专题八的上篇大致讨论了MemberRole中的Membership实现，对于运用Membership进行web开发足够，但是对于想更深入了解Membership实现机理的朋友那是远远不够的，这个专题我们更深入一下了解Membership。
其实MemberRole是一个非常好的资源包，借住Reflector这个优秀的工具，你可以对其进行代码分析。它无论是在组建的构架、代码的设计、数据库表的建立、存储过程的使用等都是非常优秀的，你是程序员也好构架师也罢，其中可以学习的真的很多很多，我在整个分析的过程中也深深受益。
由于MemberRole中的Membership只实现了对SQL Server的操Provider类，即SqlMembershipProvider类。因此我们从SqlMembershipProvider开始分析。Provider模型在上篇已经做过介绍，SqlMembershipProvider类继承了MembershipProvider，并实现其所有的抽象方法。在分析之前先看两个类：MembershipUser与MembershipUserCollection。
MembershipUser，先看看代码：(代码中省略的具体实现，只有方法与属性名称)
public class MembershipUser
{
// Methods
protected MembershipUser();
public MembershipUser(MembershipProvider provider, string name, object providerUserKey, string email, string passwordQuestion, string comment, bool isApproved, bool isLockedOut, DateTime creationDate, DateTime lastLoginDate, DateTime lastActivityDate, DateTime lastPasswordChangedDate, DateTime lastLockoutDate);
public virtual bool ChangePassword(string oldPassword, string newPassword);
public virtual bool ChangePasswordQuestionAndAnswer(string password, string newPasswordQuestion, string newPasswordAnswer);
public virtual string GetPassword();
public virtual string GetPassword(string passwordAnswer);
public virtual string ResetPassword();
public virtual string ResetPassword(string passwordAnswer);
public override string ToString();
public virtual bool UnlockUser();
internal virtual void Update();
private void UpdateSelf();
// Properties
public virtual string Comment { get; set; }
public virtual DateTime CreationDate { get; }
public virtual string Email { get; set; }
public virtual bool IsApproved { get; set; }
public virtual bool IsLockedOut { get; }
public bool IsOnline { get; }
public virtual DateTime LastActivityDate { get; set; }
public virtual DateTime LastLockoutDate { get; }
public virtual DateTime LastLoginDate { get; set; }
public virtual DateTime LastPasswordChangedDate { get; }
public virtual string PasswordQuestion { get; }
public virtual MembershipProvider Provider { get; }
public virtual object ProviderUserKey { get; }
public virtual string UserName { get; }
// Fields
private string _Comment;
private DateTime _CreationDate;
private string _Email;
private bool _IsApproved;
private bool _IsLockedOut;
private DateTime _LastActivityDate;
private DateTime _LastLockoutDate;
private DateTime _LastLoginDate;
private DateTime _LastPasswordChangedDate;
private string _PasswordQuestion;
private MembershipProvider _Provider;
private object _ProviderUserKey;
private string _UserName;
}
这是一个实体类，表示一个由Membership创建的User，该类中有这个User的一些基本状态，如该User的UserName、Email等，还有一些方法，如ChangePassword()、ResetPassword()等（如果你是初学者，还在为建立一个对象需要什么属性，包含什么方法发愁，那这就是你应该好好学的，这也是OOP最基本的要求）。
MembershipUserCollection，这是一个MembershipUser类的容器，用来存放MembershipUser列表，记得上次广州.net俱乐部聚会时，我的演讲中有朋友在提出CS是否使用自定义类来存储用户列表，其实在这里可以看到CS中使用的就是自定义的类而不是DataSet(我想在asp.net 2.0正式发布后这也不会改变)，这样做主要是因为考虑到性能与灵活性。
好了，回到SqlMembershipProvider类上来，我们具体分析一个有代表性质的方法：
public override MembershipUser CreateUser(string username, string password, string email, string passwordQuestion, string passwordAnswer, bool isApproved, object providerUserKey, out MembershipCreateStatus status)
{
string text3;
MembershipUser user1;
if (!SecUtility.ValidateParameter(ref password, true, true, false, 0x80))
{
status = MembershipCreateStatus.InvalidPassword;
return null;
}
string text1 = base.GenerateSalt();
string text2 = base.EncodePassword(password, (int) this._PasswordFormat, text1);
if (text2.Length > 0x80)
{
status = MembershipCreateStatus.InvalidPassword;
return null;
}
if (passwordAnswer != null)
{
passwordAnswer = passwordAnswer.Trim();
}
if ((passwordAnswer != null) && (passwordAnswer.Length > 0))
{
if (passwordAnswer.Length > 0x80)
{
status = MembershipCreateStatus.InvalidAnswer;
return null;
}
text3 = base.EncodePassword(passwordAnswer.ToLower(CultureInfo.InvariantCulture), (int) this._PasswordFormat, text1);
}
else
{
text3 = passwordAnswer;
}
if (!SecUtility.ValidateParameter(ref text3, this.RequiresQuestionAndAnswer, this.RequiresQuestionAndAnswer, false, 0x80))
{
status = MembershipCreateStatus.InvalidAnswer;
return null;
}
if (!SecUtility.ValidateParameter(ref username, true, true, true, 0x100))
{
status = MembershipCreateStatus.InvalidUserName;
return null;
}
if (!SecUtility.ValidateParameter(ref email, this.RequiresUniqueEmail, this.RequiresUniqueEmail, false, 0x100))
{
status = MembershipCreateStatus.InvalidEmail;
return null;
}
if (!SecUtility.ValidateParameter(ref passwordQuestion, this.RequiresQuestionAndAnswer, this.RequiresQuestionAndAnswer, false, 0x100))
{
status = MembershipCreateStatus.InvalidQuestion;
return null;
}
if ((providerUserKey != null) && !(providerUserKey is Guid))
{
status = MembershipCreateStatus.InvalidProviderUserKey;
return null;
}
if (password.Length < this.MinRequiredPasswordLength)
{
status = MembershipCreateStatus.InvalidPassword;
return null;
}
int num1 = 0;
for (int num2 = 0; num2 < password.Length; num2++)
{
if (!char.IsLetterOrDigit(password, num2))
{
num1++;
}
}
if (num1 < this.MinRequiredNonAlphanumericCharacters)
{
status = MembershipCreateStatus.InvalidPassword;
return null;
}
if ((this.PasswordStrengthRegularExpression.Length > 0) && !Regex.IsMatch(password, this.PasswordStrengthRegularExpression))
{
status = MembershipCreateStatus.InvalidPassword;
return null;
}
ValidatePasswordEventArgs args1 = new ValidatePasswordEventArgs(username, password, true);
this.OnValidatingPassword(args1);
if (args1.Cancel)
{
status = MembershipCreateStatus.InvalidPassword;
return null;
}
try
{
SqlConnectionHolder holder1 = null;
try
{
holder1 = SqlConnectionHelper.GetConnection(this._sqlConnectionString, true);
this.CheckSchemaVersion(holder1.Connection);
SqlCommand command1 = new SqlCommand("dbo.aspnet_Membership_CreateUser", holder1.Connection);
command1.CommandTimeout = this.CommandTimeout;
command1.CommandType = CommandType.StoredProcedure;
command1.Parameters.Add(this.CreateInputParam("@ApplicationName", SqlDbType.NVarChar, this.ApplicationName));
command1.Parameters.Add(this.CreateInputParam("@UserName", SqlDbType.NVarChar, username));
command1.Parameters.Add(this.CreateInputParam("@Password", SqlDbType.NVarChar, text2));
command1.Parameters.Add(this.CreateInputParam("@PasswordSalt", SqlDbType.NVarChar, text1));
command1.Parameters.Add(this.CreateInputParam("@Email", SqlDbType.NVarChar, email));
command1.Parameters.Add(this.CreateInputParam("@PasswordQuestion", SqlDbType.NVarChar, passwordQuestion));
command1.Parameters.Add(this.CreateInputParam("@PasswordAnswer", SqlDbType.NVarChar, text3));
command1.Parameters.Add(this.CreateInputParam("@IsApproved", SqlDbType.Bit, isApproved));
command1.Parameters.Add(this.CreateInputParam("@UniqueEmail", SqlDbType.Int, this.RequiresUniqueEmail ? 1 : 0));
command1.Parameters.Add(this.CreateInputParam("@PasswordFormat", SqlDbType.Int, (int) this.PasswordFormat));
command1.Parameters.Add(this.GetTimeZoneAdjustmentParam());
SqlParameter parameter1 = this.CreateInputParam("@UserId", SqlDbType.UniqueIdentifier, providerUserKey);
parameter1.Direction = ParameterDirection.InputOutput;
command1.Parameters.Add(parameter1);
parameter1 = new SqlParameter("@ReturnValue", SqlDbType.Int);
parameter1.Direction = ParameterDirection.ReturnValue;
command1.Parameters.Add(parameter1);
object obj1 = command1.ExecuteScalar();
DateTime time1 = this.RoundToSeconds(DateTime.Now);
if ((obj1 != null) && (obj1 is DateTime))
{
time1 = (DateTime) obj1;
}
int num3 = (parameter1.Value != null) ? ((int) parameter1.Value) : -1;
if ((num3 < 0) || (num3 > 11))
{
num3 = 11;
}
status = (MembershipCreateStatus) num3;
if (num3 != 0)
{
return null;
}
providerUserKey = new Guid(command1.Parameters["@UserId"].Value.ToString());
return new MembershipUser(this, username, providerUserKey, email, passwordQuestion, null, isApproved, false, time1, time1, time1, time1, new DateTime(0x6da, 1, 1));
}
finally
{
if (holder1 != null)
{
holder1.Close();
holder1 = null;
}
}
}
catch
{
throw;
}
return user1;
}
该方法实现建立一个用户的过程，建立后返回一个被建立的MembershipUser对象，如果建立失败MembershipUser对象为null(其实我早期做过一些项目的时候喜欢在建立对象成功后返回一个ID)。可以看到在这个方法中有很多的if语句，它们是为了检验数据是否合法，这是必须的吗？其实不是，但对于构建一个强壮的底层代码这是必须的，不然一点点的错误都有可能导致系统的瘫痪。其实做项目与做开发有的时候不太一样，企业的有些项目开发很多时候只要能实现功能就可以了，而且开发过程也集中在一些现有的代码或者组建的基础上，个人的错误不会影响全局的运行，PM也不做过多要求。但如果是做产品，这个情况可能会有所改变，很多时候要求很严格，至少我是这样。在做完对输入参数的验证后，CreateUser建立与数据库的连接，这里是调用SqlConnectionHelper类下的GetConnection方法进行的，为了照顾初学者阅读，我这里讲一下为什么需要把对数据库连接与操作写在SqlConnectionHelper类下，而不是直接采用SqlConnection提供的方法，其实这是一个设计模式的问题，Membership的实现需要很多的方法与数据库进行交换数据库，如果每次方法都调用一次SqlConnection的方法建立数据库连接，一来会造成大量的代码冗余，而且一旦数据库连接语句一旦改变，你就要去修改很多个方法，如果你把这个过程都包装在一个类下面，连接数据库就有统一的入口，一来容易维护，二来不会有太多的代码冗余，再者如果需要查找错误也非常容易。这里Membership采用的是存储过程，我们可以看到使用的是dbo.aspnet_Membership_CreateUser存储过程，好了，打开你的数据库，找到这个存储过程：
CREATE PROCEDURE dbo.aspnet_Membership_CreateUser
@ApplicationName NVARCHAR(256),
@UserName NVARCHAR(256),
@Password NVARCHAR(128),
@PasswordSalt NVARCHAR(128),
@Email NVARCHAR(256),
@PasswordQuestion NVARCHAR(256),
@PasswordAnswer NVARCHAR(128),
@IsApproved BIT,
@TimeZoneAdjustment INT,
@CreateDate DATETIME = NULL,
@UniqueEmail INT = 0,
@PasswordFormat INT = 0,
@UserId UNIQUEIDENTIFIER OUTPUT
AS
BEGIN
DECLARE @ApplicationId UNIQUEIDENTIFIER
SELECT @ApplicationId = NULL
DECLARE @NewUserId UNIQUEIDENTIFIER
SELECT @NewUserId = NULL
DECLARE @IsLockedOut BIT
SET @IsLockedOut = 0
DECLARE @LastLockoutDate DATETIME
SET @LastLockoutDate = CONVERT( DATETIME, '17540101', 112 )
DECLARE @FailedPasswordAttemptCount INT
SET @FailedPasswordAttemptCount = 0
DECLARE @FailedPasswordAttemptWindowStart DATETIME
SET @FailedPasswordAttemptWindowStart = CONVERT( DATETIME, '17540101', 112 )
DECLARE @FailedPasswordAnswerAttemptCount INT
SET @FailedPasswordAnswerAttemptCount = 0
DECLARE @FailedPasswordAnswerAttemptWindowStart DATETIME
SET @FailedPasswordAnswerAttemptWindowStart = CONVERT( DATETIME, '17540101', 112 )
DECLARE @NewUserCreated BIT
DECLARE @ReturnValue INT
SET @ReturnValue = 0
DECLARE @ErrorCode INT
SET @ErrorCode = 0
DECLARE @TranStarted BIT
SET @TranStarted = 0
IF( @@TRANCOUNT = 0 )
BEGIN
BEGIN TRANSACTION
SET @TranStarted = 1
END
ELSE
SET @TranStarted = 0
EXEC dbo.aspnet_Applications_CreateApplication @ApplicationName, @ApplicationId OUTPUT
IF( @@ERROR <> 0 )
BEGIN
SET @ErrorCode = -1
GOTO Cleanup
END
IF (@CreateDate IS NULL)
EXEC dbo.aspnet_GetUtcDate @TimeZoneAdjustment, @CreateDate OUTPUT
ELSE
SELECT @CreateDate = DATEADD(n, -@TimeZoneAdjustment, @CreateDate) -- switch TO UTC time
SELECT @NewUserId = UserId FROM dbo.aspnet_Users WHERE LOWER(@UserName) = LoweredUserName AND @ApplicationId = ApplicationId
IF ( @NewUserId IS NULL )
BEGIN
SET @NewUserId = @UserId
EXEC @ReturnValue = dbo.aspnet_Users_CreateUser @ApplicationId, @UserName, 0, @CreateDate, @NewUserId OUTPUT
SET @NewUserCreated = 1
END
ELSE
BEGIN
SET @NewUserCreated = 0
IF( @NewUserId <> @UserId AND @UserId IS NOT NULL )
BEGIN
SET @ErrorCode = 6
GOTO Cleanup
END
END
IF( @@ERROR <> 0 )
BEGIN
SET @ErrorCode = -1
GOTO Cleanup
END
IF( @ReturnValue = -1 )
BEGIN
SET @ErrorCode = 10
GOTO Cleanup
END
IF ( EXISTS ( SELECT UserId
FROM dbo.aspnet_Membership
WHERE @NewUserId = UserId ) )
BEGIN
SET @ErrorCode = 6
GOTO Cleanup
END
SET @UserId = @NewUserId
IF (@UniqueEmail = 1)
BEGIN
IF (EXISTS (SELECT *
FROM dbo.aspnet_Membership m WITH ( UPDLOCK, HOLDLOCK )
WHERE ApplicationId = @ApplicationId AND LoweredEmail = LOWER(@Email)))
BEGIN
SET @ErrorCode = 7
GOTO Cleanup
END
END
INSERT INTO dbo.aspnet_Membership
( ApplicationId,
UserId,
Password,
PasswordSalt,
Email,
LoweredEmail,
PasswordQuestion,
PasswordAnswer,
PasswordFormat,
IsApproved,
IsLockedOut,
CreateDate,
LastLoginDate,
LastPasswordChangedDate,
LastLockoutDate,
FailedPasswordAttemptCount,
FailedPasswordAttemptWindowStart,
FailedPasswordAnswerAttemptCount,
FailedPasswordAnswerAttemptWindowStart )
VALUES ( @ApplicationId,
@UserId,
@Password,
@PasswordSalt,
@Email,
LOWER(@Email),
@PasswordQuestion,
@PasswordAnswer,
@PasswordFormat,
@IsApproved,
@IsLockedOut,
@CreateDate,
@CreateDate,
@CreateDate,
@LastLockoutDate,
@FailedPasswordAttemptCount,
@FailedPasswordAttemptWindowStart,
@FailedPasswordAnswerAttemptCount,
@FailedPasswordAnswerAttemptWindowStart )
IF( @@ERROR <> 0 )
BEGIN
SET @ErrorCode = -1
GOTO Cleanup
END
IF (@NewUserCreated = 0)
BEGIN
UPDATE dbo.aspnet_Users
SET LastActivityDate = @CreateDate
WHERE @UserId = UserId
IF( @@ERROR <> 0 )
BEGIN
SET @ErrorCode = -1
GOTO Cleanup
END
END
SELECT @CreateDate = DATEADD( n, @TimeZoneAdjustment, @CreateDate )
IF( @TranStarted = 1 )
BEGIN
SET @TranStarted = 0
COMMIT TRANSACTION
END
RETURN 0
Cleanup:
IF( @TranStarted = 1 )
BEGIN
SET @TranStarted = 0
ROLLBACK TRANSACTION
END
RETURN @ErrorCode
END
GO
够长的，不过没有关系，分几个部分看，首先是定义一些要发挥得参数，然后初始化，接着EXEC dbo.aspnet_Applications_CreateApplication，调用aspnet_Applications_CreateApplication存储过程，建立一个名字为@ApplicationName 的Application，如果该Application不存在的话。并且返回该Application的ID，这里的ApplicationName在web.config membership节点中设置过，即：dev。如果执行以上过程有错误，通过SQL的GOTO语句跳至Cleanup部分，执行ROLLBACK TRANSACTION，回滚这次操作。如果没有错误存储过程就接着向下执行，EXEC dbo.aspnet_GetUtcDate @TimeZoneAdjustment, @CreateDate OUTPUT，这是获得当前Utc时间。再下来就判断aspnet_Users表中用户的UserId是否在数据库中有该UserId(UserId是一个Guid)，如果没有就在表aspnet_Users中建立。这时在进行一次失分发生错误的判断，执行的方法与前一次一样。再下来判断aspnet_Membership表中是否有该UserId存在，如果没有就根据@UniqueEmail参数判断是否允许Email在数据库中重复。最后才是把User的信息插入aspnet_Membership表,再下来还有一些对错误的处理
其实这个存储过程并不复杂，但是非常繁琐的，也可以看出设计者对数据库检验的严格性的要求非常高。有了对存储过程一定的了解后，我们接下来那些传递的参数也就明白有何用处了，最后关闭数据库的连接，把返回的这些参数通过实例化一个MembershipUser类传递过去，然后返回这个实例化的MembershipUser，这样该方法就完成了一次操作。
最后我们看看数据库，Membership直接关联的有3个表
表很简单，关系也很明了，我就不多说了，总要给我留点时间吧，也给你自己留一些分析的空间，我要是全都说完了那你做什么？呵呵。
如果你了解CS系统，你肯定会提出这样一个疑问：用户信息不只表Membership中这一点呀，保存用户个性化设置的如选用什么语言、什么皮肤等等信息的数据都在哪里？期待吧，那是后面的Profile专题需要叙述的问题
