dotnet/src/webdriver/Response.cs

// <copyright file="Response.cs" company="Selenium Committers">
// Licensed to the Software Freedom Conservancy (SFC) under one
// or more contributor license agreements.  See the NOTICE file
// distributed with this work for additional information
// regarding copyright ownership.  The SFC licenses this file
// to you under the Apache License, Version 2.0 (the
// "License"); you may not use this file except in compliance
// with the License.  You may obtain a copy of the License at
//
//   http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing,
// software distributed under the License is distributed on an
// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
// KIND, either express or implied.  See the License for the
// specific language governing permissions and limitations
// under the License.
// </copyright>

using OpenQA.Selenium.Internal;
using System;
using System.Collections.Generic;
using System.Globalization;
using System.Text.Json;
using System.Text.Json.Serialization;

namespace OpenQA.Selenium
{
    /// <summary>
    /// Handles reponses from the browser
    /// </summary>
    public class Response
    {
        private static readonly JsonSerializerOptions s_jsonSerializerOptions = new()
        {
            TypeInfoResolver = ResponseJsonSerializerContext.Default,
            Converters = { new ResponseValueJsonConverter() } // we still need it to make `Object` as `Dictionary`
        };

        /// <summary>
        /// Initializes a new instance of the <see cref="Response"/> class
        /// </summary>
        public Response()
        {
        }

        /// <summary>
        /// Initializes a new instance of the <see cref="Response"/> class
        /// </summary>
        /// <param name="sessionId">Session ID in use</param>
        public Response(SessionId sessionId)
        {
            if (sessionId != null)
            {
                this.SessionId = sessionId.ToString();
            }
        }

        /// <summary>
        /// Returns a new <see cref="Response"/> from a JSON-encoded string.
        /// </summary>
        /// <param name="value">The JSON string to deserialize into a <see cref="Response"/>.</param>
        /// <returns>A <see cref="Response"/> object described by the JSON string.</returns>
        public static Response FromJson(string value)
        {
            Dictionary<string, object> rawResponse = JsonSerializer.Deserialize<Dictionary<string, object>>(value, s_jsonSerializerOptions)
                ?? throw new WebDriverException("JSON success response returned \"null\" value");

            var response = new Response();

            if (rawResponse.ContainsKey("sessionId"))
            {
                if (rawResponse["sessionId"] != null)
                {
                    response.SessionId = rawResponse["sessionId"].ToString();
                }
            }

            if (rawResponse.TryGetValue("value", out object valueObj))
            {
                response.Value = valueObj;
            }

            // 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") && response.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"))
                {
                    response.Value = rawResponse["capabilities"];
                }
                else
                {
                    response.Value = rawResponse;
                }
            }

            if (response.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"))
                {
                    response.SessionId = valueDictionary["sessionId"].ToString();
                    if (valueDictionary.TryGetValue("capabilities", out object capabilities))
                    {
                        response.Value = capabilities;
                    }
                    else
                    {
                        response.Value = valueDictionary["value"];
                    }
                }
            }

            return response;
        }

        /// <summary>
        /// Gets or sets the value from JSON.
        /// </summary>
        public object Value { get; set; }

        /// <summary>
        /// Gets or sets the session ID.
        /// </summary>
        public string SessionId { get; set; }

        /// <summary>
        /// Gets or sets the status value of the response.
        /// </summary>
        public WebDriverResult Status { get; set; }


        /// <summary>
        /// Returns a new <see cref="Response"/> from a JSON-encoded string.
        /// </summary>
        /// <param name="value">The JSON string to deserialize into a <see cref="Response"/>.</param>
        /// <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)
                ?? throw new WebDriverException("JSON error response returned \"null\" value");

            var response = new Response();

            if (!deserializedResponse.TryGetValue("value", out var valueObject))
            {
                throw new WebDriverException($"The 'value' property was not found in the response:{Environment.NewLine}{value}");
            }

            if (valueObject is not Dictionary<string, object> valueDictionary)
            {
                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 errorString)
            {
                throw new WebDriverException($"The 'value > error' property is not a string{Environment.NewLine}{value}");
            }

            response.Value = deserializedResponse["value"];

            response.Status = WebDriverError.ResultFromError(errorString);

            return response;
        }

        /// <summary>
        /// Returns this object as a JSON-encoded string.
        /// </summary>
        /// <returns>A JSON-encoded string representing this <see cref="Response"/> object.</returns>
        public string ToJson()
        {
            return JsonSerializer.Serialize(this);
        }

        /// <summary>
        /// Returns the object as a string.
        /// </summary>
        /// <returns>A string with the Session ID, status value, and the value from JSON.</returns>
        public override string ToString()
        {
            return string.Format(CultureInfo.InvariantCulture, "({0} {1}: {2})", this.SessionId, this.Status, this.Value);
        }
    }

    [JsonSerializable(typeof(Dictionary<string, object>))]
    internal sealed partial class ResponseJsonSerializerContext : JsonSerializerContext;
}