Add null check to Json.Get<T> (#199)

add null check to Json.Get<T>

Author: shacharPash

src/NRedisStack/Json/JsonCommands.cs

@@ -225,7 +225,7 @@ public RedisResult Get(RedisKey key, string[] paths, RedisValue? indent = null,
     public T? Get<T>(RedisKey key, string path = "$", JsonSerializerOptions? serializerOptions = default)
     {
         var res = _db.Execute(JsonCommandBuilder.Get<T>(key, path));
-        if (res.Type == ResultType.BulkString)
+        if (res.Type == ResultType.BulkString && !res.IsNull)
         {
             var arr = JsonSerializer.Deserialize<JsonArray>(res.ToString()!);
             if (arr?.Count > 0)

src/NRedisStack/Json/JsonCommandsAsync.cs

@@ -81,7 +81,7 @@ public async Task<RedisResult> GetAsync(RedisKey key, string[] paths, RedisValue
     public async Task<T?> GetAsync<T>(RedisKey key, string path = "$", JsonSerializerOptions? serializerOptions = default)
     {
         var res = await _db.ExecuteAsync(JsonCommandBuilder.Get<T>(key, path));
-        if (res.Type == ResultType.BulkString)
+        if (res.Type == ResultType.BulkString && !res.IsNull)
         {
             var arr = JsonSerializer.Deserialize<JsonArray>(res.ToString()!);
             if (arr?.Count > 0)

tests/NRedisStack.Tests/Json/JsonTests.cs

@@ -1118,4 +1118,38 @@ public void TestJsonCommandBuilder()
         }
         Assert.Equal("JSON.GET", getBuild2.Command);
     }
+
+    [Fact]
+    public void TestGetIssue198()
+    {
+        var commands = new JsonCommands(redisFixture.Redis.GetDatabase());
+        var keys = CreateKeyNames(1);
+        var key = keys[0];
+        commands.Set(key, "$", new Person() { Age = 35, Name = "Alice" });
+
+        // Path not found:
+        var result = commands.Get<Person>(key, "$.a"); // returns "[]" because the path is not found (but the key is)
+        // Key not found:
+        var result2 = commands.Get<Person>("notExistKey", "$.a"); // returns (nil) because the key is not found
+
+        Assert.Null(result);
+        Assert.Null(result2);
+    }
+
+    [Fact]
+    public async Task TestGetIssue198_Async()
+    {
+        var commands = new JsonCommandsAsync(redisFixture.Redis.GetDatabase());
+        var keys = CreateKeyNames(1);
+        var key = keys[0];
+        await commands.SetAsync(key, "$", new Person() { Age = 35, Name = "Alice" });
+
+        // Path not found:
+        var result = await commands.GetAsync<Person>(key, "$.a"); // returns "[]" because the path is not found (but the key is)
+        // Key not found:
+        var result2 = await commands.GetAsync<Person>("notExistKey", "$.a"); // returns (nil) because the key is not found
+
+        Assert.Null(result);
+        Assert.Null(result2);
+    }
 }