I want to list all methods from a WCF service that has the attribute "OperationContractAttribute"
For that, I use the following code:
var service = assembly.GetType(typeName);
if (service == null)
return webMethodsInfo;
var methodsInfo = service.GetMethods();
webMethods = methodsInfo.Where(method => method.GetCustomAttributes
(typeof(OperationContractAttribute), true).Any()).ToList();
So, the OperationContractAttribute is specified in the interface (IClassA) and when I try to search this method attribute in the ClassA class, it can't find it however I specified the flag true for method GetCustomAttributes for searching to ancestors
This will do
MethodInfo[] methods = typeof(ITimeService).GetMethods();
foreach (var method in methods)
{
if (((System.Attribute)(method.GetCustomAttributes(true)[0])).TypeId.ToString() == "System.ServiceModel.OperationContractAttribute")
{
string methodName = method.Name;
}
}
webMethods = service.GetInterface(serviceContract).GetMethods().Where(
method => method.GetCustomAttributes
(typeof(OperationContractAttribute)).Any())
.ToList();
Related
I'm unit testing my API service and all is well using the MockRquestContext. The calls to this.GetSession() always returns an IAuthSession, but I have a custom AuthUserSession and as far as I can tell, there's no way to create an instance of my custom AuthUserSession and add it to the mock context. Is this possible?
var service = container.Resolve<AgencyCaseService>();
service.SetResolver(new BasicResolver(container));
var context = new MockRequestContext() { ResponseContentType = ContentType.Json };
//Something like this
MyCustomAuthSession session = new MyCustomAuthSession() { set some values}
context.AuthSession = session//this doesn't exist but it's the type of thing i need to do
service.RequestContext = context;
The Session isn't on the Request Context, it requires a mixture of ICacheClient, SessionFeature and HttpRequest cookies to create.
You can look at the implementation for the way to mock it inside a Service, which shows it first tries to resolve it in a Container:
private object userSession;
protected virtual TUserSession SessionAs<TUserSession>()
{
if (userSession == null)
{
userSession = TryResolve<TUserSession>(); //Easier to mock
if (userSession == null)
userSession = Cache.SessionAs<TUserSession>(Request, Response);
}
return (TUserSession)userSession;
}
So to mock it you could just do:
container.Register(new MyCustomAuthSession() { /* set some values*/ });
...or "How to determine which WCF method will be called based on URI?"
In a WCF service, suppose a method is invoked and I have the URI that was used to invoke it. How can I get information about the WCF end point, method, parameters, etc. that the URI maps to?
[OperationContract]
[WebGet(UriTemplate = "/People/{id}")]
public Person GetPersonByID(int id)
{
//...
}
For instance, if the URI is: GET http://localhost/Contacts.svc/People/1, I want to get this information: service name (Service), Method (GetPersonByID), Parameters (PersonID=1). The point is to be able to listen for the request and then extract the details of the request in order to track the API call.
The service is hosted via http. This information is required before the .Net caching can kick in so each call (whether cached or not) can be tracked. This probably means doing this inside HttpApplication.BeginRequest.
FYI I'm hoping to not use reflection. I'd like to make use of the same methods WCF uses to determine this. E.g. MagicEndPointFinder.Resolve(uri)
Here is what I ended up doing, still interested if there is a cleaner way!
REST
private static class OperationContractResolver
{
private static readonly Dictionary<string, MethodInfo> RegularExpressionsByMethod = null;
static OperationContractResolver()
{
OperationContractResolver.RegularExpressionsByMethod = new Dictionary<string, MethodInfo>();
foreach (MethodInfo method in typeof(IREST).GetMethods())
{
WebGetAttribute attribute = (WebGetAttribute)method.GetCustomAttributes(typeof(WebGetAttribute), false).FirstOrDefault();
if (attribute != null)
{
string regex = attribute.UriTemplate;
//Escape question marks. Looks strange but replaces a literal "?" with "\?".
regex = Regex.Replace(regex, #"\?", #"\?");
//Replace all parameters.
regex = Regex.Replace(regex, #"\{[^/$\?]+?}", #"[^/$\?]+?");
//Add it to the dictionary.
OperationContractResolver.RegularExpressionsByMethod.Add(regex, method);
}
}
}
public static string ExtractApiCallInfo(string relativeUri)
{
foreach (string regex in OperationContractResolver.RegularExpressionsByMethod.Keys)
if (Regex.IsMatch(relativeUri, regex, RegexOptions.IgnoreCase))
return OperationContractResolver.RegularExpressionsByMethod[regex].Name;
return null;
}
}
SOAP
private static void TrackSoapApiCallInfo(HttpContext context)
{
string filePath = Path.GetTempFileName();
string title = null;
//Save the request content. (Unfortunately it can't be written to a stream directly.)
context.Request.SaveAs(filePath, false);
//If the title can't be extracted then it's not an API method call, ignore it.
try
{
//Read the name of the first element within the SOAP body.
using (XmlReader reader = XmlReader.Create(filePath))
{
if (!reader.EOF)
{
XmlNamespaceManager nsManager = new XmlNamespaceManager(reader.NameTable);
XDocument document = XDocument.Load(reader);
//Need to add the SOAP Envelope namespace to the name table.
nsManager.AddNamespace("s", "http://schemas.xmlsoap.org/soap/envelope/");
title = document.XPathSelectElement("s:Envelope/s:Body", nsManager).Elements().First().Name.LocalName;
}
}
//Delete the temporary file.
File.Delete(filePath);
}
catch { }
//Track the page view.
}
I'm getting the following error:
'object' does not contain a definition for 'RatingName'
When you look at the anonymous dynamic type, it clearly does have RatingName.
I realize I can do this with a Tuple, but I would like to understand why the error message occurs.
Anonymous types having internal properties is a poor .NET framework design decision, in my opinion.
Here is a quick and nice extension to fix this problem i.e. by converting the anonymous object into an ExpandoObject right away.
public static ExpandoObject ToExpando(this object anonymousObject)
{
IDictionary<string, object> anonymousDictionary = new RouteValueDictionary(anonymousObject);
IDictionary<string, object> expando = new ExpandoObject();
foreach (var item in anonymousDictionary)
expando.Add(item);
return (ExpandoObject)expando;
}
It's very easy to use:
return View("ViewName", someLinq.Select(new { x=1, y=2}.ToExpando());
Of course in your view:
#foreach (var item in Model) {
<div>x = #item.x, y = #item.y</div>
}
I found the answer in a related question. The answer is specified on David Ebbo's blog post Passing anonymous objects to MVC views and accessing them using dynamic
The reason for this is that the
anonymous type being passed in the
controller in internal, so it can only
be accessed from within the assembly
in which it’s declared. Since views
get compiled separately, the dynamic
binder complains that it can’t go over
that assembly boundary.
But if you think about it, this
restriction from the dynamic binder is
actually quite artificial, because if
you use private reflection, nothing is
stopping you from accessing those
internal members (yes, it even work in
Medium trust). So the default dynamic
binder is going out of its way to
enforce C# compilation rules (where
you can’t access internal members),
instead of letting you do what the CLR
runtime allows.
Using ToExpando method is the best solution.
Here is the version that doesn't require System.Web assembly:
public static ExpandoObject ToExpando(this object anonymousObject)
{
IDictionary<string, object> expando = new ExpandoObject();
foreach (PropertyDescriptor propertyDescriptor in TypeDescriptor.GetProperties(anonymousObject))
{
var obj = propertyDescriptor.GetValue(anonymousObject);
expando.Add(propertyDescriptor.Name, obj);
}
return (ExpandoObject)expando;
}
Instead of creating a model from an anonymous type and then trying to convert the anonymous object to an ExpandoObject like this ...
var model = new
{
Profile = profile,
Foo = foo
};
return View(model.ToExpando()); // not a framework method (see other answers)
You can just create the ExpandoObject directly:
dynamic model = new ExpandoObject();
model.Profile = profile;
model.Foo = foo;
return View(model);
Then in your view you set the model type as dynamic #model dynamic and you can access the properties directly :
#Model.Profile.Name
#Model.Foo
I'd normally recommend strongly typed view models for most views, but sometimes this flexibility is handy.
You can use the framework impromptu interface to wrap an anonymous type in an interface.
You'd just return an IEnumerable<IMadeUpInterface> and at the end of your Linq use .AllActLike<IMadeUpInterface>(); this works because it calls the anonymous property using the DLR with a context of the assembly that declared the anonymous type.
Wrote a console application and add Mono.Cecil as reference (you can now add it from NuGet), then write the piece of code:
static void Main(string[] args)
{
var asmFile = args[0];
Console.WriteLine("Making anonymous types public for '{0}'.", asmFile);
var asmDef = AssemblyDefinition.ReadAssembly(asmFile, new ReaderParameters
{
ReadSymbols = true
});
var anonymousTypes = asmDef.Modules
.SelectMany(m => m.Types)
.Where(t => t.Name.Contains("<>f__AnonymousType"));
foreach (var type in anonymousTypes)
{
type.IsPublic = true;
}
asmDef.Write(asmFile, new WriterParameters
{
WriteSymbols = true
});
}
The code above would get the assembly file from input args and use Mono.Cecil to change the accessibility from internal to public, and that would resolve the problem.
We can run the program in the Post Build event of the website. I wrote a blog post about this in Chinese but I believe you can just read the code and snapshots. :)
Based on the accepted answer, I have overridden in the controller to make it work in general and behind the scenes.
Here is the code:
protected override void OnResultExecuting(ResultExecutingContext filterContext)
{
base.OnResultExecuting(filterContext);
//This is needed to allow the anonymous type as they are intenal to the assembly, while razor compiles .cshtml files into a seperate assembly
if (ViewData != null && ViewData.Model != null && ViewData.Model.GetType().IsNotPublic)
{
try
{
IDictionary<string, object> expando = new ExpandoObject();
(new RouteValueDictionary(ViewData.Model)).ToList().ForEach(item => expando.Add(item));
ViewData.Model = expando;
}
catch
{
throw new Exception("The model provided is not 'public' and therefore not avaialable to the view, and there was no way of handing it over");
}
}
}
Now you can just pass an anonymous object as the model, and it will work as expected.
I'm going to do a little bit of stealing from https://stackoverflow.com/a/7478600/37055
If you install-package dynamitey you can do this:
return View(Build<ExpandoObject>.NewObject(RatingName: name, Comment: comment));
And the peasants rejoice.
The reason of RuntimeBinderException triggered, I think there have good answer in other posts. I just focus to explain how I actually make it work.
By refer to answer #DotNetWise and Binding views with Anonymous type collection in ASP.NET MVC,
Firstly, Create a static class for extension
public static class impFunctions
{
//converting the anonymous object into an ExpandoObject
public static ExpandoObject ToExpando(this object anonymousObject)
{
//IDictionary<string, object> anonymousDictionary = new RouteValueDictionary(anonymousObject);
IDictionary<string, object> anonymousDictionary = HtmlHelper.AnonymousObjectToHtmlAttributes(anonymousObject);
IDictionary<string, object> expando = new ExpandoObject();
foreach (var item in anonymousDictionary)
expando.Add(item);
return (ExpandoObject)expando;
}
}
In controller
public ActionResult VisitCount()
{
dynamic Visitor = db.Visitors
.GroupBy(p => p.NRIC)
.Select(g => new { nric = g.Key, count = g.Count()})
.OrderByDescending(g => g.count)
.AsEnumerable() //important to convert to Enumerable
.Select(c => c.ToExpando()); //convert to ExpandoObject
return View(Visitor);
}
In View, #model IEnumerable (dynamic, not a model class), this is very important as we are going to bind the anonymous type object.
#model IEnumerable<dynamic>
#*#foreach (dynamic item in Model)*#
#foreach (var item in Model)
{
<div>x=#item.nric, y=#item.count</div>
}
The type in foreach, I have no error either using var or dynamic.
By the way, create a new ViewModel that is matching the new fields also can be the way to pass the result to the view.
Now in recursive flavor
public static ExpandoObject ToExpando(this object obj)
{
IDictionary<string, object> expandoObject = new ExpandoObject();
new RouteValueDictionary(obj).ForEach(o => expandoObject.Add(o.Key, o.Value == null || new[]
{
typeof (Enum),
typeof (String),
typeof (Char),
typeof (Guid),
typeof (Boolean),
typeof (Byte),
typeof (Int16),
typeof (Int32),
typeof (Int64),
typeof (Single),
typeof (Double),
typeof (Decimal),
typeof (SByte),
typeof (UInt16),
typeof (UInt32),
typeof (UInt64),
typeof (DateTime),
typeof (DateTimeOffset),
typeof (TimeSpan),
}.Any(oo => oo.IsInstanceOfType(o.Value))
? o.Value
: o.Value.ToExpando()));
return (ExpandoObject) expandoObject;
}
Using the ExpandoObject Extension works but breaks when using nested anonymous objects.
Such as
var projectInfo = new {
Id = proj.Id,
UserName = user.Name
};
var workitem = WorkBL.Get(id);
return View(new
{
Project = projectInfo,
WorkItem = workitem
}.ToExpando());
To accomplish this I use this.
public static class RazorDynamicExtension
{
/// <summary>
/// Dynamic object that we'll utilize to return anonymous type parameters in Views
/// </summary>
public class RazorDynamicObject : DynamicObject
{
internal object Model { get; set; }
public override bool TryGetMember(GetMemberBinder binder, out object result)
{
if (binder.Name.ToUpper() == "ANONVALUE")
{
result = Model;
return true;
}
else
{
PropertyInfo propInfo = Model.GetType().GetProperty(binder.Name);
if (propInfo == null)
{
throw new InvalidOperationException(binder.Name);
}
object returnObject = propInfo.GetValue(Model, null);
Type modelType = returnObject.GetType();
if (modelType != null
&& !modelType.IsPublic
&& modelType.BaseType == typeof(Object)
&& modelType.DeclaringType == null)
{
result = new RazorDynamicObject() { Model = returnObject };
}
else
{
result = returnObject;
}
return true;
}
}
}
public static RazorDynamicObject ToRazorDynamic(this object anonymousObject)
{
return new RazorDynamicObject() { Model = anonymousObject };
}
}
Usage in the controller is the same except you use ToRazorDynamic() instead of ToExpando().
In your view to get the entire anonymous object you just add ".AnonValue" to the end.
var project = #(Html.Raw(JsonConvert.SerializeObject(Model.Project.AnonValue)));
var projectName = #Model.Project.Name;
I tried the ExpandoObject but it didn't work with a nested anonymous complex type like this:
var model = new { value = 1, child = new { value = 2 } };
So my solution was to return a JObject to View model:
return View(JObject.FromObject(model));
and convert to dynamic in .cshtml:
#using Newtonsoft.Json.Linq;
#model JObject
#{
dynamic model = (dynamic)Model;
}
<span>Value of child is: #model.child.value</span>
I'm doing a message inspector in WCF:
public class LogMessageInspector :
IDispatchMessageInspector, IClientMessageInspector
which implements the method:
public object AfterReceiveRequest(ref Message request,
IClientChannel channel, InstanceContext instanceContext)
I can get the name of the invoked service with:
instanceContext.GetServiceInstance().GetType().Name
But how do I get the name of the invoked operation?
It's not pretty, but this is what I did to get the operation name:
var action = OperationContext.Current.IncomingMessageHeaders.Action;
var operationName = action.Substring(action.LastIndexOf("/", StringComparison.OrdinalIgnoreCase) + 1);
var operationName = OperationContext.Current.IncomingMessageProperties["HttpOperationName"] as string;
This approach is similar to others presented here, but uses Path.GetFileName:
Path.GetFileName(OperationContext.Current.IncomingMessageHeaders.Action);
The return value of this method and the format of the path string work quite harmoniously in this scenario:
The characters after the last directory character in path. If the last
character of path is a directory or volume separator character, this
method returns String.Empty. If path is null, this method returns
null.
OperationContext.Current.IncomingMessageHeaders.Action.Split('/').ToList().Last();
Little late to the party but I had to dig a little deeper than existing answers on this question because they seem to involve getting the action name and not the operation name. (Frequently they are the same so getting the action name does, in fact, get the operation name.)
Microsoft's Application Insights SDK Labs' WCF library makes this concerted effort:
private string DiscoverOperationName(OperationContext operationContext)
{
var runtime = operationContext.EndpointDispatcher.DispatchRuntime;
string action = operationContext.IncomingMessageHeaders.Action;
if (!string.IsNullOrEmpty(action))
{
foreach (var op in runtime.Operations)
{
if (op.Action == action)
{
return op.Name;
}
}
}
else
{
// WebHttpDispatchOperationSelector will stick the
// selected operation name into a message property
return this.GetWebHttpOperationName(operationContext);
}
var catchAll = runtime.UnhandledDispatchOperation;
if (catchAll != null)
{
return catchAll.Name;
}
return "*";
}
private string GetWebHttpOperationName(OperationContext operationContext)
{
var name = WebHttpDispatchOperationSelector.HttpOperationNamePropertyName;
if (this.HasIncomingMessageProperty(name))
{
return this.GetIncomingMessageProperty(name) as string;
}
return "<unknown>";
}
Is anybody using JSON.NET with nHibernate? I notice that I am getting errors when I try to load a class with child collections.
I was facing the same problem so I tried to use #Liedman's code but the GetSerializableMembers() was never get called for the proxied reference.
I found another method to override:
public class NHibernateContractResolver : DefaultContractResolver
{
protected override JsonContract CreateContract(Type objectType)
{
if (typeof(NHibernate.Proxy.INHibernateProxy).IsAssignableFrom(objectType))
return base.CreateContract(objectType.BaseType);
else
return base.CreateContract(objectType);
}
}
We had this exact problem, which was solved with inspiration from Handcraftsman's response here.
The problem arises from JSON.NET being confused about how to serialize NHibernate's proxy classes. Solution: serialize the proxy instances like their base class.
A simplified version of Handcraftsman's code goes like this:
public class NHibernateContractResolver : DefaultContractResolver {
protected override List<MemberInfo> GetSerializableMembers(Type objectType) {
if (typeof(INHibernateProxy).IsAssignableFrom(objectType)) {
return base.GetSerializableMembers(objectType.BaseType);
} else {
return base.GetSerializableMembers(objectType);
}
}
}
IMHO, this code has the advantage of still relying on JSON.NET's default behaviour regarding custom attributes, etc. (and the code is a lot shorter!).
It is used like this
var serializer = new JsonSerializer{
ReferenceLoopHandling = ReferenceLoopHandling.Ignore,
ContractResolver = new NHibernateContractResolver()
};
StringWriter stringWriter = new StringWriter();
JsonWriter jsonWriter = new Newtonsoft.Json.JsonTextWriter(stringWriter);
serializer.Serialize(jsonWriter, objectToSerialize);
string serializedObject = stringWriter.ToString();
Note: This code was written for and used with NHibernate 2.1. As some commenters have pointed out, it doesn't work out of the box with later versions of NHibernate, you will have to make some adjustments. I will try to update the code if I ever have to do it with later versions of NHibernate.
I use NHibernate with Json.NET and noticed that I was getting inexplicable "__interceptors" properties in my serialized objects. A google search turned up this excellent solution by Lee Henson which I adapted to work with Json.NET 3.5 Release 5 as follows.
public class NHibernateContractResolver : DefaultContractResolver
{
private static readonly MemberInfo[] NHibernateProxyInterfaceMembers = typeof(INHibernateProxy).GetMembers();
protected override List<MemberInfo> GetSerializableMembers(Type objectType)
{
var members = base.GetSerializableMembers(objectType);
members.RemoveAll(memberInfo =>
(IsMemberPartOfNHibernateProxyInterface(memberInfo)) ||
(IsMemberDynamicProxyMixin(memberInfo)) ||
(IsMemberMarkedWithIgnoreAttribute(memberInfo, objectType)) ||
(IsMemberInheritedFromProxySuperclass(memberInfo, objectType)));
var actualMemberInfos = new List<MemberInfo>();
foreach (var memberInfo in members)
{
var infos = memberInfo.DeclaringType.BaseType.GetMember(memberInfo.Name);
actualMemberInfos.Add(infos.Length == 0 ? memberInfo : infos[0]);
}
return actualMemberInfos;
}
private static bool IsMemberDynamicProxyMixin(MemberInfo memberInfo)
{
return memberInfo.Name == "__interceptors";
}
private static bool IsMemberInheritedFromProxySuperclass(MemberInfo memberInfo, Type objectType)
{
return memberInfo.DeclaringType.Assembly == typeof(INHibernateProxy).Assembly;
}
private static bool IsMemberMarkedWithIgnoreAttribute(MemberInfo memberInfo, Type objectType)
{
var infos = typeof(INHibernateProxy).IsAssignableFrom(objectType)
? objectType.BaseType.GetMember(memberInfo.Name)
: objectType.GetMember(memberInfo.Name);
return infos[0].GetCustomAttributes(typeof(JsonIgnoreAttribute), true).Length > 0;
}
private static bool IsMemberPartOfNHibernateProxyInterface(MemberInfo memberInfo)
{
return Array.Exists(NHibernateProxyInterfaceMembers, mi => memberInfo.Name == mi.Name);
}
}
To use it just put an instance in the ContractResolver property of your JsonSerializer. The circular dependency problem noted by jishi can be resolved by setting the ReferenceLoopHandling property to ReferenceLoopHandling.Ignore . Here's an extension method that can be used to serialize objects using Json.Net
public static void SerializeToJsonFile<T>(this T itemToSerialize, string filePath)
{
using (StreamWriter streamWriter = new StreamWriter(filePath))
{
using (JsonWriter jsonWriter = new JsonTextWriter(streamWriter))
{
jsonWriter.Formatting = Formatting.Indented;
JsonSerializer serializer = new JsonSerializer
{
NullValueHandling = NullValueHandling.Ignore,
ReferenceLoopHandling = ReferenceLoopHandling.Ignore,
ContractResolver = new NHibernateContractResolver(),
};
serializer.Serialize(jsonWriter, itemToSerialize);
}
}
}
Are you getting a circular dependancy-error? How do you ignore objects from serialization?
Since lazy loading generates a proxy-objects, any attributes your class-members have will be lost. I ran into the same issue with Newtonsoft JSON-serializer, since the proxy-object didn't have the [JsonIgnore] attributes anymore.
You will probably want to eager load most of the object so that it can be serialized:
ICriteria ic = _session.CreateCriteria(typeof(Person));
ic.Add(Restrictions.Eq("Id", id));
if (fetchEager)
{
ic.SetFetchMode("Person", FetchMode.Eager);
}
A nice way to do this is to add a bool to the constructor (bool isFetchEager) of your data provider method.
I'd say this is a design problem in my opinion. Because NH makes connections to the database underneath all and has proxies in the middle, it is not good for the transparency of your application to serialize them directly (and as you can see Json.NET does not like them at all).
You should not serialize the entities themselves, but you should convert them into "view" objects or POCO or DTO objects (whatever you want to call them) and then serialize these.
The difference is that while NH entity may have proxies, lazy attributes, etc. View objects are simple objects with only primitives which are serializable by default.
How to manage FKs?
My personal rule is:
Entity level: Person class and with a Gender class associated
View level: Person view with GenderId and GenderName properties.
This means that you need to expand your properties into primitives when converting to view objects. This way also your json objects are simpler and easier to handle.
When you need to push the changes to the DB, in my case I use AutoMapper and do a ValueResolver class which can convert your new Guid to the Gender object.
UPDATE: Check http://blog.andrewawhitaker.com/blog/2014/06/19/queryover-series-part-4-transforming/ for a way to get the view directly (AliasToBean) from NH. This would be a boost in the DB side.
The problem can happen when NHibernate wraps the nested collection properties in a PersistentGenericBag<> type.
The GetSerializableMembers and CreateContract overrides cannot detect that these nested collection properties are "proxied". One way to resolve this is to override the CreateProperty method. The trick is to get the value from the property using reflection and test whether the type is of PersistentGenericBag. This method also has the ability to filter any properties that generated exceptions.
public class NHibernateContractResolver : DefaultContractResolver
{
protected override JsonProperty CreateProperty(MemberInfo member, MemberSerialization memberSerialization)
{
JsonProperty property = base.CreateProperty(member, memberSerialization);
property.ShouldSerialize = instance =>
{
try
{
PropertyInfo prop = (PropertyInfo)member;
if (prop.CanRead)
{
var value = prop.GetValue(instance, null);
if (value != null && typeof(NHibernate.Collection.Generic.PersistentGenericBag<>).IsSubclassOfRawGeneric(value.GetType()))
return false;
return true;
}
}
catch
{ }
return false;
};
return property;
}
}
The IsSubclassOfRawGeneric extension used above:
public static class TypeExtensions
{
public static bool IsSubclassOfRawGeneric(this Type generic, Type? toCheck)
{
while (toCheck != null && toCheck != typeof(object))
{
var cur = toCheck.IsGenericType ? toCheck.GetGenericTypeDefinition() : toCheck;
if (generic == cur)
{
return true;
}
toCheck = toCheck?.BaseType;
}
return false;
}
}
If you serialize objects that contain NHibernate proxy classes you might end up downloading the whole database, because once the property is accessed NHibernate would trigger a request to the database.
I've just implemented a Unit of Work for NHibernate: NHUnit that fixes two of the most annoying issues from NHibernate: proxy classes and cartesian product when using fetch.
How would you use this?
var customer = await _dbContext.Customers.Get(customerId) //returns a wrapper to configure the query
.Include(c => c.Addresses.Single().Country, //include Addresses and Country
c => c.PhoneNumbers.Single().PhoneNumberType) //include all PhoneNumbers with PhoneNumberType
.Unproxy() //instructs the framework to strip all the proxy classes when the Value is returned
.Deferred() //instructs the framework to delay execution (future)
.ValueAsync(token); //this is where all deferred queries get executed
The above code is basically configuring a query: return a customer by id with multiple child objects which should be executed with other queries (futures) and the returned result should be stripped of NHibernate proxies. The query gets executed when ValueAsync is called.
NHUnit determines if it should do join with the main query, create new future queries or make use of batch fetch.
There is a simple example project on Github to show you how to use NHUnit package. If others are interested in this project I will invest more time to make it better.
This is what I use:
Have a marker interface and inherit it on your entities, e.g. in my case empty IEntity.
We will use the marker interface to detect NHibernate entity types in the contract resolver.
public class CustomerEntity : IEntity { ... }
Create a custom contract resolver for JSON.NET
public class NHibernateProxyJsonValueProvider : IValueProvider {
private readonly IValueProvider _valueProvider;
public NHibernateProxyJsonValueProvider(IValueProvider valueProvider)
{
_valueProvider = valueProvider;
}
public void SetValue(object target, object value)
{
_valueProvider.SetValue(target, value);
}
private static (bool isProxy, bool isInitialized) GetProxy(object proxy)
{
// this is pretty much what NHibernateUtil.IsInitialized() does.
switch (proxy)
{
case INHibernateProxy hibernateProxy:
return (true, !hibernateProxy.HibernateLazyInitializer.IsUninitialized);
case ILazyInitializedCollection initializedCollection:
return (true, initializedCollection.WasInitialized);
case IPersistentCollection persistentCollection:
return (true, persistentCollection.WasInitialized);
default:
return (false, false);
}
}
public object GetValue(object target)
{
object value = _valueProvider.GetValue(target);
(bool isProxy, bool isInitialized) = GetProxy(value);
if (isProxy)
{
if (isInitialized)
{
return value;
}
if (value is IEnumerable)
{
return Enumerable.Empty<object>();
}
return null;
}
return value;
}
}
public class NHibernateContractResolver : CamelCasePropertyNamesContractResolver {
protected override JsonContract CreateContract(Type objectType)
{
if (objectType.IsAssignableTo(typeof(IEntity)))
{
return base.CreateObjectContract(objectType);
}
return base.CreateContract(objectType);
}
protected override JsonProperty CreateProperty(MemberInfo member, MemberSerialization memberSerialization)
{
JsonProperty property = base.CreateProperty(member, memberSerialization);
property.ValueProvider = new NHibernateProxyJsonValueProvider(property.ValueProvider);
return property;
}
}
Normal uninitialized lazy loaded properties will result in null in the json output.
Collection uninitialized lazy loaded properties will result in an [] empty array in json.
So for a lazy loaded property to appear in the json output you need to eagerly load it in the query or in code before serialization.
Usage:
JsonConvert.SerializeObject(entityToSerialize, new JsonSerializerSettings() {
ContractResolver = new NHibernateContractResolver()
});
Or globally in in ASP.NET Core Startup class
services.AddNewtonsoftJson(options =>
{
options.SerializerSettings.ContractResolver = new NHibernateContractResolver();
});
Using:
NET 5.0
NHibernate 5.3.8
JSON.NET latest via ASP.NET Core