如何优雅的使用AbpSettings

在Abp中配置虽然使用方便，但是每个配置要先定义key，要去provider中定义，再最后使用key从ISetting中获取还是挺麻烦的一件事，

最主要是获取修改的时候，比如，修改用户配置，是从获取一批key/value来返回前端，并从前端提交修改保存就比较麻烦了。

很早之前做过一些尝试，如下：

https://www.cnblogs.com/crazyboy/p/8064387.html

但是那个时候比较菜也没怎么搞太清楚所以感觉也不太好用。

之前也想过使用定义配置类使用基类中注入的ISettingManager的方式来处理，如下

        public string Item
        {
            get { return this.SettingManager.GetSettingValue(nameof(Item)); }
            set { this.SettingManager.ChangeSettingForApplication(nameof(Item), value); }
        }

但是这样对配置类污染比较大，也就放弃了，前段时间在看Abp源代码的时候，突然想到，是否可以通过拦截器来代理配置类的get ,set方法来达到获取和修改配置的目的呢

于是便开始了配置的改造工作，首先，定义一个配置的接口来注册拦截器：

using Abp.Dependency;

namespace SKYS.Charger.Configuration
{
    /// <summary>
    /// 配置类接口，要实现从SettingManager更新/获取数据，请所有属性用virtual标识
    /// </summary>
    public interface ISettings : ISingletonDependency
    {

    }
}

为了定义设置的一些配置，我们还需要定义一个特性用于设置的默认值/范围等：

using Abp.Configuration;
using System;

namespace SKYS.Charger.Configuration
{
    [AttributeUsage(AttributeTargets.Property)]
    public class AutoSettingDefinitionAttribute : Attribute
    {
        public object DefaultValue { get; private set; }

        public bool IsVisibleToClients { get; private set; }

        public SettingScopes Scopes { get; private set; }

        public AutoSettingDefinitionAttribute(object defaultValue, bool isVisibleToClients = true, SettingScopes scopes = SettingScopes.Application)
        {
            this.DefaultValue = defaultValue;
            this.IsVisibleToClients = isVisibleToClients;
            this.Scopes = scopes;
        }
    }
}

接下来，我们需要把所有继承至ISettings的设置类都注册到SettingProvider中，这里我直接使用的反射，从属性特性上读取设置的配置：

using Abp.Configuration;
using System.Collections.Generic;
using System.Linq;
using System.Reflection;

namespace SKYS.Charger.Configuration
{
    /// <summary>
    /// 
    /// </summary>
    public class AutoSettingsProvider : SettingProvider
    {
        public override IEnumerable<SettingDefinition> GetSettingDefinitions(SettingDefinitionProviderContext context)
        {
            var settings = new List<SettingDefinition>();

            var types = this.GetType().Assembly
                                      .GetTypes()
                                      .Where(t => t.IsClass && typeof(ISettings).IsAssignableFrom(t));

            foreach (var type in types)
            {
                var scopes = SettingScopes.All;
                foreach (var p in type.GetProperties())
                {
                    var key = AutoSettingsUtils.CreateSettingName(type, p.Name);
                    var isVisibleToClients = false;
                    var defaultValue = AutoSettingsUtils.GetDefaultValue(p.PropertyType);
                    var attr = p.GetCustomAttribute<AutoSettingDefinitionAttribute>();
                    if (attr != null)
                    {
                        scopes = attr.Scopes;
                        defaultValue = attr.DefaultValue;
                        isVisibleToClients = attr.IsVisibleToClients;
                    }
                    settings.Add(new SettingDefinition(
                           name: key,
                           defaultValue: defaultValue?.ToString(),
                           scopes: scopes,
                           isVisibleToClients: isVisibleToClients
                            ));
                }
            }

            return settings;
        }
    }
}

接下来定义一个Interceptor用于拦截设置类中属性的get/set方法，在拦截器中注入了ISettingManager及AbpSession用于获取和修改设置，在修改的时候如果scope支持User优先修改用户设置，然后是租户设置，最后是应用设置

using Abp.Configuration;
using Abp.Runtime.Session;
using Castle.DynamicProxy;
using SKYS.Charger.Utilities;

namespace SKYS.Charger.Configuration
{
    /// <summary>
    /// 自动配置拦截器，用于获取/修改配置值
    /// </summary>
    public class AutoSettingsInterceptor : IInterceptor
    {
        private readonly ISettingManager _settingManager;
        private readonly ISettingDefinitionManager _settingDefinitionManager;
        public IAbpSession AbpSession { get; set; }
        public AutoSettingsInterceptor(ISettingManager settingManager, ISettingDefinitionManager settingDefinitionManager)
        {
            this._settingManager = settingManager;
            this._settingDefinitionManager = settingDefinitionManager;
            this.AbpSession = NullAbpSession.Instance;
        }

        protected void PostProceed(IInvocation invocation)
        {
            var setFlag = "set_";
            var getFlag = "get_";

            var isSet = invocation.Method.Name.StartsWith(setFlag);
            var isGet = invocation.Method.Name.StartsWith(getFlag);
            //非属性方法不处理
            if (!isSet && !isGet)
                return;

            var pname = invocation.Method.Name.Replace(setFlag, "")
                                              .Replace(getFlag, "");
            var settingName = AutoSettingsUtils.CreateSettingName(invocation.TargetType, pname);
            //配置 设置
            if (isSet)
            {
                var setting = this._settingDefinitionManager.GetSettingDefinition(settingName);
                this.ChangeSettingValue(setting, invocation.Arguments[0]?.ToString());
            }
            //配置 获取
            else
            {
                var val = this._settingManager.GetSettingValue(settingName);
                invocation.ReturnValue = ConvertHelper.ChangeType(val, invocation.Method.ReturnType);
            }
        }
        protected void ChangeSettingValue(SettingDefinition settings, object value)
        {
            var val = value?.ToString();
            if (settings.Scopes.HasFlag(SettingScopes.User) && this.AbpSession.UserId.HasValue)
                this._settingManager.ChangeSettingForUser(this.AbpSession.ToUserIdentifier(), settings.Name, val);
            else if (settings.Scopes.HasFlag(SettingScopes.Tenant) && this.AbpSession.TenantId.HasValue)
                this._settingManager.ChangeSettingForTenant(this.AbpSession.TenantId.Value, settings.Name, val);
            else if (settings.Scopes.HasFlag(SettingScopes.Application))
                this._settingManager.ChangeSettingForApplication(settings.Name, val);
        }

        public void Intercept(IInvocation invocation)
        {
            invocation.Proceed();
            this.PostProceed(invocation);
        }
    }
}

定义完以后，我们还需要注册我们的拦截器，这里我使用了一个Manager来注册，通过传入AbpModule中的Configuration来完成注册

using Abp.Configuration.Startup;
using Castle.Core;

namespace SKYS.Charger.Configuration
{
    public class AutoSettingsManager
    {
        public static void Initialize(IAbpStartupConfiguration configuration)
        {
            configuration.IocManager.IocContainer.Kernel.ComponentRegistered += (key, handler) =>
            {
                if (typeof(ISettings).IsAssignableFrom(handler.ComponentModel.Implementation))
                {
                    handler.ComponentModel.Interceptors.Add(new InterceptorReference(typeof(AutoSettingsInterceptor)));
                }
            };

　　　　　　　//把自动属性的Provider注册
            configuration.Settings.Providers.Add<AutoSettingsProvider>();
        }
    }
}

 然后在你定义配置类型的Module的PreInitialize()中完成注册：

//自动配置初始化
            AutoSettingsManager.Initialize(Configuration);

 到这里我们的工作基本上也就完成了，接下来我们就可以定义我们自己的设置类了，因为我们注入使用是类，所以定义的属性都需要加上virtual以便拦截器能正常工具 

using Abp.AutoMapper;
using Abp.Configuration;

namespace SKYS.Charger.Configuration.Settings
{
    [AutoMap(typeof(AppSettings))]
    public class AppSettings : ISettings
    {
        [AutoSettingDefinition("SKYS.Charger")]
        public virtual string SystemName { get; set; }

        [AutoSettingDefinition(20)]
        public virtual int PageSize { get; set; }

        /// <summary>
        /// 得现手续费
        /// </summary>
        [AutoSettingDefinition(0.02)]
        public virtual decimal TakeServiceFeeRate { get; set; }
    }
}

在任意使用的地方，直接注入即可使用，并且只要是注入的配置类型，设置它的属性即可完成修改并保存到数据库，获取也是直接从ISettingManager中获取值，再配合前端修改的时候就方便多了

namespace SKYS.Charger.Configuration
{
    public class ConfigurationAppService : ApplicationService
    {
        private readonly AppSettings _appSettings;
        public ConfigurationAppService(AppSettings appSettings)
        {
            this._appSettings = appSettings;
        }

        /// <summary>
        /// 获取系统配置
        /// </summary>
        public async Task<AppSettings> GetSystemSettings()
        {
            return await Task.FromResult(_appSettings);
        }
        /// <summary>
        /// 修改系统配置
        /// </summary>
        [ManagerAuthorize]
        public async Task ChangeSystemSettings(AppSettings appSettings)
        {
            this.ObjectMapper.Map(appSettings, _appSettings);

            await Task.CompletedTask;
        }
    }
}

 是不是比原来的使用方式简单了很多呢，因为是所有配置类型都是ISingletonDependency在不方便的地方还可以直接使用IocManager.Instance.Resolve<AppSettings>()直接获取：

    public class PagedRequestFilter : IShouldNormalize
    {
        //public ISettingManager SettingManager { get; set; }

        public const int DefaultSize = 20;

        //[Range(1, 10000)]
        public int Page { get; set; }

        //[Range(1,100)]
        public int Size { get; set; }

        public void Normalize()
        {
            if (this.Page <= 0)
                this.Page = 1;
            if (this.Size <= 0)
            {
                var appSettings = IocManager.Instance.Resolve<AppSettings>();
                this.Size = appSettings.PageSize;
            }
        }
    }

 最后附上中间使用过的两个工具类AutoSettingsUtils和ConvertHelper

    public static class AutoSettingsUtils
    {
        public static string CreateSettingName(Type type, string propertyName)
        {
            return $"{type.Name}.{propertyName}";
        }

        public static object GetDefaultValue(Type targetType)
        {
            return targetType.IsValueType ? Activator.CreateInstance(targetType) : null;
        }
    }

    /// <summary>
    /// 数据转换帮助类
    /// </summary>
    public static class ConvertHelper
    {
        #region = ChangeType =
        public static object ChangeType(object obj, Type conversionType)
        {
            return ChangeType(obj, conversionType, Thread.CurrentThread.CurrentCulture);
        }
        public static object ChangeType(object obj, Type conversionType, IFormatProvider provider)
        {
            #region Nullable
            Type nullableType = Nullable.GetUnderlyingType(conversionType);
            if (nullableType != null)
            {
                if (obj == null)
                {
                    return null;
                }
                return Convert.ChangeType(obj, nullableType, provider);
            }
            #endregion
            if (typeof(System.Enum).IsAssignableFrom(conversionType))
            {
                return Enum.Parse(conversionType, obj.ToString());
            }
            return Convert.ChangeType(obj, conversionType, provider);
        }
        #endregion
    }