Add possibility for caller proxy to return an observable

When subscribed to it will call a progressive RPC

#238

Author: Johan 't Hart

src/netstandard/Tests/WampSharp.Tests.Wampv2/Integration/RpcProgressTests.cs

@@ -1,6 +1,8 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
+using System.Reactive.Disposables;
+using System.Reactive.Linq;
 using System.Threading.Tasks;
 using NUnit.Framework;
 using WampSharp.Core.Serialization;
@@ -64,6 +66,42 @@ public async Task ProgressiveCallsCalleeProxyProgress()
             Assert.That(result.Result, Is.EqualTo(10));
         }
 
+        [Test]
+        public async Task ProgressiveCallsCalleeProxyObservable()
+        {
+            WampPlayground playground = new WampPlayground();
+
+            CallerCallee dualChannel = await playground.GetCallerCalleeDualChannel();
+            IWampChannel calleeChannel = dualChannel.CalleeChannel;
+            IWampChannel callerChannel = dualChannel.CallerChannel;
+
+            MyOperation myOperation = new MyOperation();
+
+            await calleeChannel.RealmProxy.RpcCatalog.Register(myOperation, new RegisterOptions());
+            ILongOpObsService proxy = callerChannel.RealmProxy.Services.GetCalleeProxy<ILongOpObsService>();
+
+            IEnumerable<int> results = proxy.LongOp(9, false).ToEnumerable(); // it will emit one more than asked
+
+            CollectionAssert.AreEquivalent(Enumerable.Range(0, 10), results);
+        }
+
+        [Test]
+        public async Task ProgressiveCallsCalleeProxyObservableError()
+        {
+            WampPlayground playground = new WampPlayground();
+
+            CallerCallee dualChannel = await playground.GetCallerCalleeDualChannel();
+            IWampChannel calleeChannel = dualChannel.CalleeChannel;
+            IWampChannel callerChannel = dualChannel.CallerChannel;
+
+            MyOperation myOperation = new MyOperation();
+
+            await calleeChannel.RealmProxy.RpcCatalog.Register(myOperation, new RegisterOptions());
+            ILongOpObsService proxy = callerChannel.RealmProxy.Services.GetCalleeProxy<ILongOpObsService>();
+
+            Assert.Throws(typeof(WampException), () => proxy.LongOp(9, true).ToEnumerable().Count());
+        }
+
         public class MyOperation : IWampRpcOperation
         {
             public string Procedure => "com.myapp.longop";
@@ -80,16 +118,27 @@ public IWampCancellableInvocation Invoke<TMessage>(IWampRawRpcOperationRouterCal
                 TMessage number = arguments[0];
                 int n = formatter.Deserialize<int>(number);
 
+                bool endWithError = arguments.Length > 1 && formatter.Deserialize<bool>(arguments[1]);
+
                 for (int i = 0; i < n; i++)
                 {
                     caller.Result(WampObjectFormatter.Value,
                         new YieldOptions {Progress = true},
                         new object[] {i});
                 }
 
-                caller.Result(WampObjectFormatter.Value,
-                    new YieldOptions(),
-                    new object[] {n});
+                if (endWithError)
+                {
+                    caller.Error(WampObjectFormatter.Value,
+                        new Dictionary<string, string>(),
+                        "Something bad happened");
+                }
+                else
+                {
+                    caller.Result(WampObjectFormatter.Value,
+                        new YieldOptions(),
+                        new object[] { n });
+                }
 
                 return null;
             }
@@ -122,6 +171,31 @@ public async Task<int> LongOp(int n, IProgress<int> progress)
             }
         }
 
+        public interface ILongOpObsService
+        {
+            [WampProcedure("com.myapp.longop")]
+            [WampProgressiveResultProcedure]
+            IObservable<int> LongOp(int n, bool endWithError);
+        }
+
+        public class LongOpObsService : ILongOpObsService
+        {
+            public IObservable<int> LongOp(int n, bool endWithError) => Observable.Create<int>(async obs =>
+            {
+                for (int i = 0; i < n; i++)
+                {
+                    obs.OnNext(i);
+                    await Task.Delay(100);
+                }
+                if (endWithError)
+                    obs.OnError(new WampException("wamp.error", "Something bad happened"));
+                else
+                    obs.OnCompleted();
+
+                return Disposable.Empty;
+            });
+        }
+
         public class MyCallback : IWampRawRpcOperationClientCallback
         {
             private readonly TaskCompletionSource<int> mTask = new TaskCompletionSource<int>();
@@ -187,4 +261,4 @@ public void Report(T value)
             mAction(value);
         }
     }
-}
+}

src/netstandard/WampSharp/WAMP2/V2/Api/CalleeProxy/CalleeProxyInterceptor.cs

@@ -1,3 +1,4 @@
+using System;
 using System.Reflection;
 using WampSharp.V2.Core.Contracts;
 using WampSharp.V2.Rpc;
@@ -37,7 +38,7 @@ public virtual CallOptions GetCallOptions(MethodInfo method)
 
         public virtual string GetProcedureUri(MethodInfo method)
         {
-            WampProcedureAttribute attribute = 
+            WampProcedureAttribute attribute =
                 method.GetCustomAttribute<WampProcedureAttribute>();
 
             if (attribute == null)
@@ -48,4 +49,4 @@ public virtual string GetProcedureUri(MethodInfo method)
             return attribute.Procedure;
         }
     }
-}
+}

src/netstandard/WampSharp/WAMP2/V2/Api/CalleeProxy/CalleeProxyInterceptorFactory.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Reactive;
 using System.Reflection;
 using System.Threading.Tasks;
 using WampSharp.V2.Rpc;
@@ -28,7 +29,12 @@ private static Type GetRelevantInterceptorType(MethodInfo method)
             Type genericArgument;
             Type interceptorType;
 
-            if (!typeof(Task).IsAssignableFrom(returnType))
+            if (returnType.IsGenericType && returnType.GetGenericTypeDefinition() == typeof(IObservable<>))
+            {
+                genericArgument = returnType.GetGenericArguments()[0];
+                interceptorType = typeof(ObservableCalleeProxyInterceptor<>);
+            }
+            else if (!typeof(Task).IsAssignableFrom(returnType))
             {
                 MethodInfoValidation.ValidateSyncMethod(method);
 
@@ -55,4 +61,4 @@ private static Type GetRelevantInterceptorType(MethodInfo method)
             return closedGenericType;
         }
     }
-}
+}

src/netstandard/WampSharp/WAMP2/V2/Api/CalleeProxy/ObservableCalleeProxyInterceptor.cs

@@ -0,0 +1,22 @@
+using System.Reactive;
+using System.Reactive.Linq;
+using System.Reflection;
+
+namespace WampSharp.V2.CalleeProxy
+{
+    internal class ObservableCalleeProxyInterceptor<T> : CalleeProxyInterceptorBase<T>
+    {
+        public ObservableCalleeProxyInterceptor(MethodInfo method, IWampCalleeProxyInvocationHandler handler, ICalleeProxyInterceptor interceptor) : base(method, handler, interceptor)
+        {
+        }
+
+        public override object Invoke(MethodInfo method, object[] arguments) => Observable.Create<T>(async (obs, cancellationToken) =>
+        {
+            var last = await Handler.InvokeProgressiveAsync
+                (Interceptor, method, Extractor, arguments, obs.ToProgress(), cancellationToken);
+            if (last != null)
+                obs.OnNext(last);
+            obs.OnCompleted();
+        });
+    }
+}