A friend of mine (from work) asked me a question.
Remove the static keyword from the Dictionary Live from the Members class.
Don't use new Members(); to create an instance in Check(...) method.
So with these rules, what you have to do for call Live from other class like:
Members.Live.TryGetValue(signatureFromRequest, out userId);
I have this;
using System;
using System.Collections.Generic;
namespace Webbing.Session
{
public class Members
{
// THAT Dictionary Live was a static... public static Dictionary...
public Dictionary Guid, int> Live = new Dictionary Guid,int>();
}
}
and this:
using System;
using WcfService.Session;
namespace Webbing.BusinessDb
{
public class Signature
{
public static bool Check(Guid signatureFromRequest)
{
bool result = false;
int userId;
Members checker = new Members(); // <--------- don't use this
checker.Live.TryGetValue(signatureFromRequest, out userId);
if (userId != 0)
{
result = true;
}
return result;
}
}
}
He is saying, "there is way to do it.", but I can't find it and I don't believe there actually is. What is your opinion?
UPDATE/ANSWER:
I solved the question with Daniel Hilgarth 's help... Here it is;
using System;
using System.Collections.Generic;
namespace Webbing.Session
{
public class Members
{
// Guid, userId
public Dictionary Guid, int> Live = new Dictionary Guid,int>();
private static readonly Members __instance = new Members();
public static Members Instance
{
get
{
return __instance;
}
}
}
}
Usage: Members.Instance.Live.TryGetValue(signatureFromRequest, out userId);
There is no way with the exact syntax you provided.
One possibility would be a singleton, but it would look like this:
Members.Instance.Live.TryGetValue(signatureFromRequest, out userId);
Note the .Instance part.
See here for several ways to implement a singleton.
As you can see, now the Live property isn't static anymore but the new property Instance is...
I guess it will be best to simply ask your colleague what he meant.
Related
Just wanted to know if there is a way bind a type and resolve a collection. I dont know if Ninject can do this out of the box. I'm using MVC4 with Ninject3 so I have the NinjectWebCommon.cs where I register the services. There is nowhere I can get the kernel (I read that it was bad practice to access the kernel from elsewhere, but that can certainly be the solution to this).
For example, I'm having this class:
public class CacheManager
{
public IEnumerable<SelectListItem> Get<T>() where T : INameValue
I want to be able to send
CacheManager.Get<City>
and obtain the CityRepository class.
Is it this you want to do? :
using System.Collections.Generic;
using System.Linq;
using Ninject;
using Ninject.Modules;
using Ninject.Syntax;
public class Temp
{
public interface ICity { }
public class SelectListItem
{
}
public class FooCity : SelectListItem, ICity { }
public class BarCity : SelectListItem, ICity {}
public class CityModule : NinjectModule
{
public override void Load()
{
this.Bind<ICity>().To<FooCity>();
this.Bind<ICity>().To<BarCity>();
}
}
public class CacheManager
{
private readonly IResolutionRoot resolutionRoot;
public CacheManager(IResolutionRoot resolutionRoot)
{
this.resolutionRoot = resolutionRoot;
}
public IEnumerable<SelectListItem> Get<T>()
{
return this.resolutionRoot.GetAll<T>().OfType<SelectListItem>();
}
}
}
I'm unclear as to whether you have multiple implementations of T (ICity) or one implementation but several instances (like retrieving a list of city names from the database and creating one instance per name). The later you could solve by a this.Bind>().ToProvider(...) binding.
I ended up doing:
In NinjectWebCommon.cs:
kernel.Bind(typeof(CacheManager))
.ToSelf()
.InSingletonScope();
kernel.Bind<IDataListRepository<Locale>>()
.To<LocaleRepository>();
In CacheManager.cs:
public class CacheManager: IDisposable
{
private IKernel kernel;
public CacheManager(IKernel kernel)
{
this.kernel = kernel;
}
public IEnumerable<T> GetAsEnumerable<T>()
{
var rep = kernel.Get<IDataListRepository<T>>();
return rep.GetAll();
}
I don't know if this is bad-practice (since kernel in theory should only be used in the initialization phase), but I didn't find any other way to do it.
If better options exist, please let me know.
I am writing my first WCF service. I am trying to understand how Datacontracts work. I have read the MSDN Article that describes how custom types should be marked up to create a data contract but I cannot get my example to work.
I have a simple DTO object that I have placed in a shared library because I want the client and the service to know about this type (right?) it looks like this:
using System.Collections.Generic;
using System.Runtime.Serialization;
namespace org.healthwise.gatewayinterfaces.mocks
{
[DataContract]
public class MockCheckInDTO : ICheckInDTO
{
[DataMember]
private string _testPackageFilePath = "testpackages\\973eb455-6acc-486b-a1dd-2cf527872b1e.zip";
[DataMember]
private IDictionary<string, string> _testMetaData;
public MockCheckInDTO()
{
_testMetaData = MakeTestMetaDataDictionary();
}
private IDictionary<string, string> MakeTestMetaDataDictionary()
{
IDictionary<string, string> testMetaData = new Dictionary<string, string>();
testMetaData.Add("Version", "9.0.1");
testMetaData.Add("Product Family", "Learning Modules");
return testMetaData;
}
[DataMember]
public string PackageFileLocation
{
get { return _testPackageFilePath; }
set { _testPackageFilePath = value; }
}
[DataMember]
public IDictionary<string, string> PackageMetaData
{
get { return _testMetaData; }
set { _testMetaData = value; }
}
}
}
This is the ServiceContract:
[ServiceContract]
public interface IIndexCheckIn
{
[OperationContract]
void AddToIndex(MockCheckInDTO mockCheckInDto);
}
I have created a little console application to attempt to send this MockCheckInDTO over to my service but it never gets there. It seems that I am having and issue serializing the MockCheckInDTO object. Can someone help me out?
This is the exception I am seeing:
System.Runtime.Serialization.SerializationException: Type 'org.healthwise.gatewayinterfaces.mocks.MockCheckInDTO' with data contract name 'MockCheckInDTO:http://schemas.datacontract.org/2004/07/org.healthwise.gatewayinterfaces.mocks' is not expected. Consider using a DataContractResolver or add any types not known statically to the list of known type
Try removing [DataMember] from the private fields, so it's just on the public properties. If you're still having trouble, it might be good for educating yourself on what's going on with your DataContract to, instead of having the DC in a shared library, have it automatically created from the service metadata. Then take a look at it and see if it's what you expect. If not, you'll at least have an idea of what's going wrong when you try to serialize/deserialize the object.
first of all, it is weired that you serialize the same data twice: the private fields and the public properties. As Tim S. said it's better to remove one.
I tried to reproduce your problem by using DataContractSerializer directly, but I failed.
DataContractSerializer serializer = new DataContractSerializer(typeof(MockCheckInDTO));
var data = new MockCheckInDTO();
using (var file = File.OpenWrite("dto.xml"))
using (var xmlWriter = XmlDictionaryWriter.CreateTextWriter(file))
{
serializer.WriteObject(xmlWriter, data);
}
using (var file = File.OpenRead("dto.xml"))
using (var xmlReader = XmlDictionaryReader.CreateTextReader(file, XmlDictionaryReaderQuotas.Max))
{
var result = serializer.ReadObject(xmlReader);
}
My aim is to implement a quite generic search mechanism. Here's the general idea:
you can search based on any property of the entity you're searching for (for example- by Employee's salary, or by Department name etc.).
Each property you can search by is represented by a class, which inherits from EntityProperty:
public abstract class EntityProperty<T>
where T:Entity
{
public enum Operator
{
In,
NotIn,
}
/// <summary>
/// Name of the property
/// </summary>
public abstract string Name { get; }
//Add a search term to the given query, using the given values
public abstract IQueryable<T> AddSearchTerm(IQueryable<T> query, IEnumerable<object> values);
public abstract IQueryable<T> AddSortingTerm(IQueryable<T> query);
protected Operator _operator = Operator.In;
protected bool _sortAscending = false;
public EntityProperty(Operator op)
{
_operator = op;
}
//use this c'tor if you're using the property for sorting only
public EntityProperty(bool sortAscending)
{
_sortAscending = sortAscending;
}
}
all of the properties you're searching / sorting by are stored in a simple collection class:
public class SearchParametersCollection<T>
where T: Entity
{
public IDictionary<EntityProperty<T>,IEnumerable<object>> SearchProperties { get; private set; }
public IList<EntityProperty<T>> SortProperties { get; private set; }
public SearchParametersCollection()
{
SearchProperties = new Dictionary<EntityProperty<T>, IEnumerable<object>>();
SortProperties = new List<EntityProperty<T>>();
}
public void AddSearchProperty(EntityProperty<T> property, IEnumerable<object> values)
{
SearchProperties.Add(property, values);
}
public void AddSortProperty(EntityProperty<T> property)
{
if (SortProperties.Contains(property))
{
throw new ArgumentException(string.Format("property {0} already exists in sorting order", property.Name));
}
SortProperties.Add(property);
}
}
now, all the repository class has to do is:
protected IEnumerable<T> Search<T>(SearchParametersCollection<T> parameters)
where T : Entity
{
IQueryable<T> query = this.Session.Linq<T>();
foreach (var searchParam in parameters.SearchProperties)
{
query = searchParam.Key.AddSearchTerm(query, searchParam.Value);
}
//add order
foreach (var sortParam in parameters.SortProperties)
{
query = sortParam.AddSortingTerm(query);
}
return query.AsEnumerable();
}
for example, here's a class which implements searching a user by their full name:
public class UserFullName : EntityProperty<User>
{
public override string Name
{
get { return "Full Name"; }
}
public override IQueryable<User> AddSearchTerm(IQueryable<User> query, IEnumerable<object> values)
{
switch (_operator)
{
case Operator.In:
//btw- this doesn't work with nHibernate... :(
return query.Where(u => (values.Cast<string>().Count(v => u.FullName.Contains(v)) > 0));
case Operator.NotIn:
return query.Where(u => (values.Cast<string>().Count(v => u.FullName.Contains(v)) == 0));
default:
throw new InvalidOperationException("Unrecognized operator " + _operator.ToString());
}
}
public override IQueryable<User> AddSortingTerm(IQueryable<User> query)
{
return (_sortAscending) ? query.OrderBy(u => u.FullName) : query.OrderByDescending(u => u.FullName);
}
public UserFullName(bool sortAscending)
: base(sortAscending)
{
}
public UserFullName(Operator op)
: base(op)
{
}
}
my questions are:
1. firstly- am I even on the right track? I don't know of any well-known method for achieving what I want, but I may be wrong...
2. it seems to me that the Properties classes should be in the domain layer and not in the DAL, since I'd like the controller layers to be able to use them. However, that prevents me from using any nHibernate-specific implementation of the search (i.e any other interface but Linq). Can anybody think of a solution that would enable me to utilize the full power of nH while keeping these classes visible to upper layers? I've thought about moving them to the 'Common' project, but 'Common' has no knowledge of the Model entities, and I'd like to keep it that way.
3. as you can see by my comment for the AddSearchTerm method- I haven't really been able to implement 'in' operator using nH (I'm using nH 2.1.2 with Linq provider). any sugggestions in that respect would be appriciated. (see also my question from yesterday).
thanks!
If you need good API to query NHIbernate objects then you should use ICriteria (for NH 2.x) or QueryOver (for NH 3.x).
You over complicating DAL with these searches. Ayende has a nice post about why you should not do it
I ended up using query objects, which greatly simplified things.
I think this falls under the concept of contextual binding, but the Ninject documentation, while very thorough, does not have any examples close enough to my current situation for me to really be certain. I'm still pretty confused.
I basically have classes that represent parameter structures for queries. For instance..
class CurrentUser {
string Email { get; set; }
}
And then an interface that represents its database retrieval (in the data layer)
class CurrentUserQuery : IQueryFor<CurrentUser> {
public CurrentUserQuery(ISession session) {
this.session = session;
}
public Member ExecuteQuery(CurrentUser parameters) {
var member = session.Query<Member>().Where(n => n.Email == CurrentUser.Email);
// validation logic
return member;
}
}
Now then, what I want to do is to establish a simple class that can take a given object and from it get the IQueryFor<T> class, construct it from my Ninject.IKernel (constructor parameter), and perform the ExecuteQuery method on it, passing through the given object.
The only way I have been able to do this was to basically do the following...
Bind<IQueryFor<CurrentUser>>().To<CurrentUserQuery>();
This solves the problem for that one query. But I anticipate there will be a great number of queries... so this method will become not only tedious, but also very prone to redundancy.
I was wondering if there is an inherit way in Ninject to incorporate this kind of behavior.
:-
In the end, my (ideal) way of using this would be ...
class HomeController : Controller {
public HomeController(ITransit transit) {
// injection of the transit service
}
public ActionResult CurrentMember() {
var member = transit.Send(new CurrentUser{ Email = User.Identity.Name });
}
}
Obviously that's not going to work right, since the Send method has no way of knowing the return type.
I've been dissecting Rhino Service Bus extensively and project Alexandria to try and make my light, light, lightweight implementation.
Update
I have been able to get a fairly desired result using .NET 4.0 dynamic objects, such as the following...
dynamic Send<T>(object message);
And then declaring my interface...
public interface IQueryFor<T,K>
{
K Execute(T message);
}
And then its use ...
public class TestCurrentMember
{
public string Email { get; set; }
}
public class TestCurrentMemberQuery : IConsumerFor<TestCurrentMember, Member>
{
private readonly ISession session;
public TestCurrentMemberQuery(ISession session) {
this.session = session;
}
public Member Execute(TestCurrentMember user)
{
// query the session for the current member
var member = session.Query<Member>()
.Where(n => n.Email == user.Email).SingleOrDefault();
return member;
}
}
And then in my Controller...
var member = Transit.Send<TestCurrentMemberQuery>(
new TestCurrentMember {
Email = User.Identity.Name
}
);
effectively using the <T> as my 'Hey, This is what implements the query parameters!'. It does work, but I feel pretty uncomfortable with it. Is this an inappropriate use of the dynamic function of .NET 4.0? Or is this more the reason why it exists in the first place?
Update (2)
For the sake of consistency and keeping this post relative to just the initial question, I'm opening up a different question for the dynamic issue.
Yes, you should be able to handle this with Ninject Conventions. I am just learning the Conventions part of Ninject, and the documentation is sparse; however, the source code for the Conventions extension is quite light and easy to read/navigate, also Remo Gloor is very helpful both here and on the mailing list.
The first thing I would try is a GenericBindingGenerator (changing the filters and scope as needed for your application):
internal class YourModule : NinjectModule
{
public override void Load()
{
Kernel.Scan(a => {
a.From(System.Reflection.Assembly.GetExecutingAssembly());
a.InTransientScope();
a.BindWith(new GenericBindingGenerator(typeof(IQueryFor<>)));
});
}
}
The heart of any BindingGenerator is this interface:
public interface IBindingGenerator
{
void Process(Type type, Func<IContext, object> scopeCallback, IKernel kernel);
}
The Default Binding Generator simply checks if the name of the class matches the name of the interface:
public void Process(Type type, Func<IContext, object> scopeCallback, IKernel kernel)
{
if (!type.IsInterface && !type.IsAbstract)
{
Type service = type.GetInterface("I" + type.Name, false);
if (service != null)
{
kernel.Bind(service).To(type).InScope(scopeCallback);
}
}
}
The GenericBindingGenerator takes a type as a constructor argument, and checks interfaces on classes scanned to see if the Generic definitions of those interfaces match the type passed into the constructor:
public GenericBindingGenerator(Type contractType)
{
if (!contractType.IsGenericType && !contractType.ContainsGenericParameters)
{
throw new ArgumentException("The contract must be an open generic type.", "contractType");
}
this._contractType = contractType;
}
public void Process(Type type, Func<IContext, object> scopeCallback, IKernel kernel)
{
Type service = this.ResolveClosingInterface(type);
if (service != null)
{
kernel.Bind(service).To(type).InScope(scopeCallback);
}
}
public Type ResolveClosingInterface(Type targetType)
{
if (!targetType.IsInterface && !targetType.IsAbstract)
{
do
{
foreach (Type type in targetType.GetInterfaces())
{
if (type.IsGenericType && (type.GetGenericTypeDefinition() == this._contractType))
{
return type;
}
}
targetType = targetType.BaseType;
}
while (targetType != TypeOfObject);
}
return null;
}
So, when the Conventions extension scans the class CurrentUserQuery it will see the interface IQueryFor<CurrentUser>. The generic definition of that interface is IQueryFor<>, so it will match and that type should get registered for that interface.
Lastly, there is a RegexBindingGenerator. It tries to match interfaces of the classes scanned to a Regex given as a constructor argument. If you want to see the details of how that operates, you should be able to peruse the source code for it now.
Also, you should be able to write any implementation of IBindingGenerator that you may need, as the contract is quite simple.
First question is, how can I get the type of an object stored in a variable? Generally we do:
Type t = typeof(ClassName); //if I know the class
but, how can I say something:
Type t = typeof(varClassName); //if the class name is stored in a variable
Second question, a broader picture is, I have a WCF service that contains a DataContract class say "MyClass" and I have defined a custom attribute called "MyAttribute" to it. There is one method say "GetDataUsingDataContract" with a parameter of type MyClass. Now on client, I invoke the webservice. I use MethodInfo and ParameterInfo classes to get the parameters of the method in question. But how can I access the attributes of the method parameter which is actually a class Myclass? Here is the code that I tried:
MyService.Service1Client client = new MyService.Service1Client();
Type t = typeof(MyService.Service1Client);
MethodInfo members = t.GetMethod("GetDataUsingDataContract");
ParameterInfo[] parameters = members.GetParameters();
foreach (var parameter in parameters)
{
MemberInfo mi = parameter.ParameterType; //Not sure if this the way
object[] attributes;
attributes = mi.GetCustomAttributes(true);
}
Above code doesn't retrieve me the custom attribute "MyAttribute". I tried the concept in the class that is defined in the same project and it works. Please HELP!
but, how can I say something:
Type t = typeof(varClassName); //if the class name is stored in a variable
Try
Type.GetType("varClassName", false, true);
As to your second question:
Above code doesn't retrieve me the
custom attribute "MyAttribute". I
tried the concept in the class that is
defined in the same project and it
works. Please HELP!
Just guessing, I'm not sure that attributes are exposed to the client, by default. I think its the same issue as an untrusted assembly. Some attributes are sensitive info. See this:
http://blogs.msdn.com/b/haibo_luo/archive/2006/02/21/536470.aspx
But you could try linking the service project types into your app by first referencing the service assembly in your client project, then going to your service reference -> "Configure Service Reference" and selecting "Reuse types in all referenced assemblies". I'm not sure this option will affect the service interface classes, but I use it often with my domain objects. Worth a try.
Type mi = parameter.ParameterType; //Not sure if this the way
object[] attributes;
attributes = mi.GetCustomAttributes(true);
Ensure your proxy class has knowledge on attributes
Hope this will help
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.ServiceModel;
using System.Runtime.Serialization;
using System.Reflection;
namespace WindowsFormsApplication1
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
StartService();
}
string url = "http://localhost:234/MyService/";
private void StartClient()
{
IMyService myService = ChannelFactory<IMyService>.CreateChannel(new BasicHttpBinding(), new EndpointAddress(url));
Type t = typeof(IMyService);
MethodInfo members = t.GetMethod("MyMethod");
ParameterInfo[] parameters = members.GetParameters();
foreach (var parameter in parameters)
{
Type mi = parameter.ParameterType;
object[] attributes;
attributes = mi.GetCustomAttributes(true);
}
}
private void StartService()
{
ServiceHost host = new ServiceHost(typeof(MyService), new Uri(url));
host.AddServiceEndpoint(typeof(IMyService), new BasicHttpBinding(), "");
host.Open();
}
private void button1_Click(object sender, EventArgs e)
{
StartClient();
}
}
[AttributeUsage(AttributeTargets.Interface)]
public class MyAttrib : Attribute
{
}
[MyAttrib]
public interface IMyContract
{
string Name { get; set; }
}
[DataContract]
public class MyContract : IMyContract
{
[DataMember]
public string Name { get; set; }
}
[ServiceContract]
public interface IMyService
{
[OperationContract]
bool MyMethod(IMyContract dummy);
}
[ServiceBehavior(UseSynchronizationContext = false)]
public class MyService : IMyService
{
public bool MyMethod(IMyContract dummy)
{
return true;
}
}
}