Let's say that I have simple model with required attribute above property.
public class User
{
[Required]
string Name {get;set;}
string Surname {get;set;}
}
When I POST/PUT only one instance of User and Name is empty it works pretty well. ModelState is not valid and contains error.
When I POST/PUT collection of objects User and in some of them Name is empty then ModelState is valid and it does not contain any validation errors.
Could you tell me what is wrong with it and why it concerns only collections? I noticed same behaviour when I have one object with relation one-many. Then collection within this object also is not validated by ModelState.
I don't want to validate required fields manually, it should work automatically.
You need to create a ActionFilter
public class ModelStateValidActionFilter : IAsyncActionFilter
{
public Task OnActionExecutionAsync(ActionExecutingContext context, ActionExecutionDelegate next)
{
// Validate ICollection
if (context.ActionArguments.Count == 1 && context.ActionArguments.First().Value.GetType().IsListType())
{
foreach (var arg in (IList)context.ActionArguments.First().Value )
{
var parameters = arg.GetType().GetProperties();
foreach (var parameter in parameters)
{
var argument = context.ActionArguments.GetOrDefault(parameter.Name);
EvaluateValidationAttributes(parameter, argument, context.ModelState);
}
}
}
if (context.ModelState.IsValid)
{
return next();
}
context.Result = new BadRequestObjectResult(context.ModelState);
return Task.CompletedTask;
}
private void EvaluateValidationAttributes(PropertyInfo parameter, object argument, ModelStateDictionary modelState)
{
var validationAttributes = parameter.CustomAttributes;
foreach (var attributeData in validationAttributes)
{
var attributeInstance = parameter.GetCustomAttribute(attributeData.AttributeType);
var validationAttribute = attributeInstance as ValidationAttribute;
if (validationAttribute != null)
{
var isValid = validationAttribute.IsValid(argument);
if (!isValid)
{
modelState.AddModelError(parameter.Name, validationAttribute.FormatErrorMessage(parameter.Name));
}
}
}
}
and add it into your MVC options
services.AddMvc()
.AddMvcOptions(opts =>
{
opts.Filters.Add(new ModelStateValidActionFilter());
}
Related
I'm currently converting a ASP.NET library to ASP.NET Core that's heavy on Model Binding, and one issue I'm unable to resolve is that for cases where a model binder wants to try and get values via Value Providers both from (From)Query and (From)Route (as in, they have different BindingSource) it can only access one, resulting in the binding to fail since it fails to find the target value.
While debugging the application I can see that the ModelBindingContext does have both value providers in its private OriginalValueProvider, but when trying to access the ValueProvider it only returns one of the providers - in this case, only the QueryStringValueProvider and not the RouteValueProvider).
This seems not to have been the behavior back in regular ASP.NET, as there the existing application happily uses both value providers to find its value - and does so successfully. Is this some breaking change between System.Web.Http.ModelBinding -> Microsoft.AspNetCore.Mvc.ModelBinding? Is there some option that must be enabled? Some guidance would be appreciated.
Here follows some screen caps from my debugging:
System.Web.Http original:
Microsoft.AspNetCore.Mvc rework:
Microsoft.AspNetCore.Mvc OriginalValueProvider(s) proof:
Edit:
And here follows some code snippets, as requested:
Controller:
[HttpGet]
[Route("accounts/{accountId}/catalogs/{catalogId}/medias", Name = "GetCatalogMedias")]
[ProducesResponseType(typeof(IList<MediaResponse>), (int)HttpStatusCode.OK)]
public async Task<IActionResult> GetCatalogMedias(
[FromRoute] string accountId,
[FromRoute] string catalogId,
[FromQuery, SortingFieldDefaultValue("created", SortingDirection.Desc)] IEnumerable<SortingField> sort,
[FromQuery] QueryTree<MediaResponse> q = null,
[FromQuery, Range(0, int.MaxValue)] int offset = 0,
[FromQuery, Range(1, 200)] int limit = 200)
{
if (!ModelState.IsValid)
{
return await _responseFactory.CreateBadRequest(ModelState);
}
Binder:
public class CatalogMediasQueryModelBinder<T> : BaseBinder, IModelBinder
{
private readonly QueryModelBinder _queryModelBinder;
public CatalogMediasQueryModelBinder(QueryModelBinder queryModelBinder)
{
_queryModelBinder = queryModelBinder;
}
public async Task BindModelAsync(ModelBindingContext bindingContext)
{
var success = TryGetValueProviderResult(bindingContext, out var catalogId, "catalogId");
if (!success)
{
bindingContext.ModelState.AddModelError(bindingContext.ModelName, "Missing catalogId");
return;
}
//...
Base Binder:
public class BaseBinder
{
protected bool TryGetValueProviderResult(ModelBindingContext bindingContext, out string result, string findValue = null)
{
if (bindingContext?.ValueProvider == null)
{
throw new ArgumentNullException(nameof(bindingContext));
}
result = null;
var modelName = findValue ?? bindingContext.ModelName;
var valueProviderResult = bindingContext.ValueProvider.GetValue(modelName);
if (valueProviderResult == ValueProviderResult.None)
{
return false;
}
bindingContext.ModelState.SetModelValue(modelName, valueProviderResult);
var value = valueProviderResult.FirstValue;
if (string.IsNullOrWhiteSpace(value))
{
return false;
}
result = value;
return true;
}
protected Task SetModelBindingResult<T>(ModelBindingContext bindingContext, T value)
{
bindingContext.Result = ModelBindingResult.Success(value);
return Task.CompletedTask;
}
}
I have more then one property I need to grab, that starts with the same prefix but I can only get the exact value by key for ModelBindingContext.ValueProvider. Is there a way to grab multiple ValueProviders or iterate the System.Web.Mvc.DictionaryValueProvider<object>?
var value = bindingContext.ValueProvider.GetValue(propertyDescriptor.Name);
The reason for doing this is a dynamic property called Settings which will bind to json properties below. Right now there is no property called "Enable" on Settings so it doesnt bind normally.
public class Integration
{
public dynamic Settings {get;set;}
}
"Integrations[0].Settings.Enable": "true"
"Integrations[0].Settings.Name": "Will"
Got it
public class DynamicPropertyBinder : PropertyBinderAttribute
{
public override bool BindProperty(ControllerContext controllerContext, ModelBindingContext bindingContext, PropertyDescriptor propertyDescriptor)
{
if (propertyDescriptor.PropertyType == typeof(Object))
{
foreach(var valueProvider in bindingContext.ValueProvider as System.Collections.IList)
{
var dictionary = valueProvider as DictionaryValueProvider<object>;
if (dictionary != null)
{
var keys = dictionary.GetKeysFromPrefix($"{bindingContext.ModelName}.{propertyDescriptor.Name}");
if (keys.Any())
{
var expando = new ExpandoObject();
foreach (var key in keys)
{
var keyValue = dictionary.GetValue(key.Value);
if (keyValue != null)
{
AddProperty(expando, key.Key, keyValue.RawValue);
}
}
propertyDescriptor.SetValue(bindingContext.Model, expando);
return true;
}
}
}
}
return false;
}
public static void AddProperty(ExpandoObject expando, string propertyName, object propertyValue)
{
var expandoDict = expando as IDictionary<string, object>;
if (expandoDict.ContainsKey(propertyName))
expandoDict[propertyName] = propertyValue;
else
expandoDict.Add(propertyName, propertyValue);
}
}
This is an old question, but I will post the solution that I've found.
You can get all submitted keys from the request object, and then iterating over them get the actual values:
var keys = controllerContext.RequestContext.HttpContext.Request.Form.AllKeys.ToList();
foreach (var key in keys)
{
var value = bindingContext.ValueProvider.GetValue(key).AttemptedValue;
}
Is it possible to ignore ExpandoObject properties, in particular those of Delegate type, when using JsonConvert(expando, formatting, serializerSettings)?
Essentially I'm trying to ignore all parsing of the func property in this example expando object:
//{
// func: () => {}
//}
Action func = () => {};
dynamic expando = new ExpandoObject();
expando.func = func;
// should be empty object {}
string json = JsonConvert(expando, formatting, serializerSettings);
The first thing I tried was overriding the converter. Unfortunately this doesn't work, as I see CanConvert called recursively for Action -> DelegateEntry -> some generic type -> RuntimeMethodInfo.
private class ExpandoObjectIgnoreConverter : ExpandoObjectConverter
{
public override bool CanConvert(Type objectType)
{
if (typeof(Delegate).IsAssignableFrom(objectType))
{
return false;
}
return base.CanConvert(objectType);
}
}
A method that works is using an error handler in serialization settings and a contract resolver. When I throw the error, all further processing of the property is ignored, i.e. Action -> DelegateEntry -> some generic type -> RuntimeMethodInfo. However, I'd like to do this more elegantly than throwing an exception if possible.
Error handler:
serializationSettings.Error = (sender, args) =>
{
if (args.ErrorContext.Error is InvalidCastException)
{
args.ErrorContext.Handled = true;
}
}
Contract resolver:
private class ExpandoObjectContractResolver : DefaultContractResolver
{
public override JsonContract ResolveContract(Type type)
{
if (typeof(Delegate).IsAssignableFrom(type))
{
throw new InvalidCastException();
}
else
{
return base.ResolveContract(type);
}
}
}
I'm using the edge library to script nodejs from within a C# process. I'm trying to remove functions from the returned javascript objects from within C#, as they are assigned a Delegate type that doesn't play nicely with JsonConvert.
ExpandoObjectConverter does not have any custom code to write an ExpandoObject. Instead it overrides JsonConverter.CanWrite to return false thereby allowing the expando to be serialized generically as an IDictionary<string, object>.
Thus you can override CanWrite and WriteJson() yourself to filter undesired key/value pairs before serialization:
public class FilteredExpandoObjectConverter : ExpandoObjectConverter
{
public override bool CanWrite { get { return true; } }
public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
{
var expando = (IDictionary<string, object>)value;
var dictionary = expando
.Where(p => !(p.Value is System.Delegate))
.ToDictionary(p => p.Key, p => p.Value);
serializer.Serialize(writer, dictionary);
}
}
Then use the converter in settings as follows:
var formatting = Formatting.Indented;
var serializerSettings = new JsonSerializerSettings
{
Converters = { new FilteredExpandoObjectConverter() },
};
var json = JsonConvert.SerializeObject(expando, formatting, serializerSettings);
Note this will only filter delegates values directly owned by an ExpandoObject. If you have a collection containing some delegates, or delegate-valued members in some POCO, they will not be filtered by this code.
Sample fiddle.
I have this class as a part of EF Model:
class Person {
public int Id { get; set; }
[MaxLength(100, ErrorMessage="Name cannot be more than 100 characters")]
public string Name { get; set; }
}
And I have this method in my controller:
public IActionResult ChangeName(int id, string name) {
var person = db.Persons.Find(id);
if(person == null) return NotFound();
person.Name = name;
db.SaveChanges();
return Json(new {result = "Saved Successfully"});
}
Is there any way to validate person after changing the Name property using the annotation MaxLength rather than manually check for it. Becuase sometimes I might have more than one validation and I don't want to examine each one of them. Also, I might change these parameters in the future (e.g. make the max length 200), and that means I have to change it everywhere else.
So is it possible?
Your method works as long as there is one validation error per property. Also, it's quite elaborate. You can use db.GetValidationErrors() to get the same result. One difference is that errors are collected in a collection per property name:
var errors = db.GetValidationErrors()
.SelectMany(devr => devr.ValidationErrors)
.GroupBy(ve => ve.PropertyName)
.ToDictionary(ve => ve.Key, ve => ve.Select(v => v.ErrorMessage));
Okay, I found a solution to my problem, I created a method that takes the model and checks for errors:
private IDictionary<string, string> ValidateModel(Person model)
{
var errors = new Dictionary<string, string>();
foreach (var property in model.GetType().GetProperties())
{
foreach (var attribute in property.GetCustomAttributes())
{
var validationAttribute = attribute as ValidationAttribute;
if(validationAttribute == null) continue;
var value = property.GetValue(model);
if (!validationAttribute.IsValid(value))
{
errors.Add(property.Name, validationAttribute.ErrorMessage);
}
}
}
return errors;
}
UPDATE:
As stated by #Gert Arnold, the method above returns only one validation per property. Below is the fixed version which returns a list of errors for each property
public static IDictionary<string, IList<string>> ValidateModel(Person model)
{
var errors = new Dictionary<string, IList<string>>();
foreach (var property in model.GetType().GetProperties())
{
foreach (var attribute in property.GetCustomAttributes())
{
var validationAttribute = attribute as ValidationAttribute;
if (validationAttribute == null) continue;
var value = property.GetValue(model);
if (validationAttribute.IsValid(value)) continue;
if (!errors.ContainsKey(property.Name))
errors[property.Name] = new List<string>();
errors[property.Name].Add(validationAttribute.ErrorMessage);
}
}
return errors;
}
First of all it might be worth looking at this question:
How can I cache objects in ASP.NET MVC?
There some pseudo code that almost does what i want:
public class CacheExtensions
{
public static T GetOrStore<T>(this Cache cache, string key, Func<T> generator)
{
var result = cache[key];
if(result == null)
{
result = generator();
cache[key] = result;
}
return (T)result;
}
}
However, what I'd really like to do, is auto-generate the "key" from the generator. I figure i need to change the method signature to:
public static T GetOrStore<T>(this Cache cache,
System.Linq.Expressions.Expression<Func<T>> generator)
I want to use the method name, but also any parameters and their values to generate the key. I can get the method body from the expression, and the paramter names (sort of), but I have no idea how to get the paramter values...?
Or am I going about this the wrong way? Any ideas much appreciated.
Here's how I did it:
public static class ICacheExtensions
{
public static T GetOrAdd<T>(this ICache cache, Expression<Func<T>> getterExp)
{
var key = BuildCacheKey<T>(getterExp);
return cache.GetOrAdd(key, () => getterExp.Compile().Invoke());
}
private static string BuildCacheKey<T>(Expression<Func<T>> getterExp)
{
var body = getterExp.Body;
var methodCall = body as MethodCallExpression;
if (methodCall == null)
{
throw new NotSupportedException("The getterExp must be a MethodCallExpression");
}
var typeName = methodCall.Method.DeclaringType.FullName;
var methodName = methodCall.Method.Name;
var arguments = methodCall.Arguments
.Select(a => ExpressionHelper.Evaluate(a))
.ToArray();
return String.Format("{0}_{1}_{2}",
typeName,
methodName,
String.Join("|", arguments));
}
}
with this helper to evaluate nodes of an expression tree:
internal static class ExpressionHelper
{
public static object Evaluate(Expression e)
{
Type type = e.Type;
if (e.NodeType == ExpressionType.Convert)
{
var u = (UnaryExpression)e;
if (TypeHelper.GetNonNullableType(u.Operand.Type) == TypeHelper.GetNonNullableType(type))
{
e = ((UnaryExpression)e).Operand;
}
}
if (e.NodeType == ExpressionType.Constant)
{
if (e.Type == type)
{
return ((ConstantExpression)e).Value;
}
else if (TypeHelper.GetNonNullableType(e.Type) == TypeHelper.GetNonNullableType(type))
{
return ((ConstantExpression)e).Value;
}
}
var me = e as MemberExpression;
if (me != null)
{
var ce = me.Expression as ConstantExpression;
if (ce != null)
{
return me.Member.GetValue(ce.Value);
}
}
if (type.IsValueType)
{
e = Expression.Convert(e, typeof(object));
}
Expression<Func<object>> lambda = Expression.Lambda<Func<object>>(e);
Func<object> fn = lambda.Compile();
return fn();
}
}
When calling a function that produces a collection i want to cache i pass all my function's parameters and function name to the cache function which creates a key from it.
All my classes implement an interface that has and ID field so i can use it in my cache keys.
I'm sure there's a nicer way but somehow i gotta sleep at times too.
I also pass 1 or more keywords that i can use to invalidate related collections.