fix crash with null to-one relationships

Author: Chris Santero

JSONAPI.Tests/Data/SerializerIntegrationTest.json

@@ -1,3 +1,3 @@
-{"posts":[{"id":"1","title":"Linkbait!","links":{"comments":["2","3","4"],"author":"1"}},{"id":"2","title":"Rant #1023","links":{"comments":["5"],"author":"1"}},{"id":"3","title":"Polemic in E-flat minor #824","links":{"comments":null,"author":"1"}}],"linked":{"comments":[{"id":"2","body":"Nuh uh!","links":{"post":"1"}},{"id":"3","body":"Yeah huh!","links":{"post":"1"}},{"id":"4","body":"Third Reich.","links":{"post":"1"}},{"id":"5","body":"I laughed, I cried!","links":{"post":"2"}}],"authors":[{"id":"1","name":"Jason Hater","links":{"posts":["1","2","3"]}}]}}
+{"posts":[{"id":"1","title":"Linkbait!","links":{"comments":["2","3","4"],"author":"1"}},{"id":"2","title":"Rant #1023","links":{"comments":["5"],"author":"1"}},{"id":"3","title":"Polemic in E-flat minor #824","links":{"comments":null,"author":"1"}},{"id":"4","title":"This post has no author.","links":{"comments":null,"author":null}}],"linked":{"comments":[{"id":"2","body":"Nuh uh!","links":{"post":"1"}},{"id":"3","body":"Yeah huh!","links":{"post":"1"}},{"id":"4","body":"Third Reich.","links":{"post":"1"}},{"id":"5","body":"I laughed, I cried!","links":{"post":"2"}}],"authors":[{"id":"1","name":"Jason Hater","links":{"posts":["1","2","3"]}}]}}
 
 

JSONAPI.Tests/Json/JsonApiMediaFormaterTests.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Linq;
 using Microsoft.VisualStudio.TestTools.UnitTesting;
 using JSONAPI.Tests.Models;
 using Newtonsoft.Json;
@@ -14,7 +15,7 @@ namespace JSONAPI.Tests.Json
     public class JsonApiMediaFormaterTests
     {
         Author a;
-        Post p, p2, p3;
+        Post p, p2, p3, p4;
 
         [TestInitialize]
         public void SetupModels()
@@ -43,6 +44,11 @@ public void SetupModels()
                 Title = "Polemic in E-flat minor #824",
                 Author = a
             };
+            p4 = new Post
+            {
+                Id = 4,
+                Title = "This post has no author."
+            };
 
             a.Posts = new List<Post> { p, p2, p3 };
 
@@ -108,7 +114,7 @@ public void SerializerIntegrationTest()
             // Act
             //Payload payload = new Payload(a.Posts);
             //js.Serialize(jw, payload);
-            formatter.WriteToStreamAsync(typeof(Post), a.Posts, stream, (System.Net.Http.HttpContent)null, (System.Net.TransportContext)null);
+            formatter.WriteToStreamAsync(typeof(Post), new[] { p, p2, p3, p4 }.ToList(), stream, (System.Net.Http.HttpContent)null, (System.Net.TransportContext)null);
 
             // Assert
             string output = System.Text.Encoding.ASCII.GetString(stream.ToArray());

JSONAPI/Json/JsonApiFormatter.cs

@@ -249,30 +249,40 @@ protected void Serialize(object value, Stream writeStream, JsonWriter writer, Js
                 }
                 else
                 {
-                    string objId;
-
-                    objId = GetIdFor(prop.GetValue(value, null));
-
-                    switch (sa)
+                    var propertyValue = prop.GetValue(value, null);
+                    if (propertyValue == null)
                     {
-                        case SerializeAsOptions.Ids:
-                            //writer.WritePropertyName(ContractResolver.FormatPropertyName(prop.Name));
-                            serializer.Serialize(writer, objId);
-                            if (iip)
-                                if (aggregator != null) aggregator.Add(prop.PropertyType, prop.GetValue(value, null));
-                            break;
-                        case SerializeAsOptions.Link:
-                            if (lt == null) throw new JsonSerializationException("A property was decorated with SerializeAs(SerializeAsOptions.Link) but no LinkTemplate attribute was provided.");
-                            string link = String.Format(lt, objId, value.GetType().GetProperty("Id").GetValue(value, null));
-                            //writer.WritePropertyName(ContractResolver.FormatPropertyName(prop.Name));
-                            writer.WriteValue(link);
-                            break;
-                        case SerializeAsOptions.Embedded:
-                            // Not really supported by Ember Data yet, incidentally...but easy to implement here.
-                            //writer.WritePropertyName(ContractResolver.FormatPropertyName(prop.Name));
-                            //serializer.Serialize(writer, prop.GetValue(value, null));
-                            this.Serialize(prop.GetValue(value, null), writeStream, writer, serializer, aggregator);
-                            break;
+                        writer.WriteNull();
+                    }
+                    else
+                    {
+                        string objId = GetIdFor(propertyValue);
+
+                        switch (sa)
+                        {
+                            case SerializeAsOptions.Ids:
+                                //writer.WritePropertyName(ContractResolver.FormatPropertyName(prop.Name));
+                                serializer.Serialize(writer, objId);
+                                if (iip)
+                                    if (aggregator != null)
+                                        aggregator.Add(prop.PropertyType, prop.GetValue(value, null));
+                                break;
+                            case SerializeAsOptions.Link:
+                                if (lt == null)
+                                    throw new JsonSerializationException(
+                                        "A property was decorated with SerializeAs(SerializeAsOptions.Link) but no LinkTemplate attribute was provided.");
+                                string link = String.Format(lt, objId,
+                                    value.GetType().GetProperty("Id").GetValue(value, null));
+                                //writer.WritePropertyName(ContractResolver.FormatPropertyName(prop.Name));
+                                writer.WriteValue(link);
+                                break;
+                            case SerializeAsOptions.Embedded:
+                                // Not really supported by Ember Data yet, incidentally...but easy to implement here.
+                                //writer.WritePropertyName(ContractResolver.FormatPropertyName(prop.Name));
+                                //serializer.Serialize(writer, prop.GetValue(value, null));
+                                this.Serialize(prop.GetValue(value, null), writeStream, writer, serializer, aggregator);
+                                break;
+                        }
                     }
                 }