
Directly in the Binder?
Any other idea?
All the above scenario discuss about the User creation. But what about User logon?
Let's say user uses the username and password to login in the application, so it won't need to validate the e-mail.
Where this validation should be?
In the Model being called from the controller?
In the Service being called from the controller?
Any other idea?
Check out the ASP.NET MVC Contact Manager Sample Application it has a very good architecture im my opinion
http://www.asp.net/learn/mvc/tutorial-26-cs.aspx'>http://www.asp.net/learn/mvc/tutorial-26-cs.aspx
I'm a big fan of putting calling the validation from the controllers and having the validation routine return an ActionResult so the controller can know what to do with the result.
For what it's worth, here's what I have scrounged up in my current project:
I have Models, Repositories (you can call them Services if you like), and ViewModels. I try to avoid writing custom model binders because (a) it's boring and (b) a strange place to put validation, IMHO. To me, a model binder is just taking items from the request and shoving them into an object. PHP, for example, doesn't do any validation when plucking items from a header into the $_POST array; it's the thing we plug the array into that cares about its contents.
My Model objects generally never allow themselves to enter an invalid state. This means that required parameters are passed in during constructors and properties will throw exceptions if they're attempted to be set with invalid values. And, in general, I try to design my Model objects to be immutable. For example, I have an Address object for mailing addresses that is constructed with an AddressBuilder object with looks at the field requirements for a given country by inspecting an AddressScheme that can be retrieved from the AddressSchemeRepository. Phew. But I think it's a good example because it takes something conceptually simple ("validate a mailing address") and makes it complicated in real world usage ("we accept addresses from over 30 countries, and those formatting rules are sitting in a database, not in my code").
Since constructing this Model object is kind of a pain--as well it should be, since it's being quite particular about the data that gets loaded into it--I have a, say, InputAddressViewModel object that my view binds to. The InputAddressViewModel implements IDataErrorInfo so that I get ASP.NET MVC's DefaultModelBinder to add errors to the ModelState automatically. For simple validation routines that I know ahead of time (phone number formatting, first name required, e-mail address format), I can implement these right in the InputAddressViewModel.
The other advantage of having a view model is that because it is shamelessly tailored to a particular view, your real model is more reusable because it doesn't have to make any weird concessions to make it suitable for UI display (e.g., needs to implement INotifyPropertyChanged or Serializable or any of that mess).
Other validation errors about the address I won't know about until I interact with my AddressScheme in my actual Model. Those errors will be there controller's job of orchestrating into the ModelState. Something like:
public ActionResult InputAddress(InputAddressViewModel model)
{
if (ModelState.IsValid)
{
// "Front-line" validation passed; let's execute the save operation
// in the our view model
var result = model.Execute();
// The view model returns a status code to help the
// controller decide where to redirect the user next
switch (result.Status)
{
case InputAddressViewModelExecuteResult.Saved:
return RedirectToAction("my-work-is-done-here");
case InputAddressViewModelExecuteResult.UserCorrectableError:
// Something went wrong after we interacted with the
// datastore, like a bogus Canadian postal code or
// something. Our view model will have updated the
// Error property, but we need to call TryUpdateModel()
// to get these new errors to get added to
// the ModelState, since they were just added and the
// model binder ran before this method even got called.
TryUpdateModel(model);
break;
}
// Redisplay the input form to the user, using that nifty
// Html.ValidationMessage to convey model state errors
return View(model);
}
}
The switch may seem repulsive, but I think it makes sense: the view model is just a plain old class and doesn't have any knowledge of the Request or the HttpContext. This makes the logic of the view model easy to test in isolation without resorting to mocking and leaves the controller code left to, well, control by interpreting the model's result in a manner that makes sense on a Web site--it could redirect, it could set cookies, etc.
And the InputAddressViewModel's Execute() methods looks something like (some people would insist on putting this code into a Service object that the controller would call, but to me the view model will do so much finagling of the data to make it fit the real model that it makes sense to put it here):
public InputAddressViewModelExecuteResult Execute()
{
InputAddressViewModelExecuteResult result;
if (this.errors.Count > 0)
{
throw new InvalidOperationException(
"Don't call me when I have errors");
}
// This is just my abstraction for clearly demarcating when
// I have an open connection to a highly contentious resource,
// like a database connection or a network share
using (ConnectionScope cs = new ConnectionScope())
{
var scheme = new AddressSchemeRepository().Load(this.Country);
var builder = new AddressBuilder(scheme)
.WithCityAs(this.City)
.WithStateOrProvinceAs(this.StateOrProvince);
if (!builder.CanBuild())
{
this.errors.Add("Blah", builder.Error);
result = new InputAddressViewModelExecuteResult()
{
Status = InputAddressViewModelExecuteStatus
.UserCorrectableError
};
}
else
{
var address = builder.Build();
// save the address or something...
result = new InputAddressViewModelExecuteResult()
{
Status = InputAddressViewModelExecuteStatus.Success,
Address = address
};
}
}
return result;
}
Does this make sense? Is it a best practice? I have no idea; it's certainly verbose; it's what I just came up with in the past two weeks after thinking about this problem. I think you're going to have some duplication of validation--your UI can't be a complete imbecile and not know what fields are required or not before submitting them to your model/repositories/services/whatever--otherwise the form could simply generate itself.
I should add that the impetus for this is that I've always kind of detested the Microsoft mentality of "set one property -> validate one property" because nothing ever works like that in reality. And you always end up getting an invalid object persisted because someone forgot to call IsValid or some such on the way to the data store. So another reason for having a view model is that it tailors itself to this concession so we get a lot of CRUD work of pulling items from the request, validation errors in the model state, etc quite easily without having to compromise the integrity of our model itself. If I have an Address object in hand, I know it's good. If I have an InputAddressViewModel object in hand, I know I need to call it's Execute() method to get that golden Address object.
I'll look forward to reading some of the other answers.
After a lot of research I think I got the answers to my question so i decided to share.
The validation code should be on Model.
As per the idea of "thin controller, fat model" AND considering that a model would know what it needs to validate or not.
For example, let's say I decide to user the Foo.Models in other solution but I decide NOT to use any other project and the validation is in other project.
I'll have to re-code the entire validation in this case what is a total waste of time, right?
OK. The validation code must be in the model but where should it be called?
This validation must be called where you're saving it to your database or file.
As in the proposed scenario I'm considering the repository as a domain, then we should consider putting the validation just before the change saving [in this example I'm using Entity Framework but it's not necessary, it's just to show]:
public class UserRepository : IRepository<User>
{
public void Create(User user)
{
user.Validate();
var db = dbFooEntities();
db.AddToUsers(user);
db.SaveChanges();
}
}
As per MS recommendation, the model validation should raise an exception and the controller must populate the ModelState with the errors found [I'll try to update this answer with a sample code on that as soon as I finish my app].
With that we have an answer for question #1.
What about question #2, regarding the login validation?
As login is not a situation where you're persisting your data, the validation should stay on the Service since logging in is a service in this case.
So, the answers for the question are:
In the Model being called from the REPOSITORY [that is called by the controller]
In the Service being called from the controller
This is very interesting and it helps me a lot in deciding where to put validation.
currently I feel the most for each model implementing a "Validate" method, which is called from a Repository or a Service.
However, what about validating if a chosen username is unique?
Should that code be inside the User model, or inside the UserService class, or in the UserRepository class?
If the uniqueness validation should be inside the User model, then the User model should have access to either the UserService or the UserRepository class. Is that OK, or is that against any "best practice" pattern?
For example:
class User
{
string Username { get; set; }
string Email { get; set; }
string Password { get; set; } // hashed and salted of course :)
IEnumerable<RuleViolation> Validate()
{
List<RuleViolation> violations = new List<RuleViolation>();
IUserService service = MyApplicationService.UserService; // MyApplicationService is a singleton class, especialy designed so that the User model can access application services
// Username is required
if ( string.IsNullOrEmpty(Username) )
violations.Add(new RuleViolation("Username", "Username is required"));
// Username must be unique: Should uniqueness be validated here?
else if( !service.IsUsernameAvailable(Username)
violations.Add(new RuleViolation("Username", "Username is already taken!"));
// Validate email etc...
return violations;
}
}
interface IUserRepository
{
void Save(User item);
}
interface IUserService
{
IUserRepository UserRepository { get; }
void Save(User item);
}
class UserService : IUserService
{
public UserService(IUserRepository userRepository)
{
this.UserRepository = userRepository;
}
IUserRepository UserRepository { get; private set}
public void Save(User user)
{
IEnumerable<RuleViolation> violations = user.Validate();
if(violations.Count() > 0)
throw new RuleViolationException(violations); // this will be catched by the Controller, which will copy the violations to the ModelState errors collection. But the question is, should we validat the user here, or in the UserRepository class?
UserRepository.Save(user);
}
}
class UserRepository : IUserRepository
{
void Save(User item)
{
IEnumerable<RuleViolation> violations = user.Validate();
if(violations.Count() > 0)
throw new RuleViolationException(violations); // this will be catched by the Controller, which will copy the violations to the ModelState errors collection. But the question is, should we validate the user here, or in the UserService class?
UserRepository.Save(user);
}
}
My guess would be that validation should be as close to the model as possible. So I'd say that the UserRepository should be the one responsible for validating it's model being added.
The most important queston for me is: Should the User model know about the IUserService / IUserRepository interfaces so that it can validate the Username uniqueness?
Or should the IUserService service validate uniqueness?
I'm curious about your views on this!
I'm using the DataAnnotations attributes in combination with a MVC model binder to do my validation and its pretty awesome. Since I treat User input as Command View Models its the cleanest way to keep domain clean from outside concerns.
http://bradwilson.typepad.com/blog/2009/04/dataannotations-and-aspnet-mvc.html
This also allows me to take advantage of AutoForm by LosTechies.com:
http://www.lostechies.com/blogs/hex/archive/2009/06/17/opinionated-input-builders-part-8-the-auto-form.aspx
And I expect the client side validation tools in MVC 2, VS 2010 to take advantage of these attributes as well.
So I'm whipping out user input view models, commands, at a furious pace right now and tying them into not only the AutoForm functionality but my own custom UI templates to get AutoGrid and AutoOutput from these attributes as well.
Nothing is better than saying:
Html.AutoForm(Model);
Or
Html.AutoGrid(Model.Products);
And getting validation and html generation in a very DRY and orthogonal way. My controllers are light, my domain pristine, and my time is unoccupied by writing the same if( string.IsNullOrEmpty() ) method on every object with a FirstName property.
For me the approach was not as "philosophical" as others have written about. I'm trying to be very pragmatic about MVC development and I get a ton of bang for the buck out of these bits.

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