我有多个流程服务。这些服务具有我需要在使用特定服务之前填写的属性。但是,这些过程服务还使用1-n生成器子服务,该子服务也具有与过程服务相同的属性。
public interface IProcess
{
IEnumerable<string> metadata;
//...
}
public class Process1 : IProcess
{
public IEnumerable<string> Metadata {get; set;}
private readonly IGenerator1 Generator1;
private readonly IGenerator2 Generator2;
public Process1(
IGenerator1 generator1,
IGenerator2 generator2,
IEnumerable<string> metadata)
{
Generator1 = generator1;
Generator2 = generator2;
Metadata = metadata;
}
}
public interface IGenerator
{
IEnumerable<string> metadata;
//...
}
public class Generator1 : IGenerator
{
public IEnumerable<string> Metadata {get; set;}
private readonly ILogger Logger;
public Generator1(
ILogger logger,
IEnumerable<string> metadata)
{
Logger = logger;
Metadata = metadata;
}
}
我使用DI并解决ServiceBuilder中的依赖项
public class ServiceBuilder
{
public ServiceBuilder()
{
var services = new ServiceCollection();
services.AddTransient<IProcess, Process1>();
services.AddSingleton<IProcessFactory, ProcessFactory>();
services.AddTransient<IDeliverySiteGenerator, DeliverySiteGenerator>();
services.AddTransient<INewConnectionErrandGenerator, NewConnectionErrandGenerator>();
//...
ServiceProvider = services.BuildServiceProvider();
}
}
并使用ProcessFactory类及其'方法GetProcess来检索我要使用的进程。我将这些进程添加到List<IProcess>
中,然后使用此列表从所有检索到的IProcess服务中执行特定方法。 configData
由用户输入提供,并且还包括我们想要的属性IEnumerable<string> Metadata
。
public class ProcessFactory : IProcessFactory
{
private readonly IServiceProvider serviceProvider;
//...
public IProcess GetProcess(SomeConfigData configData)
{
var processExists = registeredProcesses.TryGetValue(configData, out var processType);
if (!processExists)
throw new InvalidArgumentException($"Process not supported.");
return (IProcess)serviceProvider.GetService(processType);
}
}
[现在,当Metadata
具有公共设置器时,通过GetProcess
方法检索到Metadata
后,将其添加到IProcess服务。但这并不能解决如何将其传递给生成器子服务的问题。不想遍历流程服务的所有生成器实例,并通过公共设置器添加Metadata
。有什么办法可以做到这一点?
一种方法是创建范围服务以提供对元数据的访问:
public interface IMetadataAccessor
{
IEnumerable<string> Metadata { get; set; }
}
public class MetadataProcessor : IMetadataAccessor
{
public IEnumerable<string> Metadata { get; set; }
}
将服务注册为范围:
serviceCollection.AddScoped<IMetadataAccessor, MetadataProcessor>();
更改流程和生成器类以通过构造函数注入IMetadataAccessor
,并读取像这样的元数据:
public IEnumerable<string> Metadata => _metadataAccessor.Metadata;
更改工厂以在范围内实例化处理器:
public Processor CreateProcessor(IEnumerable<string> metadata)
{
// Resolve services within a child scope
using (var scope = _services.CreateScope())
{
// Resolve the accessor service and set metadata
var accessor = scope.ServiceProvider.GetRequiredService<IMetadataAccessor>();
accessor.Metadata = metadata;
// Within the current scope, there is only one IMetadataAccessor.
// So both process and generator will be getting same accessor instance via the constructor.
// If we set metadata to the instance, all services can get the value.
var process = scope.ServiceProvider.GetRequiredService<Process>();
return process;
}
}