ConfigReader.cs

public class ConfigReader
{
    private readonly string _configFilePath;

    // Constructor that initializes the config file path
    public ConfigReader(string configFilePath = "appsettings.json")
    {
        _configFilePath = configFilePath;
    }

    /// <summary>
    /// Reads a key from the appsettings.json file.
    /// </summary>
    /// <param name="key">The key to search for in appsettings.json.</param>
    /// <returns>The value of the key from appsettings.json or null if not found.</returns>
    public string GetAppSetting(string key)
    {
        // Check if the file exists
        if (!File.Exists(_configFilePath))
        {
            return null; // Return null if the file is not found
        }

        try
        {
            // Read the content of the appsettings.json file
            var jsonContent = File.ReadAllText(_configFilePath);

            // Deserialize the JSON content into a dictionary
            var jsonObject = DeserializeJson<Dictionary<string, object>>(jsonContent);

            // Check if the key exists and return the value
            if (jsonObject.ContainsKey(key))
            {
                return jsonObject[key]?.ToString();
            }
        }
        catch (Exception)
        {
            return null; // Return null if an error occurs during reading or deserialization
        }

        return null; // Return null if the key is not found
    }

    /// <summary>
    /// Reads a connection string from the appsettings.json file.
    /// </summary>
    /// <param name="name">The name of the connection string to retrieve.</param>
    /// <returns>The connection string value or null if not found.</returns>
    public string GetConnectionString(string name)
    {
        // Check if the file exists
        if (!File.Exists(_configFilePath))
        {
            return null; // Return null if the file is not found
        }

        try
        {
            // Read the content of the appsettings.json file
            var jsonContent = File.ReadAllText(_configFilePath);

            // Deserialize the JSON content into a dictionary
            var jsonObject = DeserializeJson<Dictionary<string, object>>(jsonContent);

            // Check if the "ConnectionStrings" section exists
            if (jsonObject.ContainsKey("ConnectionStrings"))
            {
                var connectionStrings = jsonObject["ConnectionStrings"] as Dictionary<string, object>;

                // If connection strings exist, try to retrieve the connection string by name
                if (connectionStrings != null && connectionStrings.ContainsKey(name))
                {
                    return connectionStrings[name]?.ToString();
                }
            }
        }
        catch (Exception)
        {
            return null; // Return null if an error occurs during reading or deserialization
        }

        return null; // Return null if the connection string is not found
    }

    /// <summary>
    /// Helper method to deserialize JSON content into a specified object type.
    /// </summary>
    /// <typeparam name="T">The type to deserialize the JSON content into.</typeparam>
    /// <param name="jsonContent">The JSON content as a string.</param>
    /// <returns>The deserialized object.</returns>
    private T DeserializeJson<T>(string jsonContent)
    {
        using (var memoryStream = new MemoryStream(Encoding.UTF8.GetBytes(jsonContent)))
        {
            var serializer = new DataContractJsonSerializer(typeof(T));
            return (T)serializer.ReadObject(memoryStream);
        }
    }
}