System.Web.Services.WebService - 是否可以隔离每个客户端的服务 [英] System.Web.Services.WebService - Is it possible to isolate the service per client
问题描述
我有一个遗产System.Web.Services.WebService（不是WCF），我必须维护。
I have an legacy System.Web.Services.WebService (not WCF) that I have to maintain.
偶尔我遇到一些我会描述的有线行为作为竞争条件。
Ocassionly I run into some wired behaviours that I would describe as race conditions.
-
服务挂起并且必须重新启动。
Either the service hangs and has to be restarted.
有时我得到这个例外：
System.NotSupportedException: Multiple simultaneous connections
or connections with different connection strings inside the same
transaction are not currently supported.
at MySql.Data.MySqlClient.MySqlConnection.Open()
...
我知道根本原因是什么。该服务使用一个与mysql对话的lib，并没有考虑到webservices的设计。不幸的是我无法更改此库。
I know whats the root cause. The service utilizes a lib that talks to mysql and was not designed with webservices in mind. Unfortunatly I cannot change this lib.
一个示例webmethod如下所示：
One example webmethod looks like this:
[WebMethod(EnableSession = true)]
public void DoSomething()
{
var login = this.Session["login"] as LoginDetails;
ExternalLib.SetLoginData(login.Schema, login.User, login.Pass);
ExternalLib.PerformTask();
}
所以这里的问题是：
-
ExternalLib.SetLoginData只设置一些全局变量 -
ExternalLib.PerformTask执行数据库调用，有些是在事务中。 - 过程类似于
1。创建MySqlConnection或从缓存中获取2.创建MySqlCommand 3.执行命令4. Dispose命令
ExternalLib.SetLoginDatajust set's some global varsExternalLib.PerformTaskperforms database calls, some inside a transaction.- The process is like
1. Create MySqlConnection or take it from cache 2. Create MySqlCommand 3. Execute Command 4. Dispose command
客户端a）调用 DoSomething（）并初始化他的连接。完成他的工作的一半客户端b）调用 DoSomething（）这显然改变了客户端a的登录数据，并且事务中的下一个调用将使用来自客户端b的登录）导致交易。
Client a) calls DoSomething() and I init his connection. Half way done with his job Client b) calls DoSomething() which apparently changes the Login-Data for client a and the next call inside the transaction will use the login from client b) which causes the transaction.
无论如何，我知道这是一个糟糕的设计，但我的问题是如何解决这个问题。
目前（因为我只有10个客户端）我在不同的端口上创建了一个专用网站，它们都指向相同的根目录，但这是一个不方便的解决方案。
Anyway, I know this is a bad design but my question is how to workaround this. Currently (since I only have 10 clients) I created a dedicated Website on a differnet port which all point to the same root directory but this is an akward solution.
也许有可能在其领域内运行每个会话。有什么建议么。如果我正确理解此页面的WCF是默认行为： http：// msdn .microsoft.com / zh-CN / magazine / cc163590.aspx
Maybe there is a possibility to run every session inside its on realm. Any suggestions. If I understand this page correctly for WCF is is the default behaviour: http://msdn.microsoft.com/en-us/magazine/cc163590.aspx
每次呼叫服务
每次呼叫服务是Windows Communication
基础默认实例化模式。当为每次调用激活配置的服务类型为
时，服务实例（公共
语言运行时（CLR）对象）仅在客户端调用处于
进度时存在。每个客户端请求都会获得一个新的专用服务实例。
Per-Call Services
Per-call services are the Windows Communication Foundation default instantiation mode. When the service type is configured for per-call activation, a service instance, a common language runtime (CLR) object, exists only while a client call is in progress. Every client request gets a new dedicated service instance.
推荐答案
看来这可能是一个线程问题是你可以锁定 ExternalLib 以防止单独的实例调用代码。
Seeing as this is probably a threading issue you can lock the ExternalLib to prevent separate instances from calling the code.
public class ExtenalLibWrapper
{
private static object Locker = new object();
public void DoSomething(LoginDetails details)
{
lock(Locker)
{
ExternalLib.SetLoginData(login.Schema, login.User, login.pass);
ExternalLib.PerformTask();
}
}
}
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