用静态方法代替规范

Question

我正在尝试使用Ionad plugin for Fody。我已经创建了替换，但依赖代码没有调用替换。

替换

[StaticReplacement(typeof(AppUtils))]
public static class AppUtilsSubsitute
{
    public static void LogException(string func, Exception ex) => Write("Exception", ex.ToJson());

    public static void LogError(string err) => Write("Error", err);

    public static void LogInfo(string info) => Write("Info", info);

    public static void LogWarning(string info) => Write("Warning", info);

    public static void LogCypherQuery(string func, ICypherFluentQuery query) => Write(func, query.ToJson());

    static void Write(string logType, string message)
    {
        var dictionary = new Dictionary<string, string> { { logType, message } };
        var assembly = Assembly.GetExecutingAssembly();
        using (var writer = new StreamWriter(assembly.Location + "Machine.Specifications.log"))
        {
            writer.Write(dictionary.ToJson());
        }
    }

    public static Dictionary<string, string> Log()
    {
        var assembly = Assembly.GetExecutingAssembly();
        Dictionary<string, string> content;
        using (var reader = new StreamReader(assembly.GetManifestResourceStream("Machine.Specifications.log")))
        {
            content = JsonConvert.DeserializeObject<Dictionary<string, string>>(reader.ReadToEnd());
        }
        return content;
    }
}

依赖方法

[AttributeUsage(AttributeTargets.Method)]
public class EnsurePresencesOfAttribute : ActionFilterAttribute
{
    internal virtual string Required { get; }
    internal virtual string Param { get; }
    public EnsurePresencesOfAttribute(string required = "", string param="request")
    {
        Required = required;
        Param = param;
    }

    public override void OnActionExecuting(HttpActionContext actionContext)
    {
        Dictionary<string, object> model = actionContext.ActionArguments;
        if (model == null || model.Count == 0 || !model.ContainsKey(Param))
        {
            ValueError(actionContext, $"{Param} parameter");
            return;
        }
        foreach (var requirement in Required.Split(',').Select(e => e.Trim()))
        {
            if (model[requirement] == null)
            {
                ValueError(actionContext, requirement);
                return;
            }
        }
        base.OnActionExecuting(actionContext);
    }

    public override Task OnActionExecutingAsync(HttpActionContext context, CancellationToken token)
    {
        Dictionary<string, object> model = context.ActionArguments;
        if(model == null || model.Count == 0 || !model.ContainsKey(Param))
        {
            ValueError(context, $"{Param} parameter");
            return Task.FromResult(0);
        }
        foreach (var requirement in Required.Split(',').Select(e => e.Trim()))
        {
            if (model[requirement] == null)
            {
                ValueError(context, requirement);
                Task.FromResult(0);
            }
        }
        return base.OnActionExecutingAsync(context, token);
    }

    private static void ValueError(HttpActionContext context, string requirement)
    {
        var action = context.ActionDescriptor.ActionName;
        AppUtils.LogError($"{action} Failed : Missing Required Attribute {requirement}. ");
        using (var controller = new BaseApiController { Request = new HttpRequestMessage() })
        {
            controller.Request.Properties.Add(HttpPropertyKeys.HttpConfigurationKey, new HttpConfiguration());
            context.Response = controller.InvalidInputResponse();
        }
    }
}

Answer 1

静态依赖往往会使与它们紧密耦合的代码难以维护和测试。

ASP.NET Web API 提供了可避免此类依赖项的扩展点。主要是用于Dependency Injection in ASP.NET Web API 2的IDependencyResolver。

因此，我建议将该静态实用程序转换为抽象，或者至少将其抽象为可以轻松替换的接口。

public interface ILogger {
    void LogException(string func, Exception ex);
    void LogError(string err);
    void LogInfo(string info);
    void LogWarning(string info);
    void LogCypherQuery(string func, ICypherFluentQuery query);
    Dictionary<string, string> Log();
}

这将允许任意数量的实现，尤其是在需要时可用于单元测试的存根。

public class AppUtilsSubsitute : ILogger {
    public void LogException(string func, Exception ex) => Write("Exception", ex.ToJson());

    public void LogError(string err) => Write("Error", err);

    public void LogInfo(string info) => Write("Info", info);

    public void LogWarning(string info) => Write("Warning", info);

    public void LogCypherQuery(string func, ICypherFluentQuery query) => Write(func, query.ToJson());

    static void Write(string logType, string message) {
        var dictionary = new Dictionary<string, string> { { logType, message } };
        var assembly = Assembly.GetExecutingAssembly();
        using (var writer = new StreamWriter(assembly.Location + "Machine.Specifications.log")) {
            writer.Write(dictionary.ToJson());
        }
    }

    public Dictionary<string, string> Log() {
        var assembly = Assembly.GetExecutingAssembly();
        Dictionary<string, string> content;
        using (var reader = new StreamReader(assembly.GetManifestResourceStream("Machine.Specifications.log"))) {
            content = JsonConvert.DeserializeObject<Dictionary<string, string>>(reader.ReadToEnd());
        }
        return content;
    }
}

依赖的代码现在将被重构为依赖于抽象，而不是可能是任何东西的实现。

private static void ValueError(HttpActionContext context, string requirement) {
    var httpConfiguration = context.RequestContext.Configuration;
    var resolver = httpConfiguration.DependencyResolver;
    var logger = resolver.GetService(typeof(ILogger));
    var action = context.ActionDescriptor.ActionName;
    logger.LogError($"{action} Failed : Missing Required Attribute {requirement}. ");
    using (var controller = new BaseApiController { Request = new HttpRequestMessage() }) {
        //USE THE GLOBAL HTTPCONFIGURATION ALREADY ASSOCIATED WITH THE
        //REQUEST INSTEAD OF CREATING A NEW ONE THAT HAS NONE OF THE 
        //WEB API CONFIG THAT WOULD HAVE BEEN ADDED AT STARTUP
        controller.Request.Properties.Add(HttpPropertyKeys.HttpConfigurationKey, httpConfiguration);
        context.Response = controller.InvalidInputResponse();
    }
}

只需确保在启动时使用您选择的 IoC 容器配置 Dependency Resolver。

在DependencyResolver 属性上设置依赖解析器 全局 HttpConfiguration 对象。

以下代码将ILogger 接口注册到 Unity 和 然后创建一个UnityResolver。

public static void Register(HttpConfiguration config)    {
    var container = new UnityContainer();
    container.RegisterType<ILogger, AppUtilsSubsitute>(new HierarchicalLifetimeManager());
    config.DependencyResolver = new UnityResolver(container);

    // Other Web API configuration not shown.    
}