PluginStateStore.cs

using System.Text.Json;

namespace SecRandom.ExamplePlugin;

/// <summary>
///     演示插件的运行时状态。
/// </summary>
public sealed class PluginState
{
    /// <summary>插件被加载的次数。</summary>
    public int LoadCount { get; set; }

    /// <summary>最近一次写入状态的时间。</summary>
    public DateTimeOffset? LastUpdated { get; set; }

    /// <summary>最近一次操作留下的说明，便于在设置页展示。</summary>
    public string LastMessage { get; set; } = string.Empty;
}

/// <summary>
///     演示如何在插件的专属配置目录中读写自己的数据。
///     <para>
///         <see cref="SecRandom.Core.Plugins.PluginBase.PluginConfigFolder" /> 由宿主在加载插件时创建，
///         每个插件一个目录，通常位于 <c>data/config/plugins/&lt;插件 id&gt;</c>。
///         插件不应把数据写到主程序目录的其他位置。
///     </para>
/// </summary>
public sealed class PluginStateStore
{
    private static readonly JsonSerializerOptions SerializerOptions = new()
    {
        WriteIndented = true
    };

    private readonly string _filePath;
    private readonly object _gate = new();

    public PluginStateStore(string configFolder)
    {
        _filePath = Path.Combine(configFolder, "state.json");
    }

    /// <summary>状态文件的绝对路径，便于在设置页展示，方便排查问题。</summary>
    public string FilePath => _filePath;

    public PluginState Load()
    {
        lock (_gate)
        {
            try
            {
                if (!File.Exists(_filePath))
                    return new PluginState();

                var json = File.ReadAllText(_filePath);
                return JsonSerializer.Deserialize<PluginState>(json, SerializerOptions) ?? new PluginState();
            }
            catch (Exception)
            {
                // 状态文件损坏不影响插件加载，退回默认值。
                return new PluginState();
            }
        }
    }

    public void Save(PluginState state)
    {
        lock (_gate)
        {
            state.LastUpdated = DateTimeOffset.Now;

            var directory = Path.GetDirectoryName(_filePath);
            if (!string.IsNullOrEmpty(directory))
                Directory.CreateDirectory(directory);

            File.WriteAllText(_filePath, JsonSerializer.Serialize(state, SerializerOptions));
        }
    }
}