[转载]Session共享的解决方案 – 心海巨澜 – 博客园.

Session共享的解决方案

1、客户端SessionID值唯一；

对于不同的域名：主域名、子域名、跨站点域名或跨服务器域名，用户在打开页面时会产生不同的SessionID，

为了使这些站点在用户登录时只登录一次，那我们就要解决SessionID的问题，必须使SessionID在这些共享Session的站点中只产 生一次。而SessionID是存储在客户端的cookie之中键值为ASP.NET_SessionId的一个字符串（也可以存储在URL中，这里不作 使介绍），为此只须使各站点存储的SP.NET_SessionId唯一即可。

因每个客户端在打开时会产生一个SessionID，为此我们要做的就是重置SessionID。我们可以在继承HttpModule，在结束请求时重写SessionID。

代码如下

    public class MakeSessionIDOneOnly : IHttpModule
    {
        private string m_RootDomain = string.Empty;

        #region IHttpModule Members

        public void Dispose()
        {
            
        }

        public void Init(HttpApplication context)
        {
            m_RootDomain = ConfigurationManager.AppSettings["RootDomain"];

            Type stateServerSessionProvider = typeof(HttpSessionState).Assembly.GetType("System.Web.SessionState.OutOfProcSessionStateStore");
            FieldInfo uriField = stateServerSessionProvider.GetField("s_uribase", BindingFlags.Static | BindingFlags.NonPublic);

            if (uriField == null)
                throw new ArgumentException("UriField was not found");

            uriField.SetValue(null, m_RootDomain);
            
            context.EndRequest += new System.EventHandler(context_EndRequest);
        }

        void context_EndRequest(object sender, System.EventArgs e)
        {
            HttpApplication app = sender as HttpApplication;
            for (int i = 0; i < app.Context.Response.Cookies.Count; i++)
            {
                if (app.Context.Response.Cookies[i].Name == "ASP.NET_SessionId")
                {
                    app.Context.Response.Cookies[i].Domain = m_RootDomain;
                }
            }
        }

        #endregion
    }

为使用以上代码，须配置下面节点项。

<httpModules>

<add name=”节点名称” type=”类名全称, 程序集”/>

</httpModules>

2、Session值的共享；

配置sessionState置节点，使用StateServer或SQLServer来实现Session共享。

为实现跨服务器共享，必须在Web.config配置：

<machineKey decryptionKey=”FD69B2EB9A11E3063518F1932E314E4AA1577BF0B824F369″ validationKey=”5F32295C31223A362286DD5777916FCD0FD2A8EF882783FD3E29AB1FCDFE931F8FA45A8E468B7A40269E50A748778CBB8DB2262D44A86BBCEA96DCA46CBC05C3″ validation=”SHA1″ decryption=”Auto”/>

并且，不同服务器上站点配置必须用相同的Web.config，各站点目录配置也要相同。

2.1、使用StateServer：

存储Session的服务器必须开启StateServer：ASP.NET状态服务。只有机器重起的情况下才导致Session丢失。

<sessionState cookieless=”false” timeout=”50″ mode=”StateServer” stateConnectionString=”tcpip=IpAddress:42424″/>

若StateServer在本机存储，则IpAddress为：127.0.0.1；若StateServer为远程服务器，则为IpAddress为远程服务器IP地址，并且修改注册表项如下：

Windows Registry Editor Version 5.00

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\aspnet_state\Parameters]

“Port”=dword:0000a5b8

“AllowRemoteConnection”=dword:00000001

2.2、使用SQLServer：

必须开启SQLServer代理服务，此服务负责清除过期的Session，若没有开服务，则Session不会过期。

使用SQLServer在机器重启后Session不会丢失。

Web.config配置：

<sessionState mode=”SQLServer” sqlConnectionString=”server=DBIpAddress; uid=myid; pwd=mypwd;”/>

数据库配置：

使用aspnet_regsql.exe工具

ASP.NET 2.0版本后微软提供了aspnet_regsql.exe工具可以方便的配置Session数据库.该工具位于 Web 服务器上的”系统根目录\Microsoft.NET\Framework\版本号”文件夹中.

使用举例:

aspnet_regsql.exe -S . -U sa -P 123456 -ssadd -sstype p

-S参数:

表示数据库实例名称. 可以用”.”表示本机.

-U和-P参数:

表示用户名和密码.

-E参数:

可以再-U –P 与 -E中选择一组. –E表示以当前系统用户通过windows身份验证登录数据库, -U -P则是使用SqlServer用户登录数据库.

-ssadd / –ssremove 参数:

-ssadd表示是添加Session数据库, -ssremove表示移除Session数据库.

sstype 参数说明:

sessionState参数说明：

[转载]MVC模式参数传递的探究 – 丁丁3 – 博客园.

MVC模式还有很多妙用，以后还会写更多有关MVC的文章。

[转载]JSON资料汇总 – 肖品 – 博客园.

JSON(JavaScript Object Notation) 是一种轻量级的数据交换格式。易于人阅读和编写。同时也易于机器解析和生成。它基于JavaScript Programming Language, Standard ECMA-262 3rd Edition – December 1999的一个子集。 JSON采用完全独立于语言的文本格式，但是也使用了类似于C语言家族的习惯（包括C, C++, C#, Java, JavaScript, Perl, Python等）。这些特性使JSON成为理想的数据交换语言。

JSON建构于两种结构：

• “名称/值”对的集合（A collection of name/value pairs）。不同的语言中，它被理解为对象（object），纪录（record），结构（struct），字典（dictionary），哈希表（hash table），有键列表（keyed list），或者关联数组 （associative array）。
• 值的有序列表（An ordered list of values）。在大部分语言中，它被理解为数组（array）。

这些都是常见的数据结构。事实上大部分现代计算机语言都以某种形式支持它们。这使得一种数据格式在同样基于这些结构的编程语言之间交换成为可能。

JSON具有以下这些形式：

对象是一个无序的“‘名称/值’对”集合。一个对象以“{”（左括号）开始，“}”（右括号）结束。每个“名称”后跟一个“:”（冒号）；“‘名称/值’ 对”之间使用“,”（逗号）分隔。

数组是值（value）的有序集合。一个数组以“[”（左中括号）开始，“]”（右中括号）结束。值之间使用“,”（逗号）分隔。

值（value）可以是双引号括起来的字符串（string）、数值(number)、true、false、 null、对象（object）或者数组（array）。这些结构可以嵌套。

字符串（string）是由双引号包围的任意数量Unicode字符的集合，使用反斜线转义。一个字符（character）即一个单独的字符串（character string）。

字符串（string）与C或者Java的字符串非常相似。

数值（number）也与C或者Java的数值非常相似。除去未曾使用的八进制与十六进制格式。除去一些编码细节。

空白可以加入到任何符号之间。

以下是相关学习资料：

官方介绍：
http://www.json.org/json-zh.html

微软介绍：
http://msdn.microsoft.com/zh-cn/library/bb299886.aspx

IBM介绍：
http://www.ibm.com/developerworks/cn/web/wa-ajaxintro/

实例说明：

JSON 基础

简单地说，JSON 可以将 JavaScript 对象中表示的一组数据转换为字符串，然后就可以在函数之间轻松地传递这个字符串，或者在异步应用程序中将字符串从 Web 客户机传递给服务器端程序。这个字符串看起来有点儿古怪（稍后会看到几个示例），但是 JavaScript 很容易解释它，而且 JSON 可以表示比名称/值对更复杂的结构。例如，可以表示数组和复杂的对象，而不仅仅是键和值的简单列表。

简单 JSON 示例

按照最简单的形式，可以用下面这样的 JSON 表示名称/值对：

{ “firstName”: “Brett” }
这个示例非常基本，而且实际上比等效的纯文本名称/值对占用更多的空间：

firstName=Brett
但是，当将多个名称/值对串在一起时，JSON 就会体现出它的价值了。首先，可以创建包含多个名称/值对的记录，比如：

{ “firstName”: “Brett”, “lastName”:”McLaughlin”, “email”: “brett@newInstance.com” }
从语法方面来看，这与名称/值对相比并没有很大的优势，但是在这种情况下 JSON 更容易使用，而且可读性更好。例如，它明确地表示以上三个值都是同一记录的一部分；花括号使这些值有了某种联系。

值的数组

当需要表示一组值时，JSON 不但能够提高可读性，而且可以减少复杂性。例如，假设您希望表示一个人名列表。在 XML 中，需要许多开始标记和结束标记；如果使用典型的名称/值对（就像在本系列前面文章中看到的那种名称/值对），那么必须建立一种专有的数据格式，或者将键 名称修改为 person1-firstName 这样的形式。

如果使用 JSON，就只需将多个带花括号的记录分组在一起：

{ “people”: [
{ “firstName”: “Brett”, “lastName”:”McLaughlin”, “email”: “brett@newInstance.com” },
{ “firstName”: “Jason”, “lastName”:”Hunter”, “email”: “jason@servlets.com” },
{ “firstName”: “Elliotte”, “lastName”:”Harold”, “email”: “elharo@macfaq.com” }
]}
这不难理解。在这个示例中，只有一个名为 people 的变量，值是包含三个条目的数组，每个条目是一个人的记录，其中包含名、姓和电子邮件地址。上面的示例演示如何用括号将记录组合成一个值。当然，可以使用相同的语法表示多个值（每个值包含多个记录）：

{ “programmers”: [
{ “firstName”: “Brett”, “lastName”:”McLaughlin”, “email”: “brett@newInstance.com” },
{ “firstName”: “Jason”, “lastName”:”Hunter”, “email”: “jason@servlets.com” },
{ “firstName”: “Elliotte”, “lastName”:”Harold”, “email”: “elharo@macfaq.com” }
],
“authors”: [
{ “firstName”: “Isaac”, “lastName”: “Asimov”, “genre”: “science fiction” },
{ “firstName”: “Tad”, “lastName”: “Williams”, “genre”: “fantasy” },
{ “firstName”: “Frank”, “lastName”: “Peretti”, “genre”: “christian fiction” }
],
“musicians”: [
{ “firstName”: “Eric”, “lastName”: “Clapton”, “instrument”: “guitar” },
{ “firstName”: “Sergei”, “lastName”: “Rachmaninoff”, “instrument”: “piano” }
]
}
这里最值得注意的是，能够表示多个值，每个值进而包含多个值。但是还应该注意，在不同的主条目（programmers、authors 和 musicians）之间，记录中实际的名称/值对可以不一样。JSON 是完全动态的，允许在 JSON 结构的中间改变表示数据的方式。

在处理 JSON 格式的数据时，没有需要遵守的预定义的约束。所以，在同样的数据结构中，可以改变表示数据的方式，甚至可以以不同方式表示同一事物。

在 JavaScript 中使用 JSON

掌握了 JSON 格式之后，在 JavaScript 中使用它就很简单了。JSON 是 JavaScript 原生格式，这意味着在 JavaScript 中处理 JSON 数据不需要任何特殊的 API 或工具包。

将 JSON 数据赋值给变量

例如，可以创建一个新的 JavaScript 变量，然后将 JSON 格式的数据字符串直接赋值给它：

var people =
{ “programmers”: [
{ “firstName”: “Brett”, “lastName”:”McLaughlin”, “email”: “brett@newInstance.com” },
{ “firstName”: “Jason”, “lastName”:”Hunter”, “email”: “jason@servlets.com” },
{ “firstName”: “Elliotte”, “lastName”:”Harold”, “email”: “elharo@macfaq.com” }
],
“authors”: [
{ “firstName”: “Isaac”, “lastName”: “Asimov”, “genre”: “science fiction” },
{ “firstName”: “Tad”, “lastName”: “Williams”, “genre”: “fantasy” },
{ “firstName”: “Frank”, “lastName”: “Peretti”, “genre”: “christian fiction” }
],
“musicians”: [
{ “firstName”: “Eric”, “lastName”: “Clapton”, “instrument”: “guitar” },
{ “firstName”: “Sergei”, “lastName”: “Rachmaninoff”, “instrument”: “piano” }
]
}
这非常简单；现在 people 包含前面看到的 JSON 格式的数据。但是，这还不够，因为访问数据的方式似乎还不明显。

访问数据

尽管看起来不明显，但是上面的长字符串实际上只是一个数组；将这个数组放进 JavaScript 变量之后，就可以很轻松地访问它。实际上，只需用点号表示法来表示数组元素。所以，要想访问 programmers 列表的第一个条目的姓氏，只需在 JavaScript 中使用下面这样的代码：

people.programmers[0].lastName;
注意，数组索引是从零开始的。所以，这行代码首先访问 people 变量中的数据；然后移动到称为 programmers 的条目，再移动到第一个记录（[0]）；最后，访问 lastName 键的值。结果是字符串值 “McLaughlin”。

下面是使用同一变量的几个示例。

people.authors[1].genre   // Value is “fantasy”

people.musicians[3].lastName // Undefined. This refers to the fourth entry,
and there isn’t one

people.programmers.[2].firstName // Value is “Elliotte”
利用这样的语法，可以处理任何 JSON 格式的数据，而不需要使用任何额外的 JavaScript 工具包或 API。

修改 JSON 数据

正如可以用点号和括号访问数据，也可以按照同样的方式轻松地修改数据：

people.musicians[1].lastName = “Rachmaninov”;
在将字符串转换为 JavaScript 对象之后，就可以像这样修改变量中的数据。

转换回字符串

当然，如果不能轻松地将对象转换回本文提到的文本格式，那么所有数据修改都没有太大的价值。在 JavaScript 中这种转换也很简单：

String newJSONtext = people.toJSONString();
这样就行了！现在就获得了一个可以在任何地方使用的文本字符串，例如，可以将它用作 Ajax 应用程序中的请求字符串。

更重要的是，可以将任何 JavaScript 对象转换为 JSON 文本。并非只能处理原来用 JSON 字符串赋值的变量。为了对名为 myObject 的对象进行转换，只需执行相同形式的命令：

String myObjectInJSON = myObject.toJSONString();
这就是 JSON 与本系列讨论的其他数据格式之间最大的差异。如果使用 JSON，只需调用一个简单的函数，就可以获得经过格式化的数据，可以直接使用了。对于其他数据格式，需要在原始数据和格式化数据之间进行转换。即使使用 Document Object Model 这样的 API（提供了将自己的数据结构转换为文本的函数），也需要学习这个 API 并使用 API 的对象，而不是使用原生的 JavaScript 对象和语法。

最终结论是，如果要处理大量 JavaScript 对象，那么 JSON 几乎肯定是一个好选择，这样就可以轻松地将数据转换为可以在请求中发送给服务器端程序的格式。

[转载]MSSQL分页：一个高效的二分法TOP MAX/TOP MIN分页存储过程 – 熊哥 www.relaxlife.net – 博客园.

CREATE PROCEDURE [dbo].[getPagerTopMAX] (
@tblName nvarchar(2000), —–要显示的表或多个表的连接,如：”myTable”
@ID nvarchar(150), —–主表的主键，如：”id”
@page int = 1, —–要显示那一页的记录
@pageSize int = 10, —–每页显示的记录个数
@fldName nvarchar(500) = ‘*‘, —–要显示的字段列表,如：”id, cdsinger, cdsingertype, area, cdsingerreadme”
@fldSort nvarchar(200) = @ID, —–排序字段列表或条件
@Sort bit = 1, —–排序方法，0为升序，1为降序(如果是多字段排列Sort指代最后一个排序字段的排列顺序(最后一个排序字段不加排序标记)–程序传参如：’ SortA Asc,SortB Desc,SortC ‘)
@strCondition nvarchar(1000) = null, —–查询条件,不需where,如：”and a=1 and b=2″
@Dist bit = 0, —–是否添加查询字段的 DISTINCT 默认0不添加/1添加
@Counts int = 1 output, —–查询到的记录数
@pageCount int = 1 output —–查询结果分页后的总页数
) AS begin
SET NOCOUNT ON
Declare @SQLTmp nvarchar(3000) —–存放动态生成的SQL语句
Declare @strTmp nvarchar(3000) —–存放取得查询结果总数的查询语句
Declare @strID nvarchar(3000) —–存放取得查询开头或结尾ID的查询语句

Declare @strSortType nvarchar(10) —–数据排序规则A
Declare @strFSortType nvarchar(10) —–数据排序规则B

Declare @SQLSelect nvarchar(50) —–对含有DISTINCT的查询进行SQL构造
Declare @SqlCounts nvarchar(50) —–对含有DISTINCT的总数查询进行SQL构造

if @Dist = 0
begin
set @SqlSelect = ‘select ‘
set @SqlCounts = ‘Count(*)‘
end
else
begin
set @SqlSelect = ‘select distinct ‘
set @SqlCounts = ‘Count(DISTINCT ‘+@ID+‘)‘
end

if @Sort=0
begin
set @strFSortType=‘ ASC ‘
set @strSortType=‘ DESC ‘
end
else
begin
set @strFSortType=‘ DESC ‘
set @strSortType=‘ ASC ‘
end

———生成查询语句——–

—此处@strTmp为取得查询结果数量的语句
if @strCondition is null or @strCondition=” —没有设置显示条件
begin
set @sqlTmp = @fldName + ‘ From ‘ + @tblName
set @strTmp = @SqlSelect+‘ @Counts=‘+@SqlCounts+‘ FROM ‘+@tblName
set @strID = ‘ From ‘ + @tblName
end
else
begin
set @sqlTmp = + @fldName + ‘From ‘ + @tblName + ‘ where (1>0) ‘ + @strCondition
set @strTmp = @SqlSelect+‘ @Counts=‘+@SqlCounts+‘ FROM ‘+@tblName + ‘ where (1>0) ‘ + @strCondition
set @strID = ‘ From ‘ + @tblName + ‘ where (1>0) ‘ + @strCondition
end

—–取得查询结果总数量—–
exec sp_executesql @strTmp,N‘@Counts int out ‘,@Counts out
declare @tmpCounts int
if @Counts = 0
set @tmpCounts = 1
else
set @tmpCounts = @Counts

—取得分页总数
set @pageCount=(@tmpCounts+@pageSize–1)/@pageSize

/**//**当前页大于总页数 取最后一页**/
if @page>@pageCount
set @page=@pageCount

—/*—–数据分页2分处理——-*/
declare @pageIndex int —总数/页大小
declare @lastcount int —总数%页大小

set @pageIndex = @tmpCounts/@pageSize
set @lastcount = @tmpCounts%@pageSize
if @lastcount > 0
set @pageIndex = @pageIndex + 1
else
set @lastcount = @pagesize

—//***显示分页
if @strCondition is null or @strCondition=” —没有设置显示条件
begin
if @pageIndex<2 or @page<=@pageIndex / 2 + @pageIndex % 2 —前半部分数据处理
begin
if @page=1
set @strTmp=@SqlSelect+‘ top ‘+ CAST(@pageSize as VARCHAR(20))+‘ ‘+ @fldName+‘ from ‘+@tblName
+‘ order by ‘+ @fldSort +‘ ‘+ @strFSortType
else
begin
set @strTmp=@SqlSelect+‘ top ‘+ CAST(@pageSize as VARCHAR(20))+‘ ‘+ @fldName+‘ from ‘+@tblName
+‘ where ‘+@ID+‘ <(select min(‘+ @ID +‘) from (‘+ @SqlSelect+‘ top ‘+ CAST(@pageSize*(@page–1) as Varchar(20)) +‘ ‘+ @ID +‘ from ‘+@tblName
+‘ order by ‘+ @fldSort +‘ ‘+ @strFSortType+‘) AS TBMinID)‘
+‘ order by ‘+ @fldSort +‘ ‘+ @strFSortType
end
end
else
begin
set @page = @pageIndex–@page+1 —后半部分数据处理
if @page <= 1 —最后一页数据显示
set @strTmp=@SqlSelect+‘ * from (‘+@SqlSelect+‘ top ‘+ CAST(@lastcount as VARCHAR(20))+‘ ‘+ @fldName+‘ from ‘+@tblName
+‘ order by ‘+ @fldSort +‘ ‘+ @strSortType+‘) AS TempTB‘+‘ order by ‘+ @fldSort +‘ ‘+ @strFSortType
else
set @strTmp=@SqlSelect+‘ * from (‘+@SqlSelect+‘ top ‘+ CAST(@pageSize as VARCHAR(20))+‘ ‘+ @fldName+‘ from ‘+@tblName
+‘ where ‘+@ID+‘ >(select max(‘+ @ID +‘) from(‘+ @SqlSelect+‘ top ‘+ CAST(@pageSize*(@page–2)+@lastcount as Varchar(20)) +‘ ‘+ @ID +‘ from ‘+@tblName
+‘ order by ‘+ @fldSort +‘ ‘+ @strSortType+‘) AS TBMaxID)‘
+‘ order by ‘+ @fldSort +‘ ‘+ @strSortType+‘) AS TempTB‘+‘ order by ‘+ @fldSort +‘ ‘+ @strFSortType
end
end

else —有查询条件
begin
if @pageIndex<2 or @page<=@pageIndex / 2 + @pageIndex % 2 —前半部分数据处理
begin
if @page=1
set @strTmp=@SqlSelect+‘ top ‘+ CAST(@pageSize as VARCHAR(20))+‘ ‘+ @fldName+‘ from ‘+@tblName
+‘ where 1=1 ‘ + @strCondition + ‘ order by ‘+ @fldSort +‘ ‘+ @strFSortType
else
begin
set @strTmp=@SqlSelect+‘ top ‘+ CAST(@pageSize as VARCHAR(20))+‘ ‘+ @fldName+‘ from ‘+@tblName
+‘ where ‘+@ID+‘ <(select min(‘+ @ID +‘) from (‘+ @SqlSelect+‘ top ‘+ CAST(@pageSize*(@page–1) as Varchar(20)) +‘ ‘+ @ID +‘ from ‘+@tblName
+‘ where (1=1) ‘ + @strCondition +‘ order by ‘+ @fldSort +‘ ‘+ @strFSortType+‘) AS TBMinID)‘
+‘ ‘+ @strCondition +‘ order by ‘+ @fldSort +‘ ‘+ @strFSortType
end
end
else
begin
set @page = @pageIndex–@page+1 —后半部分数据处理
if @page <= 1 —最后一页数据显示
set @strTmp=@SqlSelect+‘ * from (‘+@SqlSelect+‘ top ‘+ CAST(@lastcount as VARCHAR(20))+‘ ‘+ @fldName+‘ from ‘+@tblName
+‘ where (1=1) ‘+ @strCondition +‘ order by ‘+ @fldSort +‘ ‘+ @strSortType+‘) AS TempTB‘+‘ order by ‘+ @fldSort +‘ ‘+ @strFSortType
else
set @strTmp=@SqlSelect+‘ * from (‘+@SqlSelect+‘ top ‘+ CAST(@pageSize as VARCHAR(20))+‘ ‘+ @fldName+‘ from ‘+@tblName
+‘ where ‘+@ID+‘ >(select max(‘+ @ID +‘) from(‘+ @SqlSelect+‘ top ‘+ CAST(@pageSize*(@page–2)+@lastcount as Varchar(20)) +‘ ‘+ @ID +‘ from ‘+@tblName
+‘ where (1=1) ‘+ @strCondition +‘ order by ‘+ @fldSort +‘ ‘+ @strSortType+‘) AS TBMaxID)‘
+‘ ‘+ @strCondition+‘ order by ‘+ @fldSort +‘ ‘+ @strSortType+‘) AS TempTB‘+‘ order by ‘+ @fldSort +‘ ‘+ @strFSortType
end
end

——-返回查询结果—–
—print @strTmp
exec (@strTmp)

SET NOCOUNT OFF

end

[转载]发型试戴原理简析 – xiaotie – 博客园.

RIA 使技术变得有趣起来，比如CAD，Matlab等工具，未来非常适合直接以RIA方式在线运行。技术转型后，给自己的技术方向定的很窄，RIA这一块也只 关注在线图形图像应用，如在线试戴、试穿、试用、试装修等功能。试发系统已经做了好几套了，当然主要还是借鉴国外的系统taaz和thehairstyles，下面简析一下发型试戴的原理。

发型试戴的两个核心问题：

（1）如何让千奇百怪的发型自动戴在千奇百怪的模特头上，戴在正确的位置上？

（2）戴上之后，用户如何调整发型？不仅仅限于放大，缩小，上下左右挪动，而是“自由”变形。

====

问题1的解决方案：

这是taaz的解决方案。假定一个标准的模特S，脸上有6个坐标点，见图：

根据5，6两点，可以求出它的中点7：

由点1，4，7构成一个三角形S(1,4,7)。

用户上传自己的头像U，也需要指定1-6点的坐标，由此也可以算出7点的坐标。U(1,4,7)构成另一个三角形。算出 S(1,4,7)=>U(1,4,7) 的仿射变换A_SU。A_SU确定了标准模特和用户上传模特的仿射变换。

关于仿射变换，这里有一篇文章给了很直观的解释。

对于发型，由于有人脸大，有人脸小，有人脸宽，有人脸窄，因此使用的是另一个定位三角形：

使用上图中的8，9，10三点进行定位。对于标准模特S，可以测量得出它的8，9，10三点构成的三角形 S(8,9,10)。对于每个发型H，我们也指定一下以上三点，构成三角形H(8,9,10)。

计算H(8,9,10)=> S(8,9,10)的仿射变换A_HS。A_HS实现了发型图像到标准模特脸上的仿射变换。

如此一来，对于一个发型H，做两次仿射变换——A_SU(A_HS(H))，即可将发型戴于用户自己的头像U上。这个映射可以让发型正确“找到”自己的位置。

====

问题2的解决方案：

如果想更精细的调整发型试戴的效果，可在发型位置增加一些控制点，使用TPS样条实现变形效果，taaz是这样做的。TPS样条见我的博文 《TPS(薄板样条) 2D 插值》，这里贴张图：

TPS更详细的描述及算法见F.L. Bookstein, “Principal Warps: Thin-Plate Splines and the Decomposition of Deformations,”

也可以使用局部变形算法（见：《图像变形算法:实现Photoshop液化工具箱中向前变形工具》），我是这样干的：

对比来说，TPS更好用一些，局部变形做细微调整的能力更强一点。

[转载]ASP.NET MVC Best Practices (Part 1) – Kazi Manzur Rashid’s Blog.

In this post, I will share some of the best practices/guideline in developing ASP.NET MVC applications which I have learned in the hard way. I will not tell you to use DI or Unit Test instead I will assume you are already doing it and you prefer craftsmanship over anything.

1. Create Extension methods of UrlHelper to generate your url from Route

Avoid passing the controller, action or route name as string, create extension methods of UrlHelper which encapsulates it, for example:

Now, You can use the following in your view:

Instead of:

And in Controller I can use:

Instead of:

Of course you can use the strongly typed version which takes the controller, method and the parameters of the future assembly or create your own to avoid the future refactoring pain, but remember it is not officially supported and might change in the future. You can also use the above with the strongly typed version, certainly “adding another layer of indirection” (Scott Ha favorite quote) has some benefits. Another benefit when writing Unit Test you will only deal with the RedirectResult rather than RediretResult and RedirectToRouteResult.

2. Create Extension Method of UrlHelper to map your JavaScript, Stylesheet and Image Folder

By default ASP.NET MVC creates Content, Scripts folder for these things, which I do not like, Instead I like the following folder structure so that I can only set static file caching  on the Assets folder in IIS instead of going to multiple folders:

Assets
+images
+scripts
+stylesheets

No matter what the structure is, create some extension method of UrlHelper to map these folders, so that you can easily refer it in your view and later on if you need to change the structure, you do not have to do massive find/replace. I would also recommend to create extension methods for those assets which are often refereed in your views. For example:

And when referring the assets you can use:

Instead of the default:

3. Use Bootstrapper in Global.asax

I have already covered it in the past, basically if you are doing a lot things in Application_Start of global.asax e.g. Registering Routes, Registering Controller Factory, Model Binders, View Engine, starting application specific background services, create individual task for specific part, then do use Bootstrapper to execute those. This make your code lot more clean and testable. This will be also helpful when developing a portal kind of app in asp.net mvc where each module can have some startup initialization without affecting others. But if you are developing a small app where the above things will never be an issue you can surly go ahead with the default global.asax.

4. Do not make any hard dependency on the DI Container, use Common Service Locator

Do not clutter your code with any specific DI reference, instead use the Common Service Locator, it is an abstraction over the underlying DI and it has the support for all of the popular DI containers, so that you can replace the underlying DI without modifying your application code as each DI Container has some unique features over the others. Tim Barcz recently wrote a excellent post on this subject, how much obsessed we are with our favorite DI Container but I am not sure why he did not mention about it. The Common Service Locator has the support for most of the regular scenarios, but for specific case for example injecting dependency in already instantiated object which as per my knowledge StructureMap, Ninject and Unity supports you can call the static ServiceLocator.Current.GetInstance in the constructor instead of calling the underlying DI. And for those who do know, Common Service Locator is a joint effort of the DI Containers creators initiated by Jeremy D Miller.

Creating Controller Factory with Common Service Locator is very easy:

I hope the MVCContrib guys will follow the same instead of creating separate Controller Factory for each Container.

5. Decorate your Action Methods with Proper AcceptVerbs Attribute

ASP.NET MVC is much more vulnerable comparing to Web Forms. Make sure the action methods that modifies the data only accepts HttpVerbs.Post. If security is too much concern use the ValidateAntiForgeryToken or you can use Captcha. Derik Whittaker has an excellent post as well as a screen cast on how to integrate reCaptcha with ASP.NET MVC application, which I highly recommend. (Side Note: Do not miss a single episode of DimeCasts.net, I have learnt a lot form those short screen casts). My rule of thumb is use HttpVerbs.Post for all data modification actions and HttpVerbs.Get for data reading operations.

6. Decorate your most frequent Action Methods with OutputCache Attribute

Use OutputCache attribute when you are returning the less frequent updated data, prime candidate may be your home page, feed etc etc. You can use it for both Html and Json data types. When using it, only specify the Cache Profile name, do not not specify any other thing, use the web.config output cache section to fine tune it. For example:

And in web.config:

7. Keep your controller free from HttpContext and its tail

Make sure your controller does not have to refer the HttpContext and its tail. it will make your life easier when unit testing your Controller. If you need to access anything from HttpContext like User, QueryString, Cookie etc use custom action filter or create some interface and wrapper and pass it in the constructor. For example, for the following Route:

But the controller action methods is declared as:

The UserNameFilter is responsible for passing the UserName:

[Update: Make sure you have decorate either the Action or the Controller with Authorize attribute, check the comments]

8. Use Action Filter to Convert to compatible Action Methods parameters

Use Action Filter to convert incoming values to your controller action method parameters, again consider the Dashboard method, we are accepting tab and orderBy as Enum.

The StoryListFilter will be responsible to convert it to proper data type from route values/querystrings.

You can also use the custom Model Binder for the same purpose. In that case you will have to create two custom Model Binders for each Enum instead of one action filter. Another issue with the Model Binder is once it is registered for a type it will always come into action, but action filter can be selectively applied.

9. Action Filter Location

If you need the same action filter to all of your controller action methods,  put it in the controller rather than each action method. If you want to apply the same action filter to all of your controller create a base controller and inherit from that base controller, for example the story controller should be only used when user is logged in and we need to pass the current user name in its methods, also the StoryController should compress the data when returning:

But if the inheritance hierarchy is going more than 2 /3 level deep, find another way to apply the filters. The latest Oxite code has some excellent technique applying filters dynamically which I highly recommend to check.

10. Use UpdateModel Carefully

I do not want to repeat what Justin Etheredge has mentioned in his post, be careful and do not fall into that trap.

11.Controller will not contain any Domain logic

Controller should be only responsible for:

• Validating Input
• Calling Model to prepare the view
• Return the view or redirect to another action

If you are doing any other thing you are doing it in a wrong place, it is rather the Model responsibility which you are doing in Controller. If you follow this rule your action method will not be more than 20 – 25 lines of code. Ian Cooper has an excellent post Skinny Controller Fat Model, do read it.

12. Avoid ViewData, use ViewData.Model

Depending upon the dictionary key will not only make your code hard to refactor, also you will have to write the casting code in your view. It is completely okay even you end up per class for each action method of your controller.  If you think, creating these kind of classes is a tedious job, you can use the ViewDataExtensions of the MVCContrib project, it has some nice extension for returning strongly typed objects, though you still have to depend upon the string key if you have more than one data type in ViewData Dictionary.

13. Use PRG Pattern for Data Modification

Tim Barcz, Matt Hawley, Stephen Walther and even The Gu has blogged this over here, here, here and here. One of the issue with this pattern is when a validation fails or any  exception occurs you have to copy the ModelState into TempData. If you are doing it manually, please stop it, you can do this automatically with Action Filters, like the following:

And the Action Filers

The MVCContrib project also has this feature but they are doing it in a single class which I do not like, I would like to have more control which method to export and which to import.

14. Create Layer Super Type for your ViewModel and Use Action Filter to populate common parts.

Create a layer super type for your view model classes and use action filter to populate common things into it . For example the tiny little application that I am developing I need to know the User Name and whether the User is authenticated.

and the action filter:

As you can see that it not replacing the model, if it is previously set in the controller, rather it populates the common part if it finds it compatible. Other benefit is, the views that only depends the layer super type you can simply return View() instead of creating the model.

That’s it for today, I will post rest of the items tomorrow.

Stay tuned.

[转载]ASP.NET MVC Best Practices (Part 2) – Kazi Manzur Rashid’s Blog.

ASP.NET MVC Best Practices (Part 2)

This is the second part of the series and may be the last, till I find some thing new. My plan was to start with routing, controller, controller to model, controller to view and last of all the view, but some how I missed one important thing in routing, so I will begin with that in this post.

15. Routing consideration

If you are developing a pure ASP.NET MVC application, turn off existing file check of routes, it will eliminate unnecessary file system check. Once you do it there are few more things you have to consider. Remember when you are hosting application in IIS7 integrated mode, your ASP.NET application will intercept all kind of request, no matter what the file extension is. So you have to add few more things in the ignore list which your ASP.NET MVC application will not process. This might include static files like html, htm, text file specially robots.txt, favicon.ico, script, image and css etc. This is one of the reason, why I do not like the default directory structure (Contents and Scripts folder) mentioned in my #2 in the previous post. The following is somewhat my standard template for defining routes when hosting in IIS7:

Next, few of my personal preference rather than guideline, by default ASP.NET MVC generates url like {controller}/{action} which is okay when you are developing multi-module application,  for a small application, I usually prefer the action name without the controller name, so instead of www.yourdomain.com/Story/Dashboard, www.yourdomain.com/Membership/SignIn it will generate www.yourdomain.com/Dashboard, www.yourdomain.com/Signin. So I add few more routes:

16. Create new ActionResult if required

ASP.NET MVC has quite a number of ActionResult for different purposes, but still we might need new ActionResult. For example xml, rss, atom etc. In those cases, I would suggest instead of using the generic ContentResult, create new ActionResult. The MVCContrib has an XmlResult which you can use for returning xml but no support for feed. Yes it is obviously tricky to convert an unknown object into rss/atom, in those cases you can create model specific ActionResult. For example:

And in Controller:

17. Split your View into multiple ViewUserControl

Split your view into multiple ViewUserControl when it is getting bigger, it really does not matter whether the same UserControl is reused in another page, it makes the very view much more readable. Consider the following view:

18. HtmlHelper extension

First, read this great post of Rob Conery and I completely agree, you should create helper methods for each condition and I would also suggest to create helper methods for reusable UI elements like the ASP.NET MVC team did, but I have a different suggestion about the placing of these methods that we are currently practicing.

Application Developer

Do only create extension methods of HtmlHelper if you are using it in more than one view. Otherwise create a view specific helper and create an extension method of the HtmlHelper which returns the view specific helper. for example: