UA-.NETStandard/Libraries/Opc.Ua.Gds.Server.Common/ApplicationsDatabase/JsonApplicationsDatabase.cs

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 *
 * OPC Foundation MIT License 1.00
 *
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 * obtaining a copy of this software and associated documentation
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using System;
using System.IO;
using System.Text.Json;
using System.Text.Json.Serialization;

namespace Opc.Ua.Gds.Server.Database.Linq
{
    /// <summary>
    /// A GDS database with JSON storage.
    /// </summary>
    /// <remarks>
    /// This db is good for testing but not for production use.
    /// </remarks>
    public class JsonApplicationsDatabase : LinqApplicationsDatabase
    {
        /// <summary>
        /// Create a JSON database.
        /// </summary>
        public JsonApplicationsDatabase(string fileName)
        {
            FileName = fileName;
        }

        /// <summary>
        /// Load the JSON application database.
        /// </summary>
        /// <exception cref="ArgumentNullException"><paramref name="fileName"/> is <c>null</c>.</exception>
        public static JsonApplicationsDatabase Load(string fileName)
        {
            if (fileName == null)
            {
                throw new ArgumentNullException(nameof(fileName));
            }

            try
            {
                if (File.Exists(fileName))
                {
                    string json = File.ReadAllText(fileName);
                    JsonApplicationsDatabase? db =
                        JsonSerializer.Deserialize(json, GdsApplicationsDatabaseJsonContext.Default.JsonApplicationsDatabase);
                    if (db != null)
                    {
                        db.FileName = fileName;
                        return db;
                    }
                }
            }
            catch
            {
            }
            return new JsonApplicationsDatabase(fileName);
        }

        /// <summary>
        /// Save the complete database.
        /// </summary>
        public override void Save()
        {
            string json = JsonSerializer.Serialize(
                this, GdsApplicationsDatabaseJsonContext.Default.JsonApplicationsDatabase);
            File.WriteAllText(FileName, json);
        }

        /// <summary>
        /// Get or set the filename.
        /// </summary>
        [JsonIgnore]
        public string FileName { get; private set; }
    }

    [JsonSerializable(typeof(JsonApplicationsDatabase))]
    [JsonSourceGenerationOptions(
        WriteIndented = true,
        DefaultIgnoreCondition = JsonIgnoreCondition.Never,
        IncludeFields = false)]
    internal partial class GdsApplicationsDatabaseJsonContext : JsonSerializerContext;
}