BlogEngine.NET (一)配置

因为日志的配置信息比较多，而且可能每个人的配置都不相同，所以BlogEngine.NET中的 配置信息需要统一管理，日志结构图如下：

BlogBasePage类是个抽象类，是其他web页面的基类，它会使用BlogSettings获得配置信息，代码如下：

public abstract class BlogBasePage : System.Web.UI.Page
  ...{

    private string _Theme = BlogSettings.Instance.Theme;
    /**//// <summary>
    /// Assignes the selected theme to the pages.
    /// </summary>
    protected override void OnPreInit(EventArgs e)
    ...{
      if (Request.QueryString["theme"] != null)
        _Theme = Request.QueryString["theme"];

      MasterPageFile = "~/themes/" + _Theme + "/site.master";

      base.OnPreInit(e);

      if (!Page.IsPostBack && !string.IsNullOrEmpty(Request.QueryString["deletepost"]))
      ...{
        if (Page.User.Identity.IsAuthenticated)
        ...{
          Post post = BlogEngine.Core.Post.GetPost(new Guid(Request.QueryString["deletepost"]));
          post.Delete();
          post.Save();
          Response.Redirect("~/");
        }
      }
    }
}

BlogSettings中使用单件模式：

 public static BlogSettings Instance
    ...{
      get
      ...{
        if (blogSettingsSingleton == null)
        ...{
          blogSettingsSingleton = new BlogSettings();
        }
        return blogSettingsSingleton;
      }
    }

在BlogSettings的私有构造函数中调用了 Load();方法，这个方法使用BlogService类获得配置信息，使用反射技术给BlogSettings实例对象中的属性赋值

 private void Load()
    ...{
      Type settingsType = this.GetType();

      //------------------------------------------------------------
      //    Enumerate through individual settings nodes
      //------------------------------------------------------------
      System.Collections.Specialized.StringDictionary dic = Providers.BlogService.LoadSettings();
      foreach (string key in dic.Keys)
      ...{
        //------------------------------------------------------------
        //    Extract the setting's name/value pair
        //------------------------------------------------------------
        string name = key;
        string value = dic[key];

        //------------------------------------------------------------
        //    Enumerate through public properties of this instance
        //------------------------------------------------------------
        foreach (PropertyInfo propertyInformation in settingsType.GetProperties())
        ...{
          //------------------------------------------------------------
          //    Determine if configured setting matches current setting based on name
          //------------------------------------------------------------
          if (propertyInformation.Name.Equals(name, StringComparison.OrdinalIgnoreCase))
          ...{
            //------------------------------------------------------------
            //    Attempt to apply configured setting
            //------------------------------------------------------------
            try
            ...{
              propertyInformation.SetValue(this, Convert.ChangeType(value, propertyInformation.PropertyType, CultureInfo.CurrentCulture), null);
            }
            catch
            ...{
              // TODO: Log exception to a common logging framework?
            }
            break;
          }
        }
      }
    }

BlogService通过读取webconfig中的section同时利用反射技术获得provider的具体类

private static void LoadProviders()
        ...{
            // Avoid claiming lock if providers are already loaded
            if (_provider == null)
            ...{
                lock (_lock)
                ...{
                    // Do this again to make sure _provider is still null
                    if (_provider == null)
                    ...{
                        // Get a reference to the <blogProvider> section
                        BlogProviderSection section = (BlogProviderSection)WebConfigurationManager.GetSection("BlogEngine/blogProvider");

                        // Load registered providers and point _provider
                        // to the default provider
                        _providers = new BlogProviderCollection();
                        ProvidersHelper.InstantiateProviders(section.Providers, _providers, typeof(BlogProvider));
                        _provider = _providers[section.DefaultProvider];

                        if (_provider == null)
                            throw new ProviderException("Unable to load default BlogProvider");
                    }
                }
            }
        }

webconfig中的相关信息为

<configSections>
    <sectionGroup name="BlogEngine">
      <section name="blogProvider" requirePermission="false" type="BlogEngine.Core.Providers.BlogProviderSection, BlogEngine.Core" allowDefinition="MachineToApplication" restartOnExternalChanges="true"/>
    </sectionGroup>
  </configSections>

  <BlogEngine>
    <blogProvider defaultProvider="XmlBlogProvider">
      <providers>
        <add name="XmlBlogProvider" type="BlogEngine.Core.Providers.XmlBlogProvider"/>
        <add name="MSSQLBlogProvider" type="BlogEngine.Core.Providers.MSSQLBlogProvider"/>
      </providers>
    </blogProvider>
  </BlogEngine>