birbmap/MQTTnet.TestApp.WinForm/JsonServerStorage.cs

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2020-11-08 18:51:19 +01:00
// --------------------------------------------------------------------------------------------------------------------
// <copyright file="JsonServerStorage.cs" company="Haemmer Electronics">
// Copyright (c) 2020 All rights reserved.
// </copyright>
// <summary>
// The JSON server storage.
// </summary>
// --------------------------------------------------------------------------------------------------------------------
namespace MQTTnet.TestApp.WinForm
{
using System.Collections.Generic;
using System.IO;
using System.Threading.Tasks;
using MQTTnet.Server;
using Newtonsoft.Json;
/// <inheritdoc cref="IMqttServerStorage"/>
/// <summary>
/// The JSON server storage.
/// </summary>
/// <seealso cref="IMqttServerStorage"/>
public class JsonServerStorage : IMqttServerStorage
{
/// <summary>
/// The file name.
/// </summary>
private readonly string filename = Path.Combine(Directory.GetCurrentDirectory(), "Retained.json");
/// <summary>
/// Clears the file.
/// </summary>
public void Clear()
{
if (File.Exists(this.filename))
{
File.Delete(this.filename);
}
}
/// <inheritdoc cref="IMqttServerStorage"/>
/// <summary>
/// Loads the retained messages.
/// </summary>
/// <returns>A <see cref="IList{T}"/> of <see cref="MqttApplicationMessage"/>.</returns>
/// <seealso cref="IMqttServerStorage"/>
public async Task<IList<MqttApplicationMessage>> LoadRetainedMessagesAsync()
{
await Task.CompletedTask;
if (!File.Exists(this.filename))
{
return new List<MqttApplicationMessage>();
}
try
{
var json = await File.ReadAllTextAsync(this.filename);
return JsonConvert.DeserializeObject<List<MqttApplicationMessage>>(json);
}
catch
{
return new List<MqttApplicationMessage>();
}
}
/// <inheritdoc cref="IMqttServerStorage"/>
/// <summary>
/// Saves the retained messages to a file.
/// </summary>
/// <param name="messages">The messages.</param>
/// <returns>A <see cref="Task"/> representing any asynchronous operation.</returns>
/// <seealso cref="IMqttServerStorage"/>
public async Task SaveRetainedMessagesAsync(IList<MqttApplicationMessage> messages)
{
await Task.CompletedTask;
var json = JsonConvert.SerializeObject(messages);
await File.WriteAllTextAsync(this.filename, json);
}
}
}