[dotnet] Modernize Response type

dotnet/src/webdriver/Response.cs

@@ -31,16 +31,12 @@ namespace OpenQA.Selenium
     /// </summary>
     public class Response
     {
-        private readonly static JsonSerializerOptions s_jsonSerializerOptions = new()
+        private static readonly JsonSerializerOptions s_jsonSerializerOptions = new()
         {
             TypeInfoResolver = ResponseJsonSerializerContext.Default,
             Converters = { new ResponseValueJsonConverter() } // we still need it to make `Object` as `Dictionary`
         };
 
-        private object responseValue;
-        private string responseSessionId;
-        private WebDriverResult responseStatus;
-
         /// <summary>
         /// Initializes a new instance of the <see cref="Response"/> class
         /// </summary>
@@ -56,59 +52,65 @@ public Response(SessionId sessionId)
         {
             if (sessionId != null)
             {
-                this.responseSessionId = sessionId.ToString();
+                this.SessionId = sessionId.ToString();
             }
         }
 
+        internal Response(SessionId sessionId, WebDriverResult status, object value)
+        {
+            this.SessionId = sessionId?.ToString();
+            this.Status = status;
+            this.Value = value;
+        }
+
         private Response(Dictionary<string, object> rawResponse)
         {
             if (rawResponse.ContainsKey("sessionId"))
             {
                 if (rawResponse["sessionId"] != null)
                 {
-                    this.responseSessionId = rawResponse["sessionId"].ToString();
+                    this.SessionId = rawResponse["sessionId"].ToString();
                 }
             }
 
-            if (rawResponse.ContainsKey("value"))
+            if (rawResponse.TryGetValue("value", out object value))
             {
-                this.responseValue = rawResponse["value"];
+                this.Value = value;
             }
 
             // If the returned object does *not* have a "value" property
             // the response value should be the entirety of the response.
             // TODO: Remove this if statement altogether; there should
             // never be a spec-compliant response that does not contain a
             // value property.
-            if (!rawResponse.ContainsKey("value") && this.responseValue == null)
+            if (!rawResponse.ContainsKey("value") && this.Value == null)
             {
                 // Special-case for the new session command, where the "capabilities"
                 // property of the response is the actual value we're interested in.
                 if (rawResponse.ContainsKey("capabilities"))
                 {
-                    this.responseValue = rawResponse["capabilities"];
+                    this.Value = rawResponse["capabilities"];
                 }
                 else
                 {
-                    this.responseValue = rawResponse;
+                    this.Value = rawResponse;
                 }
             }
 
-            Dictionary<string, object> valueDictionary = this.responseValue as Dictionary<string, object>;
-            if (valueDictionary != null)
+            if (this.Value is Dictionary<string, object> valueDictionary)
             {
                 // Special case code for the new session command. If the response contains
                 // sessionId and capabilities properties, fix up the session ID and value members.
                 if (valueDictionary.ContainsKey("sessionId"))
                 {
-                    this.responseSessionId = valueDictionary["sessionId"].ToString();
-                    if (valueDictionary.ContainsKey("capabilities"))
+                    this.SessionId = valueDictionary["sessionId"].ToString();
+                    if (valueDictionary.TryGetValue("capabilities", out object capabilities))
                     {
-                        this.responseValue = valueDictionary["capabilities"];
+                        this.Value = capabilities;
                     }
                     else
                     {
-                        this.responseValue = valueDictionary["value"];
+                        this.Value = valueDictionary["value"];
                     }
                 }
             }
@@ -117,29 +119,17 @@ private Response(Dictionary<string, object> rawResponse)
         /// <summary>
         /// Gets or sets the value from JSON.
         /// </summary>
-        public object Value
-        {
-            get { return this.responseValue; }
-            set { this.responseValue = value; }
-        }
+        public object Value { get; set; }
 
         /// <summary>
         /// Gets or sets the session ID.
         /// </summary>
-        public string SessionId
-        {
-            get { return this.responseSessionId; }
-            set { this.responseSessionId = value; }
-        }
+        public string SessionId { get; set; }
 
         /// <summary>
         /// Gets or sets the status value of the response.
         /// </summary>
-        public WebDriverResult Status
-        {
-            get { return this.responseStatus; }
-            set { this.responseStatus = value; }
-        }
+        public WebDriverResult Status { get; set; }
 
         /// <summary>
         /// Returns a new <see cref="Response"/> from a JSON-encoded string.
@@ -148,9 +138,10 @@ public WebDriverResult Status
         /// <returns>A <see cref="Response"/> object described by the JSON string.</returns>
         public static Response FromJson(string value)
         {
-            Dictionary<string, object> deserializedResponse = JsonSerializer.Deserialize<Dictionary<string, object>>(value, s_jsonSerializerOptions);
-            Response response = new Response(deserializedResponse);
-            return response;
+            Dictionary<string, object> deserializedResponse = JsonSerializer.Deserialize<Dictionary<string, object>>(value, s_jsonSerializerOptions)
+                ?? throw new WebDriverException("JSON success response returned \"null\" value");
+
+            return new Response(deserializedResponse);
         }
 
         /// <summary>
@@ -160,9 +151,8 @@ public static Response FromJson(string value)
         /// <returns>A <see cref="Response"/> object described by the JSON string.</returns>
         public static Response FromErrorJson(string value)
         {
-            var deserializedResponse = JsonSerializer.Deserialize<Dictionary<string, object>>(value, s_jsonSerializerOptions);
-
-            var response = new Response();
+            var deserializedResponse = JsonSerializer.Deserialize<Dictionary<string, object>>(value, s_jsonSerializerOptions)
+                ?? throw new WebDriverException("JSON error response returned \"null\" value");
 
             if (!deserializedResponse.TryGetValue("value", out var valueObject))
             {
@@ -174,23 +164,19 @@ public static Response FromErrorJson(string value)
                 throw new WebDriverException($"The 'value' property is not a dictionary of <string, object>{Environment.NewLine}{value}");
             }
 
-            response.Value = valueDictionary;
-
             if (!valueDictionary.TryGetValue("error", out var errorObject))
             {
                 throw new WebDriverException($"The 'value > error' property was not found in the response:{Environment.NewLine}{value}");
             }
 
-            if (errorObject is not string)
+            if (errorObject is not string errorString)
             {
                 throw new WebDriverException($"The 'value > error' property is not a string{Environment.NewLine}{value}");
             }
 
-            response.Value = deserializedResponse["value"];
+            var status = WebDriverError.ResultFromError(errorString);
 
-            response.Status = WebDriverError.ResultFromError(errorObject.ToString());
-
-            return response;
+            return new Response(sessionId: null, status, valueDictionary);
         }
 
         /// <summary>
@@ -213,8 +199,5 @@ public override string ToString()
     }
 
     [JsonSerializable(typeof(Dictionary<string, object>))]
-    internal partial class ResponseJsonSerializerContext : JsonSerializerContext
-    {
-
-    }
+    internal sealed partial class ResponseJsonSerializerContext : JsonSerializerContext;
 }

dotnet/src/webdriver/WebDriver.cs

@@ -622,11 +622,7 @@ protected virtual async Task<Response> ExecuteAsync(string driverCommandToExecut
             }
             catch (System.Net.Http.HttpRequestException e)
             {
-                commandResponse = new Response
-                {
-                    Status = WebDriverResult.UnhandledError,
-                    Value = e
-                };
+                commandResponse = new Response(sessionId: null, WebDriverResult.UnhandledError, e);
             }
 
             if (commandResponse.Status != WebDriverResult.Success)