Implement better exception handling in CoapHandler

NZSmartie · Aug 23, 2017 · 8e547da · 8e547da
1 parent 330ade3
commit 8e547da
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Showing 3 changed files with 69 additions and 23 deletions.
diff --git a/CoAPNet.Tests/CoapResourceHandlerTests.cs b/CoAPNet.Tests/CoapResourceHandlerTests.cs
@@ -152,7 +152,7 @@ public void TestResourceMethodNotImplemented()
         {
             // Arrange
             var expectedMessage = CoapMessageUtility
-                .CreateMessage(CoapMessageCode.NotImplemented, new NotImplementedException().Message).Serialise();
+                .FromException(new NotImplementedException()).Serialise();
             _endpoint
                 .Setup(c => c.SendAsync(It.Is<CoapPacket>(p => p.Payload.SequenceEqual(expectedMessage)), It.IsAny<CancellationToken>()))
                 .Returns(Task.FromResult(0))
@@ -180,7 +180,8 @@ public void TestResourceMethodNotImplemented()
         public void TestResourceNotFound()
         {
             // Arrange
-            var expectedMessage = CoapMessageUtility.CreateMessage(CoapMessageCode.NotFound, $"Resouce {new Uri(_baseUri, "/test")} was not found").Serialise();
+            var expectedMessage = CoapMessageUtility.CreateMessage(CoapMessageCode.NotFound, $"Resouce {new Uri(_baseUri, "/test")} was not found", CoapMessageType.Acknowledgement).Serialise();
+
             _endpoint
                 .Setup(e => e.SendAsync(It.Is<CoapPacket>(p => p.Payload.SequenceEqual(expectedMessage)), It.IsAny<CancellationToken>()))
                 .Returns(Task.FromResult(0))

diff --git a/CoAPNet/CoapHander.cs → CoAPNet/CoapHandler.cs b/CoAPNet/CoapHander.cs → CoAPNet/CoapHandler.cs
@@ -8,7 +8,7 @@
 
 namespace CoAPNet
 {
-    public class CoapResourceHandler : CoapHander
+    public class CoapResourceHandler : CoapHandler
     {
         public readonly IList<CoapResource> Resources = new List<CoapResource>();
 
@@ -35,7 +35,7 @@ public CoapResourceHandler(Uri baseUri)
         }
     }
 
-    public class CoapHander : ICoapHandler
+    public class CoapHandler : ICoapHandler
     {
         public virtual CoapResource GetResource(Uri requesstUri)
         {
@@ -46,23 +46,36 @@ public virtual CoapResource GetResource(Uri requesstUri)
 
         public virtual Uri BaseUri { get; } = new Uri("coap://localhost/");
 
-        public async Task ProcessRequestAsync(ICoapConnectionInformation connection, byte[] payload)
-        {
-            var message = new CoapMessage();
-            message.Deserialise(payload);
+        private int _messageId;
 
-            //TODO: check if message is multicast, ignore Confirmable requests and delay response
+        public CoapHandler()
+        {
+            _messageId = new Random().Next() & 0xFFFF;
+        }
 
-            if (!message.Code.IsRequest())
-            {
-                // TODO: send CoapMessageCode.Reset or ignore them, i dunno
-                throw new NotImplementedException("TODO: Send CoapMessageCode.Reset or ignore them");
-            }
+        private int GetNextMessageId()
+        {
+            return Interlocked.Increment(ref _messageId) & ushort.MaxValue;
+        }
 
-            var resource = GetResource(new Uri(BaseUri, message.GetUri()));
+        public async Task ProcessRequestAsync(ICoapConnectionInformation connection, byte[] payload)
+        {
             CoapMessage result = null;
+            var message = new CoapMessage();
             try
             {
+                message.Deserialise(payload);
+
+                //TODO: check if message is multicast, ignore Confirmable requests and delay response
+
+                if (!message.Code.IsRequest())
+                {
+                    // TODO: send CoapMessageCode.Reset or ignore them, i dunno
+                    throw new NotImplementedException("TODO: Send CoapMessageCode.Reset or ignore them");
+                }
+
+                var resource = GetResource(new Uri(BaseUri, message.GetUri()));
+
                 if (resource == null)
                 {
                     result = CoapMessageUtility.CreateMessage(CoapMessageCode.NotFound,
@@ -90,20 +103,39 @@ public async Task ProcessRequestAsync(ICoapConnectionInformation connection, byt
                     }
                 }
             }
-            catch (NotImplementedException ex)
+            catch (CoapException ex)
             {
-                result = CoapMessageUtility.CreateMessage(CoapMessageCode.NotImplemented, ex.Message);
-                //Debug.Fail(ex.Message);
+                result = CoapMessageUtility.FromException(ex);
             }
-            catch (Exception ex)
+            catch (NotImplementedException ex)
             {
                 result = CoapMessageUtility.FromException(ex);
-                //Debug.Fail(ex.Message);
+            }
+            catch (Exception)
+            {
+                result = CoapMessageUtility.CreateMessage(CoapMessageCode.InternalServerError,
+                    "An unexpected error occured", CoapMessageType.Reset);
+                throw;
             }
             finally
             {
                 Debug.Assert(result != null);
 
+                if (message.Type == CoapMessageType.Confirmable)
+                {
+                    if (result.Type != CoapMessageType.Reset)
+                        result.Type = CoapMessageType.Acknowledgement;
+
+                    // TODO: create unit tests to ensure message.Id and message.Token are set when exceptions are thrown
+                    result.Id = message.Id;
+                }
+                else
+                {
+                    result.Id = GetNextMessageId();
+                }
+
+                result.Token = message.Token;
+
                 await connection.LocalEndpoint.SendAsync(
                     new CoapPacket
                     {

diff --git a/CoAPNet/Utils/CoapMessageUtility.cs b/CoAPNet/Utils/CoapMessageUtility.cs
@@ -6,24 +6,37 @@ namespace CoAPNet.Utils
 {
     public static class CoapMessageUtility
     {
-        public static CoapMessage CreateMessage(CoapMessageCode code, string message)
+        public static CoapMessage CreateMessage(CoapMessageCode code, string message, CoapMessageType type = CoapMessageType.Confirmable)
         {
             return new CoapMessage
             {
                 Code = code,
+                Type = type,
                 Options = {new ContentFormat(ContentFormatType.TextPlain)},
                 Payload = Encoding.UTF8.GetBytes(message)
             };
         }
 
         public static CoapMessage FromException(Exception exception)
         {
-            return new CoapMessage
+            var result = new CoapMessage
             {
+                Type = CoapMessageType.Reset,
                 Code = CoapMessageCode.InternalServerError,
-                Options = { new ContentFormat(ContentFormatType.TextPlain) },
+                Options = {new ContentFormat(ContentFormatType.TextPlain)},
                 Payload = Encoding.UTF8.GetBytes(exception.Message)
             };
+
+            switch (exception)
+            {
+                case CoapOptionException _:
+                    result.Code = CoapMessageCode.BadOption;
+                    break;
+                case NotImplementedException _:
+                    result.Code = CoapMessageCode.NotImplemented;
+                    break;
+            }
+            return result;
         }
     }
 }