自定义Configuration配置源
实现自定义配置源至少需要添加如下成员：[*]实现IConfigurationSource接口的配置源；
[*]实现IConfigurationProvider接口或虚基类ConfigurationProvider的配置提供程序；
[*]添加配置源的IConfigurationBuilder扩展方法；
如自定义一个TXT文本文件配置源：
添加配置源
配置源负责创建配置提供程序，以及监听文件修改。监听文件修改可以使用FileSystemWatcher，通过监听Changed事件监听配置文件的修改。使用ConfigurationReloadToken作为IChangeToken，当监听到文件修改时调用取消令牌的取消操作，进而通知订阅者文件已更改。
public class TxtConfigurationSource : IConfigurationSource, IDisposable
{
private FileSystemWatcher? _fileWatcher;
private ConfigurationReloadToken _reloadToken;
public TxtConfigurationSource(string path, bool reloadOnChange = true)
{
FilePath = path;
ReloadOnChange = reloadOnChange;
_fileWatcher = new FileSystemWatcher(Directory.GetCurrentDirectory());
_fileWatcher.Filter = "*.txt";
_fileWatcher.EnableRaisingEvents = true;
_fileWatcher.Changed += _fileWatcher_Changed;
_reloadToken = new ConfigurationReloadToken();
}
private void _fileWatcher_Changed(object sender, FileSystemEventArgs e)
{
if (e.FullPath != FilePath)
return;
if (_reloadToken.HasChanged)
return;
// 触发事件
ConfigurationReloadToken previousToken = Interlocked.Exchange(ref _reloadToken,
new ConfigurationReloadToken());
previousToken.OnReload();
}
public bool ReloadOnChange { get; set; }
public string FilePath { get; set; }
public IConfigurationProvider Build(IConfigurationBuilder builder)
{
return new TxtConfigurationProvider(this);
}
public IChangeToken GetChangeToken() => _reloadToken;
public void Dispose() => Dispose(true);
protected virtual void Dispose(bool disposing)
{
_fileWatcher?.Dispose();
}
}添加配置提供程序
配置提供程序负责加载配置文件，并订阅配置源中的配置修改事件。通过ChangeToken.OnChange()方法进行事件订阅，当监听到文件改变时，重新加载文件：
public class TxtConfigurationProvider : ConfigurationProvider, IDisposable
{
private readonly IDisposable _changeTokenRegistration;
public TxtConfigurationProvider(TxtConfigurationSource source)
:base()
{
Source = source ?? throw new ArgumentNullException(nameof(source));
if (Source.ReloadOnChange)
{
_changeTokenRegistration = ChangeToken.OnChange(
() => Source.GetChangeToken(),
() =>
{
Thread.Sleep(300);
Load();
});
}
}
public TxtConfigurationSource Source { get; }
public override void Load()
{
if (!File.Exists(Source.FilePath))
return;
else
{
Data = new Dictionary<string, string>(StringComparer.OrdinalIgnoreCase);
var lines = File.ReadAllLines(Source.FilePath);
foreach (var line in lines)
{
var array = line.Replace("：", ":").Split(':');
if (array.Length < 2)
continue;
Data.Add(line.Substring(0, line.LastIndexOf(':')), array.Last());
}
}
OnReload();
}
public void Dispose() => Dispose(true);
protected virtual void Dispose(bool disposing)
{
_changeTokenRegistration?.Dispose();
}
}添加配置源扩展方法
添加IConfigurationBuilder扩展方法，方便将自定义配置源添加到IConfigurationBuilder中：
public static IConfigurationBuilder AddTxtFile(this IConfigurationBuilder builder,
string path, bool reloadOnChange)
{
if (builder == null)
throw new ArgumentNullException(nameof(builder));
if (string.IsNullOrEmpty(path))
throw new ArgumentException($"文件不能为空：{nameof(path)}");
return builder.Add(new TxtConfigurationSource(path, reloadOnChange));
}使用
首先通过扩展方法添加配置源，调用IConfigurationBuilder.Build()方法后即可通过IConfiguration获取配置项。通过ChangeToken.OnChange()方法订阅配置修改事件。
using ConfigurationTest;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.Primitives;
IConfigurationBuilder configurationBuilder = new ConfigurationBuilder()
.AddTxtFile(Path.Combine(Directory.GetCurrentDirectory(), "config.txt"), reloadOnChange: true);
// 通过IConfiguration直接读取指定配置
IConfiguration configuration = configurationBuilder.Build();
Console.WriteLine($"FileProvider:Source:{configuration.GetSection("FileProvider:Source").Value}");
Console.WriteLine($"Provider:{configuration["FileProvider:Provider"]}");
Console.WriteLine();
// 通过绑定选项获取配置
FileProviderOptions fileProviderOptions = new FileProviderOptions();
configuration.GetSection("FileProvider").Bind(fileProviderOptions);
Console.WriteLine($"FileProvider.Source = {fileProviderOptions.Source}");
Console.WriteLine($"FileProvider.Provider = {fileProviderOptions.Provider}");
Console.WriteLine();
// 监听配置修改
var disable = ChangeToken.OnChange(() => configuration.GetReloadToken(),
() =>
{
foreach (var section in configuration.GetChildren())
{
PrintAllConfig(section);
}
Console.WriteLine();
Console.WriteLine("按“q”退出");
});
Console.WriteLine("按“q”退出");
while (Console.ReadLine() != "q")
{
}
disable.Dispose();
void PrintAllConfig(IConfigurationSection config)
{
var sections = config.GetChildren();
if(sections == null || sections.Count() == 0)
Console.WriteLine($"{config.Key} : {config.Value}");
else
{
foreach (var section in sections)
{
PrintAllConfig(section);
}
}
}
class FileProviderOptions
{
public string Source { get; set; }
public string Provider { get; set; }
}// config.txt
FileProvider:Source:TxtSource
FileProvider:Provider:TxtProvider
来源:https://www.cnblogs.com/louzixl/archive/2023/12/02/17871159.html
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