WCF serialization and IEnumerable<T> vs ICollection<T> inheritance - wcf

I am aware about the problem when creating custom collections that inherits from List<T> or ICollection<T> with additional custom properties:
public class MyCollection: List<int>
{
public string MyCustomProperty { get; set; }
}
As I know, such collection will passed throw WCF as ArrayOfInt and WCF will not serialize my custom property. The solution is to create the wrapper class that will manage collection inside and will have a custom property.
I want to make a nicer workaround for my needs...does IEnumerable<T> will have the same problem?
public class MyCollection: IEnumerable<int>
{
/**************/
/* Code that implements IEnumerable<int> and manages the internal List<T> */
/* I know I will not able to cast it to List<T>, but I don't need it. */
/* If I will need it, I will implement cast operators later */
/**************/
public string MyCustomProperty { get; set; }
}
Will the class above pass throw WCF include MyCustomProperty value?
Thanks

I tried it and it does not serialize custom property.
I just returned the entire class object from the service method. Result is still ArrayOfInt (i used List as container)
public class MyExtension: IEnumerable<int>
{
public string CustomString { get; set; }
private List<int> lst = new List<int>();
public void Add(int i)
{
lst.Add(i);
}
public IEnumerator<int> GetEnumerator()
{
return lst.GetEnumerator();
}
System.Collections.IEnumerator System.Collections.IEnumerable.GetEnumerator()
{
return lst.GetEnumerator();
}
}
I had to mark it as DataContract and every member as DataMember to have all the properties serialized.
<MyExtension xmlns="http://schemas.datacontract.org/2004/07/GetRequestTest" xmlns:i="http://www.w3.org/2001/XMLSchema-instance">
<CustomString>sunny</CustomString>
<lst xmlns:a="http://schemas.microsoft.com/2003/10/Serialization/Arrays">
<a:int>1</a:int>
</lst>
</MyExtension>

Related

Json Serialize an interface's properties which have non primitive types [duplicate]

With a simple class/interface like this
public interface IThing
{
string Name { get; set; }
}
public class Thing : IThing
{
public int Id { get; set; }
public string Name { get; set; }
}
How can I get the JSON string with only the "Name" property (only the properties of the underlying interface) ?
Actually, when i make that :
var serialized = JsonConvert.SerializeObject((IThing)theObjToSerialize, Formatting.Indented);
Console.WriteLine(serialized);
I get the full object as JSON (Id + Name);
The method I use,
public class InterfaceContractResolver : DefaultContractResolver
{
private readonly Type _InterfaceType;
public InterfaceContractResolver (Type InterfaceType)
{
_InterfaceType = InterfaceType;
}
protected override IList<JsonProperty> CreateProperties(Type type, MemberSerialization memberSerialization)
{
//IList<JsonProperty> properties = base.CreateProperties(type, memberSerialization);
IList<JsonProperty> properties = base.CreateProperties(_InterfaceType, memberSerialization);
return properties;
}
}
// To serialize do this:
var settings = new JsonSerializerSettings() {
ContractResolver = new InterfaceContractResolver (typeof(IThing))
};
string json = JsonConvert.SerializeObject(theObjToSerialize, settings);
Improved version with nested interfaces + support for xsd.exe objects
Yet another variation here. The code came from http://www.tomdupont.net/2015/09/how-to-only-serialize-interface.html with the following improvements over other answers here
Handles hierarchy, so if you have an Interface2[] within an Interface1 then it will get serialized.
I was trying to serialize a WCF proxy object and the resultant JSON came up as {}. Turned out all properties were set to Ignore=true so I had to add a loop to set them all to not being ignored.
public class InterfaceContractResolver : DefaultContractResolver
{
private readonly Type[] _interfaceTypes;
private readonly ConcurrentDictionary<Type, Type> _typeToSerializeMap;
public InterfaceContractResolver(params Type[] interfaceTypes)
{
_interfaceTypes = interfaceTypes;
_typeToSerializeMap = new ConcurrentDictionary<Type, Type>();
}
protected override IList<JsonProperty> CreateProperties(
Type type,
MemberSerialization memberSerialization)
{
var typeToSerialize = _typeToSerializeMap.GetOrAdd(
type,
t => _interfaceTypes.FirstOrDefault(
it => it.IsAssignableFrom(t)) ?? t);
var props = base.CreateProperties(typeToSerialize, memberSerialization);
// mark all props as not ignored
foreach (var prop in props)
{
prop.Ignored = false;
}
return props;
}
}
Inspired by #user3161686, here's a small modification to InterfaceContractResolver:
public class InterfaceContractResolver<TInterface> : DefaultContractResolver where TInterface : class
{
protected override IList<JsonProperty> CreateProperties(Type type, MemberSerialization memberSerialization)
{
IList<JsonProperty> properties = base.CreateProperties(typeof(TInterface), memberSerialization);
return properties;
}
}
You can use conditional serialization. Take a look at this link. Basicly, you need to implement the IContractResolver interface, overload the ShouldSerialize method and pass your resolver to the constructor of the Json Serializer.
An alternative to [JsonIgnore] are the [DataContract] and [DataMember] attributes. If you class is tagged with [DataContract] the serializer will only process properties tagged with the [DataMember] attribute (JsonIgnore is an "opt-out" model while DataContract is "op-in").
[DataContract]
public class Thing : IThing
{
[DataMember]
public int Id { get; set; }
public string Name { get; set; }
}
The limitation of both approaches is that they must be implemented in the class, you cannot add them to the interface definition.
You can add the [JsonIgnore] annotation to ignore an attribute.
I'd like to share what we ended up doing when confronted with this task. Given the OP's interface and class...
public interface IThing
{
string Name { get; set; }
}
public class Thing : IThing
{
public int Id { get; set; }
public string Name { get; set; }
}
...we created a class that is the direct implementation of the interface...
public class DirectThing : IThing
{
public string Name { get; set; }
}
Then simply serialized our Thing instance, deserialized it as a DirectThing, then Serialized it as a DirectThing:
var thing = new Thing();
JsonConvert.SerializeObject(
JsonConvert.DeserializeObject<DirectThing>(JsonConvert.SerializeObject(thing)));
This approach can work with a long interface inheritance chain...you just need to make a direct class (DirectThing in this example) at the level of interest. No need to worry about reflection or attributes.
From a maintenance perspective, the DirectThing class is easy to maintain if you add members to IThing because the compiler will give errors if you haven't also put them in DirectThing. However, if you remove a member X from IThing and put it in Thing instead, then you'll have to remember to remove it from DirectThing or else X would be in the end result.
From a performance perspective there are three (de)serialization operations happening here instead of one, so depending on your situation you might like to evaluate the performance difference of reflector/attribute-based solutions versus this solution. In my case I was just doing this on a small scale, so I wasn't concerned about potential losses of some micro/milliseconds.
Hope that helps someone!
in addition to the answer given by #monrow you can use the default [DataContract] and [DataMember]
have a look at this
http://james.newtonking.com/archive/2009/10/23/efficient-json-with-json-net-reducing-serialized-json-size.aspx
Finally I got when it will not work...
If you want to have inside another complex object it will not be properly serialized.
So I have made version which will extract only data stored in specific assembly and for types which have the same base interface.
So it is made as .Net Core JsonContractResolver.
In addition to data extraction it solves:
a) camelCase conversion before sending data to client
b) uses top most interface from allowed scope (by assembly)
c) fixes order of fields: field from most base class will be listed first and nested object will meet this rule as well.
public class OutputJsonResolver : DefaultContractResolver
{
#region Static Members
private static readonly object syncTargets = new object();
private static readonly Dictionary<Type, IList<JsonProperty>> Targets = new Dictionary<Type, IList<JsonProperty>>();
private static readonly Assembly CommonAssembly = typeof(ICommon).Assembly;
#endregion
#region Override Members
protected override IList<JsonProperty> CreateProperties(Type type, MemberSerialization memberSerialization)
{
if (type.Assembly != OutputJsonResolver.CommonAssembly)
return base.CreateProperties(type, memberSerialization);
IList<JsonProperty> properties;
if (OutputJsonResolver.Targets.TryGetValue(type, out properties) == false)
{
lock (OutputJsonResolver.syncTargets)
{
if (OutputJsonResolver.Targets.ContainsKey(type) == false)
{
properties = this.CreateCustomProperties(type, memberSerialization);
OutputJsonResolver.Targets[type] = properties;
}
}
}
return properties;
}
protected override string ResolvePropertyName(string propertyName)
{
return propertyName.ToCase(Casing.Camel);
}
#endregion
#region Assistants
private IList<JsonProperty> CreateCustomProperties(Type type, MemberSerialization memberSerialization)
{
// Hierarchy
IReadOnlyList<Type> types = this.GetTypes(type);
// Head
Type head = types.OrderByDescending(item => item.GetInterfaces().Length).FirstOrDefault();
// Sources
IList<JsonProperty> sources = base.CreateProperties(head, memberSerialization);
// Targets
IList<JsonProperty> targets = new List<JsonProperty>(sources.Count);
// Repository
IReadOnlyDistribution<Type, JsonProperty> repository = sources.ToDistribution(item => item.DeclaringType);
foreach (Type current in types.Reverse())
{
IReadOnlyPage<JsonProperty> page;
if (repository.TryGetValue(current, out page) == true)
targets.AddRange(page);
}
return targets;
}
private IReadOnlyList<Type> GetTypes(Type type)
{
List<Type> types = new List<Type>();
if (type.IsInterface == true)
types.Add(type);
types.AddRange(type.GetInterfaces());
return types;
}
#endregion
}

Deserialization of reference types without parameterless constructor is not supported

I have this API
public ActionResult AddDocument([FromBody]AddDocumentRequestModel documentRequestModel)
{
AddDocumentStatus documentState = _documentService.AddDocument(documentRequestModel, DocumentType.OutgoingPosShipment);
if (documentState.IsSuccess)
return Ok();
return BadRequest();
}
And this is my request model
public class AddDocumentRequestModel
{
public AddDocumentRequestModel(int partnerId, List<ProductRequestModel> products)
{
PartnerId = partnerId;
Products = products;
}
[Range(1, int.MaxValue, ErrorMessage = "Value for {0} must be between {1} and {2}.")]
public int PartnerId { get; private set; }
[Required, MustHaveOneElement(ErrorMessage = "At least one product is required")]
public List<ProductRequestModel> Products { get; private set; }
}
so when I'm trying to hit the API with this body
{
"partnerId": 101,
"products": [{
"productId": 100,
"unitOfMeasureId": 102,
"quantity":5
}
]
}
this is the request : System.NotSupportedException: Deserialization of reference types without parameterless constructor is not supported. Type 'Alati.Commerce.Sync.Api.Controllers.AddDocumentRequestModel'
I don't need parameterless constructor,because it doesn't read the body parameters.Is there any other way for deserialization?
You can achieve your desired result. You need to switch to NewtonsoftJson serialization (from package Microsoft.AspNetCore.Mvc.NewtonsoftJson)
Call this in Startup.cs in the ConfigureServices method:
services.AddControllers().AddNewtonsoftJson();
After this, your constructor will be called by deserialization.
Extra info: I am using ASP Net Core 3.1
Later Edit: I wanted to give more info on this, as it seems that this can also be achieved by using System.Text.Json, although custom implementation is necessary. The answer from jawa states that Deserializing to immutable classes and structs can be achieved with System.Text.Json, by creating a custom converter (inherit from JsonConverter) and registering it to the converters collection (JsonSerializerOptions.Converters) like so:
public class ImmutablePointConverter : JsonConverter<ImmutablePoint>
{
...
}
and then...
var serializeOptions = new JsonSerializerOptions();
serializeOptions.Converters.Add(new ImmutablePointConverter());
serializeOptions.WriteIndented = true;
Just in case someone have the same issue I had, I was using abstract class, once removed the abstract key word, it all worked just fine.
Just Add [JsonConstructor] before your constructor
like this
public class Person
{
public string Name { get; set; }
public int LuckyNumber { get; private set; }
[JsonConstructor]
public Person(int luckyNumber)
{
LuckyNumber = luckyNumber;
}
public Person() { }
}
There are still some limitations using System.Text.Json - have a look here: https://learn.microsoft.com/en-us/dotnet/standard/serialization/system-text-json-migrate-from-newtonsoft-how-to#table-of-differences-between-newtonsoftjson-and-systemtextjson
Deserialization without parameterless constructor using a parameterized constructor is not supported yet (but it's on their plan). You can implement your custom JsonConverter (like in this example: https://learn.microsoft.com/en-us/dotnet/standard/serialization/system-text-json-migrate-from-newtonsoft-how-to#deserialize-to-immutable-classes-and-structs) or - like Adrian Nasul above suggested: use Newtonsoft.Json and then you can use the [JsonConstructor] attribute
In my case I had set a class as internal and when I made it public it worked. The error message was really of little help with this specific circumstance.
Old (actual class name changed to ClassName in the example
internal class Rootobject
{
[JsonConstructor]
public Rootobject(ClassName className)
{
ClassName = className?? throw new ArgumentNullException(nameof(className));
}
public ClassName ClassName { get; set; }
}
New:
public class Rootobject
{
[JsonConstructor]
public Rootobject(ClassName className)
{
ClassName = branding ?? throw new ArgumentNullException(nameof(className));
}
public ClassName ClassName { get; set; }
}
In my case error, caused was inside InnerException. There is my class had a field with a custom class type that did not have a parameterless constructor. I've added a parameterless constructor to the inner class and the problem has gone away.

Cannot create a DbSet for 'Model' because this type is not included in the model for the context

I do a Generic and using DI
so I create a empty class
public class DBRepo
{
}
and my model class to inheriting class DBRepo
public partial class UserAccount : DBRepo
{
public int Id { get; set; }
public string Account { get; set; }
public string Pwd { get; set; }
}
then this is a Interface to do CRUD
public interface IDBAction<TEntity> where TEntity : class,new()
{
void UpdateData(TEntity _entity);
void GetAllData(TEntity _entity);
}
public class DBService<TEntity> : IDBAction<TEntity> where TEntity : class,new()
{
private readonly CoreContext _db;
public DBService(CoreContext _db)
{
this._db = _db;
}
public void UpdateData(TEntity _entity)
{
this._db.Set<TEntity>().UpdateRange(_entity);
this._db.SaveChanges();
}
public void GetAllData(TEntity _entity)
{
var x = this._db.Set<TEntity>().Select(o => o).ToList();
}
}
And I Dependency Injection Service Provider in constructor
this.DBProvider = new ServiceCollection()
.AddScoped<IDBAction<DBRepo>, DBService<DBRepo>>()
.AddScoped<DBContext>()
.AddDbContext<CoreContext>(options => options.UseSqlServer(ConnectionString))
.BuildServiceProvider();
last step I Get Services
DBProvider.GetService<IDBAction<DBRepo>>().GetAllData(new UserAccount());
I will get a error message same with title
or I change to
DBProvider.GetService<IDBAction<UserAccount>>().GetAllData(new UserAccount());
I'll get other message
Object reference not set to an instance of an object.'
but the void UpdateData() is can work,
so how to fix GetAllData() problem?
The error simply is because the class you're using here UserAccount has apparently not been added to your context, CoreContext. There should be a property there like:
public DbSet<UserAccount> UserAccounts { get; set; }
Regardless of whether you end up using the generic Set<T> accessor, you still must defined a DbSet for the entity on your context.
That said, you should absolutely not be creating your own service collection inside your repo. Register your context and your repo with the main service collection in Startup.cs and then simply inject your repo where you need it. The DI framework will take care of instantiating it with your context, as long as you have a constructor that takes your context (which you seem to).
And that said, you should ditch the repo entirely. It still requires a dependency on Entity Framework and doesn't do anything but proxy to Entity Framework methods. This is just an extra thing you have to maintain and test with no added benefit.

Common WCF Response Handler?

I have a WCF Client, and the Endpoint has just been upgraded with a new method (OperationContract). I want to write a common method to handle the response from this new method as well as from the existing method at the endpoint.
I am trying to create a "Base" response class and adding common properties to it provided by the WCF endpoint, but I notice in my handler method, the properties are not being retained.
The code for the class I want all responses to inherit from looks like this :
public class ResponseBase
{
public string[] ItemsReturned;
public bool ItemsWereAvailable;
}
So I add partial declarations to get this onto the objects in the endpoint.
public partial class RetrieveResponse :ResponseBase
{
}
public partial class RetrieveResponse2 :ResponseBase
{
}
This way I have a handler method that just accepts "ResponseBase" as its input.
Am I doing this all wrong?
Any class whose instances will be return values and/or parameters of an operation contract should be decorated with the DataContract attribute, and the properties, as DataMembers:
[DataContract]
public class ResponseBase
{
[DataMember]
public string[] ItemsReturned { get; set; }
[DataMember]
public bool ItemsWereAvailable { get; set; }
}
http://msdn.microsoft.com/en-us/library/ms733127.aspx
If they are not, the DataContractSerializer doesn't serialize them.

DataContract composite Class

I have a problem with serialization composite class (using WCF Service).
here my class in namespace1 (it is not in service namespace) :
[DataContract]
public class UpData
{
[DataMember]
public double Version ;
public UpData()
{
this.Version = -1;
}
}
In my Service namespace (in interface) I deсlare this procedure :
ArrayList GetDownloadPath(Dictionary<string,string> lib1, Dictionary<string,string> lib2);
ArrayList contains UpData objects.
I have error(
How will be right to send ArrayList of UpData objects? (may be specific DataContract?)
Thanks a lot!
I'm not sure if ArrayList is serializable by default. Using a generic list could solve your problem:
[OperationContract]
List<UpData> GetDownloadPath(Dictionary<string,string> lib1, Dictionary<string,string> lib2);
EDIT: I think you also need to specify a getter and setter for your Version property, i.e.
[DataContract]
public class UpData
{
[DataMember]
public double Version { get; set; }
public UpData()
{
this.Version = -1;
}
}
More info here.