C# 在为同一功能实现同时具有同步和异步API的库时使用async await
关于如何在库中提供相同功能的同步和异步实现,我有几个问题。我将首先询问他们,然后提供下面的示例代码(这实际上相当多,但实际上非常简单)C# 在为同一功能实现同时具有同步和异步API的库时使用async await,c#,.net,async-await,dry,C#,.net,Async Await,Dry,关于如何在库中提供相同功能的同步和异步实现,我有几个问题。我将首先询问他们,然后提供下面的示例代码(这实际上相当多,但实际上非常简单) 是否有避免违反干燥原则的方法?考虑 jsRooSurviv.Read < >代码> jsRooScript。编写< >代码> jsRooScript。FLASH , PrimoLoMeService。发送< /COD>, PrimoLoMeSung.Engule及其异步版本。 当对同一方法的同步和异步版本进行单元测试时,是否有一种方法可以避免违反DRY原则?
Take 1
和Take 2
变量ComplexClass.Send
和ComplexClass.Receive
,如何实现返回Task
或Task
的方法?哪一个是正确的,为什么等待
之后始终包含.ConfigureAwait(false)
是否正确IWriter
和JsonStreamWriter
:
public interface IWriter
{
void Write(object obj);
Task WriteAsync(object obj);
void Flush();
Task FlushAsync();
}
public class JsonStreamWriter : IWriter
{
private readonly Stream _stream;
public JsonStreamWriter(Stream stream)
{
_stream = stream;
}
public void Write(object obj)
{
string json = JsonConvert.SerializeObject(obj);
byte[] bytes = Encoding.UTF8.GetBytes(json);
_stream.Write(bytes, 0, bytes.Length);
}
public async Task WriteAsync(object obj)
{
string json = JsonConvert.SerializeObject(obj);
byte[] bytes = Encoding.UTF8.GetBytes(json);
await _stream.WriteAsync(bytes, 0, bytes.Length).ConfigureAwait(false);
}
public void Flush()
{
_stream.Flush();
}
public async Task FlushAsync()
{
await _stream.FlushAsync().ConfigureAwait(false);
}
}
public interface IReader
{
object Read(Type objectType);
Task<object> ReadAsync(Type objectType);
}
public class JsonStreamReader : IReader
{
private readonly Stream _stream;
public JsonStreamReader(Stream stream)
{
_stream = stream;
}
public object Read(Type objectType)
{
byte[] bytes = new byte[1024];
int bytesRead = _stream.Read(bytes, 0, bytes.Length);
string json = Encoding.UTF8.GetString(bytes, 0, bytesRead);
object obj = JsonConvert.DeserializeObject(json, objectType);
return obj;
}
public async Task<object> ReadAsync(Type objectType)
{
byte[] bytes = new byte[1024];
int bytesRead = await _stream.ReadAsync(bytes, 0, bytes.Length).ConfigureAwait(false);
string json = Encoding.UTF8.GetString(bytes, 0, bytesRead);
object obj = JsonConvert.DeserializeObject(json, objectType);
return obj;
}
}
public interface IMessenger
{
void Send(object message);
Task SendAsync(object message);
object Receive();
Task<object> ReceiveAsync();
}
public interface IMessageDescriptor
{
string GetMessageName(Type messageType);
Type GetMessageType(string messageName);
}
public class Header
{
public string MessageName { get; set; }
}
public class ProtocolMessenger : IMessenger
{
private readonly IMessageDescriptor _messageDescriptor;
private readonly IWriter _writer;
private readonly IReader _reader;
public ProtocolMessenger(IMessageDescriptor messageDescriptor, IWriter writer, IReader reader)
{
_messageDescriptor = messageDescriptor;
_writer = writer;
_reader = reader;
}
public void Send(object message)
{
Header header = new Header();
header.MessageName = _messageDescriptor.GetMessageName(message.GetType());
_writer.Write(header);
_writer.Write(message);
_writer.Flush();
}
public async Task SendAsync(object message)
{
Header header = new Header();
header.MessageName = _messageDescriptor.GetMessageName(message.GetType());
await _writer.WriteAsync(header).ConfigureAwait(false);
await _writer.WriteAsync(message).ConfigureAwait(false);
await _writer.FlushAsync().ConfigureAwait(false);
}
public object Receive()
{
Header header = (Header)_reader.Read(typeof(Header));
Type messageType = _messageDescriptor.GetMessageType(header.MessageName);
object message = _reader.Read(messageType);
return message;
}
public async Task<object> ReceiveAsync()
{
Header header = (Header)await _reader.ReadAsync(typeof(Header)).ConfigureAwait(false);
Type messageType = _messageDescriptor.GetMessageType(header.MessageName);
object message = await _reader.ReadAsync(messageType).ConfigureAwait(false);
return message;
}
}
IReader
和JsonStreamReader
:
public interface IWriter
{
void Write(object obj);
Task WriteAsync(object obj);
void Flush();
Task FlushAsync();
}
public class JsonStreamWriter : IWriter
{
private readonly Stream _stream;
public JsonStreamWriter(Stream stream)
{
_stream = stream;
}
public void Write(object obj)
{
string json = JsonConvert.SerializeObject(obj);
byte[] bytes = Encoding.UTF8.GetBytes(json);
_stream.Write(bytes, 0, bytes.Length);
}
public async Task WriteAsync(object obj)
{
string json = JsonConvert.SerializeObject(obj);
byte[] bytes = Encoding.UTF8.GetBytes(json);
await _stream.WriteAsync(bytes, 0, bytes.Length).ConfigureAwait(false);
}
public void Flush()
{
_stream.Flush();
}
public async Task FlushAsync()
{
await _stream.FlushAsync().ConfigureAwait(false);
}
}
public interface IReader
{
object Read(Type objectType);
Task<object> ReadAsync(Type objectType);
}
public class JsonStreamReader : IReader
{
private readonly Stream _stream;
public JsonStreamReader(Stream stream)
{
_stream = stream;
}
public object Read(Type objectType)
{
byte[] bytes = new byte[1024];
int bytesRead = _stream.Read(bytes, 0, bytes.Length);
string json = Encoding.UTF8.GetString(bytes, 0, bytesRead);
object obj = JsonConvert.DeserializeObject(json, objectType);
return obj;
}
public async Task<object> ReadAsync(Type objectType)
{
byte[] bytes = new byte[1024];
int bytesRead = await _stream.ReadAsync(bytes, 0, bytes.Length).ConfigureAwait(false);
string json = Encoding.UTF8.GetString(bytes, 0, bytesRead);
object obj = JsonConvert.DeserializeObject(json, objectType);
return obj;
}
}
public interface IMessenger
{
void Send(object message);
Task SendAsync(object message);
object Receive();
Task<object> ReceiveAsync();
}
public interface IMessageDescriptor
{
string GetMessageName(Type messageType);
Type GetMessageType(string messageName);
}
public class Header
{
public string MessageName { get; set; }
}
public class ProtocolMessenger : IMessenger
{
private readonly IMessageDescriptor _messageDescriptor;
private readonly IWriter _writer;
private readonly IReader _reader;
public ProtocolMessenger(IMessageDescriptor messageDescriptor, IWriter writer, IReader reader)
{
_messageDescriptor = messageDescriptor;
_writer = writer;
_reader = reader;
}
public void Send(object message)
{
Header header = new Header();
header.MessageName = _messageDescriptor.GetMessageName(message.GetType());
_writer.Write(header);
_writer.Write(message);
_writer.Flush();
}
public async Task SendAsync(object message)
{
Header header = new Header();
header.MessageName = _messageDescriptor.GetMessageName(message.GetType());
await _writer.WriteAsync(header).ConfigureAwait(false);
await _writer.WriteAsync(message).ConfigureAwait(false);
await _writer.FlushAsync().ConfigureAwait(false);
}
public object Receive()
{
Header header = (Header)_reader.Read(typeof(Header));
Type messageType = _messageDescriptor.GetMessageType(header.MessageName);
object message = _reader.Read(messageType);
return message;
}
public async Task<object> ReceiveAsync()
{
Header header = (Header)await _reader.ReadAsync(typeof(Header)).ConfigureAwait(false);
Type messageType = _messageDescriptor.GetMessageType(header.MessageName);
object message = await _reader.ReadAsync(messageType).ConfigureAwait(false);
return message;
}
}
ComplexClass
:
public interface ISomeOtherInterface
{
void DoSomething();
}
public class ComplexClass : IMessenger, ISomeOtherInterface
{
private readonly IMessenger _messenger;
private readonly ISomeOtherInterface _someOtherInterface;
public ComplexClass(IMessenger messenger, ISomeOtherInterface someOtherInterface)
{
_messenger = messenger;
_someOtherInterface = someOtherInterface;
}
public void DoSomething()
{
_someOtherInterface.DoSomething();
}
public void Send(object message)
{
_messenger.Send(message);
}
// Take 1
public Task SendAsync(object message)
{
return _messenger.SendAsync(message);
}
// Take 2
public async Task SendAsync(object message)
{
await _messenger.SendAsync(message).ConfigureAwait(false);
}
public object Receive()
{
return _messenger.Receive();
}
// Take 1
public Task<object> ReceiveAsync()
{
return _messenger.ReceiveAsync();
}
// Take 2
public async Task<object> ReceiveAsync()
{
return await _messenger.ReceiveAsync().ConfigureAwait(false);
}
}
公共接口
{
无效剂量();
}
公共类ComplexClass:IMessenger,IsoOtherInterface
{
私人只读IMessenger\u messenger;
私有只读IsometherInterface\u someOtherInterface;
公共ComplexClass(IMessenger messenger、IsoOtherInterface和someOtherInterface)
{
_信使=信使;
_someOtherInterface=someOtherInterface;
}
公共无效剂量测定法()
{
_someOtherInterface.DoSomething();
}
公共无效发送(对象消息)
{
_信使。发送(消息);
}
//拿1
公共任务SendAsync(对象消息)
{
返回\u messenger.SendAsync(消息);
}
//拿2块
公共异步任务SendAsync(对象消息)
{
wait\u messenger.SendAsync(message).configurewait(false);
}
公共对象接收()
{
return _messenger.Receive();
}
//拿1
公共任务ReceiveAsync()
{
返回_messenger.ReceiveAsync();
}
//拿2块
公共异步任务ReceiveAsync()
{
返回wait\u messenger.ReceiveAsync().ConfigureWait(false);
}
}
这里的一般答案是,使真正的异步
和同步版本的相同功能需要两种不同(可能相似,可能不相似)的实现。您可以尝试找到重复的部件,并使用基类(或实用程序类)重用它们,但实现方式可能会有所不同
在许多情况下,人们选择只提供一个版本的API,不管它是否异步。例如,整个过程都是异步的。如果你负担得起(许多人负担不起),那将是我的建议
关于您的具体问题:
async
方法需要在async
上下文中测试Take 1
(即直接返回任务)最好有两种方式:
- 它没有创建整个不需要的
状态机的开销,这只会略微提高性能async
在本例中,仅影响其后面的代码,在本例中,该代码根本不起作用。无论是否使用ConfigureAwait
,它都不会影响调用方的代码configurewait
ConfigureAwait(false)
,并仅在特定需要时将其删除一般来说,API应该是异步的或同步的。例如,如果您的实现包括I/O,那么它应该是异步的 也就是说,在某些场景中,您确实希望同时使用同步和异步API。例如,如果工作自然是异步的,但需要保留同步API以实现向后兼容性
如果您处于这种情况,我建议使用来最小化重复代码的数量。和都是反模式。你说3是什么意思?我为同一个异步方法提供了两个实现:一个上面有Take 1注释,另一个上面有Take 2注释。我的意思是-哪一个是正确的,为什么?明白了。在我的回答中补充了这一点。不确定你是否在试图引导人们远离的道路上跌跌撞撞。@Damien_不信者我在发布我的问题之前阅读了这两篇文章。即使在我的第一个例子中,你也会看到我没有走这条路。不过,如果你在假设之前读过它们会更好。无论如何,谢谢你指出这一点。我已经看过了关于不同问题的所有不同答案。有些人会说“你永远不需要同步,它应该是异步的。”其他人则指向AsyncHelper上下文,或者你的文章所涉及的任何种类的内容,唯一可靠的答案是你的布尔建议,它与“我的it死锁”无关。我推荐给任何需要用sync包装async的人。是的,布尔参数hack是我个人最喜欢的。不过,这实际上并不是一种用sync包装async的方法。它创建了一个可以是异步或同步的(私有)方法,