如何用autofac实现多依赖注入装饰器

本文关键字：注入 依赖 何用 autofac 实现 | 更新日期: 2023-09-27 18:19:58

我想用IOC容器autofac调用MessageStore类。

如何在最新版本的autofac中注册这个装饰器和复合模式？

这段代码结合了composite和decorator模式，并注意SOLID Principal。

我对此感到困惑。我的问题是，这个代码如何定义与autofac

var fileStore = new FileStore(new DirectoryInfo(HostingEnvironment.MapPath("~/file"))); var cacheStore = new CacheStore(fileStore, fileStore); var logStore = new LogStore(cacheStore, cacheStore); var messageStore = new MessageStore(logStore, logStore); messageStore.Save(12, "Hello");

public class FileStore :  IFileLocator, IStoreWriter,IStoreReader
{
    private readonly DirectoryInfo _workingDirectory;
    public FileStore(DirectoryInfo workDirectory)
    {
        if (workDirectory == null)
            throw new ArgumentNullException("workDirectory");
        if (!workDirectory.Exists)
            throw new ArgumentException("Directory not found", "workDirectory");
        _workingDirectory = workDirectory;
    }
    public virtual void Save(int id, string message)
    {
        var path = GetFileInfo(id).FullName;
        File.WriteAllText(path, message);
    }
    public virtual Maybe<string> Read(int id)
    {
        var file = GetFileInfo(id);
        if (!file.Exists)
            return new Maybe<string>();
        var path = file.FullName;
        return new Maybe<string>(File.ReadAllText(path));
    }
    public virtual FileInfo GetFileInfo(int id)
    {
        return new FileInfo(
            Path.Combine(_workingDirectory.FullName, id + ".txt"));
    }
}
public class CacheStore : IStoreWriter, IStoreReader
{
    private readonly ConcurrentDictionary<int, Maybe<string>> _cache;
    private readonly IStoreWriter _writer;
    private readonly IStoreReader _reader;
    public CacheStore(IStoreWriter writer, IStoreReader reader)
    {
        _cache = new ConcurrentDictionary<int, Maybe<string>>();
        _writer = writer;
        _reader = reader;
    }
    public virtual void Save(int id, string message)
    {
        _writer.Save(id, message);
        var m = new Maybe<string>(message);
        _cache.AddOrUpdate(id, m, (i, s) => m);
    }
    public virtual Maybe<string> Read(int id)
    {
        Maybe<string> retVal;
        if (_cache.TryGetValue(id, out retVal))
            return retVal;
        retVal = _reader.Read(id);
        if (retVal.Any())
            _cache.AddOrUpdate(id, retVal, (i, s) => retVal);
        return retVal;
    }
}
public class LogStore :  IStoreWriter, IStoreReader
{
    private readonly IStoreWriter _writer;
    private readonly IStoreReader _reader;
    public LogStore(IStoreWriter writer, IStoreReader reader)
    {
        _writer = writer;
        _reader = reader;
    }
    public void Save(int id, string message)
    {
        Log.Information("Saving message {id}.", id);
        _writer.Save(id, message);
        Log.Information("Saved message {id}.", id);
    }
    public Maybe<string> Read(int id)
    {
        Log.Debug("Reading message {id}.", id);
        var retVal = _reader.Read(id);
        if (retVal.Any())
            Log.Debug("Returning message {id}.", id);
        else
            Log.Debug("No message {id} found.", id);
        return retVal;
    }
}
 public class MessageStore
{
    private readonly IStoreWriter _writer;
    private readonly IStoreReader _reader;
    public MessageStore(IStoreWriter writer, IStoreReader reader)
    {
        if (writer == null)
            throw new ArgumentNullException("writer");
        if (reader == null)
            throw new ArgumentNullException("reader");
        _writer = writer;
        _reader = reader;
    }
    public void Save(int id, string message)
    {
        _writer.Save(id, message);
    }
    public Maybe<string> Read(int id)
    {
        return _reader.Read(id);
    }
}

如何用autofac实现多依赖注入装饰器

假设您的所有商店都实现并使用IStoreReader和IStoreWriter，您可以将它们组合到一个IStore接口中，从而使事情变得更简单。这可以是定义Save和Read方法的单个接口，也可以根据需要继承现有的IStoreReader和IStoreWriter接口。

然后，您可以将FileStore（它似乎是主要实现）注册为键控服务。然后使用RegisterDecorator来注册缓存和日志装饰器。最后，注册MessageStore并解析没有密钥的服务，该密钥将是最外层的decorator。

builder.Register(f => new FileStore(new DirectoryInfo(HostingEnvironment.MapPath("~/file"))))
    .Keyed<IStore>("file");
builder.RegisterDecorator<IStore>(
    (c, inner) => new CacheStore(inner), fromKey: "file", toKey: "cache");
builder.RegisterDecorator<IStore>(
    (c, inner) => new LogStore(inner), fromKey: "cache", toKey: null);
builder.Register(c => new MessageStore(c.Resolve<IStore>()));

我确信围绕装饰器的API可以得到改进，这肯定是我打算很快做的事情。

谢谢Alex。但我用下面的代码解决了问题，因为我不想创建IStore。你觉得我的讨论怎么样？

builder.Register(f => new FileStore(new DirectoryInfo(HostingEnvironment.MapPath("~/file")))) 
            .Named<IStoreWriter>("F-writer").Named<IStoreReader>("F-reader");
        builder.Register( 
            c => new CacheStore(c.ResolveNamed<IStoreWriter>("F-writer"), c.ResolveNamed<IStoreReader>("F-reader"))) 
            .Named<IStoreWriter>("C-writer").Named<IStoreReader>("C-reader"); 
        builder.Register( 
            c => new LogStore(c.ResolveNamed<IStoreWriter>("C-writer"), c.ResolveNamed<IStoreReader>("C-reader"))) 
            .Named<IStoreWriter>("L-writer").Named<IStoreReader>("L-reader"); 
        builder.Register( 
            c => 
                new MessageStore(c.ResolveNamed<IStoreWriter>("L-writer"), c.ResolveNamed<IStoreReader>("L-reader")));
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