ABP系统设置

代码分析

在abp中添加系统设置，都是在模块的预初始化方法中添加的.

 Configuration.Settings.Providers.Add<EmailSettingProvider>();

Configuration之前已经说过了，这是AbpModule里的属性，IAbpStartupConfiguration 这个类就是负责abp启动时的配置，以及模块的配置。之前说的模块配置是通过IAbpStartupConfiguration里的ModuleConfigurations Modules配置的.

public interface IAbpStartupConfiguration : IDictionaryBasedConfig
{
    //  其他代码略
    IModuleConfigurations Modules { get; }
    ISettingsConfiguration Settings { get; }
    // 略。
}

初始化的话，之前也说过了，是在AbpBootstrapper中，通过ioc容器取得AbpStartupConfiguration。然后执行初始化方法.在初始化方法中通过ioc容器取得每个属性的对应实例，赋值。也就是说 Settings就是这时候被初始化的

ISettingsConfiguration

public interface ISettingsConfiguration
{
    /// <summary>
    /// List of settings providers.
    /// </summary>
    ITypeList<SettingProvider> Providers { get; }
}

internal class SettingsConfiguration : ISettingsConfiguration
{
    public ITypeList<SettingProvider> Providers { get; private set; }

    public SettingsConfiguration()
    {
        Providers = new TypeList<SettingProvider>();
    }
}

通过看到详细代码，这个就很明显了，这里维护了一个 SettingProvider 集合
开头可以看到就是通过这个集合添加我们自定义设置的,这里集合的类型是一个SettingProvider
也就是说我们自定义的设置，必须继承自SettringProvider才可以被添加

/// Inherit this class to define settings for a module/application.
/// </summary>
public abstract class SettingProvider : ITransientDependency
{
    /// <summary>
    /// Gets all setting definitions provided by this provider.
    /// </summary>
    /// <returns>List of settings</returns>
    public abstract IEnumerable<SettingDefinition> GetSettingDefinitions(SettingDefinitionProviderContext context);
}

这是一个抽象类也就是说我们自定义的settingprovier必须实现GetSettingDefinitions方法咯.
例如，清除缓存的设置

public class ClearCacheSettingProvider : SettingProvider
{
    public override IEnumerable<SettingDefinition> GetSettingDefinitions(SettingDefinitionProviderContext context)
    {
        return new[]
        {
            new SettingDefinition(ClearCacheSettingNames.Password, "123qweasdZXC")
        };
    }
}

那么SettingDefinition是什么呢
看名字是设置的定义的意思,设置用于配置和更改应用程序的行为 里面有Name，DisplayName Scopes等属性.
那么我们定义好了SettingProvider，在模块与初始化方法中加入到我们的Providers集合之后.又做了什么呢.

SettingDefinitionManager

如果你熟悉ABP的话，你就会知道，我们把一个配置存入了集合中，那肯定也要是可以取出来的
我们在写代码的时候，都是通过SettingManager来获取配置的.

//Getting a boolean value (async call)
var value1 = await SettingManager.GetSettingValueAsync<bool>("PassiveUsersCanNotLogin");

public class SettingManager : ISettingManager, ISingletonDependency
{
    // 其他代码 略.
    private readonly ISettingDefinitionManager _settingDefinitionManager;
}

SettingManager中有个ISettingDefinitionManager,其实 GetSettingValue方法最终调用的是settingDefinitionManager的GetSettingDefinition方法

private async Task<string> GetSettingValueInternalAsync(string name, int? tenantId = null, long? userId = null, bool fallbackToDefault = true)
{
    var settingDefinition = _settingDefinitionManager.GetSettingDefinition(name);
}

接下来看看SettingDefinitionManager

internal class SettingDefinitionManager : ISettingDefinitionManager, ISingletonDependency
{
    private readonly IIocManager _iocManager;
    private readonly ISettingsConfiguration _settingsConfiguration;
    private readonly IDictionary<string, SettingDefinition> _settings;

    /// <summary>
    /// Constructor.
    /// </summary>
    public SettingDefinitionManager(IIocManager iocManager, ISettingsConfiguration settingsConfiguration)
    {
        _iocManager = iocManager;
        _settingsConfiguration = settingsConfiguration;
        _settings = new Dictionary<string, SettingDefinition>();
    }

    public void Initialize()
    {
        var context = new SettingDefinitionProviderContext(this);

        foreach (var providerType in _settingsConfiguration.Providers)
        {
            using (var provider = CreateProvider(providerType))
            {
                foreach (var settings in provider.Object.GetSettingDefinitions(context))
                {
                    _settings[settings.Name] = settings;
                }
            }
        }
    }

    public SettingDefinition GetSettingDefinition(string name)
    {
        if (!_settings.TryGetValue(name, out var settingDefinition))
        {
            throw new AbpException("There is no setting defined with name: " + name);
        }

        return settingDefinition;
    }
}

可以看到这里维护了一个 字典,key是string,value是SettingDefinition,那么是什么时候加入到字典中的呢?
可以看到在initialize方法中遍历我们SettingConfiguration的Providers属性，然后从IOC容器中取出,追加进字典集合中。那么想知道是什么时候执行的，只需要看看Initialize方法的调用就知道了。
嗯，只有一个调用。就是在AbpKernelModule中 初始化完成方法中 执行的

public sealed class AbpKernelModule
{
    public override void PostInitialize()
    {
        //  其他代码.. 略
        IocManager.Resolve<SettingDefinitionManager>().Initialize();
        //  略。
    }
}