Implement IS_NULL operator and INTEGER value type

dot-net-sdk/EppoClient.cs

@@ -40,6 +40,12 @@ private EppoClient(ConfigurationStore configurationStore, EppoClientConfig eppoC
     }
 
 
+    public int? GetIntegerAssignment(string subjectKey, string flagKey, SubjectAttributes? subjectAttributes = null)
+    {
+        return GetAssignment(subjectKey, flagKey, subjectAttributes ?? new SubjectAttributes())?.IntegerValue();
+    }
+
+
     public string? GetStringAssignment(string subjectKey, string flagKey, SubjectAttributes? subjectAttributes = null)
     {
         return GetAssignment(subjectKey, flagKey, subjectAttributes ?? new SubjectAttributes())?.StringValue();
@@ -59,7 +65,7 @@ private EppoClient(ConfigurationStore configurationStore, EppoClientConfig eppoC
         }
 
         var subjectVariationOverride = this.GetSubjectVariationOverride(subjectKey, configuration);
-        if (!subjectVariationOverride.isNull())
+        if (!subjectVariationOverride.IsNull())
         {
             return subjectVariationOverride;
         }

dot-net-sdk/dto/EppoValue.cs

@@ -6,17 +6,25 @@ namespace eppo_sdk.dto;
 [JsonConverter(typeof(EppoValueDeserializer))]
 public class EppoValue
 {
-    public string value { get; set; }
+    public string? value { get; set; }
 
     public EppoValueType type { get; set; } = EppoValueType.NULL;
 
-    public List<string> array { get; set; }
+    public List<string>? array { get; set; }
+
+
+    public static EppoValue Bool(string? value) => new(value, EppoValueType.BOOLEAN);
+    public static EppoValue Bool(bool value) => new(value.ToString(), EppoValueType.BOOLEAN);
+    public static EppoValue Number(string value) => new(value, EppoValueType.NUMBER);
+    public static EppoValue String(string? value) => new(value, EppoValueType.STRING);
+    public static EppoValue Integer(string value) => new(value, EppoValueType.INTEGER);
+    public static EppoValue Null() => new();
 
     public EppoValue()
     {
     }
 
-    public EppoValue(string value, EppoValueType type)
+    public EppoValue(string? value, EppoValueType type)
     {
         this.value = value;
         this.type = type;
@@ -28,38 +36,25 @@ public EppoValue(List<string> array)
         this.type = EppoValueType.ARRAY_OF_STRING;
     }
 
-    public EppoValue(EppoValueType type)
-    {
-        this.type = type;
-    }
+    public EppoValue(EppoValueType type) => this.type = type;
 
-    public bool BoolValue()
-    {
-        return bool.Parse(value);
-    }
+    public bool BoolValue() => bool.Parse(value);
 
-    public double DoubleValue()
-    {
-        return double.Parse(value, NumberStyles.Number);
-    }
+    public double DoubleValue() => double.Parse(value, NumberStyles.Number);
 
-    public bool isNumeric()
-    {
-        return double.TryParse(value, out _);
-    }
+    public int IntegerValue() => int.Parse(value, NumberStyles.Number);
 
-    public string StringValue()
-    {
-        return value;
-    }
+    public bool IsNumeric() => double.TryParse(value, out _);
 
-    public List<string> ArrayValue()
-    {
-        return array;
-    }
+    public string StringValue() => value;
 
-    public bool isNull()
-    {
-        return EppoValueType.NULL.Equals(type);
-    }
-}
+    public List<string> ArrayValue() => array;
+
+    public bool IsNull() => EppoValueType.NULL.Equals(type);
+
+    public static bool IsNullValue(EppoValue? value) =>
+     value == null /* null pointer */ ||
+         value.IsNull() /* parsed as a null JSON token type */ ||
+         value.value == null; /* Value type is set but value is null */
+
+}

dot-net-sdk/dto/EppoValueDeserializer.cs

@@ -18,14 +18,15 @@ public override void WriteJson(JsonWriter writer, EppoValue? value, JsonSerializ
         switch (reader.TokenType)
         {
             case JsonToken.String:
-                return new EppoValue(value.ToString(), EppoValueType.STRING);
+                return EppoValue.String(value.ToString());
             case JsonToken.Integer:
+                return EppoValue.Integer(value.ToString());
             case JsonToken.Float:
-                return new EppoValue(value.ToString(), EppoValueType.NUMBER);
+                return EppoValue.Number(value.ToString());
             case JsonToken.Boolean:
-                return new EppoValue(value.ToString(), EppoValueType.BOOLEAN);
+                return EppoValue.Bool(value.ToString());
             case JsonToken.Null:
-                return new EppoValue(EppoValueType.NULL);
+                return EppoValue.Null();
             case JsonToken.StartArray:
                 var val = new List<string>();
                 reader.Read();
@@ -36,7 +37,7 @@ public override void WriteJson(JsonWriter writer, EppoValue? value, JsonSerializ
                 }
                 return new EppoValue(val);
             default:
-                throw new UnsupportedEppoValueException("Unsupported Eppo Values");
+                throw new UnsupportedEppoValueException("Unsupported Eppo Value Type: " + reader.TokenType.ToString());
         }
     }
 }

dot-net-sdk/dto/EppoValueType.cs

@@ -3,6 +3,7 @@ namespace eppo_sdk.dto;
 public enum EppoValueType
 {
     NUMBER,
+    INTEGER,
     STRING,
     BOOLEAN,
     NULL,

dot-net-sdk/dto/OperatorType.cs

@@ -12,5 +12,6 @@ public enum OperatorType
     LTE,
     LT,
     ONE_OF,
-    NOT_ONE_OF
+    NOT_ONE_OF,
+    IS_NULL
 }

dot-net-sdk/http/ExperimentConfigurationRequester.cs

@@ -15,20 +15,15 @@ public ExperimentConfigurationRequester(EppoHttpClient eppoHttpClient) {
 
     public ExperimentConfigurationResponse? FetchExperimentConfiguration()
     {
-        ExperimentConfigurationResponse? config = null;
         try
         {
             return this.eppoHttpClient.Get(Constants.RAC_ENDPOINT);
         }
-        catch (UnauthorizedAccessException e)
-        {
-            throw e;
-        }
         catch (Exception e)
         {
             logger.Warn($"Unable to Fetch Experiment Configuration: {e.Message}");
         }
 
-        return config;
+        return null;
     }
 }

dot-net-sdk/validators/RuleValidator.cs

@@ -28,14 +28,18 @@ private static bool EvaluateCondition(SubjectAttributes subjectAttributes, Condi
     {
         try
         {
-            if (subjectAttributes.ContainsKey(condition.attribute) &&
-                subjectAttributes.TryGetValue(condition.attribute, out EppoValue outVal))
+            // Operators other than `IS_NULL` need to assume non-null
+            if (condition.operatorType == IS_NULL) {
+                bool isNull = !subjectAttributes.TryGetValue(condition.attribute, out EppoValue? outVal) || EppoValue.IsNullValue(outVal);
+                return condition.value.BoolValue() == isNull;
+            }
+            else if (subjectAttributes.TryGetValue(condition.attribute, out EppoValue? outVal))
             {
                 var value = outVal!; // Assuming non-null for simplicity, handle nulls as necessary
 
                 if (condition.operatorType == GTE)
                 {
-                    if (value.isNumeric() && condition.value.isNumeric())
+                    if (value.IsNumeric() && condition.value.IsNumeric())
                     {
                         return value.DoubleValue() >= condition.value.DoubleValue();
                     }
@@ -50,7 +54,7 @@ private static bool EvaluateCondition(SubjectAttributes subjectAttributes, Condi
                 }
                 else if (condition.operatorType == GT)
                 {
-                    if (value.isNumeric() && condition.value.isNumeric())
+                    if (value.IsNumeric() && condition.value.IsNumeric())
                     {
                         return value.DoubleValue() > condition.value.DoubleValue();
                     }
@@ -65,7 +69,7 @@ private static bool EvaluateCondition(SubjectAttributes subjectAttributes, Condi
                 }
                 else if (condition.operatorType == LTE)
                 {
-                    if (value.isNumeric() && condition.value.isNumeric())
+                    if (value.IsNumeric() && condition.value.IsNumeric())
                     {
                         return value.DoubleValue() <= condition.value.DoubleValue();
                     }
@@ -80,7 +84,7 @@ private static bool EvaluateCondition(SubjectAttributes subjectAttributes, Condi
                 }
                 else if (condition.operatorType == LT)
                 {
-                    if (value.isNumeric() && condition.value.isNumeric())
+                    if (value.IsNumeric() && condition.value.IsNumeric())
                     {
                         return value.DoubleValue() < condition.value.DoubleValue();
                     }

eppo-sdk-test/EppoClientTest.cs

@@ -64,6 +64,11 @@ public void ShouldValidateAssignments(AssignmentTestCase assignmentTestCase)
                 var numericExpectations = assignmentTestCase.expectedAssignments.ConvertAll(x => x.DoubleValue());
                 Assert.That(GetNumericAssignments(assignmentTestCase), Is.EqualTo(numericExpectations));
 
+                break;
+            case "integer":
+                var intExpectations = assignmentTestCase.expectedAssignments.ConvertAll(x => x.IntegerValue());
+                Assert.That(GetIntegerAssignments(assignmentTestCase), Is.EqualTo(intExpectations));
+
                 break;
             case "string":
                 var stringExpectations = assignmentTestCase.expectedAssignments.ConvertAll(x => x.StringValue());
@@ -99,6 +104,19 @@ public void ShouldValidateAssignments(AssignmentTestCase assignmentTestCase)
             client.GetNumericAssignment(subject, assignmentTestCase.experiment));
     }
 
+    private static List<int?> GetIntegerAssignments(AssignmentTestCase assignmentTestCase)
+    {
+        var client = EppoClient.GetInstance();
+        if (assignmentTestCase.subjectsWithAttributes != null)
+        {
+            return assignmentTestCase.subjectsWithAttributes.ConvertAll(subject => client.GetIntegerAssignment(subject.subjectKey, assignmentTestCase.experiment,
+                subject.subjectAttributes));
+        }
+
+        return assignmentTestCase.subjects.ConvertAll(subject =>
+            client.GetIntegerAssignment(subject, assignmentTestCase.experiment));
+    }
+
     private static List<string?> GetStringAssignments(AssignmentTestCase assignmentTestCase)
     {
         var client = EppoClient.GetInstance();